Concrete, its manufacture and use

TA

ONCRETE

ITS

MANUFACTURE
AND USE

KOEBRINC

GIFT OF

CONCRETE

ITS

MANUFACTURE
AND USE

Copyright 1921

by
Koehring Company

-f f^

11

Published by

KOEHRING COMPANY

Milwaukee, Wisconsin

TABLE OF

Chapter 1.

Field Operations in Concrete Construction. ... 9

Chapter 2.

Materials Entering Concrete 23

Chapter 3.

Concrete in Highway Construction 34

Chapter 4.

Miscellaneous Notes for Superintendent and
Foreman 85

Chapter 5.

Forms for Concrete Construction 95

Chapter 6.

Use of Reinforcing Steel in Concrete. 105

Chapter 7.

Notes on Specifications 113

Chapter 8.

Estimating Cost of Concrete Construction. ... 121

Chapter 9.

Notes on Culvert and Bridge Construction . . .127

Chapter 10.

Convenient Estimating Tables and Exam-
ples of Use 135

Chapter 11.

Foundations and Footings 141

Chapter 12.

Waterproofing of Concrete 143

Chapter 13.

Placing Concrete under Water 147

Chapter 14.

Notes on Silos, Coal and Material Bins, and
Grain Tanks 149

Chapter 15.

Mechanical Equipment — Its Starting, Care

and Operation 157

6

H

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INTRODUCTION

The opportunities of a manufacturer of construc-
tion equipment to be of assistance to the inspector,
superintendent, foreman and engineer are not nu-
merous. Yet we have felt that there was a distinct
need for a handbook that could be carried in the
pocket and which would contain information con-
cerning the best practice in the manufacture and
use of concrete.

The word "manufacture" is here employed in its
true sense — "To make from raw materials by any
means into a form suitable for use." The construc-
tion engineer, whether he represents a contractor,
or a private or government owner, who combines
cement, sand, stone and water, by mixing them in a
concrete mixer is as truly a manufacturer as he who
combines steel, cast iron and bronze in the con-
struction of equipment. In the same degree that
the mixer manufacturer must fit all of the consti-
tuent parts to make the finished machine, so must
the concrete manufacturer control the materials
entering his product and the methods employed in
their combination and use.

In presenting this little book no attempt is made
to have it serve as a text book, nor to prescribe
formulas or rules. It was compiled as a book of
reference, of sound engineering practice, in concise
and easily readable form. It is not a finished expo-
sition of methods employed in all types of con-
struction work in which concrete is used, and could
not be made complete due largely to the ever
changing conditions encountered.

Accept the book, therefore, in the spirit in which
it has been prepared — a guide to the construction
man who manufactures and places concrete in
America's permanent structures, and a suggestion
for the better care of equipment.

KOEHRING COMPANY.

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CHAPTER 1

FIELD OPERATIONS IN CONCRETE
CONSTRUCTION

Careful Planning Means Economical
Completion of Project

The owner for whom the work is being done, be
he an individual, a corporation, or a government
agency, is interested in quality, speed and cost. The
contractor and the construction superintendent are
interested in cost, speed and quality. The sequence
of these items is in accordance with their relative
importance to the two parties to the contract.

Both are interested in each but to a different
degree. The owner, whose money pays for the work,
desires a structure on which depreciation will be
negligible, completed in as short a time as possible
after the decision has been made to go ahead, and at
as low cost as is consistent with quality. Having de-
cided to make the expenditure, his whole thought is
of quality and the time at which he can put the
building to use. On the other hand, the contractor
having given an estimate of the cost of construction,
is vitally interested in keeping the cost below that
figure. To him speed means the ability to obtain his
reward or profit at an earlier date, provided it can
be done at equal cost with that obtained by a little
slower progress. The element of interest on bor-
rowed money must be offset against larger payrolls
or a greater expenditure for plant. But even though
the viewpoints of the two contracting parties are not
exactly alike they are closely allied. Both are inter-
ested in the relation between cost, speed, quality
and mechanical equipment.

It is not possible to give any fixed rule for field
organization or for the plant required for a project.
The character of the enterprise, its location, relation
to railroad facilities and to other structures, and
local traffic conditions over which the contractor has
no control affect the decision as to the most economi-

pal method of consumption. It is evident, however,

-irhas/sh^lsucsess ot'.tlxe '-enterprise depends entirely

'upon "the care'ful* planning of the method by which

the work is prosecuted, and the proper coordination

of all items entering into it. These items will be

taken up in accordance with their relation to the

placing of the concrete.'

Receipt of Materials and Plant for
Handling

In the construction of every project, whether it
be a highway, building, dam, or bridge, a consider-
able amount of time must be given to the prepara-
tions of the site. During this time receipt of ma-
terials for the concrete should be arranged for and
delivery commenced. These materials include ce-
ment, sand, stone, reinforcing steel, and lumber and
steel for forms. Finally the construction plant should
come on the ground. The construction plant has
been given last place, not because it is least impor-
tant, but to emphasize the fact that without the ma-
terials of construction available the plant can do
nothing. Many contractors have found themselves
fully equipped with expensive plants but with no
materials to keep them busy.

This condition can be overcome only by storing
a considerable quantity of materials before the plant
is erected or provided. Aggregates and cement must
be on hand in such quantities as to insure continuous
operation of the concrete plant. The cost of storage
and rehandling is more than offset by the wages paid
to skilled mechanics and superintendents if the work
is delayed after the organization is in the field.

Storage of aggregates and cement may be at the
point of deposit or at the point of delivery from boat
or car. It is probable that the contractor can pro-
tect himself against delays due to truck breakdowns
while hauling material from the point of delivery to
the point of deposit, yet it is impossible with the
present condition of railroad transportation to insure
regular delivery from the source of supply to the
railroad siding. Such storage means increased handl-
ing. Practically all materials must be rehandled at

10

least once. Such factors as interest on money and
the tying up of working capital must be taken into
consideration. This entails more expense to the
contractor unless he can reduce cost at some other
point to justify it.

The first essential for economical handling of
aggregates is the substitution of mechanical equip-
ment for man power. Three types of equipment are
available: first, bucket or skip elevators carrying
material from bin under the track to the stock pile;
second, locomotive cranes operating on a track, or on
wheels or multiple traction, handling materials from
cars into piles; and third, a derrick equipped with
clam-shell bucket. The quantity of materials to be
handled per day, ability to reload materials into
transportation units and the quantity of storage re-
quired will determine the style of equipment best
suited. In selecting this equipment the quantity of
materials to be handled must be kept constantly in
mind. It will be remembered that the aggregates
are received in a loose state and as a result the clam-
shell must handle 1% yards of aggregate for each
yard of concrete. Aggregate must be handled at
least twice, making necessary the use of equipment
with a capacity, measured in loose materials, of at
least three times that of the maximum quantity of
concrete placed each day. The unloading plant is
the first of those items which go to make up a per-
fectly balanced construction plant.

Amount of Concrete to be Placed

In laying out the remainder of the plant the one
item of importance is the quantity of concrete to be
placed. When this is determined it becomes a simple
matter to determine the relation between plant
charge and labor charge. The decision will depend
upon the cost of plant, the cost of freight from the
contractor's headquarters or from the point of man-
ufacture to the point of installation, additional costs
of removal, maintenance and repairs. If 25,000 cubic
yards of concrete are to be placed, the allowable
plant charge against the job can and should be much

11

greater than if only 500 cubic yards were to be
handled. Not only should the total cost be more but
the plant expenditure chargeable to the undertaking
can be more per cubic yard of concrete, in order that
the number of men may be reduced, thereby allow-
ing more rapid completion of the contract even with
a scarcity of men.

Character of Plant

It has been found advisable in many instances
to divide the work into two distinct parts, that
handled by small portable mixers and that placed by
the large central mixing plant. For the preliminary
work such as footings or foundation walls where the
quantity of concrete required does not justify the
operation of a large plant a 7-foot portable mixer,
taking a one-sack batch of a 1 :2 :4 or a 1 :3 :6 mix,
will prove most satisfactory. This type of machine
can be set up at any convenient point, the aggregates
delivered to the point of deposit and the concrete
put in at lower cost than by any other method. Upon
the completion of the job there will always be a lot of
odds and ends that are in need of similar treatment.

Mixer Most Important Piece of Plant

The concrete mixer, because of its ability to turn
out the element for which payment is received,
namely, concrete, is the most important unit of the
construction plant. With the increased use of con-
crete construction and the development of large and
expensive placing plants, the ability of the concrete
mixed to stand up under hard usage is a big item. in
making the decision for the adoption of a given
machine. Delays due to breakdowns mean excessive
cost. Continuity of operation spells profits. This
demands heavy duty construction — a machine built
of the best materials available — by competent work-
men, with careful supervision.

Organization of Remainder of Plant Around
Mixer

The remainder of the construction organization
must be built around the mixer. Its capacity in

12

cubic yards per day will depend largely on the equip-
ment with which it is surrounded. This not only
requires that the hoisting and placing equipment be
able to take care of the output but that every link in
the chain from the receipt of the cement and aggre-
gates through the transportation, the bending of the
steel, and the erection of the forms be planned en-
tirely on the maximum mixer capacity. A little
item, such as the size of the water line feeding the
mixer may result in slowing down the operation
from five to ten per cent. With a large plant
charge constantly going on, these items must be
given consideration. It must always be remem-
bered that no pay is received except for concrete
in place, and that unless the mixer is doing its work,
that pay stops.

Character of Placing Equipment

The type of placing equipment and the justifiable
expenditure will depend entirely on the size and
character of the work. Naturally, the same type of
equipment cannot be used on a highway where the
concrete is placed in a thin, comparatively narrow
ribbon as would be used on a building or on heavy
dam construction.

For building work three general types of placing
plants have been used. The first consists of a tower
up which is hoisted a concrete bucket. From this
tower the concrete is distributed by gravity through
chutes to the point of deposit. The same type of
tower is used in the second plan, together with a
floor hopper from which the materials are discharged
into concrete buggies or barrows. The third method
consists in the use of material elevators, the concrete
being elevated in carts or barrows to the point of
distribution and then wheeled to place. Three items
are essential regardless of the system used; first,
the concrete must be placed without segregation of
the particles; second, there must be control of the
amount of water consistent with maintaining the
flowability of concrete ; and third, the concrete must
be of such quality that it will flow around the rein-
is

forcing steel. Where spouts are used it is essential
that the material be fed to the spouts slowly from
hoppers, so that there is a constant stream of con-
crete. By doing this it will be found possible to use
a mix which is easily handled in the forms and with
which there will be no segregation.

On construction work, such as retaining walls
where there is comparatively little concrete per
linear foot it is sometimes desirable to set up a cen-
tral mixing plant and haul the concrete for distances
not to exceed 1,000 feet in each direction. If this is
done, care must be taken to see that the aggregate
is thoroughly wet before going into the mixer or
that the concrete is mixed for a considerable length
of time and that the amount of water used is kept to
a minimum. Otherwise, there will be segregation
causing difficulty in placing the concrete and irregu-
lar distribution of cement and aggregate in the
forms.

The distribution of concrete in highway con-
struction has been practically standardized by the
adoption of the end charging paving mixer equipped
with distributing boom and bucket. After being
mixed the concrete is discharged from the drum into
the bucket, a full batch at one time, run out on the
boom and dumped on the grade. The adoption of
the bottom dump bucket has made possible the de-
positing of concrete in place without segregation.

Quality of Concrete Desired

The character of the work to be done will deter-
mine the quality of concrete desired. It may be for
a highway, for mass work or for heavily reinforced
sections. Reference to table No. 1 on pages 28 and 29
shows the recommended proportions for each char-
acter of work. Peculiar grading of aggregates or the
availability of certain sizes of materials may take it
desirable to vary from these arbitary proportions.
Before definitely determining the mix to be used on
a large project, it will be found desirable to have
the aggregates examined to determine their phys-
ical properties and to make compressive tests to de-

14

termine the strength of concrete obtained by use of
the various proportions.

Uniform Strength Demands Uniform
Consistency of Concrete

The quality of concrete is dependent largely on
the uniform control of the quantity of water. It is
evident that the same consistency cannot be used for
thin, reinforced sections as would be the case in
highway construction. Yet, having adopted a con-
sistency it is essential that this be strictly adhered
to. This is easily done by measuring the water with
an automatic water measuring tank with which the
mixer can be equipped. The quantity of water in the
aggregate will affect the amount necessary to be
put into a batch, and although this water content of
the aggregate will vary from day to day, depending
on weather conditions, it will not be found neces-
sary often to change the water control. It is readily
appreciated that if one batch of concrete is flooded
with water and the next comes out dry that the
strength of the two will not be the same, as the dis-
tribution of cement will not be alike throughout the
two batches.

Placing Concretelin Forms

The concrete having been brought to the point of
deposit, it is essential that it be placed with care,
first, in order that there may be no voids between the
reinforcing steel and the concrete, thereby insuring
proper bond, and second, that no honeycombed spots
appear when the forms are removed. This is possible
by careful spading at the sides of the form and spad-
ing or rodding the concrete sufficiently to make sure
that there are no porous places left in the concrete.
Satisfactory surfaces are much more readily ob-
tained by proper spading of a plastic concrete than
by trying to place the concrete when so wet that
segregation results. Attention should be given to
the forcing of the concrete around the reinforcing
steel particularly in long, narrow or deep girders
which are heavily reinforced. Reference to table 1
on pages 28 and 29 shows that in this type of con-

15

struction it is desirable to use a comparative!
small aggregate, so that the concrete can be place
around the reinforcing steel. Even with this aj
gregate, however, there is a tendency for the stone
to bunch, thus forming porous spots.

Too much water, improper mixing, and impropc
methods of handling concrete result in laitanc
Laitance consists of the finely divided dirt, silt an
a certain amount of the cement, which being con
paratively light and having no adhesive qualit;
flow to the surface. This may be generally obviate
by reducing the quantity of water to the point whei
there is no large excess on the surface. Laitance hz
no strength and if allowed to accumulate will mal
a weak, porous layer in the structure. Special cai
should be taken in the concreting of wing walls fc
bridges and culverts when the wall is sloped to tf
outer end, thereby making it difficult to force tf
concrete into place at the end of the form. Often coi
crete will be allowed to fill the center of the abu
ment with the idea that, like water, it will seek I
own level and fill up the end of the wing wall forr
What happens actually is that the lighter particle
including the excess water, flow into this portion <
the form and remain there until the forms are r<
moved. If the laitance is not immediately remove
and the wall repaired there will be insufficiei
strength in this portion of the structure to wit]
stand frost action, to say nothing of withstandin
pressure. Where laitance occurs it should be in
mediately cleaned from the surface before a ne
layer of concrete is put into place.

Curing

Reference has been made elsewhere to the ne
essity of proper curing of concrete, yet it may n<
be out of place at this point to refer to the respon
ibilities which this particular work puts upon tf
contractor. In country road construction where tit
concrete can be readily cured either by ponding <
by wetting of an earth covering, the expense can t
very readily calculated, the only additional equi]

16

ment being a little larger pipe line than will other-
wise be required and possibly a little larger pump.
On concrete floors in buildings the question of prop-
er curing is a much more difficult matter. Two
methods have been largely employed, the first one
using sawdust which is kept wet and the second
method covering the floor with sand. Both of these
have their drawbacks due to the expense of getting
the material in place and removing it. However,
the results obtained by curing more than justify the
expense. It is suggested that every contractor put
into his bid an item to cover curing of concrete in
floors and roof slabs, as well as all pavements.

Strength

All of the foregoing items have an ettect upon
strength, and it is probable that in the future we
will be able to increase materially our present
standard for highway construction because of high
strength concrete made available by more careful
control of the materials entering the mixer. How-
ever, at the present time this art has not been car-
ried far enough so that we can do no more than pay
very strict attention to all these details. The item
of strength is one that is of more than passing in-
terest. True, a building may be designed for con-
crete having a strength of only 2,000 pounds per
square inch but may inadverdently be so loaded in
spots as to throw a higher stress upon it. Floors
which are subject to heavy trucking, industrial
driveways, and concrete pavements all must nec-
essarily withstand great impact as well as compres-
sion. It is evident that there is a relation between
strength and resistance to wear, although other fac-
tors, such as quality of aggregates materially affect
this relation.

Effect of Design of Mixer on Quality of Concrete

The development of the concrete mixer has been
the result of a demand on the part of contractors
for a more economical way of mixing concrete, on
the one hand, and a demand on the part of en-
gineers and owners for a more uniform and stronger

17

concrete, on the other. It is interesting to note that
by far the largest part of experimental work on con-
crete done in laboratories has been done with con-
crete mixed by hand, but tests in the field show that
uniformity of product is available only when prop-
erly mixed in a mixer of proper design.

Batch concrete mixers can roughly be divided
into two general types. First, those that mix by a
churning action only, and second, those having an
action wherein the materials are alternately
scattered and brought together. In the mixing of
any material it is evident to obtain maximum mix-
ing in the minimum time it is necessary to dislodge
each particle of material from the particle with
which it was in contact and then recombine it with
another particle. In this way only can there be a
true mixing action.

In the mixing of concrete there are four materi-
als which are placed in the drum in their natural
state and which must be discharged from the drum in
a homogeneous, uniform mass. These materials are
cement, sand, stone and water. The sand and stone
are more or less of the same general character and
would take their own positions with comparatively
little mixing. However, it is essential that the cement
and water be formed into a cement paste which
thoroughly covers all of the particles of stone and
sand making a matrix to hold the entire mass in
place. In order that this may be done in a short time
(from 1 minute to iy2 minutes) there must be a
large number of actions, scattering and bringing ihe
materials together. If, on the other hand, the ma-
terials are simply carried to the top of the drum and
dropped into the mass as a whole there can be very
little mixing. If a swing chute, pivoted on the in-
side of the drum, so as to allow it to stand at a
steep angle and to throw the materials which are
carried up in the pickup buckets over to the charg-
ing side, is inserted into the mixer, an entirely dif-
ferent mixing action takes place. The materials
having been placed in the charging side of the
drum, the throw-over blades, which are attached to

18

the shell diagonally to the axis of the drum, cut
through the material, moving a portion of it for-
ward and over the top of the vane. This has a
scattering effect on those particles and a mixing ac-
tion as those particles strike other particles. As the
drum continues to revolve the concrete is carried by
these blades into the pick-up bucket, there to be
carried up to the top of the drum and thrown onto
the inverted swing chute. While dropping through
space the particles have a tendency to separate. The
direction is then quickly changed as the material
strikes the swing chute, so that the concrete is
spread over the width of the chute in a thin sheet
prior to being returned to the charging side of the
mixer to go through the remixing action again.

The water should be put into the mixer at the
same time as the other materials. This is desirable
in order that the mixing of the cement, water and
aggregate may go on simultaneously. Incidentally,
the placing of water at the same time as other ma-
terials keeps the blades of the mixer clean thereby
protecting against clogging. If, on the other hand,
water is put into the drum ahead of other materials
the wet buckets and throw-over blades are struck
by the dry materials, resulting in a tendency for the
cement to stick to these parts.

It is reasonable to believe that the quality of the
concrete will be materially affected by the amount
of mixing that it receives. It is not surprising, there-
fore, that concrete of greater strength can be ob-
tained in the same time in a machine with a com-
plex mixing action than in a machine in which ma-
terial is simply churned around. Sufficient tests
are not available to make a definite statement as to
the desirability of adopting a given time of mixing as
standard for all machines. In order to obtain gen-
erally satisfactory results, however, engineers have
adopted a one minute mix as a standard minimum.

Aggregate Control

The workability of concrete can be materially
affected not only by the size, but also by the charac-

19

ter, of aggregate. For instance, if a very porous ag-
gregate is used it will be found difficult to handle
the mixed concrete unless the aggregate is either
soaked before entering the mixer or the materials
are allowed to remain in the mixer for a consider-
able length of time. If this is not done, the water
in the concrete will be quickly absorbed with the
result that there will not be a sufficient amount to
lubricate the mixture. A slight variation in the re-
lation between the quantity of sand and stone may
materially help the workability of certain materials.
This is desirable where a coarse aggregate of one
size is being used to add to a second coarse aggre-
gate to make the mixer more workable.

Water Control

The grading and character of the aggregates,
and the proportions affect the amount of water re-
quired to make a plastic, workable mix. As the
quality of concrete is dependent upon a uniform
quantity of water for each batch it is essential that
the quantity of water be mechanically controlled.

Control of Amount of Mixing

The amount of mixing required to obtain a de-
sired strength using the same amount of cement,
aggregate and water will always be the same for a
given design of machine. It may not be the same
for another concrete mixer. This, as explained above,
will depend entirely upon the mixing action. In
order that the amount of mixing may be absolutely
uniform in all instances a batchmeter has been de-
veloped which mechanically controls the number of
revolutions or time of mixing for each batch. This
instrument is of two types. The first is driven from
the mixer drum and, knowing the speed of the
drum, the time is mechanically interpolated to a
dial. The second is operated by an escapement so
that it measures elapsed time. The control which
can be set at any point between three seconds and
three minutes releases the locking mechanism allow-
ing the discharge of the mixer and announcing the
fact by the ringing of a bell.

20

Prior to the adoption of this mechanism on pav-
ing mixers many had not appreciated the economy
of building an organization around time control.
Experience has shown, however, that, knowing the
time of mix, the speed with which the concrete is
discharged, and the speed of charging the mixer, it
is possible to develop the organization necessary to
get maximum output from the machine. The whole
basis of efficiency engineering is the coordinating
of time with production. The batch meter is prov-
ing a pacemaker for the crew, measuring the same
amount of time for each batch.

Capacity of Mixing Plant

The capacity of the mixing plant is dependent
upon, first, the speed of charging the mixer, second,
time of mixing, third, time for discharging, fourth,
delays incident to preparation of forms and receipt
of materials, fifth, organization of crew, sixth, size of
batch, and seventh, ability to dispose of the concrete.
The successful contractor is the one who can place
the greatest quantity per machine at the least cost in
a season, and not the contractor who can turn out
the most concrete in an hour or even in a day.

Speed of charging is controlled largely by the
method of charging the mixer. A skillful operator
will hoist the charging skip and have the new batch
in the drum within five seconds after the last of the
concrete has been discharged from the drum, even
though it may take ten or twelve seconds to raise
the skip.

The time required for discharging the batch is
comparatively short, so that even if the concrete is
held in the drum of the mixer for a full minute it
will be possible to obtain thirty to forty batches of
concrete per hour. Time of mixing is not such a
large factor as would at first appear because there are
on every project a large number of conditions which
cause delay. Investigation of construction plants
show that the greatest delays are due to inability to
obtain materials at the proper time, inability to get
the forms in shape to receive the concrete, or ina-
bility to place the concrete after it is mixed.

21

Concrete mixers are built having capacities of
from four to thirty-four cubic feet of concrete.
Each size has its special place. It may be more
economical in certain instances to use the equip-
ment on hand for a certain time each day rather
than to purchase new equipment that is exactly the
right size for the job. However, as a general rule
there is a tendency on the part of construction or-
ganizations to give too little thought to the size of
mixer which they use on a given piece of work.

The richness of mix and the quantity of water
used do not effect the capacity of the mixer plant,
with the possible exception of the ability to place
concrete in forms by use of towers and spouts.

Conclusion

This chapter is intended as a resume of experi-
ence based on a study of construction operations
and construction plants. It has not been prepared
with the idea that it is the place of a manufacturer
of machinery to make definite recommendations as
to the exact size of plant. There are many items
which enter into such a decision and it is hoped that
these have been set forth in this chapter in a way to
be helpful suggestions.

22

CHAPTER 2
MATERIALS ENTERING CONCRETE

Concrete Aggregates

Aggregates are the inert materials, such as sand,
stone screenings, pebbles, broken stone and slag, used
with portland cement and water to make concrete.

Aggregates are usually classified as coarse or
fine. Fine aggregate is any suitable material that
will pass a No. 4 sieve or a screen having four
meshes to the linear inch. Therefore, when stone
screenings or other rock material is crushed so that
it conforms to the above, it is regarded as sand
when used in proportioning a concrete mixture.

Coarse aggregate is any suitable material such
as pebbles or crushed rock of various kinds that will
not pass a No. 4 sieve. Coarse aggregate may range
from ^4-inch to as much as 3 inches in greatest
dimension, depending upon the nature of the work
for which the concrete is to be used. As a rule,
however, the average maximum for most building
construction is 1*4 or !/4 inches.

Concrete cannot be stronger than the materials
of which it is composed. Nothing is more certain to
produce unsatisfactory concrete than poor aggre-
gates. The quality of the cement, methods of pro-
portioning and mixing the ingredients, the amount of
water used, the time of mixing and the manner of de-
positing concrete, all have their effect upon its den-
sity, strength and general quality, but good results
cannot be expected when poor aggregates are used.

Sand, or Fine Aggregate

In the selection of sand, even greater precau-
tions are necessary than when selecting coarse ag-
gregates, because sand varies in physical character-
istics and in general properties more widely than do
the materials commonly used as coarse aggregate.

A small quantity of organic matter in sand may
make it entirely unfit for use. Many impurities found
in sand affect the setting of the cement, hence, the

23

strength of the concrete. Clay in the form of a
coating on the particles is injurious since it prevents
the cement from contact with the surface of par-
ticles and thereby performing its bonding or bind-
ing function.

Clean Sand

If the sand is clean it should not discolor the
hands. A coating of vegetable matter on sand grains
appears not only to prevent the cement from hard-
ening, but may affect it chemically. Frequently
the quantity present is so small that it cannot be
detected by the eye, yet may prevent the mortar in
which it is used from ever reaching any appreciable
strength.

A simple test for the presence of organic matter
is known as the Colorimetric Test, developed by
the Structural Materials Research Laboratory, Chi-
cago. This is made as follows:

Colorimetric Test

Obtain a 12-ounce graduated prescription bottle
from any drug store and fill to the 4J/2 -ounce mark
with the sand to be tested. Add to this a 3 per cent
solution of caustic soda, also obtainable at any drug
store, until the volume of sand and solution after
shaking amounts to 7 ounces. Let this stand for
twenty-four hours. At the end of this time observe
the color of the liquid above the sand. If the solu-
tion is colorless or nearly so — that is, has but a pale
yellowish color, the sand may be considered suffi-
ciently free from organic impurities for any use. On
the other hand, if the solution is brownish yellow in
color, or darker than a pale straw color, the sand
should not be used in important concrete work such
as that required in roads and pavements or rein-
forced concrete building construction. If, in general,
the color is brownish, the sand should not be used in
anything but unimportant work such as footings or
foundations that are not to carry heavy loads nor be
subjected to frost. If the solution is dark brown in
color the sand should be rejected.

24

This test furnishes a simple and inexpensive
method of detecting the presence of such organic
impurities as decayed vegetable matter. The test is
being used by a large number of testing labora-
tories, engineers and contractors in passing on the
suitability of sand for use in concrete.

Harmful Materials

The term "silt" is used to designate all foreign
material which may be present in an aggregate in
the form of a coating on the grains or in a finely
divided state, or in the form of soft or soluble mat-
ter. Other impurities such as acids, alkalies or oils
in the sand or mixing water, usually injuriously
affect the quality of the concrete.

Effect of Physical Properties of Aggregate
on Quality of Concrete

The hardness of aggregates grows in importance
with the age of the concrete. Due to the rounded
surface of the aggregate, pebble concrete one month
old may be weaker than concrete made with com-
paratively soft broken stone, but when one year old,
it may surpass in strength the broken stone con-
crete, because as the cement becomes harder and
the bond firmer, the resistance of the aggregate to
stress becomes a more important factor. The aggre-
gate particles should offer at least as high a resist-
ance to crushing as does the cement after attaining
maximum strength. In comparing sands of the
same kind, those having the highest specific gravity
are likely, as a rule, to be the strongest. This ap-
plies in a general way to the comparison of different
kinds of coarse aggregate also.

Grading of aggregates — that is, the relative size
and quantity of the particles in the mass determines
in a large degree the density of the mass. This has
its effect on the strength of the concrete. However,
quantity of water used, time of mixing, protection of
concrete while hardening, also exert their influence,
so that grading is not all-important for strength.

A sufficient quantity of fine grains is necessary
in grading the material to reduce the voids, if for no

25

other reason than to assist with the cement in in-
creasing watertightness. An excess of fine sand has
a tendency to diminish the strength of the concrete.
Within reasonable limits, the strength of concrete
increases with the size of the aggregates. For mass
concrete, the practical maximum size is 2y2 or 3
inches. In thin reinforced sections, such as floors
and walls, the maximum size must be confined to
particles that will enable the placing of the concrete
around reinforcing steel. Generally 1 or 1J4 inches
is then the preferred maximum.

The shape of aggregate particles, especially that
of large aggregates, influences the strength of the
mortar or concrete. Flat, elongated particles pack
loosely and generally are inferior to those of more
nearly cubical fracture.

Voids

Voids are air spaces between the particles and
are usually referred to as a percentage of the whole.
An aggregate consisting of particles all uniform in
size will present the maximum of voids. This can
be illustrated as follows:

Perfect spheres of equal size piled in the most
compact manner, leave theoretically about 26 per
cent of voids. The only requirement is that the
spheres be of equal size. If, however, the spaces
between the spheres in such a pile of equal size are
filled with other perfect spheres of a diameter just
sufficient to touch the larger spheres, the voids in
the total included mass would be reduced theoretic-
ally to 20 per cent. Should this be followed up
with smaller spheres, the air spaces or voids could
theoretically be reduced to make the mass water-
tight. In practice, however, a mass of equal sized
spheres will be found to contain about 44 per cent of
voids.

Sampling Sand

In selecting a sample of sand for test, one should
make certain that representative samples have been
obtained from different parts of the pit from which
material is to be used. The most representative
sample is a blend of several samples taken from

26

different parts of the pit. Whenever possible, the
samples should be taken from the hoppers or from
the aggregate pile after delivery upon the work.

Method of Making Void Determinations

The usual method of making void determination
is by means of a graduated vessel partly filled with
the sand to be tested. The amount of sand should be
read and poured out. The vessel is next partly re-
filled with water and the graduations read. The
known amount of sand is then added to the water.
The difference between the sum of the two gradua-
tions and the reading after the sand is poured into
the water, divided by the amount of the sand, gives
the percentage of voids.

Tests on Aggregates

Accurate tests on fine and coarse aggregate such
as tensile or compressive tests can be made only in
physical laboratories properly equipped for that
purpose. There are certain to be apparent discrep-
ancies between laboratory tests and field practice
unless the laboratory tests are made under field con-
ditions of proportioning and mixing. This difference
is largely due to the exact control of quantity of
materials entering the batch when made up in a
laboratory, which is not entirely possible when the
work is done in the field.

There is concrete work which has proven un-
satisfactory because of the use of fine porous lime-
stone dust or screenings. These screenings possibly
were accepted after a laboratory test in which they
were made up into briquettes and tested in tension,
showing a strength considerably greater than the
standard sand. In making the briquettes, the ma-
terial was thoroughly kneaded so that there was a
separation of every small particle of stone dust and
a thorough coating of all grains with cement. In the
field, however, this material has a tendency to ball
up, with the result that the cement does not have an
opportunity to surround each small particle. The
concrete, therefore, never reaches full strength, is
porous, and is affected by frost.

27

Table No. 1

TABLE OF RECOMMENDED MIXTURES
AND MAXIMUM AGGREGATE SIZES

MIXTURE AND CHARACTER
OF WORK

1:1:1 Mixture for

The wearing course of two-course floors subject to
heavy trucking, such as occurs in factories, ware-
houses, on loading platforms, etc.

1 :2 :3 Mixture for

Reinforced concrete roof slabs

One-course concrete road, street, and alley pave-
ments

One-course walks and barnyard pavements . .

One-course concrete floors

Fence posts

Sills and lintels without mortar surface

Watering troughs and tanks

Reinforced concrete columns

Mine Timbers

Constructions subjected to water pressure, such as
reservoirs, swimming pools, storage tanks, cis-
terns, elevator pits, vats, etc

1:2:4 Mixture for:

Reinforced concrete walls, flloors, beams, columns,
and other concrete members designed in combi-
nation with steel reinforcing

Concrete for the arch ring of arch bridges" «nd
culverts

Foundations for engines causing heavy loading, im-
pact and vibration

Concrete work in general subject to vibration . . . ,

Reinforced concrete sewer pipe

1:2 %:4 Mixture for

Silo walls, grain bins, coal bins, elevators and simi-
lar structures

Building walls above foundation, when stucco finish
will not be applied

Walls of pits or basements, exposed to moisture. . .

Manure pits

Dipping vats, hog wallows

Backing of concrete block

Base of two-course road, street and alley pave-
ments

Recommended
Maximum Size
of Aggregate
in Inches

28

Table No. 1

TABLE OF RECOMMENDED MIXTURES
AND MAXIMUM AGGREGATE SIZES

MIXTURE AND CHARACTER
OF WORK

Recommended

Maximum Size

of Aggregate

in inches

1:2 1/2 :5 Mixture for

Walls above ground which are to have stucco finish 1 Vi

Base of two-course walks, feeding floors 1

Bridge abutments and wing walls, culverts, dams

small retaining walls, when not reinforced 2

Basement walls and foundations where water tight-
ness is not essential 2

Foundation for small engines 2

1:3:6 Mixture for

Mass concrete — large retaining walls, heavy foun-
dations and footings

1:1% Mixture for

Inside finish of water tanks, silos, and bin walls,
where required, and for facing walls belo'w ground
when necessary to afford additional protection

against the entrance of moisture To pass through

No. 8 Screen)

Back plastering of gravity retaining walls To pass through

.,_.; No. 8 Srceeen)

1 :2 Mixture for

Facing block and similar concrete products V4

Wearing course of two-course walks, floors sub-
jected only to light loads, barnyard pavements,
etc 1/4

1:2% Mixture for

Scratch coat of exterior plaster (cement and stucco) To pass through

No. 8 Screen)
Fence posts when coarse aggregate is not used Vi

1 :3 Mixture for

Intermediate and finish stucco coats To pass through

No. 8 Screen)

Concrete block when coarse aggregate is not used . Vi

Concrete brick Vi

Concrete. drain tile and pipe when coarse aggregate

is not used V4

Ornamental concrete products Vi

29

During the past few years a number of state
highway departments have undertaken field tests
with a view of ascertaining the quality of concrete
obtained in the field. It has been found that a 6 by
12 cylinder is the best size specimen to use. The
cylinders are made in the field, the concrete being
taken from the mixer during its operation. After
hardening they are shipped to the laboratory to be
tested in compression and by impact.

Washing Aggregates

If the only aggregates available for use, contain
some of the objectionable foreign materials already
mentioned, they should be washed before using.
Appreciating the importance of clean aggregates,
there are many aggregate plants which now make it
a practice to supply only washed aggregates for
concrete construction.

Small quantities of an aggregate may be washed
in trough-like devices, set at sufficient angle so that
when the materials are shoveled into the upper end
and a strong stream of water allowed to play down
the trough, silt and clay will be removed by the
tumbling, rolling, washing action as the aggregates
travel toward the lower or outlet end of the trough.
Where any considerable quantity of aggregates
must be washed, special washing plants, usually
equipped with rotary screens to size the particles are
necessary.

Effect of Aggregate on Fire Resistive Quali-
ties of Concrete

Concrete has assumed its place in building con-
struction because of its ability to resist fire. To
attain this in the greatest degree, it is necessary that
the aggregates be selected for their fire resistive
properties. Some aggregates that might be suited
to construction where the concrete is to be exposed
principally to impact or wear, would not be suitable
where fire resistance is desirable. The best aggre-
gates are siliceous sands, traprock and slag, but
some grades of hard limestone have also proven
particularly suitable to fire resistive construction.

30

Steam coal cinders also may be used, but great
care should be taken to see that they are free from
particles of unburned coal and contain no ash or
other refuse. Steam coal cinders that are burned
to a clinker are best. Both slag and trap rock have
high resistance to fire and probably make the best
coarse aggregate for the highest type of fire resist-
ing construction.

Effect of Mineral Properties of Aggregate on
Strength of Concrete

Sometimes the mineral properties of certain ag-
gregates are such as to render them unfit for use in
a concrete mixture. Iron ore and rocks containing
some other mineral substances are not suitable:
neither are slags from some smelting processes. The
slag preferred is that from blast furnaces used in
iron ore reduction. Where sand and gravel obtained
in iron producing regions have not given satisfac-
tory result in concrete, it has generally been due to
the mineral content. The oxidation of the iron pres-
ent has been known to form sulphite, so that the
chemical action was powerful enough to break up
the concrete through disintegration.

AcceptabilityJ^of Aggregates

Cinders are used principally for concrete where
very light loads are involved or to protect steel
structural members. They are frequently used as
aggregate for concrete in floor construction or in
blocks.

Stone screenings, if from hard, durable rock, such
as granite or traprock, and if well graded, clean and
free from an excess of dust, may be used in place of
sand with satisfactory results. As a wearing sur-
face for floors, clean washed screenings from granite
are very desirable. Owing to the difficulty of ob-
taining screenings that are sufficiently free from
dust they should not be used unless they are first
washed.

Broken concrete should never be used as aggre-
gate. The fact that there are but few of the original
sand and stone or pebble surfaces exposed, makes it

31

almost impossible for the cement to bond broken
particles of concrete together.

Chats, a product of zinc smelting, are frequently
used as a concrete aggregate, particularly in the zinc
mining region of Missouri where it is the principal
aggregate material available. When properly com-
bined with the necessary amount of hard sand and
cement, the result is a good concrete.

Quality of Concrete not Dependent on Ce-
ment Alone

A popular supposition among many users of
cement is that failures in concrete construction are
caused by poor cement. Portland cement is a manu-
factured product, the qualities of which can be ex-
actly controlled, and as cement manufacturers must
make a product which will meet standard specifica-
tion requirements, it can be realized that any of the
well known brands of cement, of which there are
many, must be dependable products or the manufac-
turers could not long stay in business.

Careful investigation of concrete failures has
generally shown that aggregates, workmanship, or
some factor other than the cement has been respon-
sible for failure when such has occurred. There are,
no doubt, concrete structures standing which are
not what they should be because of faults of work-
manship or the introduction of some bad practice.

A word of caution should be given concerning
the use of so-called pit-run gravel. Almost invari-
ably such material contains a volume of sand prac-
tically twice that of the volume of pebbles, while for
good concrete, the bulk of pebbles or other coarse
aggregate should be practically twice the bulk of
sand. Also gravel pits frequently are not stripped
of overlying soil before they are worked and this
soil, which is usually humus, or rotted vegetable
matter, drifts down the face of the pit and becomes
mixed with the materials. In such a case they
should not be used until washed. They should also
be passed over suitable screens so that the sand and
pebbles may be separated and remixed in proper
proportions.

Careful tests will show that no two wagon-loads
of gravel taken from the same pit are alike in con-
tained volumes of sand and pebbles, nor have
throughout the same grading of particles. Even
where the natural run of bank material is fairly well
graded, this grading will be considerably out of bal-
ance when the material is dug from the pit because
the coarser particles drift down the face, so one load
will consist largely of pebbles, while the next load
will be largely of sand. Bank-run material, therefore,
should be prepared for use by screening into two
volumes — sand and pebbles. Even were it possible
to make good concrete by disregarding the desira-
bility of screening and reproportioning the materials,
economy would dictate it because of the reduced
quantity of cement required to produce a concrete
of given strength.

Table No. 2

TABLE SHOWING CUBIC YARD WEIGHTS IN POUNDS,

EQUIVALENT WEIGHT IN TONS AND FRACTIONAL

NUMBER OF CUBIC YARDS PER TON

Weight of Aggregates
in Pounds per Cubic
yard

Equivalent Weight
in Tons

Fractional Number of
Cubic Yards per Ton

2,100

1.050

0.952

2,150

.075

0.930

2,200

.100

0.909

2,250

.125

0.888

2,300

.150

0.869

2,350

.175

0.851

2,400

.200

0.833

2,450

.225

0.816

2,500

.250

0.800

2,550 A
2,600 f

.275
.300

0.784
0.769

2,650--

.325

0.754

2,700

.350

0.740

2,750

.375

0.727

2,800

.400

0.714

2,850

.425

0.701

2,900

.450

0.689

2,950

.475

0.677

3,000

.500

0.666

3,050

.525

0.655

3,100

.550

0.645

3,150

.575

0.635

3,200

.600

0.625

3,250

.625

0.615

3,300

.650

0.606

33

CHAPTER 3.
CONCRETE IN HIGHWAY CONSTRUCTION

In this chapter the discussion of the use of con-
crete in highway construction will be limited to the
improvement of streets, roads, and alleys by paving.

Concrete has become an important factor in the
construction of highways whether it is used as a
material forming the entire pavement slab, as in the
case of concrete pavements, or forms the founda-
tions to support various types of surface such as
brick, sheet asphalt and asphaltic concrete. When
used for the entire pavement, it must be designed
and built to give the type of surface required of a
first class heavy duty highway. When concrete
serves as a base or a foundation its principal func-
tion becomes one of carrying the load and distrib-
uting it over the subgrade.

Probably in no other field of use is concrete sub-
jected to such severe abuse as when used for the
construction of the all-concrete highway, whether
this be road, street or alley. The concrete not only
must be relied upon to furnish the desired surface
for traffic but must resist the impact and abrasion
resulting from the weight and volume of such traf-
fic. It is evident that more exacting requirements
must be made for concrete in the all-concrete pave-
ment than in concrete used as the base or founda-
tion for another type of wearing surface. This does
not mean, however, that the concrete foundation
work for any type of wearing surface can be mixed
or placed in a slipshod manner.

One and Two Course Construction

As a rule concrete pavements are of one course
construction. So-called two course construction is
used in case the supply of local materials is of such
quality that the required resistance to wear and
surface impact cannot be met by a concrete wearing
course in which the local aggregates are used. In
other words, in two course concrete highway con-

34

struction the top or wearing course contains aggre-
gates especially selected for toughness and wear
resistance.

Design of Pavements

The design of concrete pavements is still in the
process of evolution. Many practices have come to
be regarded as standard because this type of pave-
ment has now had sufficient years of test to have
proven the desirability of making certain require-
ments fundamental. Among these are drainage of
foundation or subgrade, proper crown of the pave-
ment surface, so that the water may be quickly re-
moved, slope of shoulders to the gutters, suitable
outlets for delivering water to culverts and natural
channels, and associated details which render and
maintain the foundation or subgrade in a suitable
condition. Naturally soil conditions as well as cli-
matic conditions may require that some one or more
of these features be given particular attention.

Width is determined principally by traffic de-
mands. With motor traffic now predominating on
most highways it is evident that the minimum
width should be established with particular refer-
ence to the safety of motor traffic when passing at
prevailing speeds.

The thickness required to meet traffic conditions
has not been standardized. Traffic has changed
both in amount and volume with greater rapidity
than has the knowledge of the requirements of high-
way construction. The same lack of standardiza-
tion is apparent in the reinforcement of concrete
pavements, although it is pretty well established
that reinforcement under many conditions of sub-
soil is not only desirable but extremely advisable.
The duty of the reinforcement is to prevent ap-
preciable opening of cracks which may form.

Concrete Base

When concrete is used as a base for other types
of surfacing, it may be plain or reinforced, but since
the base is designed almost entirely from the stand-
point of load carrying capacity the mixtures used

35

usually are different from the standard mixtures
used in the all-concrete pavement.

Curves

The need for utmost safety of traffic on modern
highways because of the predominance of motor
traffic has caused more attention to be given in the
past two or three years to certain requirements
of design and construction which a few years ago
were not recognized as necessary. Among these
are easy curves, super-elevated and widened, so that
motor vehicles can take them in safety without un-
necessary reduction in speed.

Shoulders

Shoulders for a concrete road are provided to
allow additional room for passing, to give the en-
tire roadway a finished appearance and to assist in
carrying away the water from the pavement. In
the case of narrow roads, shoulders are usually con-
structed and maintained to receive a portion of the
traffic. They are made of macadam, either water
bound or tar bound, or of gravel or of natural earth,
properly graded toward the side. If of ordinary
earth the usual practice is to endeavor, as soon as
possible to cover them with a growth of grass, ex-
cept for that portion used for passing vehicles, thus
preventing wash and making maintenance easier
and less costly.

Curbs

In certain cases roads as well as streets are
bordered by curbs. This is particularly true of
curves on grades, and on stretches through cuts.
Usually such curbs are made integral with the
pavement and together with the surface of the
pavement form a gutter to carry surface water to a
permanently located outlet. The integral curb is
suitable for boulevard, avenue, business thorough-
fare, alley, driveway or road.

Materials of Construction

The materials entering into concrete used in
highway construction are the same as when used

36

for other structural purposes. They are cement,
aggregates and water. Elsewhere the required
physical properties of materials have been consid-
ered. These apply to concrete used in highway
construction, whether for base or for the all-con-
crete pavement, except that in the base the aggre-
gates are not exposed to the immediate contact of
traffic. Table No. 10 on page 58 gives the cubic
yards of concrete per linear foot and per mile of
pavement for various widths and thicknesses. Ta-
ble No. 11 shows the quantity of cement, sand and
stone required per linear foot and per mile of road
for different mixtures of concrete. The following
table gives recommended thickness for concrete
roads and streets.

Table No. 3

THICKNESS FOR LIGHT TRAFFIC ROADS AND STREETS

Width Feet

Sides Inches

Center Inches

10

6

8 (inside)

18

6

8

27

6

9

36

6

9V2

Table No. 4

THICKNESS FOR HEAVY TRAFFIC ROADS AND STREETS

Width Feet

Sides Inches

Center Inches

20
30
40

8
8
8

10
11
12

Just as it has been the practice to increase the
thickness of the all-concrete highway pavement, so
has the tendency within the past year or two been
to increase the thickness of concrete base used for
the other types of wearing surface. Also the mix-
ture for concrete bases has been made richer. In
Illinois the standard mix for concrete foundation
for other types of surface is 1 :2 :3J£, and the thick-
ness from four to six inches. The tendency in oth-
er parts of the country is also toward wider and

37

thicker concrete pavements and concrete bases in
keeping with the great increase of heavy motor traf-
fic on all classes of highways.

Drainage

As already mentioned, much of the stability of
any type of road surface depends upon the care
given to draining the foundation or subgrade. The
purpose of drainage is to secure and maintain uni-
formity of subgrade condition. It may be neces-
sary to lay tile drains not only paralleling the
pavement but beneath it. In flat country, for ex-
ample, shoulder drains are generally necessary if
the pavement is placed on clay soil. In case the
construction of a highway necessitates the cutting
of a clay or shale hill where sub-surface water is
troublesome it is advisable to construct herring-
bone cross drains of broken stone or tile at least
eighteen inches deep and one foot wide. These
drains have their beginnings at the center of the
road and extend to the gutter, at an angle of from
thirty-five to forty-five degrees to the center line
of the pavement. This construction is particularly
applicable where the slope of the rock strata is
such that the roadway cuts natural water-bearing
seams.

Mechanical Equipment

As the increasing highway programs of the
state and federal governments developed, improved
methods of handling materials and organizing the
projects made their appearance. Those interested
in the construction industry, including contractors,
engineers and manufacturers of equipment, have
developed new machines to meet the new require-
ments, or have adapted to highway work the ma-
chines used successfully in other lines.

The paving mixer has gone through an interest-
ing development. As originally designed, the ma-
terial was placed in a narrow skip barely wide
enough to allow one wheelbarrow to dump into it.
Concrete was distributed by spout or by horse
drawn cart. The next prominent step was the de-

38

velopment of the boom and distributing bucket,
which was made automatic the next year. Then
came the widening of the skip which allowed two
men to discharge their wheelbarrows into it at the
same time. Next came multiplane traction to take
the place of road wheels on the traction end of the
mixer. Finally, with the development of the use of
industrial railroads, a derrick was added to pick
the batch boxes from the cars. Today the paving
mixer stands, an example of the highest type of
construction equipment.

The capacity of the mixer to be used on a spe-
cific contract or to be adopted as standard by a
contractor should be based upon the following:

(1) the quantity of highway to be placed per year;

(2) availability of sufficient materials to keep the
equipment busy; (3) railroad facilities, car supply,
etc.; (4) storage space for materials and availabil-
ity of railroad sidings along line of the work;

(5) type of hauling equipment to be used;

(6) character of work to be undertaken.

Having determined the size of the machine to
be adopted, all other equipment should be pur-
chased with one idea, to keep the machine going to
full capacity with a minimum expense. This does
not mean a minimum first cost for equipment, but
does mean a balanced plant that will reduce labor
costs to a minimum consistent with capacity pro-
duction.

Equipment is naturally divided according to its
use into handling and storage, hauling, pumping,
mixing and placing, and finishing. The relation of
equipment to the economical completion of a pro-
ject will be considered in the order named.

Handling Materials

Methods of handling materials from cars vary.
The size of the project and the method of handling
other parts of the job will affect the choice. The
methods of unloading include, first, unloading by
hand either into wagons or trucks, or into movable
bodies hung against the side of the car from which

39

The Koehring Crane Excavator

with gasoline engine
and multiplane traction.

•in

the material is dumped into trucks or wagons;
second, mechanical unloading, using bucket eleva-
tors or skip hoists from pits below the track; and
third, the use of a clam shell bucket on a derrick or
a traction crane. The first and second of these
methods have proved very successful where com-
paratively small amounts of materials were handled
or where the material could be obtained in bottom
dump gondola cars, but they do not give the re-
quired capacity in case the storage must be at the
railroad station and not on the subgrade.

The crane fits the requirements so much better
than the others that even at a larger initial invest-
ment it has been found an economical addition to
a plant. The speed of its swing, its ability to travel
alongside the piles, and thus to increase the storage
capacity, are large factors in its favor.

Opinion is divided as to the effectiveness of two
types of material storage units — the bin and the
tunnel. Bins are less expensive in first cost, but
the tunnel system has the advantage of reducing
the amount of rehandling. The nature of the re-
mainder of the plant used will have an effect upon
the decision.

No very satisfactory mechanical equipment has
been developed for handling cement from cars to
storage and into the haulage units. For sacked
cement manually operated two-wheel trucks have
proved the most satisfactory. Some progress has
been made in the use of mechanical appliances but
at best the handling of the cement is expensive.
Bulk cement has been found practicable when
shipped either in box cars or in open top gondolas
protected by tarpaulins. When shipped in box cars,
handling is accomplished with a power scoop draw-
ing the material through the door of the car into
the boot of a conveyor. When received in gon-
dolas the material is handled by locomotive crane
or derrick equipped with clamshell bucket.

In case materials of construction are not stored
on the sub-grade concentrated storage at one point
or at several points along the line of the road must
be adopted. Not only does this change the system

41

of operation but it increases the amount of railroad
track facilities required to complete a project. If
the mixer is charged by wheelbarrows or with the
mixer loader, it is not uncommon to see materials
distributed for from one-half to two miles, ready to
be placed in the mixer. This equals 1500 to 8000
cubic yards of aggregate or sufficient materials to
carry on the operation from one week to one
month. Cement storage may be available in barns
along the line of the work. The storage space re-
quired at the railroad siding under this method of
construction therefore is small.

If the materials are to be kept off the sub-grade,
all this is changed. Facilities must be provided
at the railroad for a large amount of material. It is
probable that the economy resulting justifies the
added expenditure for plant, yet the new condition
must be studied closely to determine whether
available facilities are sufficient to operate economi-
cally or whether it is necessary to increase the ex-
isting trackage or build sidings at another point.

In order to bring out more clearly the method of
designing such a plant an assumed job will be dis-
cussed. On this project there is sixteen miles of
sixteen foot road, six inches thick at the sides and
eight inches thick at the center. Proportions speci-
fied are one part cement, one and one-half part sand
and three parts stone. Further, because of the
peculiar railroad situation it is necessary to haul
materials for the whole sixteen miles from one point
near the center of the section. Based on experi-
ence in highway work, it is reasonable to believe
that there will be an average of twenty working
days per month, this taking into consideration Sun-
days and rainy days but not considering any delays
due to lack of materials. The experience gained in
1920 shows that there should be at least one
month's supply of materials on hand at all times if
this progress is to be maintained and that there
will be times after the start of the shipping season
for aggregate when two month's supply may have
to be stored.

42

Table No. 5 shows the quantity of materials
required per hour, day, week and month.

Table No. 6 gives the number of cars required
per day and per month for the three sizes of pav-
ing mixers.

The basis on which these tables have been pre-
pared is an average production of thirty batches
per hour for eight working hours, six days per
week. It is appreciated that with proper organiza-
tion this can be pushed up to four hundred batches
in a ten hour day without great difficulty or at the
rate of forty batches per hour; yet considering the
delays to which such a project is subjected it seems
reasonable to adopt thirty batches per hour over an
eight hour day as a basis on which to calculate the
quantity of storage space required.

The railroad facilities will be controlled by the
maximum number of cars to be received per day.
As there is a tendency toward bunching it is evi-
dent that trackage must be provided for at least
twice the daily requirement. The quantity of
trackage required for each individual job will de-
pend upon the switching service rendered by the
railroad and the distance to yards of sufficient ca-
pacity to absorb the bunching of materials. With
the average project located at a considerable dis-
tance from a large city or division point it is not
probable that there will be made available more
than two car deliveries per day, and materials will
be placed in considerable quantity only once a day.
One of these switches will come in in the morning
and the other either later in the day or at night.
This requires that space be made available for at
least twelve cars if a 14E paver is used, eighteen
cars if a 21E paver is used, and twenty-nine cars if
a 32E paver is used. Some leeway must be given,
so that the empty cars can be pushed out of the
way. Assuming 40 feet per car, and that it is neces-
sary to have a tail track capacity for at least fifty
per cent of the cars, 720 feet of track is required
for a 14E paver, 1080 feet of track for 21E paver
and 1740 feet of track for a 32E paver. If switch-

43

ing facilities are better than here given this quan-
tity of track may be cut in half.

Table No. 5

Minimum Quantity of Storage Required for Eco-
nomical Operation of Highway Project

Mix 1-11/2-3.

Machine

Quantity
pef Hour

Quantity
per day

Quantity
per 6 Days

Quantity
per 20 Days

cement
14E sand
stone

30 bbls.
6.66cu.yd.
13.33 cu. yd.

240 bbls.
53.3 cu yd.
106.6 cu. yd.

1440 bbls.
320 cu. yd.
640 cu. yd.

4800 bbls.
1066 cu. yd.
2132 cu. yd.

cement
21 E sand
stone

45 bbls.
10 cu. yd.
20 cu. yd.

360 bbls.
80 cu. yd.
160 cu. yd.

2160 bbls.
480 cu. yd.
960 cu. yd.

7200 bbls.
1600 cu. yd.
3200 cu. yd.

Tcement
32E sand
stone

67.5 bbls.
15 cu. yd.
30 cu. yd.

540 bbls.
120 cu. yd.
240 cu. yd.

2890 bbls.
720 cu. yd.
1440 cu. yd.

11800 bbls.
2400 cu. yd.
4800 cu. yd

Table No. 6

Cars of Materials Required per Day and per Month
for Three Sizes of Pavers

Mix 1-11/2-3.
14-E PAVER

Cars per Day:

Cars per Month:

1 car

cement

19 cars

sand ....

2 cars

sand

. . 36 cars

stone

4 cars

stone

72 cars

21-E PAVER

cement

1 1/2 cars

cement

30 cars

sand

21/2 cars

sand »,

50 cars

stone

5 cars

stone .

100 cars

32-E PAVER

cement 2-1/6 cars

sand 4 cars

stone 8 cars

cement .
sand. . .
stone. .

43 cars

80 cj-rs

. . 160 cars

Table No. 7

Minimum Trackage Required for
Economical Operation

14E

21E

32E

Minimum side track space
„ required for daily car
i storage

280 ft.
720 ft.

400 ft.
1080 ft.

600 ft.
1740 ft.

Recommended track space
for economical operation
One switch per day — by
railroad

44

As very few individual sidings exist with this
capacity which are not in constant use, the con-
tractor may be forced to build one for himself.
If so, the expense of this must be taken into con-
sideration at the time of submitting his bid and the
total expense charged against the job.

From the above figures the necessity for a large
storage area and sufficient trackage is evident.

Rehandling Materials

The handling of this material from cars to stor-
age piles is easily accomplished with the crane, but
the next step is of equal importance if the opera-
tion is to prove financially successful. How best to
re-handle the materials into haulage units for trans-
portation to the mixer is the problem. Three
types of equipment are in general use, — first, fixed
bins; second, portable bins on wheels; third, tun-
nels. The last of these has not been used extens-
ively except for projects equipped with industrial
railroad. The relative cost of the three methods
is in accordance with the order in which they are
given above. The economy of each is so depend-
ent upon the amount of work to be completed that
it is not practicable to discuss their relative effi-
ciency at this time. When bins are adopted they
should have a capacity of at least two hours run,
so that no delays will result in case the crane is em-
ployed handling cars at the other end of the pile,
and that short stoppages due to unforseen condi-
tions can be bridged.

Below is given the recommended capacity for
bins of each size of mixer.

Table No. 8

Minimum Capacity of Material Bins
Based on 2 hours supply for mixer

14E

21E

32E

Sand
Stone

13 y2 cu. yd.
27 cu. yd.

20 cu. yd.
40 cu. yd.

30 cu. yd.
60 cu. yd.

Bins of the portable type can be mounted either
on railroad or road wheels, so that they may move

45

as required by the condition of the storage piles.
This moving will actually be done seldom, as under
normal conditions material will be handled from
cars to bins without rehandling and storing. If the
material is used from storage there will be suffi-
cient of it within the reach of the crane to keep the
operation going for at least one-half day without
changing the location of the bins.

Drag scrapers operated by a light hoist have
proved economical for cleaning up the piles when
materials are deposited beyond the reach of the
crane.

Ha u lage^ Un its

Haulage units may naturally be divided into
two distinct classes; first, trucks and second, indus-
trial railroad. Ten years ago teams had a large
place in hauling on highway construction work.
This, however, has changed until their use is so
limited that there seems to be no necessity for dis-
cussing them here.

Trucks again may be divided into heavy trucks
— three tons and over, — and light trucks, of one and
one-half ton capacity. In the past the tendency has
been to use the five-ton truck for hauling materials.
The only objection to this unit has been the tend-
ency to cut up the grade and the difficulty of its
use under anything but the best of road conditions.
During the last two years, therefore, a number of
contractors have adopted lighter trucks equipped
with pneumatic tires. These are easily handled,
can go over the road rapidly and do not cut up the
grade as much as do the larger trucks. They have
a big disadvantage, however, in the labor involved
per ton of material hauled. About all that can be
said concerning the size of truck to adopt is that
it will depend entirely on the condition of the roads
on which the hauling is to be done, the method of
handling the work, and length of haul.

The use of industrial railroad is comparatively
new to the highway construction industry. True,
it was used some years ago but not extensively and
it was only in 1919 that the present system of use

46

was developed. The use of batch boxes, two boxes
to a car, two-foot gauge equipment, and either gaso-
line or steam locomotives has become practically
standard practice. At the loading station, the batch
is prepared, the proper amount of cement, sand and
stone being put into the batch box and hauled in
its dry state to the paving mixer to be mixed and
placed on the road.

The only criticism of this system is the fact that
any delay in the transportation results in a direct de-
lay to the mixer. In highway work the contractor re-
ceives no remuneration until the concrete has passed
through the mixer and is in place on the road.

There are three other methods of handling ma-
terials: first by trucks direct from the railroad sid-
ing to the sub- grade, from which the material is re-
handled into the mixer; second, the handling of it
in the same manner from stock piles at distances of
from five hundred feet to one mile; and third, the
use of batch boxes on flat bed trucks, hauling over
the completed concrete and transferring the batch to
industrial cars for hauling along the concrete already
placed but not yet sufficiently hardened to be used.

This system appears to combine the advantages
of both types of haulage equipment. In the first
place the truck has the opportunity to travel on a
hard surfaced road. In the second place, the length
of the industrial railroad (and the delays incident
to an industrial railroad vary at least directly as its
length) is reduced to not to exceed two miles and
probably not to exceed one and one-half miles.

Mixer Plant

The type and size of paving mixer to adopt will
depend almost entirely on the amount of road to be
placed in one season, but will be affected by the
method of charging the mixer.

The central mixing plant has been used on a
number of highway projects. Yet the cost of
hauling the concrete as opposed to hauling the dry
batch, in addition to the other costs of this method
seems to be such as to make this method less effi-
cient than the use of a paving mixer on the sub-

47

grade. Undoubtedly the boom and automatic dis-
tributing bucket is the only method which has been
evolved for distributing concrete in place in the
proper condition to obtain the maximum strength.
It is very desirable that after the concrete leaves
the drum of the mixer it be put into its final place
rapidly. By so doing less water can be used than
would be necessary if the concrete were hauled and
the resulting concrete will be denser and more
homogeneous.

Of the four sizes of paving mixers it is probable
that the No. 14E will remain the popular machine
for any but the small or large contracts. On the
small contracts the 10E will be popular while on
the large contracts the support will be divided be-
tween the 21E and the 32E. The decision as to
which of these sizes should be used rests entirely
upon the remaining equipment and organization of
the contractor.

Pump and Water Line

Rapid highway construction necessitates suffi-
cient water at all times to insure water for the
mixer, and for sprinkling and curing, as well as
water for steam purposes for the other pieces of
equipment on the project. Necessarily this requires
a pump which automatically regulates the quantity
forced into the pipe depending upon the amount
used. The mistake has very often been made of
using too small a pipe line on construction work.
It is recommended that no pipe line less than two
inches be adopted and that for distances of over
one mile that two and one-half inches be adopted.
The quantity of water required to carry on a pro-
ject is as follows:

For mixer 10 gallons per sq. yd.

For sprinkling and curing . . 25 gallons per sq. yd.

Additional for miscellaneous

equipment 10 gallons per sq. yd.

It is recommended that a pump of a capacity
sufficient to give thirty pounds pressure at the
mixer be furnished. The graph and table may be
used in determining the size of pipe to use.

49

Table No. 9

Size of Pipe Required for Varying Length and Head

50

Use of Tables

An example of the use of Table No. 9 is as
follows :

Required the size of pipe for delivery of 40 gal-
lons of water per minute through 9800 feet of pipe
to an elevation of 320 feet above the water supply.
Solution — Under the heading of 40 gallons locate
9800 feet. On this line and in column marked Ele-
vation find 200 feet. 2-inch pipes should therefore
be used.

Table may also be used as follows:

Problem — How much water will the Koehring
steam pump deliver through 4200 feet of 1%-mch
pipe against a total head of 110 feet. To obtain
this note column marked 1%-inch pipe. In this
column locate 4400 and on this line in column
marked Elevation read 100. Therefore the delivery
under stated length will be 35 gallons per minute.

The same data can be obtained by use of Figure
No. 1. Examples of the use of these figures are
given as follows: Example 1 — What size of pipe
is required to deliver 50 gallons per minute 320 feet
above and 75100 feet from the pump, suction lift
being 22 feet?

Solution: — Total head equals 320 plus 22 or
342 feet. Locate 7500 on upper pipe scale and 342
on vertical scale on the right. The intersection of
these two lines is near the 2% -inch pipe 50 gallon
curve. Hence 2y2-inch pipe is required.

EXAMPLE 2 — How much will a 2-inch pipe
deliver at 342 feet head and 7500 feet length?

Solution: — Locate 7500 on lower pipe scale and
342 on vertical scale on the left. The intersection
of the two lines is near the 2-inch pipe 40-gallon
curve. Hence nearly 40 gallons.

EXAMPLE 3— Describe the length of 2-inch
pipe that can be used to deliver 40 gallons per min-
ute against a 420-foot head.

Solution: — Note where curve marked 2 inches
40 gallons intersects with the line denoting 420-

61

52

foot head. From that point drop down to the pipe
scale and read the answer, 5000 feet.

Reference to Figure No. 1 shows the method of
obtaining length of pipe, total head, and discharge
head, which information is used in determining
size of pipe, or the quantity of water which will
flow through a pipe of a given size.

Forms and Finishing

There is little to be said concerning the type of
forms to adopt. Steel forms have proven so much
better than wood forms that they are recommend-
ed. With the general adoption of machine finish-
ing it is desirable that these forms be sufficiently
stiff to withstand the strains set up by the vibra-
tion as well as the weight of the machine. The
finishing of concrete is one of those items which,
although, it is not a major item of cost is import-
ant, as it materially affects the riding qualities of
the road. In case a machine is used it is essental
that the forms be kept clean, so that the wheels
carrying the machine will always be at the same
relative elevation and will not be forced to rise
over the concrete, therefore giving a wavy surface.
Where roller and belt is used care should be taken
to make sure that the finishing is not completed too
quickly after depositing the concrete.

Organization of Crew

The mixer capacity controls the size of the
crew on all other parts of the work if the plant is
properly balanced. Otherwise, the output of the
mixer is controlled by the capacity of the slowest
unit. The whole idea in organization of a highway
construction crew is that of efficiency, time against
production. Without efficiency, and efficiency
means the balancing of all labor going into the
production of a road, costs are going to go very
high. It must be appreciated that a highway pave-
ment is a long, thin, narrow strip for which the
contractor receives a small remuneration per run-
ning foot. When it is made clear that a 14E paver
has a capacity of about one and one-half to two

53

feet of road per batch, the necessity is apparent for
organizing the crew throughout in a way that each
action is the most effective and can be repeated
economically 3000 times in the completion of a
mile of road.

The batch meter, with which all concrete mixers
may be equipped, assists in this standardization of
operation. This is an instrument attached to the
mixer which controls the time the material remains
in the drum, automatically locking the discharge
chute as the charging skip reaches the top of its
travel and releasing the discharge upon the expira-
tion of the controlled time. Economy of organiza-
tion can best be effected by basing the crew on the
output of the mixer controlled by the meter.

Balancing of Plant

Not only is it necessary that the crew be bal-
anced, but it must be balanced in relation to the
plant, otherwise there cannot be true coordination
which results in profits at the end of the project.
From the receipt of materials through the hand-
ling, storage, hauling, mixing and placing, it is
essential that the capacity of one machine fit the
capacity of the other.

If this is done and there is proper organization
of the labor, the advantage in cost is going to ac-
crue to that contractor who has ' equipped himself
with large, efficient machinery.

Cold Weather Work

The construction of concrete pavements is not
recommended during freezing weather. It is some-
times necessary or desirable, however, to complete
a small section under unfavorable weather condi-
tions in order that an entire stretch of pavement
may be thrown open to use. The fundamental pre-
cautions to be observed when concreting is done
under such conditions is to maintain a certain de-
gree of warmth in and in the presence of the con-
crete until it has completed early hardening and
will be proof against injury from freezing.

54

Concrete should not be placed on a frozen sub-
grade. All materials excepting the cement should
be heated so that when the concrete is mixed it will
have a sufficiently high temperature that the hard-
ening process may proceed sufficiently not to be
damaged by frost. It should be placed quickly and
at once protected to prevent loss of the heat. Com-
pleted work can be housed in by using light
frames covered with canvas, or by covering the
pavement with a layer of hay or straw, a foot or
more thick, after the concrete has hardened suffi-
ciently to prevent damage to the surface from con-
tact with this covering. A one-inch layer of saw-
dust with canvas over the top has been found very
satisfactory when this means of protection is ob-
tainable and the degree of cold to be protected
against will not exceed three or four degrees be-
low freezing.

Curing

One of the most important features of concrete
pavement construction is proper protection of the
concrete while hardening. As soon as it has been
finished, the work should be covered with canvas
stretched on light frames to prevent rapid evapora-
tion of water. After hardening has advanced suffi-
ciently to permit an earth covering being thrown
on without damage to the surface, at least two
inches of such covering should be applied and be
kept wet by frequent sprinkling for a period of ten
days or more, depending upon weather and tem-
perature conditions. Hardening should be allowed
to progress slowly and uniformly.

Where possible to arrange for it, the most satis-
factory method of curing concrete pavements is to
pond them. This consists of keeping them covered
with about two inches of water retained by earth
dams built across the pavement at suitable inter-
vals. Flooding is generally done in the evening
when the water is not needed for the mixer and is
kept at a minimum depth of two inches over the
crown of the pavement for at least ten days.

55

Maintenance of Concrete Pavements

With passage of time it becomes necessary to
give attention to maintenance, although well built
concrete pavements require less maintenance than
any other type of pavement. Nevertheless, such
maintenance as is required must be regularly and
systematically given. This in general includes fill-
ing joints and cracks with tar or asphalt and repair
of spots which result from local disintegration due
to clay balls or other foreign materials in the con-
crete, or to pitting from freezing where the con-
crete was not properly protected while undergoing
early hardening.

The materials required for maintaining concrete
pavements are portland cement, sand, stone and
bitumen. The last may be some one of the coal tar
or asphaltic products. Demand for these for the
purpose mentioned has resulted in the preparation
of several standard commercial products now on
the market. Care should be taken that the prep-
arations are used in accordance with the manufac-
turer's recommendations, since some are intended
to be applied hot and others cold. Overheating the
hot preparations in general destroys their ef-
fectiveness.

But little equipment and few tools are needed
for the simple maintenance work concrete pave-
ments require. A kettle to heat tar, a can to pour
it in the cracks or holes, a stiff broom for sweeping
out cracks and some kind of a hooked tool, similar
to a stove poker but with sharp point, may be used
to scrape out compacted foreign matter from joints
or cracks. For convenience in removing the tar
heater, it is generally mounted on wheels, and
where there is considerable mileage to maintain,
the outfit is usually moved by means of a small
motor truck.

Examples of Use of Tables lO^and 11

Tables 10 and 11 have been prepared with the
belief that there is a need for a table giving the
quantity of concrete per foot and per mile of con-

66

crete pavement and base. These tables are given
for each inch of thickness, from 4 inches uniform to
8 inches at the sides and 10 inches at the center.

In table No. 11 the quantity of cement, sand and
stone for each thickness, width and mixture is
given. All calculations are based on quantities
taken from Taylor and Thompson.

It will be noticed that in the first column three
figures are given — the first is the thickness at the
edge — the next the thickness at the center and the
third the thickness of a uniform slab with equal
cross section area.

As all pavements are built with curved crowns,
the difference between the thickness given and the
average of the two thicknesses is due to the greater
cross sction resulting from the use of a curve. For
example, a pavement 6 inches thick at the side and
8 inches thick at the center has a cross section area
equal to a pavement 7% inches thick and not one
7 inches thick.

Example — To obtain the quantity of concrete
per linear foot and per mile of a pavement 18 feet
wide 7 inches thick at the edge and 8 inches thick
at the center, follow along the width until 18 feet is
reached. Then follow down the column until the
line headed 7-8-7% is reached and read .426 cubic
yards per linear foot or 2249.28 cubic yards per
mile. If, on the other hand, one is desirous to as-
certain the quantity of cement, sand and stone re-
quired for this pavement, using a 1-2-3 mixture, re-
fer to table No. 11 — under 1-2-3 mixture — Follow
down 18 foot column to point opposite 7-8-7% and
read .741 bbls. of cement per foot, .23 cubic yards
of sand per foot and .33 cubic yards of stone per
foot. In like manner the quantities of material re-
quired per mile are 3913 barrels of cement, — 1192
cubic yards of sand and 1732 cubic yards of stone.

67

Table No. 10

CUBIC YARDS OF CONCRETE PER LINEAR FOOT
AND PER MILE OF PAVEMENT

Thickness

Pavement

Width Pavement Feet

Inches

|

Per
Lin.

So "S §

Foot

9'

10'

12'

14'

16'

18'

3 QJ <

Per

Mile

444

Foot

.111

.123

.148

.173

197

.222

Mile

586.08

649.44

781.44

913-44

040 16

1172.16

4 5 4*

Foot

.130

.144

.173

.201

.230

.259

Mile

686.

760.32

913.44

1061.28

1214.40

1367.52

4 6 5H

Foot

.148

.164

.197

.230

263

.296

Mile

781.44

865.92

1040.16

1214.40

1388.64

1562.88

5 5 5

Foot

.139

.154

.185

.216

.247

.278

Mile

733.92

813.12

976.80

114048

1304.16

1467.84

5 6 5%

Foot

.157

.175

.210

.245

.280

.314

Mile

828.%

924..

1108.80

1293.60

1478.40

1657.92

5 7 6^

Foot

.176

.195

.234

.274

.313

.352

Mile

929.28

1029.60

1235.52

1446.72

1652.64

1858.56

5 8 7

Foot

.194

.216

.259

.302

.346

.389

Mile

1024.32

1140.48

1367.52

1594.56

1826.88

2053.92

666

Foot

.167

.185

.222

.259

.296

.333

Mile

881.76

976.80

1172.16

1367.52

1563.28

1758.24

6 7 6%

Foot

.185

.205

.247

288

.329

.370

Mile

976.80

1082.40

1304.16.

1520.64

1737 12

1953.60

6 8 7>i

Foot

.204

.227

.271

.317

.362

.407

Mile

1077.12

1198.56

1430.88

1673.76

1911.36

2148.96

698

Foot

.222

.247

.296

.346

.395

.444

Mile

1172.16

1304.16

1562.88

1826.88

2085.60

2344.32

777

Foot

.194

.216

.259

.302

.346

.389

Mile

1024.32

1140.48

1367.52

1594.56

1826.88

2053.92

7 8 7%

Foot

.213

.236

.284

.331

.378

.426

Mile

1124.64

1246.08

1499.52

1747.68

1995.84

2249.28

7 9 JK

Foot

.231

.257

.309

.360

.411

.463

Mile

1219.68

1356.96

1631.52

1900.80

2170.08

2444.64

7 K) 9

Foot

.250

.278

.333

.389

.444

.500

Mile

1320.

1467.84

1758.24

2053.92

2344.32

2640.

888

Foot

.222

.247

.296

.346

.395

.444

Mile

1172.16

1304 16

1562.88

1826.88

2085.60

2344.32

8 9 8%

Foot

.241

.267

.321

.374

.428

.481

Mile

1272.48

1409.76

1694.88

1974.72

2259.84

2539.68

8 10 9x

Foot

.259

.288

346

403

.461

.518

Mile

1367.52

1520.64

1826.88

2127.84

2434.08

2735.04

Table No. 10

CUBIC YARDS OF CONCRETE PER LINEAR FOOT
AND PER MILE OF PAVEMENT

Thickness

Pavement

Width Pavement Feet

Inches

». &

Per
Lin.

a |

Foot

20'

22'

24'

26'

28'

30'

2 cj <

Per

Mile

444

Foot

.247

.271

.296

.321

.346

.370

Mile

1304.16

1430.88

1563.28

1694.88

1826.88

1953.60

4 5 4«

Foot

.288

.316

.345

.374

.403

.431

Mile

1520.64

1668.48

1821 60

1974.72

2127.84

2275.68

4 6 5^

Foot

.329

.362

.395

.428

.461

.494

Mile

1737.12

1911.36

2085.60

2259.84

2434.08

2608.32

5 5 5

Foot

.309

.339

370

.401

.432

.463

Mile

1631.52

1789.92

1953.60

2117.28

2280.96

2444.64

5 6 5%

Foot

.349

.384

.419

.454

.489

.524

Mile

1842.72

2027.52

2212 32

2397.12

2581 .92

2766.72

5 7 6M

Foot

.391

.430

.469

.508

.547

.586

Mile

2064.48

2270.40

2476.32

2682.24

2888.16

3094.08

5 8 7

Foot

.432

.475

518

.562

.605

.648

Mile

2280.96

2508.

2735 04

2967.36

3194.40

3421.44

666

Foot

.370

.407

.444

.481

.519

.556

Mile

1953.60

2148.%

2344 32

2539.68

2740.32

2935.68

6 7 6^

Foot

.411

.452

.493

.534

.576

.617

Mile

2170.08

2386.56

2603.04

2819.52

3041.28

3257.76

6 8 7*

Foot

.452

.498

.543

.588

.633

.679

Mile

2386.50

2629.44

2867 04

3104.64

3342.24

3585.12

6 9 8

Foot

.494

.543

.593

.642

.691

.741

Mile

2608.32

2867.04

3131.04

3389.76

3648.48

3912.48

777

Foot

.432

.475

.518

.562

.605

.648

Mile

2280.96

2508.

2735.04

2967.36

3194.40

3421.44

7 8 7^

Foot

.473

.520

.567

.615

.662

.709

Mile

2497.44

2745.60

2993.76

3247.20

3495.36

3743.52

7 9 8*

Foot

.514

.566

.617

.668

.720

. .771

Mile

2713.92

2988.48

3257.76

3527.04

3801.60

4070.88

7 10 9

Foot

.555

.611

667

.722

.778

.833

Mile

2930.40

3226.08

3521.66

3812.16

4107.84

4398.24

8 8 8

Foot

.494

.543

.593

.642

.691

.741

Mile

2608.32

2867.04

3131.04

3389.76

3648.48

3912.48

8 9 Sy3

Foot

.535

.588

.641

.695

.748

.802

Mile

2824.80

3104.64

3384.48

3669.60

3949.44

4234.56

8 10 9n

Foot

.575

.634

.691

.748

.806

.864

Mile

3036.

3347.52

3648.48

3949.44

4255.68

4561.92

59

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

l—llA—3 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.94 Barrels Per Cubic Yard.
Sand Required: — .42 Cubic Yards Per Cubic Yard.
Stone Required:— .84 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

£

« £

•9 S Z
2 o <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.215

1137

.238

1259

.287

1515

.335

1771

.382

2018

.431

2274

SAND

.05

246

.05

273

.06

328

.07

383

.08

437

.09

492

STONE

.09

492

.10

545

.12

656

.15

767

.17

874

.19

984

4 5 4^

CEMENT

.252

1331

.279

1474

.336

1771

.390

2058

.446

2356

.502

2654

SAND

.05

288

.06

319

07

383

.08

446

.10

510

.11

576

STONE

.11

576

.12

638

.14

767

.17

891

.19

1020

.22

1149

4 6 5^

CEMENT

.287

1515

.318

1680

.382

2018

.446

2355

.510

2695

.574

3032

SAND

.06

328

.07

364

08

437

.10

510

.11

583

.12

656

STONE

.12

656

.15

727

.17

874

.19

1020

.22

1167

.25

1313

5 5 5

CEMENT

.270

1424

.299

1577

.359

1895

.419

2213

.479

2530

.539

2848

SAND

.06

308

.06

341

.08

410

.09

479

.10

548

.12

617

STONE

.12

617

.13

683

.16

821

.18

958

.21

1095

.23

1233

5 6 5^

CEMENT

.305

1608

.340

1793

.407

2151

.475

2510

.543

2868

.609

3218

SAND

.07

348

.07

388

.09

466

.10

543

.12

621

.13

696

STONE

.13

6%

.15

776

.18

932

.21

1087

.24

1242

.26

1393

5 7 6H

CEMENT

.341

1802

.378

1998

.454

2399

.532

2808

.607

3207

.683

3606

SAND

.07

390

.08

433

.10

519

.12

608

.13

694

.15

781

STONE

.15

780

.16

865

.20

1038

.23

1215

.26

1389

.30

1562

5 8 7

CEMENT

.378

1987

.419

2212

.502

2654

.586

3094

.671

3544

.755

3985

SAND

.08

430

.09

479

.11

575

.13

670

.15

767

.16

863

STONE

.16

860

.18

958

.22

149

.25

1340

.29

1535

.33

1725

666

CEMENT

.324

1711

.359

1895

.431

2275

.502

2654

.574

3032

.646

3411

SAND

.07

370

.08

410

.09

492

.11

575

.12

656

.14

738

STONE

.14

741

.16

821

.19

984

.22

149

.25

313

.28

M77

6 7 6H

CEMENT

.359

1895

.398

2099

.479

2530

.559

2951

.638

3370

.718

3791

SAND

.08

410

.09

454

.10

548

.12

639

.14

730

.16

821

STONE

.16

821

.17

909

.21

095

.24

278

.28

459

.31

641

(10

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—1^2—3 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.94 Barrels Per Cubic Yard.
Sand Required: — .42 Cubic Yards Per Cubic Yard.
Stone Required: — .84 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

o

fc. 00

& % g

3 3 -5

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.479

2530

.526

2776

.574

3032

.622

3288

.671

3544

.716

3791

SAND

.10

548

.11

601

.12

656

.13

712

.15

767

.16

821

STONE

.21

1095

.23

1202

.25

1313

-.27

1424

.29

1534

.31

1641

4 5 4%

CEMENT

.559

2951

.613

3236

.669

3535

.726

3832

.782

4128

.836

4415

SAND

.12

639

.13

701

.14

765

.16

830

.17

894

.18

956

STONE

.24

1278

.27

1401

.29

1530

.31

1659

.34

1788

.36

1912

4 6 5H

CEMENT

.638

3371

.702

3707

.766

4047

.830

4384

.894

4722

.958

5060

SAND

.14

730

.15

803

.17

876

.18

949

.19

1022

.21

1095

STONE

.28

1459

.30

1605

.33

1752

.36

1898

.39

2045

.41

2191

5 5 5

CEMENT

.599

3166

.658

3473

.718

3791

.778

4108

.838

4425

.898

4743

SAND

.13

685

.14

752

.16

821

.17

889

.18

958

.19

1027

STONE

.26

1371

.28

1504

.31

1641

.34

1778

.36

1916

.39

2054

5 6 5fc

CEMENT

.677

3576

.745

3935

.813

4291

.881

4650

.949

5009

1.017

5368

SAND

.15

774

.16

852

.18

929

.19

1007

.21

1084

.22

1162

STONE

.29

1548

.32

1704

.35

1858

.38

2013

.41

2169

.44

2324

5 7 6n

CEMENT

.759

4004

.834

4404

.910

4804

.986

5203

1.060

5603

1.137

6002

SAND

.16

867

.18

953

.20

1040

.21

1126

.23

1213

25

1299

STONE

.33

1734

.36

1915

.39

2080

.43

2253

.46

2426

.49

2599

5 8 7

CEMENT

.838

4426

.922

4867

1.005

5306

1.090

5756

1.174

6196

1.257

6636

SAND

.18

958

.20

1053

.22

1149

.24

1246

.25

1341

.27

1437

STONE

.36

1916

.40

2107

.44

2297

.47

2492

.51

2683

.54

2874

666

CEMENT

.718

3791

.790

4169

.861

4547

.933

4928

1.007

5316

1.079

5696

SAND

.16

821

.17

903

.19

984

.20

1067

.22

1151

.23

1233

STONE

.31

1641

.34

1805

.37

1969

.40

2134

.44

2302

.47

2466

6 7 6*A
CEMENT

.797

4210

.877

4631

.956

5048

1.036

5470

1.117

5900

1.197

6321

SAND

.17

911

.19

1003

.21

1093

.22

1184

.24

1277

.26

1368

STONE

.35

1823

.38

2005

.41

2186

.45

2369

.48

2554

.52

2737

61

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR

ROADS, STREETS AND ALLEYS

1— 1H— 3 MIX.

Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.94 Barrels Per Cubic Yard.
Sand Required:— .42 Cubic Yard Per Cubic Yard.
Stone Required: — .84 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

& i

B o <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 7x

CEMENT

.396

2089

.438

2314

.525

2776

.615

3248

.702

3707

.790

4169

SAND

.09

452

.09

501

.11

601

.13

703

.15

803

.17

903

STONE

.17

905

.18

1002

.23

1202

.27

1406

.30

1605

.34

1805

698

CEMENT

.431

2274

.480

2530

.574

3032

.671

3544

.766

4047

.861

4547

SAND

.09

492

.10

548

.12

656

.15

767

.17

876

.19

984

STONE

.19

984

.21

1095

.25

1313

.29

1535

.33

1752

.37

1969

7 7 7

CEMENT

.388

1986

.419

2212

.502

2654

.586

3094

.671

3544

.755

3985

SAND

.08

444

.09

479

.11

575

.13

670

.15

767

.16

863

STONE

.17

887

.18

958

.22

1149

.25

1340

.29

1535

.33

1725

787%

CEMENT

.413

2183

.458

2417

.551

2910

.642

3391

.733

3872

.826

4363

SAND

.09

473

.10

523

.12

630

.14

734

.16

838

.18

944

STONE

.18

945

.20

1047

.24

1260

.28

1468

.32

1677

.36

1889

CEMENT

.448

2367

.499

2633

.599

3166

.698

3688

.797

4210

.898

4743

SAND

.10

512

.11

570

.13

685

.15

798

.17

911

.19

1027

STONE

.19

1025

.22

1140

.26

1371

.30

1597

.35

1823

.39

2054

7 10 9

CEMENT

.485

2561

.539

2848

.646

3411

.755

3985

.861

4547

.970

5122

SAND

.11

554

.12

617

.14

738

.16

863

.19

984

.21*

1109

STONE

.21

1109

.23

1233

.28

1477

.33

1725

.37

1969

.42

2218

888

CEMENT

.431

2274

.480

2530

.574

3032

.671

3544

.766

4047

.861

4547

SAND

.09

492

.10

548

.12

656

.15

767

.17

876

.19

984

STONE

.19

984

.21

1095

.25

1313

.29

1535

.33

1752

.37

1969

898%

CEMENT

.468

2468

.518

2735

.623

3288

.726

3832

.830

4384

.933

4928

SAND

.10

534

.11

592

.13

712

.16

830

.18

949

.20

1067

STONE

.20

1068

.22

1184

.27

1424

.31

1659

.36

1898

.40

2134

8 10 9x

CEMENT

.502

2654

.559

2951

.671

3544

.782

4128

.894

4722

1.005

5306

SAND

.11

575

.12

639

.15

767

.17

894

.19

1022

.22

1149

STONE

.22

1149

.24

1278

.29

1535

.34

1788

.39

2045

.44

2297

62

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—1 ^—3 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.94 Barrels Per Cubic Yard.
Sand Required: — .42 Cubic Yard Per Cubic Yard.
Stone Required; — .84 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

, . &
o S 2

a J 4

Foot

Mil

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 ?H

CEMENT

.877

463

.966

5100

1.053

5562

1.141

6024

1.228

6483

1.317

6955

SAND

.19

1003

.21

1104

.23

1204

.25

1304

.27

1404

.29

1506

STONE

.38

2005

.42

2208

.46

2408

.49

2608

.53

2807

.57

3011

698

CEMENT

.958

5060

1.053

5562

1.150

6074

1.246

6577

1.341

7077

1.438

7589

SAND

.21

1095

.23

1204

.25

1315

.27

1424

.29

1532

.31

1643

STONE

.41

219

.46

2408

.50

2630

.54

2848

.58

3064

.62

3286

7 7 7

CEMENT

.838

4426

.922

4867

1.005

5306

1.090

2756

1.174

6196

1.257

6636

SAND

.18

958

.20

1053

M

1149

.24

1246

.25

1341

.27

1437

STONE

.36

1916

.40

2107

.44

2297

.47

2492

.51

2683

.54

2874

787%

CEMENT

.918

4844

1.009

5327

1.100

5808

1.193

6299

1.284

6780

1.375

7263

SAND

.20

1049

.22

1153

.24

1257

.26

1364

.28

1468

.30

1572

STONE

.-40

2097

.44

2307

.48

2515

.52

2727

.56

2936

.60

3145

7 9 8n

CEMENT

.997

5265

.098

5797

.197

6321

.296

6842

1.397

7376

1.496

7898

SAND

.22

140

.24

255

.26

1368

.28

481

.30

1597

.32

1710

STONE

.43

2280

.48

2510

.52

2737

.56

2963

.60

3194

.65

3420

7 10 9

CEMENT

.077

czox

.185

6258

.294

6833

.401

7395

1.509

7970

.616

8532

XXrt

SAND

.23

231

.26

355

.28

479

.30

601

.33

725

.35

847

STONE

.47

2461

.51

2710

.56

2958

.61

3202

.65

3451

.70

3694

888

CEMENT

.958

5060

.053

5562

.150

6074

.246

6577

.341

7077

.438

7589

SAND

.21

095

.23

204

.25

1315

.27

424

.29

532

.31

643

STONE

.41

2191

.46

2408

.50

2630

.54

2848

.58

3064

.62

3286

« 9 8*

CEMENT

.038

5481

.141

5024

.244

6565

.348

7120

.451

7661

.556

8216

SAND

.22

187

.25

304

.27

1421

.29

541

.31

659

.34

779

STONE

.45

2373

.49

2608

.54

2843

.58

3083

.63

317

.67

3557

8 10 9M
CEMENT

.116

5890

.230

S495

.341

.451

7661

.564

8257

.676

8850

7077

SAND

.24

275

.27

406

.29

1532

.31

659

.34

788

.36

916

STONE

.48

550

.53

2812

.58

3064

.63

3317

.68

3575

.73

3832

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—3 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required:— 1.74 Barrels Per Cubic Yard.
Sand Required: — .53 Cubic Yards Per Cubic Yard.
Stone Required: — .77 Cubic Yards Per Cubic Yard.

Thickness

Width in Feet

in
Inches

9

10

12

14

16

18

4J

3QJ >
CJ <

Foo

Mi

Foo

Mil

Foo

Mil

Foot

Mil

Foo

Mil

Foo

Mile

444

CEMENT

.19

102

.21

112

.25

135

.30

158

.34

181

.38

2039

SAND

.06

31

.07

34

.08

41

.09

48

.10

55

.12

621

STONE

.09

45

.09

49

.11

60

.13

70

.15

80

.17

902

4 5 4%

CEMENT

.22

119

.25

132

.30

158

.35

184

.4(X

211

.45

2380

SAND

.07

36

.08

40

.09

48

.11

56

.12

64

.14

725

STONE

.10

52

.11

58

.13

70

.15

81

.18

93

.20

1053

4 6 5y

CEMENT

.25

135

.28

150

.34

181

.40C

2112

.45

241

.51

2720

SAND

.08

41

.09

45

.10

55

.12

64

.14

73

.16

828

STONE

.11

60

.13

667

.15

80

.18

935

.20

107

.23

1204

5 5 5

CEMENT

.242

27

.268

1415

.322

1700

.376

1984

.43

226

.48

2554

SAND

.07

38

.08

431

.10

517

.11

604

.13

69

.15

778

STONE

.11

565

.12

626

.14

752

.17

878

.19

1004

.21

1130

5 6 $%

CEMENT

.273

442

.305

608

.365

931

.426

2252

.487

2572

.546

2885

SAND

.08

439

.09

490

.11

588

.13

686

.15

783

.17

879

STONE

.12

638

.13

711

.16

854

.19

996

.22

1138

.24

1277

5 7 6^

CEMENT

.306

616

.339

792

.407

152

.477

2518

.545

876

.612

3235

SAND

.09

492

.10

546

.12

655

.15

767

.17

876

.19'

985

STONE

.14

715

.15

793

.18

952

.21

1114

.24

273

.27

431

5 8 7

CEMENT

.338

782

.376

984

.451

380

.525

2776

.602

179

.677

574

SAND

.10

543

.11

604

.14

725

.16

845

.18

968

.21

087

STONE

.15

788

.17

878

.20

053

.23

228

.27

407

.30

582

666

CEMENT

291

535

.322

700

.386

039

.451

380

.515

720

.579

059

SAND

09

467

.10

517

.12

621

.14

725

.16

828

.18

932

STONE

13

679

.14

752

.17

902

.20

053

.23

204

.26

354

676%

CEMENT

322

700

.357

883

.430

269

.501

646

.572

022

.644

J400

SAND

10

517

11

73

.13

691

.15

806

.17

921

.20

036

STONE

14

752

16

833

.19

004

.22

171

.25

337

28

505

64

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—3 MIX.
Quantity in Barrels of Cement— Cubic Yards of Sand—

Cubic Yards of Stone.

Cement Required: — 1.74 Barrels Per Cubic Yard.
Sand Required:— .53 Cubic Yards Per Cubic Yard.
Stone Required:— .77 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

| *» Width in Feet

20

22

24

26

28

30

« £

a & 4

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.430

2269

.472

2490

.515

2720

.559

2949

.602

3179

.644

3400

SAND

.13

691

.14

758

.16

828

.17

898

.18

968

.20

1036

STONE

.19

1004

.21

1102

.23

1204

.25

1305

.27

1407

.28

1505

454^

CEMENT

.501

2647

.550

2902

.600

3170

.651

3437

.701

3704

.750

3960

SAND

.15

806

.17

884

.18

966

.20

1047

.21

1128

.23

1206

STONE

.22

1171

.24

1284

.27

1403

.29

1521

.31

1638

.33

1753

4 6 5n

CEMENT

.572

3022

.630

3325

.687

3630

.745

3932

.802

4235

.860

4538

SAND

.17

921

.19

1013

.21

1106

.23

1198

.24

1290

.26

1382

STONE

.25

1337

.28

1471

.30

1606

.33

1740

.35

1874

.38

2008

5 5 5

CEMENT

.538

2840

.590

3115

.644

3400

.698

3684

.752

3969

.806

4254

SAND

.16

865

.18

949

.20

1036

.21

1122

.23

1209

.25

12%

STONE

.24

1257

.26

1378

.28

1505

.31

1630

.33

1756

.36

1883

CEMENT

.607

3207

.668

3529

.726

3849

.790

4171

.851

4493

.912

4815

SAND

.18

977

.20

1075

.22

1172

.24

1270

.26

1368

.28

1467

STONE

.27

1419

.30

1562

.32

1703

.35

1846

.38

1888

.40

2131

5 7 6H

CEMENT

.680

3591

.748

3950

.816

4308

.884

4667

.952

5025

1.020

5384

SAND

.21

1094

.23

1203

.25

1312

.27

1421

.29

1531

.31

1640

STONE

.30

J589

.33

1748

.36

1907

.39

2065

.42

2224

.45

2382

587

CEMENT

J52

3969

.827

4364

.901

4759

.978

5163

1,053

5556

1.128

5953

SAND

.23

209

.25

329

.27

1450

.30

1573

.32

1693

.34

1813

STONE

.33

756

.37

931

.40

2106

.43

2285

.47

2459

.50

2634

666

CEMENT

.644

3400

.708

3739

.773

4079

.836

4420

.903

4768

.967

5109

SAND

.20

036

.22

139

.24

1242

.25

1346

.28

1452

.29

1556

STONE

.28

505

.31

655

.34

1805

.37

1956

.40

2110

.43

2261

CEMENT

.715

3776

.786

4153

.858

4529

.929

4907

1.002

5291

1.074

5669

SAND

.22

150

.24

265

.26

1380

.28

1495

.31

1612

.33

1727

STONE

.32

671

.35

838

.38

2004

.41

2171

.44

2342

.48

2509

65

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—3 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.74 Barrels Per Cubic Yard.
Sand Required:— .53 Cubic Yards Per Cubic Yard.
Stone Required:— .77 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

ft 1 !

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 7H

CEMENT

.355

1874

.393

2076

.472

2490

.552

2913

.630

3325

.708

3739

SAND

.11

571

.12

632

.14

758

.17

887

.19

1013

.22

1139

STONE

.16

829

.17

919

.21

1102

.24

1289

.28

1471

.31

1655

698

CEMENT

.386

2039

.430

2269

.515

2720

.602

3179

.687

3630

.773

4079

SAND

.12

621

.13

691

.16

828

.18

968

.21

1106

.24

1242

STONE

.17

902

.19

1004

.23

1204

.27

1407

.30

1606

.34

1805

7 7 7

CEMENT

.338

1782

.376

1984

.451

2380

.525

2776

.602

3179

.677

3574

SAND

.10

543

.11

604

.14

725

.16

845

.18

968

.21

1087

STONE

.15

788

.17

878

.20

1053

.23

1228

.27

1407

.30

1582

7 8 7%

CEMENT

.371

1958

.411

2169

.494

2610

.576

3043

.658

3473

.741

3913

SAND

.11

596

.13

660

.15

795

.18

926

.20

1058

.23

1192

STONE

.16

866

.18

959

.22

1155

.25

1346

.29

1537

.33

1732

7 9 8M

CEMENT

.402

2126

.447

2364

.538

2839

.626

3310

.715

3778

.805

4256

SAND

.12

646

.14

721

.16

866

.19

1009

.22

1151

.25

1296

STONE

.18

939

.20

1045

.24

1256

.28

1464

.32

1671

.36

1882

7 10 9

CEMENT

.435

2299

.484

2554

.580

3058

.677

3575

.773

4080

.870

4594

SAND

.13

700

.15

779

.18

932

.20

1090

.23

1240

.27*

1399

STONE

.19

1016

.21

1130

.26

1355

.30

1581

.34

1805

.39

2033

888

CEMENT

.386

2039

.430

2269

.515

2720

.602

3179

.687

3630

.773

4079

SAND

.12

621

.13

691

.16

828

.18

968

.21

1106

.24

1242

STONE

.17

902

.19

1004

.23

1204

.27

1407

.30

1606

.34

1805

898*

CEMENT

.419

2213

.465

2454

.559

2949

.651

3437

.745

3932

.837

4420

SAND

.13

674

.14

747

.17

898

.20

1047

.23

1198

.25

1346

STONE

.19

979

.21

1086

.25

1305

.29

1521

.33

1740

.37

1956

8 10 9*

CEMENT

.451

2383

.501

2648

.602

3181

.701

3705

.802

4239

.901

4760

SAND

.13

726

.15

806

.18

970

.21

1129

.24

1295

.27

1451

STONE

.20

1053

.22

1171

.27

1406

.31

1639

.35

1874

.40

2106

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—3 MIX.
Quantity in Barrels of Cement— Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.74 Barrels Per Cubic Yard.
Sand Required: — .53 Cubic Yards Per Cubic Yard.
Stone Required: — .77 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

ill

Foot

Mile

Foot

MUe

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

687^

CEMENT

.786

4153

.867

4574

.945

4989

.023

403

.101

5815

.181

6238

SAND

.24

1265

.26

1393

.29

520

.31

646

.34

771

.36

900

STONE

.35

1838

.38

2024

.42

2208

.45

2391

.49

2573

.52

2760

698

CEMENT

.860

4538

.945

4989

1.032

5448

1.117

5899

.202

6348

.289

6808

SAND

.26

1382

.29

1520

.31

1659

.34

797

.37

933

.39

2073

STONE

.38

2008

.42

2208

.46

2411

.49

2610

.53

2809

.57

3012

7 7 7

CEMENT

.752

3969

.827

4364

.901

4759

.978

5163

.053

5556

.128

5953

SAND

.23

1209

.25

1329

.27

1450

.30

573

.32

693

.34

813

STONE

.33

1756

.37

1931

.40

2106

.43

2285

.47

2459

.50

2634

7 8 1%

CEMENT

.823

4345

.905

4778

.987

5210

1.070

5650

1.152

6081

1.234

6515

SAND

.25

1323

.28

1455

.30

1587

.33

721

.35

1852

.38

1984

STONE

.36

1923

.40

2114

.44

2305

.47

2500

.51

2691

.55

2883

7 9 8H

CEMENT

.895

4725

.985

5203

1.074

5673

1.162

6138

1.253

6618

1.342

7087

SAND

.27

1439

.30

1585

.33

1727

.35

1873

.38

2017

.41

2162

STONE

.40

2090

.44

2292

.48

2508

.51

2716

.55

2927

.59

3135

7 10 9

CEMENT

.966

5098

1.063

5613

1.161

6127

1.256

6633

1.354

7148

1.449

7653

SAND

.29

1553

.32

1710

.35

1867

.38

2020

.41

2177

.44

2331

STONE

.43

2256

.47

2484

.51

2712

.56

2935

.60

3163

.64

3386

888

CEMENT

.860

4538

.945

4989

1.032

544£

1.117

5899

1.202

6348

1.289

6808

SAND

.26

1382

.29

1520

.31

1659

.34

1797

.37

1933

.39

2073

STONE

.38

2008

.42

7708

.46

241

.49

2610

.53

2809

.57

3012

8 9 8fc

CEMENT

.930

4916

1.023

5403

1.115

5896

1.209

6390

1.300

6873

1.395

7371

SAND

.28

1497

.31

1646

.34

1798

.37

1949

.40

2094

.43

2245

STONE

.41

2175

.45

2391

.49

im

.54

2826

.58

304

.62

3260

8 10 9tt

CEMENT

1.000

5284

1.103

5826

1.202

635C

1.30

6872

1.402

741C

1.503

7939

SAND

.30

1609

.34

1765

.37

1934

.40

2094

.43

22St

.46

2417

STONE

.44

2333

.49

2562

.53

2309

.58

304

.62

yir

.67

3512

67

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR

ROADS, STREETS AND ALLEYS

1— 2— 3^ MIX.

Cubic Yards of Concrete per Linear Foot and per Mile of Pavement
Quantity in Barrels of Cement — Cubic Yards of Sand-
Cubic Yards of Stone.

Cement Required: — 1.61 Barrels Per Cubic Yard.
Sand Required: — .49 Cubic Yards Per Cubic Yard.
Stone Required; — .85 Cubic Yards Per Cubic Yard.

Thickness

Width in Feet

in
Inches

9

10

12

14

16

18

- 2 1

S 3 4

Foot

Mil

Foo

Mil

Foot

Mil

Foot

Mil

Foot

Mil

Foot

Mile

444

CEMENT

.179

944

.196

1044

.238

1257

.279

1470

.313

1674

.357

1886

SAND

.05

28

.06

31

.07

383

.08

447

.10

510

.11

374

STONE

.09

49

.10

55

.13

664

.15

776

.17

884

.19

996

4 5 4%

CEMENT

.209

1104

.23

122

.279

1470

.324

1708

.37C

1955

.417

2202

SAND

.06

336

.07

37

.08

447

.10

520

.11

595

.13

670

STONE

.11

583

.12

646

.15

776

.17

902

.20

1032

.22

1163

4 6 5M

CEMENT

.238

1257

.264

1394

.317

1674

.370

1955

.423

2236

.477

2516

SAND

.07

383

.08

424

.10

510

.11

595

.13

681

.15

765

STONE

.13

664

.14

736

.17

884

.20

1034

.22

1181

.25

1328

5 5 5

CEMENT

.224

1182

.248

1309

.298

1573

.348

1835

.398

2099

.448

2363

SAND

.07

360

.08

398

.09

479

.11

559

.12

639

.14

r719

STONE

.12

624

.13

691

.16

830

.18

969

.21

1108

.24

1249

5 6 5%

CEMENT

.253

335

.282

488

.338

785

.394

2083

.451

2380

.506

2669

SAND

.08

406

.09

453

.10

543

.12

634

.14

724

.15

812

STONE

.13

705

.15

785

.18

943

.21

100

.24

1256

.27

409

5 7 6*

CEMENT

.283

496

.314

658

.377

990

.441

2330

.503

2661

.567

2993

SAND

.09

455

.10

505

.11

606

.13

709

.15

810

.17

911

STONE

.15

790

.17

876

.20

051

.23

230

.27

1405

.30

580

587

CEMENT

.312

1649

.348

837

.417

2202

.486

568

.557

2941

.626

3307

SAND

.10

502

.11

559

.13

670

.15

782

.17

895

.19

006

STONE

.16

870

.18

969

.22

163

.26

356

.29

1553

.33

746

666

CEMENT

.269

1420

.298

573

.357

887

.417

2202

.477

2516

.536

2830

SAND

.08

432

.09

479

.11

574

.13

670

.15

766

.16

861

STONE

.14

750

.16

830

.19

996

.22

163

.25

1329

.28

494

676%

CEMENT

.298

573

.330

742

.3%

2099

.464

449

.530

2797

.596

146

SAND

.09

479

.10

530

.12

639

.14

745

.16

851

.18

958

STONE

.16

830

.17

920

.21

108

.24

293

.28

1476

.31

662

68

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

l—2—3lA MIX.
Quantity in Barrels of Cement— Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required:— 1.61 Barrels Per Cubic Yard.
Sand Required: — .49 Cubic Yards Per Cubic Yard.
Stone Required: — .85 Cubic Yards Per Cubic Yard.

Thickness
in

Inches

Width in Feet

20

22

24

26

28

30

u 8.

1 * *

w u <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.3982099

.436

2304

.476

2516

.517

2729

.557

2941

.596

3146

SAND

.12

639

.13

701

.15

766

.16

831

.17

895

.18

957

STONE

.21

1108

.23

1216

.25

1329

.27

1441

.29

1553

.31

1661

4 5 4%

CEMENT

.464

2449

.509

2685

.555

2933

.602

3180

.649

3426

.694

3664

SAND

.14

745

.15

817

.17

893

.18

968

.20

1043

.21

1115

STONE

.24

1293

.27

1418

.29

1549

.32

1679

.34

1809

.37

1935

4 6 5ys

CEMENT

.530

2797

.583

3077

.636

3358

.689

3639

.742

3919

.795

4199

SAND

.16

851

.18

936

.19

1022

.21

1107

.23

1193

.24

1278

STONE
5 5 5

.28

1476

.31

1624

.34

1773

.36

1921

.39

2069

.4,

2217

CEMENT

.498

2628

.546

2882

.596

3146

.6463408

.696

3672

.745

3936

SAND

.15

800

.17

877

.18

957

.20

1037

.21

1118

.23

1198

STONE

.26

1387

.29

1522

.31

1661

.34

1799

.37

1939

.39

2078

5 6 5%

CEMENT

.562

2967

.618

3265

.675

3561

.731

3859

.787

4157

.844

4455

SAND

.17

903

.19

994

.21

1084

.22

1175

.24

1265

.26

1356

STONE

.30

1567

.33

1724

.36

1880

.39

2037

.42

2195

.45

2352

5 7 6n

CEMENT

.630

3323

.692

3655

.755

3986

.818

4318

.881

4650

.943

4981

SAND

.19

1011 .21

1112

.23

1213

.25

1314

.27

1415

.29

1516

STONE

.33

1754

.37

1930

.40

2105

.43

2280

.46

2455

.50

2630

587

CEMENT

.695

3672

.765

4038

.834

4403

.905

4777

.975

5142

1.043

5508

SAND

.21

1118

.23

1229

.25

1340

.28

1454

.30

1565

.32

1676

STONE

.37

1939

.40

2132

.44

2325

.48

2522

.51

2715

.55

2908

666

CEMENT

.596

3146

.655

3460

.715

3774

.774

4089

.836

4411

.895

4727

SAND

.18

958! .20

1053

.22

1149

.24

1245

.25

1343

.27

1439

STONE

.31

1662

.35

1827

.38

1992

.41

2159

.44

2329

.47

2496

6 7 6K

CEMENT

.662

3494

.728

3843

.794

4191

.860

4540

.927

48%

.993

5245

SAND

.20

1063

.22

1170

.24

1275

.26

1382

.28

1490

.30

1596

STONE

.35

1845

.38

2029

.41

2213

.45

2397

.49

2585

.52

2769

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—3% MIX.

Quantity in Barrels of Cement— Cubic Yards of Sand-
Cubic Yards of Stone.

Cement Required:— J. 61 Barrels Per Cubic Yard.
Sand Required: — .49 Cubic Yards, Per Cubic Yard.
Stone Required:— .85 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

all

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 7M

CEMENT

.371

734

.365

1930

.436

2304

.510

2695

.583

3077

.655

3460

SAND

.10

527

.11

585

.13

701

.15

820

.18

936

.20

053

STONE

.17

915

.19

1019

.23

1216

.27

1423

.31

1624

.35

827

698

CEMENT

.357

887

.398

2099

.477

2516

.557

2941

.636

3358

.715

3774

SAND

.11

574

.12

639

.15

766

.17

895

.19

1022

.22

149

STONE

.19

996

.21

1108

.25

1329

.29

1553

.34

1773

.38

1992

7 7 7

CEMENT

.312

1649

.3481837

.417

2202

.486

2568

.557

2941

.626

3307

SAND

.10

502

.11 559

.13

670

.15

782

.17

895

.19

1006

STONE

.16

870

.18 970

.22

1163

.26

1356

.29

1553

.33

1746

787%

CEMENT

.343

1811

.3802006

.457

2415

.533

2814

.609

3214

.686

3621

SAND

10

551

.12

611

.14

735

.16

857

.19

978

.21

1102

STONE

.18

956

.20

1059

.24

1275

.28

1486

.32

1697

.36

1912

CEMENT

.372

1964

.414

2185

.497

2628

.580

3061

.662

3494

.745

3936

SAND

.11

598

.13

665

.15

800

.18

931

.20

1063

.23

1198

STONE

.20

1037

.22-

1153

.26

1387

.31

1616

.35

1845

.39

2078

7 10 9

CEMENT

.403

2125

.447

2380

.536

2830

.626

3307

.715

3774

.805

4250

SAND

.12

647

.14

719

.16

861

.19

1006

.22

1149

.25

1294

STONE

.21

1122

.24

1248

.28

1494

.33

1746

.38

1992

.43

2244

888

CEMENT

.357

1887

.398

2099

.477

2516

.557

2941

.636

3358

.715

3774

SAND

.11

574

.12

639

.15

766

.17

895

.19

1022

.22

1149

STONE

.19

996

.21

1108

.25

1329

.29

1553

.34

1773

.38

1992

898%

CEMENT

.388

2048

.430

2270

.517

2729

.602

3180

.689

3639

.774

4089

SAND

.12

623

.13

691

.16

830

.18

968

.21

1107

.24

1245

STONE

.20

108

.23

1199

.27

1441

.32

1679

.36

1921

.41

2159

8 10 9^

CEMENT

.417

??0?

.464

2449

.557

2941

.649

3426

.742

3919

.834

4403

SAND

.13

670

.14

745

.17

895

.20

1043

.23

1193

.25

1340

STONE

.22

1163

.24

1293

.29

1553

.34

1809

.39

2069

.44

2325

Table No. 11

QUANTITY OF MATERIAL REQUIRED "FOR
ROADS, STREETS AND ALLEYS

1-^-2— 3 Y2 MIX.

Quantity in Barrels of Cement — Cubic Yards of Sand-
Cubic Yards of Stone.

Cement Required: — 1.61 Barrels Per Cubic Yard.
Sand Required:— .49 Cubic Yards, Per Cubic Yard.
Stone Required:— .85 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

2 ?

s J 4

Poo,

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 ?H

CEMENT

.728

3843

.802

4233

.874

4616

.947

4997

1.019

5381

1.093

5772

SAND

.22

1170

.24

1288

.27

1405

.29

1521

.31

1638

.33

1757

STONE

.38

2029

.42

2235

.46

2437

.50

2638

.54

2841

.58

3047

698

CEMENT

.795

4199

.874

4616

.955

5041

1.034

5458

1.113

5873

1.193

6298

SAND

.24

1278

.27

1405

.29

1534

.31

1661

.34

1788

.36

1917

STONE

.42

2217

.46

2437

.50

2661

.55

2882

.59

3101

.63

3325

7 7 7

CEMENT

.695

3672

,765

4038

.834

4403

.905

4777

.975

5142

1.043

5508

SAND

.21

1118

.23

1229

.25

1340

.28

1454

.30

1565

.32

1676

STONE

.37

1939

.40

2132

.44

2325

.48

2522

.51

2715

.55

2908

7 8 7%

CEMENT

.762

4020

.837

4421

.913

4820

.990

5228

1.066

5627

1.141

6028

SAND

.23

1224

.25

1346

.28

1467

.30

1591

.32

1713

.35

1835

STONE

.40

2122

.44

2334

.48

2545

.52

2760

.56

2971

.60

3182

7 9 8^

CEMENT

.828

4370

.911

4811

.993

5245

1.075

5678

1.159

6121

1.241

6554

SAND

.25

1330

.28

1464

.30

1596

.33

1728

.35

1862

.38

1995

STONE

.44

2307

.48

2540

.52

2769

.58

2998

.61

3232

.66

3460

7 10 9

CEMENT

.838

4717

.984

5194

1.074

5670

1.162

6137

1.253

6614

1.341

7081

SAND

.27

1436

.30

1581

.33

1726

.35

1868

.33

2013

.41

2155

STONE

.47

2491

.52

2742

57

2994

.61

3240

.66

3491

.71

3738

8 8 8

CEMENT

.795

4199

.874

4616

.955

5041

1.034

5458

1.113

5873

1.193

6298

SAND

.24

1278

.27

1405

.29

1534

.31

1661

.34

1788

.36

1917

STONE

.42

2217

.46

2437

.50

2661

.55

2882

.59

3101

.63

3325

898^

CEMENT

.861

4548

.947

4999

1.032

5448

1.119

5909

1.204

6358

1.291

6818

SAND

.26

1384

.29

1521

.31

1658

.34

1798

.37

1935

.39

2075

STONE

.45

2401

.50

2639

.54

2876

.59

3120

.64

3357

.68

3600

8 10 9H

CEMENT

.925

4988

1.021

5390

1.113

5873

1.204

6358

1.298

6852

1.391

*344

SAND

.28

1488

.31

1641

.34

1788

.37

1935

.39

2081

.42

2235

STONE

.49

2581

.54

2846

.59

3101

.64

3357

.69

3618

.73

3878

71

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—4 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone,

Cement Required: — 1.48 Barrels Per Cubic Yard.
Sand -Required: — .45 Cubic Yards Per Cubic Yard,
Stone Required: — .90 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

. I f

aw >
0 <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

MHe

Foot

Mile

Foot

Mile

444

CEMENT

.164

867

.182

96!

.219

1156

.256

1351

.292

1539

.329

1735

SAND

.05

264

.06

292

.07

351

.08

411

.09

468

.10

527

STONE

.10

527

11

584

.13

703

.16

822

.18

936

.20

1055

4 5 4%

CEMENT

.192

1015

.213

1125

.256

1351

.297

1570

.340

1797

.383

2025

SAND

.06

309

.06

342

.08

411

.09

477

.10

546

.12

616

STONE

.12

617

.13

684

.16

822J .18

955

.21

1093

.23

1231

4 6 5*

CEMENT

.219

1156

.243

1282

.292

153$ .340

1797

.389

2071

.438

£313

SAND

.07

351

.07

390

.09

468 .10

546

.12

625

.13

703

STONE

.13

703

.15

780

.18

936^ .21

1093 .24

1250

.27

1407

555

CEMENT

.206

1086

.227

1203

.274

144fl .320

1687

.366

1930

.411

2173

SAND

.06

330

.07

366

.08

440

.10

513

.11

587

.13

661

STONE

.13

661

.14

732

.17

879

.19

1026

.22

1174

.25

1321

5 6 5%

CEMENT

.232

1227

.259

1368

.311

1641

.363

1915

.414

2187

.465

2454

SAND

.07

373

.08

416

t09

499

.11

582

.13

665

.14

746

STONE

.14

746

.16

832

.19

998

.22

1165

.25

1330

.28

1492

5 7 6K

CEMENT

.260

1375

.289

1524

.346

1829

.406

2142

.463

2446

.521

7751

SAND

.08

418

.09

464

.11

556

.12

651

.14

744

.16

837

STONE

.16

836

.18

927

.21

1112

.25

1302

.28

1488

.32

1673

5 8 7

CEMENT

.287

1516

.3201687

.383

2025

.447

2361

.512

2704

.576

3040

SAND

.09

461

.10

513

.12

616

.14

718

.16

822

.18

924

STONE

.17

922

.19

1026

.23

1231

.27

1436

.31

644

.35

1849

666

CEMENT

.247

1305

.274

1446

.329

1735

.383

2025

.438

2313

.493

2602

SAND

.08

397

.08

440

.10

527

.12

616

.13

703

.15

791

STONE

.15

794

.17

879

.20

1055

.23

1231

.27

407

.30

1582

676%

CEMENT

.274

1446

.303

1601

.366

1930

.426,2251

.487

2571

.548

2892

SAND

.08

440

.09

487

.11

587

.13

684

.15

782

.17

879

STONE

.17

879

.18

974

.22

1174

.26

1369

.30

563

.33

759

72

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—4 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.48 Barrels Per Cubic Yard.
Sand Required: — .45 Cubic Yards Per Cubic Yard.
Stone Required: — .90 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

bC "is fe

•o 5 >
u o <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.366

1930

.401

2118

438

2313

.475

2509

.512

2704

.548

2892

SAND

.11

587

.12

644

.13

703

.14

763

.16

822

.17

879

STONE

.22

1174

.24

1288

.27

1407

.29

1526

.31

1644

.33

1759

4 5 4%

CEMENT

.426

2251

.468

2469

.511

2697

.554

2923

.596

3149

.638

3368

SAND

.13

684

.14

751

.16

820

.17

889

.18

958

.19

1024

STONE

.26

1369

.28

1501

.31

1640

.34

1778

.36

1915

.39

2048

4 6 5n

CEMENT

.487

2571

.536

2828

.585

3087

.633

3345

.682

3602

.731

3860

SAND

.15

782

.16

860

.18

939

.19

1017

.21

1095

.22

1174

STONE

.30

1563

.33

1720

.36

1877

.39

2034

.41

2191

.44

2347

5 5 5

CEMENT

.457

2415

.502

2649

.548

2892

.593

3133

.639

3376

.685

3619

SAND

.14

734

15

806

.17

879

.18

953

.19

1026

.21

1100

STONE

.28

1469

.31

1611

.33

1759

.36

1905

.39

2053

.42

2200

5 6 5%

CEMENT

.517

2728

.568

3001

.620

3274

.672

3548

.724

3821

.776

4095

SAND

.16

829

.17

913

.19

995

.20

1079

.22

1162

.24

1245

STONE

.31

1659

.35

1825

.38

1991

.41

2157

.44

2324

.47

2490

5 7 6*

CEMENT

.579

3055

.636

3360

.694

3664

.752

3969

.810

4274

.867

4579

SAND

,18

929

.19

1022

.21

1114

.23

1207

.25

1300

.26

1392

STONE

35

1858

.39

2043

.42

2228

.46

2414

:49

2599

.53

2785

5 8 7

CEMENT

.639

3376

.703

3712

.767

4048

.832

4391

.895

4727

.959

5063

SAND

19

1026

.21

1129

.23

1231

.25

1335

.27

1437

.29

1539

STONE

.39

2053

.43

2257

.47

2462

.51

2670

.54

2875

.58

3079

666

CEMENT

.548

2892

.602

3181

.657

3469

.712

3759

.768

4055

.823

4345

SAND

.17

879

.18

967

.20

1055

.22

1143

,23

1233

.25

1321

STONE

.33

1759

.37

1934

.40

2HO

.43

2286

.47

2466

.50

2642

676%

CEMENT

608

3212

.669

3533

.730

3852

.790

4174

.852

4501

.913

4822

SAND

.18

977

.20

1074

.22

1171

.24

1269

.26

1368

.28

1466

STONE

.37

1953

.41

2148

.44

2343

.48

2538

.52

2737

.55

2932

73

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—4 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.48 Barrels Per Cubic Yard.
Sand Required: — .45 Cubic Yards Per Cubic Yard.
Stone Required: — .90 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width

in Feet

9

10

12

14

16

18

ill

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 7n

CEMENT

.302

1594

.332

1766

.401

2118

.469

2478

.536

2828

.602

3181

SAND

.09

485

.10

537

.12

644

.14

753

.16

860

.18

967

STONE

.18

969

.20

1074

.24

1288

.29

1507

.33

1720

.37

1934

698

CEMENT

.329

1735

.366

1930

.438

2313

.512

2704

.585

3087

.657

3469

SAND

.10

527

.11

587

.13

703

.16

822

.18

939

.20

1055

STONE

.20

1055

.22

1174

.27

1407

.31

1643

.36

1877

.40

2110

777

CEMENT

.287

1516

.320

1687

.383

2025

.447

2361

.512

2704

.576

3040

SAND

.09

461

.10

513

.12

616

.14

718

.16

822

.18

924

STONE

.17

922

.19

1026

.23

1231

.27

1436

.31

1644

.35

1849

787%

CEMENT

.315

1665

.349

1844

.420

2220

.490

2587

.559

2954

.630

3329

SAND

.10

506

.11

561

.13

675

.15

787

.17

898

..19

1012

STONE

.19

1012

.21

1121

.26

1350

.30

1573

.34

1796

.38

2024

7 9 8n

V

CEMENT

.342

1806

.381

2008

.457

2415

.533

2813

.608

3212

.685

3619

SAND

.10

549

.12

611

.14

734

i >16

855

.18

977 .21

1100

STONE

.21

1098

.23

1221

.28

1469

.32

1711

.37

1953 .42

2201

7 10 9

CEMENT

.370

1954

.411

2173

.493

2602

.576

3040

.657

3469

.740

3907

SAND

.11

594

.13

661

.15

791

.18

924

.20

1055

.23

1188

STONE

.23

1188

.25

1321

.30

1582

.35

1849

.40

2110

.45

2376

888

CEMENT

.329

1735

.366

1930

.438

2313

.512

2704

.585

3087

.657

3469

SAND

.10

527

.11

587

.13

703

.16

822

.18

939

.20

1055

STONE

.20

1055

.22

1174

.27

1407

.31

1643

.36

1877

.40

2110

898%

CEMENT

.357

1883

.395

2087

.475

2509

.554

2923

.633

3353

.712

3759

SAND

.11

572! .12

635

.14

763

.17

889

.19

1017

.22

1143

STONE

.22

1145 .24

1269

.29

1526

.34

1778

.39

2034

.43

2286

8 10 9n

CEMENT

.383

2025

.426

2251

.512

2704

.596

3149

.682

3602

.767

4048

SAND

.12

616

.13

684

.16

822

.18

958

.21

1095

.23

1231

STONE

.23

1231

.26

1369

.31

1644

.36

1915

.41

2191

.47

2462

74

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2—4 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.48 Barrels Per Cubic Yard.
Sand Required:— .45 Cubic Yards Per Cubic Yard.
Stone Required: — .90 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

ill

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 7K

CEMENT

669

3533

737

3891

.804

4243

.870

4594

.937

4946

1.005

5306

SAND

.20

074

.22

183

24

290

.26

1397

.28

1504

.31

1613

STONE

41

2148

.45

2366

.49

2580

.53

2794

.57

3008

.61

3227

698

CEMENT

.731

3860

.804

4243

.878

4634

.950

5017

1.023

5399

1.097

5790

SAND

.22

174

.24

1290

.27

1409

.29

1526

.31

1642

.33

1760

STONE

.44

2347

.49

2580

.53

2818

.58

3051

.62

3283

.67

3521

7 7 7

CEMENT

.639

3376

.703

3712

.767

4048

.832

4391

.895

4727

.959

5063

SAND

19

1026

.21

1129

.23

1231

.25

1335

.27

1437

.29

1539

STONE

.39

2053

.43

2257

.47

2462

.51

2670

.54

2875

.58

3079

787%

CEMENT

.700

36%

.770

4064

.839

4431

.910

4806

.980

5173

1.049

5541

SAND

.21

1124

.23

1236

,26

1347

.28

1461

.30

1573

.32

1685

STONE

.43

2247

.47

2471

.51

2695

.55

2922

.60

3146

.64

3370

7 9 8H

CEMENT

.761

4017

.838

4422

.913

4822

9)89

5220

1.066

5627

1.133

6025

SAND

.23

1221

.25

1345

.28

1466

.30

1587

.32

1711

.35

1831

STONE

.46

2443

.51

2689

.56

2932

60

3174

.65

3422

.69

3664

7 10 9

CEMENT

.821

4336

.904

4774

.987

5213

1.069

5642

1.151

6080

1.233

6509

SAND

.25

1319

.27

1452

.30

1585

.32

1715

.35

1849

.37

1979

STONE

.50

2637

.55

2903

.60

3170

.65

3431

.70

3697

.75

3958

888

CEMENT

.731

3860

.804

4243

.878

4634

.950

5017

1.023

5399

1.097

5790

SAND

.22

1174

.24

1290

.27

1409

.29

1526

.31

1642

.33

1760

STONE

44

2347

.49

2580

.53

2818

.58

3051

.62

3283

.67

3521

8 9 8M

CEMENT

.792

418

.870

4594

.949

5008

1.029

5432

1.107

5845

1.187

6268

SAND

.24

127

.26

1397

.29

1523

.31

1652

.34

1777

.36

1906

STONE

.48

2543

.53

2794

.58

3046

.63

3303

67

3554

.72

3812

8 10 9*

CEMENT

.851

4493

.938

4955

1.023

5399

1.107

5845

1.193

6299

1.279

6752

SAND

.26

136*

.29

1507

.31

164

.34

1777

.36

1915

.39

2053

STONE

.52

2732

.57

301

.62

328

.67

3554

.73

383C

.78

4106

75

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2^—5 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required:— 1.21 Barrels Per Cubic Yard
Sand Required:— .46 Cubic Yards Per Cubic Yard.
Stone Required: —.92 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

ill

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

134

709

149

785

.179

945

209

1105

.238

1258

.269

1418

SAND

.05

270

.06

299

.07

359

.08

420

.09

478

.10

539

STONE

.10

539

.11

597

.14

719

16

840

.18

957

.20

1078

4 5 4%

CEMENT

.157

830

.174

920

.209

1105

.243

1284

.278

1469

.313

1655

SAND

.06

316

.07

350

.08

420

.09

488

.11

558

.12

629

STONE

12

631

.13

699

16

840

18

976

.21

1117

.24

1259

4 6 5M

CEMENT

.179

945

.198

1048

.238

1258

.278

1469

.318

1681

.358

1891

SAND

.07

359

.08

398

.09

478

.11

558

.12

639

.14

719

STONE

.14

719

.15

797

.18

957

.21

1117

.24

1278

.27

1438

555

CEMENT

.168

888

.186

984

.224

1182

.261

1379

.299

1578

.336

1776

SAND

06

338

.07

374

.09

449

.10

524

.11

600

.13

675

STONE

.13

675

.14

748

.17

899

.20

1049

.23

1200

.26

1351

CEMENT

.190

1003

.212

1118

.254

1342

.296

1566

.339

1788

.380

2006

SAND

.07

381

.08

425

.10

510

.11

595

.13

680

.14

763

STONE

.14

763

.16

850

.19

1020

.23

1190

.26

1360

.29

1525

5 7 6^
CEMENT

.212

1124

.236

1246

.283

1496

.332

1751

.379

2000

.426

2249

SAND

.08

427

.09

474

.11

569

.13

666

.14

760

.16

855

STONE

.16

855

.18

948

.22

1137

.25

1331

.29

1521

.32

1710

5 8 7

CEMENT

.235

1239

.261

1379

.313

1655

.365

1930

.419

2211

.471

2485

SAND

.09

471

.10

524

.12

629

.14

734

.16

840

.18

945

STONE

.18

942

.20

1049

.24

1259

.28

1467

.32

1681

.36

1890

666

CEMENT

.202

1067

.224

1182

.269

1418

.313

1655

.358

1891

.403

2127

SAND

.08

406

.09

449

.10

539

.12

629

.14

719

.15

809

STONE

.15

811

.17

899

.20

1078

.24

1259

.27

1438

.31

1617

6 7 6%

CEMENT

.224

1182

.248

1309

.299

1578

.348

1840

.398

2102

.448

2364

SAND

.09

449

.09

498

.11

600

.13

700

.15

799

.17

899

STONE

.17

899

.19

995

.23

1200

.26

1400

.30

1598

.34

1798

76

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—2^—5 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.21 Barrels Per Cubic Yard.
Sand Required: — .46 Cubic Yards Per Cubic Yard.
Stone Required:— .92 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

0, $ fi

a 3 1

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.299

1578

.328

1732

.358

1891

.388

2051

.419

2211

.448

2364

SAND

.11

600

.12

658

.14

719

.15

780

.16

840

.17

899

STONE

.23

1200

.25

1317

.27

1438

.30

1559

.32

1681

.34

1798

4 5 4%

CEMENT

.348

1840

.382

2018

.417

2205

.453

2390

.488

2575

.512

2754

SAND

.13

700

.15

767

.16

838

.17

909

.19

979

.20

1047

STONE

.26

1400

.29

1535

.32

1676

.34

1817

.37

1958

.40

2094

4 6 5H

CEMENT

.398

2102

.438

2312

.478

2524

.518

2735

.558

2945

.598

3156

SAND

.15

799

.17

879

.18

960

.20

1040

.21

1120

.23

1200

STONE

.30

1598

.33

1758

.36

1919

.39

2079

.42

2239

.45

2399

555

CEMENT

.374

1975

.410

2166

.448

2364

.485

2562

.523

2760

.560

2958

SAND

.14

751

.16

823

.17

899

.18

974

.20

1049

.21

1125

STONE

.28

1501

.31

1647

.34

1798

.37

1948

.40

2099

.43

2249

565%

CEMENT

.422

2230

.465

2454

.507

2677

.549

2900

.592

3124

.634

3348

SAND

.16

848

.18

933

.19

1018

.21

1103

.22

1188

.24

1273

STONE

.32

1696

.35

1866

.39

2035

.42

2205

.45

2375

.48

2546

5 7 6H

CEMENT

.473

2497

.520

2747

.567

29%

.615

3245

.662

3494

.709

3744

SAND

.18

949

.20

1044

.22

1139

.23

1234

.25

1328

.27

1423

STONE

.36

1899

.40

2088

.43

2278

.47

2467

.50

2657

.54

2846

587

CEMENT

.523

2760

.575

3035

.627

3309

.680

3590

.732

3865

.784

4139

SAND

.20

1049

.22

1154

.24

1258

.26

1365

.28

1469

.30

1574

STONE

.40

2099

.44

2307

.48

2516

.52

2730

.56

2938

.60

3147

666

CEMENT

448

2364

.492

7600

.537

2836

.582

3073

.628

3315

.673

3553

SAND

.17

899

.19

989

.20

1078

.22

1168

.24

1260

.26

1351

STONE

.34

1798

.37

1977

.41

2156

.44

2337

.48

2521

.51

2701

CEMENT

.497

2626

.547

2888

.597

3150

.646

3412

.697

3680

.747

3942

SAND

.19

r998

.21

1098

.23

1197

.25

1297

.26

1399

.28

1499

STONE

.38

19%

.42

21%

.45

2395

.49

2594

.53

2798

.57

2997

77

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR

ROADS, STREETS AND ALLEYS

1—2 H— 5 MIX.

Quantity in Barrels of Cement — Cubic Yards of Sand-
Cubic Yards of Stone.

Cement Required.—- 1.21 Barrels Per Cubic Yard.
Sand Required:- .46 Cubic Yards Per Cubic Yard.
Stone Required: -.92 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

SJ §>

3 o <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 7M

CEMENT

.247

1303

.273

1444

.328

1732

.384

2026

.438

2312

.492

2600

SAND

.09

495

.10

549

.12

658

.15

770

.17

879

.19

989

STONE

.19

991

.21

1098

.25

1317

.29

1540

.33

1758

.37

1977

698

CEMENT

.269

1418

.299

1578

.358

1891

.419

2211

.478

2524

.537

2836

SAND

.10

539

.11

600

.14

719

.16

840

.18

960

.20

1078

STONE

.20

1078

.23

1200

.27

1438

.32

1681

.36

1919

.41

2156

777

CEMENT

.235

1239

.261

1379

.313

1655

.365

1930

.419

2211

.471

2485

SAND

.09

471

.10

524

.12

629

.14

734

.16

840

.18

945

STONE

.18

942

.20

1049

.24

1259

.28

1467

.32

1681

.36

1890

CEMENT

.258

1361

.286

1508

.344

1815

.401

2115

.457

2415

.515

2721

SAND

.10

518

.11

573

.13

690

.15

804

.17

918

.20

1035

STONE

.20

1035

.22

1146

.26

1380

.30

1608

.35

1836

.39

2069

7 9 8M

CEMENT

.280

1476

.311

1642

.374

1975

.436

2300

.497

2626

.560

2958

SAND

.11

561

.12

624

.14

751

.17

874

.19

998

.21

1125

STONE

.21

1122

.24

1248

.28

1501

.33

1749

.38

1996

.43

2349

7 10 9

CEMENT

.303

1597

.336

1776

.403

2127

.471

2485

.537

2836

.605

3194

SAND

.12

607

.13

675

.15

809

.18

945

.20

1078

.23

1214

STONE

.23

1214

.26

1351

.31

1617

.36

1890

.41

2156

.46

2429

888

CEMENT

.269

1418

.299

1578

.358

1891

.419

2211

.478

2524

.537

2836

SAND

.10

539

.11

600

.14

719

.16

840

.18

960

.20

1078

STONE

.20

1078

.23

1200

.27

1438

.32

1681

.36

1919

.41

2156

898%

CEMENT

.292

1539

.323

1706

.388

2051

.453

2390

.518

2735

.582

3073

SAND

.11

585

.12

649

.15

780

.17

909

.20

1040

.22

1168

STONE

.22

1170

.25

1297

.30

1559

.34

1817

.39

2079

.44

2337

8 10 9M

CEMENT

.313

1655

.348

1840

.419

2211

.488

2575

.558

2945

.627

3309

SAND

.12

629

.13

700

.16

840

.19

979

.21

1120

.24

1258

STONE

.24

1259

.26

1400

.32

1681

.37

1958

.42

2239

.48

2516

78

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS. STREETS AND ALLEYS

1— 2K— • 5 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required:— 1.21 Barrels Per Cubic Yard.
Sand Required:— .46 Cubic Yards Per Cubic Yard.
Stone Required: — .92 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

-cf u >

u u <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

687*

CEMENT

.547

2888

.603

3181

.657

3469

.711

3757

.766

4044

822

4338

SAND

.21

1098

.23

1209

.25

1319

.27

1428

.29

1537

.31

1649

STONE

.42

2196

.46

2419

.50

2638

.54

2857

.58

3075

.62

3298

698

CEMENT

.598

3156

.657

3469

.718

3789

.777

4102

.836

4414

.897

4734

SAND

.23

1200

.25

1319

.27

1440

.30

1559

.32

1678

.34

1800

STONE

.45

2399

.50

2638

.55

2881

.59

3119

.64

3356

.68

3599

7 7 7

CEMENT

.523

2760

.575

3035

.627

3309

.680

3590

.732

3865

.784

4139

SAND

.20

1049

.22

1154

.24

1258

.26

1365

.28

1469

.30

1574

STONE

.40

2099

.44

2307

.48

2516

.52

2730

.56

2938

.60

3147

7 8 7%
CEMENT

.572

3021

.629

*323

.686

3623

.744

3929

.801

4229

.858

4530

SAND

.22

1149

.24

1263

.26

1377

.28

1494

.30

1608

.33

1722

STONE

.44

2297

.48

2526

.52

2754

.57

2987

.61

3215

.65

3444

798*

CEMENT

.622

3284

.685

3615

.747

3942

.808

4268

.871

4600

.933

4926

SAND

.24

1248

.26

1374

.28

1499

.30

1622

.33

1749

.35

1873

STONE

.47

2497

.52

2749

.57

2997

.61

3245

.66

3498

.71

3745

7 10 9

CEMENT

.672

3545

.739

3903

.807

4262

.874

4613

.941

4971

1.008

5322

SAND

.26

1348

.28

1484

.31

1620

.33

1754

.36

1890

.38

2023

STONE

.51

2696

.56

2978

.61

3240

.66

3507

.72

3779

.77

4046

388

CEMENT

.598

3156

.657

3469

.718

3789

.777

4102

.836

4414

.897

4734

SAND

.23

1200

.25

1319

.27

1440

.30

1559

.32

1678

.34

1800

STONE

.45

2399

.50

2638

.55

2881

.59

3119

.64

3356

.68

3599

898%

CEMENT

.647

3418

.711

3757

.776

4095

.841

4441

.905

4778

.970

5124

SAND

.25

1300

.27

1428

.29

1557

.32

1688

.34

1817

.37

1943

STONE

.49

2599

.54

2857

.59

3113

.64

3376

.69

3633

.74

3896

8 10 9*

CEMENT

.696

3674

767

4051

.836

4414

.905

4778

.975

5150

1.045

5520

SAND

.26

1397

.29

1540

.32

1678

.34

1817

.37

1958

.40

2099

STONE

.53

2793

.58

3080

.64

3356

.69

3633

.74

3916

.79

4197

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—3—6 MIX.

Quantity in Barrels of Cement— Cubic Yards of Sand-
Cubic Yards of Stone.

Cement Required: — 1.02 Barrels Per Cubic Yard.
Sand Required:— .47 Cubic Yards Per Cubic Yard.
Stone Required: — .93 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

u a
a | |

Foo

Mile

Foot

Mil

Foot

Mile

Foot

Mile

Foot

Mil

Foot

Mile

687^
CEMENT

.20*

109S

.231121

.27t

146C

.32

1707

.369

194

.41!

2192

SAND

.10

5M

.11

56

.13

673

.15

78

.17

89

.19

1010

STONE

.19

1002

.21

1105

.25

1331

.29

155

.34

177

.38

1999

698

CEMENT

.22

1195

.25:

!133

.302

1594

.35

1864

.403

212

.452

2391

SAND

.10

551

.12

61

.14

73

.16

85

.19

980

.21

1102

STONE

.21

1090

.23

121

.28

145

.32

1699

.37

1940

.41

2180

111

CEMENT

.19

1044

.220116

.264

139

.30*

162

.353

1864

.397

2095

SAND

.09

481

.10

53

.12

62

.14

750

.16

859

.18

965

STONE

.18

952

.20

1060

.24

1272

.28

148

.32

1699

.36

1910

787%

CEMENT

.21

1146

.241

127

.290

1530

.336

1783

.386

2036

.435

2294

SAND

.10

528

.11

586

.13

705

.16

822

.18

938

.20

1057

STONE

.20

1045

.22

1159

.26

1395

.31

1626

.35

1856

.40

2092

7 9 8n

CEMENT

.23

1244

.262

1384

.315

1665

.367

1939

.419

2213

.472

2494

SAND

.11

573 .12

638

.15

767

.17

893

.19

1020

.22

1149

STONE

.21

1135

.24

1262

.29

1518

.33

1768

.38

2018

.43

2274

7 10 9

CEMENT

.255

1346

.284

1497

.340

1793

.397

2095

.453

2391

.5!0

2693

SAND

.12

620

.13

690

.16

826

.18

965

.21

1102

.24

1241

STONE

.23

1228

.26

1365

.31

1635

.36

1910

.42

2180

.47

2455

888

CEMENT

.226

195

.252

1330

.302

1594

.353

864

.403

2128

.452

2391

SAND

.10

551

.12

613

.14

735

.16

859

.19

980

.21

1102

STONE

.21

090

.23

1213

.28

1454

.32

699

.37

1940

.41

2180

898%

CEMENT

.246

297

.272

1438

.327

1729

.381

015

.437

2305

.491

2591

SAND

.11

598

.13

663

.15

797

.18

928

.20

1062

.23

1194

STONE

.22

183

.25

1311

.30

1576

.35

837

.40

2102

.45

2362

8 10 9y3

CEMENT

.264

395

.294

551

.353

1864

.411

171

.470

2483

.528

2790

SAND

.12

643

.14

715

.16

859

.19

000

.22

144

.24

1285

STONE

.24

272

.27

1415

.32

699

.37

979

.43

2264

.48

2544

fin

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—3—6 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.02 Barrels Per Cubic Yard.
Sand Required: — .47 Cubic Yards Per Cubic Yard.
Stone Required:— .93 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

!« *

2 o <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

6 8 7M

CEMENT

.461

2435

.508

2682

.554

2924

.600

3167

.646

3409

.693

3657

SAND

.21

1122

.23

1236

.26

1349

.28

1459

.30

1571

.32

1685

STONE

.42

2220

.46

2445

.50

2666

.55

2888

.59

3108

.63

3334

698

CEMENT
SAND

.504
.23

2660
1226

.554
.26

2924
1347

.605
.28

3194
1472

.655
.30

3458
1593

.705
.32

3721
1715

.756
.35

3990
1839

STONE

.46

2425

.50

2666

.55

2912

.60

3153

.64

3393

,69

3638

111

CEMENT

.441

2327

.485

2558

.528

2790

.573

3026

.617

3259

.661

3489

SAND

CTYMVIC

.20

Af\

1072

1 1 *>l

.22

A A

1179

IITl

.24

1285

.26

1394

.28

1501

.30

1608

STONE

.40

2121

.44

2332

.48

2544

.52

2759

.56

2970

.60

3182

7 8 I*

CEMENT

.482

2547

.530

2801

.578

3054

.627

3312

.675

3565

.723

3819

SAND

.22

1174

.24

129)

.27

1407

.29

1526

.31

1643

.33

1760

STONE

.44

2322

.48

2554

.53

2784

.57

3020

.62

3250

.66

3482

7 9 8M

CEMENT

.524

2768

.577

3048

.629

3323

.681

3598

.734

.786

4152

3878

SAND

.24

1276

.27

1404

.29

1531

.31

1658

.34

1787

.362

1913

STONE

.48

2524

.53

2779

.57

3030

.62

3280

.67

3536

.72

3786

7 10 9

CEMENT

.566

2989

.623

3291

.680

3592

.736

3888

.794

4190

.850

4486

SAND

.26

1377

.29

1516

.31

1655

.34

1792

.37

1931

.39

2067

STONE

.52

2725

,57

3000

.62

3275

.67

3545

.72

3820

.77

4090

888

CEMENT

.504

2660

.554

2924

.605

3194

.655

3458

.785

3721

.756

3990

SAND

.23

1226

,26

1347

.28

1472

.30

1593

.32

1715

.35

1839

STONE

.46

2425

.50

2666

.55

2912

.60

3153

.64

3393

.69

3638

8 9 By,

CEMENT

.546

2882

.6003167

,654

3452

.709

3743

.763

4028

,818

4320

SAND

,25

1328

.28

1459

.30

1590

.33!

1725

.35

1856

.38

1990

STONE

.50

2627

.55

2888

.60

3147

.65

3413

.70

3673

.75 i

3939

8 10 9^

CEMENT

.587

3097

.647

3415

.705

3721

.763

4028

.822

4341

.881

4653

SAND

.27

1427

.30

1574

.32

1715

.35

1856

.38

2000

.41

2144

STONE

.53

7873

.59

3114

.64

3393

.70

3673

.75

3958

.80

4243

81

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—3—6 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.02 Barrels Per Cubic Yard.
Sand Required:— .47 Cubic Yards Per Cubic Yard.
Stone Required: — .03 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

9

10

12

14

16

18

,1 1

3 3 X

Foot

Vtile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.113

598

.125

662

.151

797

.176

931

.200

1061

.226

1195

SAND

.05

275

.06

305 .07

367

.08

429

.09

489

.10

551

STONE

.10

545

.11

604

.14

726

.15

849

.18

967

.21

1090

4 5 4n

CEMENT

.133

700

.147

775

.176

931

.205

1082

.235 238

.264

1395

SAND

.06

322

07

357

.08

429

.09

499

.10

571

.12

643

STONE

.12

638

.13

707

.16

849

.19

987

.21

129

.24

1272

4 6 SH

CEMENT

.151

797

.167

883

.201

061

.235

1238

.268

417

.302

1594

SAND

.07

367

08

407

.09

489

.11

571

.12

653

.14

735

STONE

.14

726

J5

805

.18

967

.21

1129

.24

292

.28

1454

555

CEMENT

.142

749

.157

829

.189

997

u220

163

.252

330

.284

1497

SAND

.07

345

07

382

.09

459

.10

536

.12

613

.13

690

STONE

.13

683

.14

756

.17

909

.20

060

.23

213

.26

1365

5 6 5%

CEMENT

.160

846

179

942

.214

1131

.250

1320

.286

508

.320

1691

SAND

.07

390

.08

434

.TO

521

.12

608

.13

695

.15

779

STONE

.15

771

.16

859

.20

1031

.23

1203

.26

375

.29

1542

5 7 6n

CEMENT

.180

948

.199

1051

.239

1261

.279

1476

.319

1686

.359

18%

SAND

.08

437

09

484

.11

581

.13

68

.15

777

.17

871

STONE

.16

864

.18

958

.22

1149

.25

1346

.29

1537

.32

1729

587

CEMENT

.198

1044

220

1163

.264

1395

.308

162

.353

1864

.397

2095

SAND

.09

4811 '10

536! .12

643

.14

750

.16

859

.18

965

STONE

.18

952

.20

1060

.24

1272

.28

148

.32

1699

.36

1910

666

CEMENT

.170

900

.189

993

.226

1195

.264

139

.302

1594

.34C

1793

SAND

.08

415

09

459

.10

55

.12

64

.14

735

.16

1826

STONE

.16

82C

.17

90S

.21

1090

.24

127

.28

1454

.31

1635

676^

CEMENT

.189

993

.209

lift

.252

133C

.294

155

.336

1772

.377

1993

SAND

.09

45S

.10

5TC

.12

61

.14

71

.15

8U

.17

918

STONE

.17

90S

.19

10(X

.23

121

.27

141

.31

1615

.34

1817

82

Table No. 11

QUANTITY OF MATERIAL REQUIRED FOR
ROADS, STREETS AND ALLEYS

1—3—6 MIX.
Quantity in Barrels of Cement — Cubic Yards of Sand —

Cubic Yards of Stone.

Cement Required: — 1.02 Barrels Per Cubic Yard.
Sand Required: — .47 Cubic Yards Per Cubic Yard.
Stone Required: — .93 Cubic Yards Per Cubic Yard.

Thickness
in
Inches

Width in Feet

20

22

24

26

28

30

* 1 1

u o <

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

Foot

Mile

444

CEMENT

.252

1330

.276

1460

.302

1594

.327

1729

.353

1864

.377

993

SAND

.12

613

.13

673

.14

735

.15

797

.16

859

.17

918

STONE

.23

1213

.25

1331

.28

1454

.30

1576

.32

1699

.34

1817

4 5 4%

CEMENT

.294

1551

.322

1701

.352

1858

.381

2015

.411

2171

.440

2322

SAND

.14

715

.15

784

.16

856

.18

928

.19

1000

.20

1070

STONE

.27

1415

.29

1551

.32

1694

.35

1837

.37

1979

.40

2117

CEMENT

.336

1772

.369

1949

.403

2128

.437

2305

.470

2483

.504

2660

SAND

.15

816

.17

898

.19

980

.20

1062

.22

1144

.23

1226

STONE

.31

1615

.34

1777

.37

1940

.40

2102

43

7764

.46

2425

5 5 5

CEMENT

.315

1665

.346

1826

.377

1993

.409

2159

.441

2327

.472

2494

SAND

.15

767

.16

841

.17

918

.19

995

.20

1072

.22

1149

STONE

.29

1518

.32

1665

.34

1817

.37

1968

.40

2121

.43

2274

5 6 5«

CEMENT

.360

1880

.392

2069

.427

2256

.463

2445

.499

2644

.534

2822

SAND

.16

866

.18

953

.20

1040

.21

1127

.23

1214

.25

1300

STONE

.32

1714

.36

1886

.39

2057

.42

2229

.45

2401

.49

2573

5 7 6H
CEMENT

.399

2105

.439

2315

.478

2526

.518

2736

.558

2946

.598

3156

SAND

.18

970

.20

1067

.22

1164

.24

1261

.26

1357

.28

1454

STONE

.36

1920

.40

2111

.44

2303

.47

2494

.51

2686

.54

2877

5 8 7

CEMENT

.441

2327

.485

2558

.528

2790

.573

3026

.617

3259

.661

3489

SAND

.20

1072

.22

1179

.24

1285

.26

1394

.28

1501

.30

1608

STONE

.40

2121

.44

2332

.48

2544

.52

2759

.56

2970

.60

3182

666

CEMENT

.377

1993

.415

2)92

.453

2391

.491

2591

.529

2795

.567

2995

SAND

.17

918

.19

1010

.21

1102

.23

1194

.24

1288

.26

1380

STONE

.34

1817

.37

1999

.41

2180

.45

2362

.48

2548

.52

2730

6 7 6H

CEMENT

.419

2213

.461

2435

.503

2655

.545

2876

.588

3102

.629

3323

SAND

.19

1020

.21

1122

.23

1223

.25

1325

.27

1429

.29

1533

STONE

.38

2018

.42

2220

..46

2421

.50

767?

.54

2828

.57

3030

S4

CHAPTER 4.

MISCELLANEOUS NOTES FOR SUPERIN-
TENDENT AND FOREMAN

Forms

Various methods of building and erecting
forms, and other important essentials related to
their use, have been more fully discussed elsewhere.
There are, however, a number of precautions which
should always be observed which are of such im-
portance that repetition of mention can be excused.

Forms should be built exactly as called for by
the drawings unless proved impractical. The su-
perintendent should be able to determine whether
forms are sufficiently strong to support the load of
concrete that will be placed upon them and should
see that they are sufficiently braced so that they will
neither collapse nor sag when filled. They should be
cleaned of all refuse or rubbish before any concrete
is placed. This is particularly true of column forms,
but special reference to column form does not mean
that any part of the inspection is to be slighted.

Reinforcing steel must be properly placed and
when in place should be carefully checked against
the drawings to make certain that the required
amount has been used and is in proper position.

Many failures have been caused by weakness of
supports for concrete forms and centering. If the
forms shake or vibrate considerably when work is in
progress, it is almost certain that such disturbance
will affect the concrete while hardening. An interfer-
ence of this kind during the hardening of the concrete
impairs the effectiveness of the cement as a binder.

Forms should be so placed and so supported,
particularly when the uprights rest upon the earth,
as to prevent warping, twisting or sagging. The
maximum safe loads for wood posts of various
lengths and sections are given below. Knowing the
length of post, total weight of concrete and form to
be supported and the economical number of posts,
the load per post and size can readily be determined.

85

A corner post carries only one-half of the load car-
ried by the side post, while a side post carries one-
half the load that must be borne by the inside one.

Table No. 12

MAXIMUM SAFE LOAD FOR WOOD COLUMNS

Length in Feet

Minimum Dimensions

4 in.

6 in.

8 in.

5

9,400

6

8,800

7

8,200

8

7,500

20,700

9

6,900

19,800

10

6,300

18,900

37,700

11

17,900

36,400

12

17,000

35,200

14

15,100

32,700

16

30,200

18

27,600

20

25,100

Example :— Flat slab 14 feet by 17 feet 8 inches,
weighing approximately 60,000 pounds, 16 posts
can be spaced economically in four rows of 4 each.
There will be 4 corner posts, 8 side posts and 4 in-
side posts — 16 posts.

4 corner posts carry load of 1 inside postal

8 side posts carry load of 4 inside post&=4

4 inside posts carry load of 4 inside posts— 4

Number of posts of equal load 9

Maximum load per post— -—• — ==6,666 Ibs.

Length of post 6 feet 0 inches.
From the table we find one 4 by 4 post 6 feet
long will carry safely a load of 8,800 pounds,
since posts should never be less than 4 by 4
inches and this size will answer in this case.
In filling forms, care should be taken to place
the proper quantities of concrete at one time. It
should be placed in layers no thicker or deeper
than can be properly consolidated and caused to
unite with concrete previously placed. The forms
for a slab and beam should be filled at the same
time. If necessary to discontinue work, good judg-
ment should be exercised as to the best place to
make such a stop so as not to leave a permanent

86

line of cleavage that will affect the final strength
of the structure.

Careful Supervision over Proportioning
and Mixing Necessary

At all times while concreting is in progress, the
contractor's superintendent or foreman should keep
careful watch over the manner in which the concrete
is being proportioned and mixed, so that there will be
no question but that specification requirements are
being complied with. Cement is sold by the barrel
but is usually received on the job in bags or sacks,
four of such containers corresponding to a so-called
barrel. At all times careful watch should be kept of
the aggregates being used to make certain that definite
proportions called for are not changed, due to careless-
ness of some of the workmen, by being carelessly mea-
sured, nor that unscreened aggregates are being substi-
tuted for the separate volumes of fine and course
aggregates specified.

In no instance should forms or centering be re-
moved until it is positively known that the concrete
has hardened sufficiently to have the required strength,
not only to carry its own weight but any weight that
may be placed on it during subsequent processes of
construction. Concrete hardens much more rapidly
during warm than in cold, damp weather. Retaining
walls that are to withstand earth pressure should not
be subjected to such pressure until all possibility of
injury from load has passed. There is no good guide
for form removal other than that acquired by long ex-
perience, which enables the superintendent or foreman
to place proper value upon the conditions under which
the concrete has been hardening. Extraordinary pre-
cautions should be taken when it comes to removing
supports from floor slabs, roofs, arches and similar
classes of work. The length of time that forms are
left in place should be much longer in cold than in
warm weather. Somewhat of a guide can be obtained
by making cubes or cylinders of concrete at the same
time as the concrete in the job is placed. These should
be examined later and tested, if necessary, to deter-
mine whether the concrete is of proper strength. Yet
such tests must not be relied upon as an invariable
guide.

87

Concreting in Cold Weather

Experience has proved the possibility of carrying
on many classes of concrete work under conditions
which a few years ago would have been thought un-
favorable. There are contracting firms who specialize
on concrete work in cold weather. Such lengthening
of the ordinary concreting season has been made pos-
sible by the application of such precautions as heating
the sand, pebbles or broken stone and water so that
sufficient warmth is added to the concrete mixture to
carry it through the period necessary for early hard-
ening. All materials except the cement are heated so
that the concrete when placed has a temperature of
from seventy to eighty degrees Fahrenheit. After
being placed, it is protected so that the mass will re-
tain this heat and the possibility of freezing be pre-
vented for at least forty-eight hours. Work so done
will be as successful as that carried on under the usual
favorable conditions. This is true of practically all
classes of concrete work except concrete road or street
construction, which it is not advisable to continue
when temperatures fall so low that continued freez-
ing may be expected.

No concrete should be laid when temperatures
may go to freezing or lower, unless precautions are ta-
ken to heat materials as described. It is better to
suspend work than to run the chance of a severe drop
in temperature which may injure the concrete if it is
frozen more than once before thoroughly hardened.
Concrete floors are laid in buildings during freezing
weather by enclosing the frame of the structure with
with tarpaulins and maintaining heat within the en
closure by means of stoves, or "salamanders".

In heating materials, a number of methods may be
employed. Mixing water can readily be heated by
leading the water through a pipe coil around which a
coke or wood fire is kept. Or it can be heated in
barrels by discharging steam from the boiler plant on
the job into the barrels filled with water; or if there
is no such plant, then the required quantities can
usually be heated in large kettles. The sand and peb-
bles or broken stone can be heated by improvising pipe
stoves made out of sections of metal smoke stack*

and piling the materials over and about a piece of
such stack with fire built inside. Materials should be
turned or raked over frequently so those next to the
stove will not be damaged by over-heating, and those
farther away will be sure to have the frost drawn
from them. Another method frequently employed to
heat the stone or sand is to insert a small perforated
pipe through which live steam is passed. It is abso-
lutely necessary to get all frost out of the aggregate
before putting it in a concrete mixture.

Very often on account of the limited space in the
street or at the site of the work, or because of unusual
conditions, it is not easy to improvise the desired
method of heating material. A heating attachment
which was originally designed for use in mixing asphal-
tic concrete, has been very sucessfully used to mix
concrete in winter where it is desirable to have all
materials thoroughly heated. The heating unit con-
sists of an oil tank for supplying fuel to the double
burner oil furnace and a blower which forces the
heated air and flame into the inside of the drum, thus
insuring the necessary degree of warmth to the con-
crete which, with other measures of protection, prevent
it from freezing in the forms until after early harden-
ing has been completed.

Various methods are used to protect the concrete
after it has been placed, from possible damage due to
freezing. Coverings of canvas, straw or similar mate-
rial can be used on flat surfaces, while vertical faces
also may be covered with canvas hung away from
the forms; or the forms can be battened and building
paper tacked on the battens, thus introducing a dead
space that does much to insulate against extreme cold.
For mass work sometimes the forms themselves afford
sufficient protection when cold is not extreme. Pad-
ing the forms with hay or straw in extreme cold
weather provides excellent protection.

Manure should never be placed directly on con-
crete as a means of protection against freezing. Exper-
iments have proved that in the process of decomposi-
tion the chemical changes which may take place in the
manure are likely to produce nitric acid. Although
this does not always happen, it may, and if it does

che result will be a scaling or pitting of the surface.
Besides, manure placed directly in contact with a con-
crete walk or floor is certain to cause considerable
staining of the surface, which in most cases would be
objectionable.

Curing of Concrete

Many persons have the impression that the hard-
ening process which takes place in concrete is due to
drying. Nothing will do more to "weaken concrete
than to allow it to dry out rapidly after placed. For
this reason concrete work requires certain protection
in warm weather to safeguard it, just as it requires
protection in cold weather. When sun or hot dry
winds strike fresh concrete much of the water intro-
duced in mixing rapidly evaporates. Water is neces-
sary to the hardening of concrete. Generally speak-
ing, the protection that should be given to concrete
during hot weather is essentially the same for all
classes of concrete work. Ways and means of apply-
ing the protection may differ slightly, but all aim
toward the same end.

Pavements in general, which properly include
floors, sidewalks, driveways, etc., have a relatively
larger area exposed to the atmosphere than has mass
concrete. Wall sections have a still greater area
exposed, usually two sides. Either canvas or earth
covering should be applied to concrete surfaces to
protect against rapid drying. In hot weather it is
very desirable to stretch canvas on frames over con-
crete street and highway pavement immediately after
the surface has been struck off and floated, and to keep
such a covering in place until the surface has hard-
ened enough to permit applying a protective layer of
earth. Walls of structures should be protected either
by frequent sprinkling or by hanging wet canvas over
them. When temperatures are not extremely high,
sprinkling of the concrete alone, if done at sufficiently
frequent intervals, will often give the desired protec-
tion.

Mass work, such as foundation walls entirely be-
low ground, heavy abutments, and retaining walls,
do not require the same extreme measures of protec-
tion as does work of thinner section. Leaving forms

in place and occasionally sprinkling or wetting down
the work for several successive days will often be all
that is necessary.

Roof slabs require essentially the same protection
as thin concrete walls, since two surfaces are essen-
tially exposed. Roofs should be covered with moist
earth or sand, sprinkled freely, and otherwise be pro-
tected like pavements. Stucco work may be ruined
by lack of proper protection while hardening. Much
of the cracking and crazing of stucco has been due to
neglect in protecting the work.

Joining New Concrete to Old

New and old concrete can be joined only with
great difficulty and the strength of such a connection
is always uncertain. It is only by using the greatest
care that a cement finish coat can be made to adhere
to a concrete base that has completely hardened.
The joining of old and new concrete work is best done
by thoroughly cleansing it from all dust and loose
particles, sometimes chipping the surface, saturating
it with water, painting it with a cement grout paint
mixed to the consistency of thick cream, and while this
coating is fresh, immediately placing the new concrete
or applying the plaster coat as the case may be. As
cement begins to harden within a very short time
after being combined with water, the grout paint
should be applied only a short distance in advance of
the work going on. The more nearly clean aggregate
faces are exposed to the new concrete or plaster to be
applied, the better will be the bond secured between
old and new work.

Concrete Surface Finish

Concrete surfaces are susceptible of a great variety
of pleasing finishes that have practically no limit
other than that imposed by individual ingenuity of
the workers on the job. The types of surface finish
may be obtained as follows:

(1) Leaving the concrete as it is when forms are removed;

(2) Using a mortar facing or plaster;

(3) Hammer dressing or tooling;

(4) Using special concrete mixtures;

(5) Coloring the surface;

(6) Washing the surface to expose aggregates selected with that en d
in view.

91

The^kind of surface finish that will result from
leaving the concrete as it is when forms are removed
depends upon two factors. Such a surface will be
truly characteristic of concrete if the forms have
been well made of planed lumber and the concrete
was carefully and thoroughly spaded next to form
faces while being placed. If these essentials have been
observed there is rarely or never any need of subse-
quent work on the surface for ordinary concrete
structures. A few pebble pockets may be in the sur-
face, and these can readily be pointed up immediately
after forms are removed by using a mortar of cement
mixed with the same number of parts of sand as were
used in the concrete mixture. For example: If the
concrete was a 1 :2 :4 mixture, then a 1 :2 sand-cement
mortar should be used for pointing. If a 1 :3 :6 : mix-
ture, then a 1 :3 mortar should be used for pointing.
This is necessary in order that the spots where the
work is pointed up will not have a color different from
the remainder of the surface.

A mortar facing or plaster may be considerably
varied. Usually when such finish is intended for
monolithic construction or for concrete block con-
struction the concrete when placed in the forms is
not thoroughly spaded next to form faces, thus in-
tentionally leaving exposed pebble pockets on the
surface which will insure a better key for the plasterer.
In block construction where stucco is to follow the
block are rough cast for the purpose of providing a
better bond for the mortar coat. But the mortar coat
itself is susceptible to considerable variation. It can
be given different floated finishes by using a steel
trowel, a wood float, or a wood float covered with a
piece of carpet or burlap. Each of these methods of
smoothing the finished surface produces a different
texture.

The plaster coat may also be varied by tinting,
but for such work only mineral pigments should be
used because other colors lack permanence. In a plas-
ter coat finish another variation consists of pebble -
dash finish which is secured by throwing pebbles of
uniform size, thoroughly washed and wet, against
the soft mortar coat. To make these pebbles adhere
better it is advisable to wet them with a thin cement

92

grout immediately before throwing against the surface
being treated.

Concrete surfaces can be tool or hammer dressed
in just the same manner as stone surfaces are so treat-
ed. For successful hammer dressing or tooling, it is
very necessary that the aggregates used shall be of
uniform hardness throughout and have been selected
in anticipation of such surface finish. If pebbles are
used for aggregate and have considerable variation
in hardness, the hammer dressing will cause some of
the pebbles to break out of the surface and the finish
will not be so pleasing as where aggregates of uniform
hardness throughout are used. Also, the appearance
of the work will be considerably influenced by the
time which the concrete is allowed to stand before
being hammered. If too soft, particles of concrete
will be loosened. If the surface is too hard, the work
will take more time and hence be more expensive

Surface finish of great attractiveness can be se-
cured by using special concrete mixtures. These are
usually facing mixtures in which the aggregates are
selected sands and stone chips, the facing being placed
at the same time as the mass of concrete by using a
metal septum in the forms. After forms have been
removed and the concrete has hardened, the aggre-
gates may be exposed in a number of ways. The sur-
face may be tooled if so desired, or it may be scrubbed
down with water if forms can be removed within
the first twelve hours or so before the cement is thor-
oughly hardened. If the work must be delayed until
later, then an acid wash and scrubbing will remove
the surface film of cement and expose the colored
aggregate. The possible variations of colored texture
to a surface, possible by using special concrete mix-
tures containing selected aggregates, is limited only
by the variety of aggregates that may be obtained;
also by the various mixtures that may be made by
combining two or more of these aggregates.

White cement, white sand, marble dust, quartz
screenings, mica spar, granite, marble chips of var-
ious colors, crushed, screened, graded selected chips
singly or in combination are used in special concrete
mixtures for various colored surfaces. In fact where

93

colors are desired, this method of securing them is
certain to result in permanence.

Aggregates are sometimes exposed by using a sand
blast which removes the plastic or pasty effect given
to the concrete by the forms, and produces a granu-
lated finish somewhat similar to sandstone but not so
uniform because the aggregates are likely to be irregu-
larly exposed. For the hammering or tooling, pneu-
matic hammers are often used, especially where large
areas must be treated in this way. Finishing with
pneumatic hammers produces a very attractive sur-
face for buildings in which concrete has appropriate
architectural features. The bush hammer is used for
intricate portions of the work and other plane portions
are dressed with the pneumatic hammer. Owing to
the cost of equipment necessary to produce sand blast
finish, this method is not used except on expensive
structures where the one item of finish does not bear a
great relation to the total cost of the work.

In finishing concrete surfaces with carborundum
stone, only the form marks can be removed by hand
methods without excessive labor. Many irregulari-
ties cannot be entirely obliterated. A machine recent-
ly placed on the market is designed to remove all
marks, giving a perfectly straight surface. The pro-
cess is a dry one. The machine is essentially a revolv-
ing disc in which are mounted a number of hardened
steel cutter wheels, which roll on the surface to be
dressed, and remove the material by a chipping
action. The disc is driven through a flexible shaft
by an electric motor, carried by the operator. The
cutting action can be made to give a surface
resembling that obtained by a bush hammer, which
offers a good bond for float or other finish.

There are also on the market several floor sur-
facing machines intended for use in finishing terrazzo
floors, or in grinding down the usual cement floor
surfaces where it is desired to obtain a finish similar
to terrazzo.

94

CHAPTER 5.
^FORMS FOR CONCRETE CONSTRUCTION

Care in Manufacture of Forms

No part of concrete construction requires more
care than the making and use of the forms in which
the concrete is placed to harden. The appearance
as well as the safety of the finished work is gov-
erned in a large degree by the care used in making
and erecting the forms. Frequently such work is
so carelessly done that ends of upright supports
or props rest on soft earth in such a manner that
beams, girders or other portions of a structure sag
out of true intended line. Often, sides of beam and
girder forms, when these members are to be deep,
are sometimes so poorly built and braced as to
bulge or warp.

Forms supporting the concrete for floors fre-
quently are not propped up with sufficiently strong
timbers and so bulge under the weight of concrete,
usually resulting in a continual sagging of the form
while the concrete is hardening, thus resulting in
permanent cracks on the under side of the slab.
This naturally prevents the floor from having the
strength for which it was designed.

Contractor responsible for forms

In all cases, care in the construction of the form
work is very evident in the appearance of the fin-
ished work. Usually it will be found that the care
and judgment displayed in building and erecting
forms will be proof of similar care exercised
throughout the construction and the results of this,
other things being equal, will insure a safe build-
ing of fine appearance.

Construction of forms should be left to the con-
tractor since he has the responsibility for the work
until it is completed. Naturally, however, there
should be necessary cooperation between represen-
tative of the engineer and architect, so that no mis-

95

interpretation of specifications will be responsible
for forms not in strict keeping with the work's re-
quirements. "The contractor's drafting forces should
be impressed with the responsibility of careful de-
sign of forms, so that in every respect the finished
structure may conform to the architect's and engi-
neer's plans. In all instances the engineer should
control the time for form removal on any engineer-
ing construction and his inspectors should be quali-
fied to insure the safety of the structure by intelli-
gent inspection of falsework and supports.

Many types of forms are used in concrete con-
struction. Wood and steel are the materials most
commonly used. Forms may vary from the most
simple to the most elaborate, depending upon the
nature of the work and its engineering or architec-
tural details. Some forms are intentionally built for
use once only. Others are and may properly be
planned for repeated use, thus insuring considerable
economy of form cost with respect to any one job.

Perhaps the most extensive use of steel forms
is in connection with the manufacture of various
classes of concrete products such as block, brick,
tile, sewer pipe, concrete trim-stone, etc. Most of
such forms or molds are in reality a part of the ma-
chine used to make or form the product. However,
steel forms are used extensively in various other
classes of concrete construction. Some of these
forms are patented, perhaps with particular refer-
ence to a patent also covering a so-called system
of construction. Many of them are, however,
adaptable to any type of monolithic concrete work.
Among the examples of use of steel forms are those
used in connection with monolithic sewer construc-
tion, bridge arches, culverts and such circular struc-
tures as silos, tanks, chimneys, etc.

Some ornamental concrete products, such as
garden furniture, trimstone and statuary, are cast in
plaster, glue or sand molds. Such work, however,
is generally confined to a central plant, therefore
hardly comes in for description in what is intended
to cover principles of field work of concrete form
construction.

Form Economy

A great amount of material and labor is required
in the construction of some forms on engineering
structures. It is evident, therefore, that the cost of
this work is not a small part of the cost of the fin-
ished building, and by exercising care in design
much material and labor can be saved. It may be
best in some cases to draw up sketches from which
the carpenters who are to build forms can work
and thus insure least waste of material.

The greatest economy is gained by building
forms so that they can be repeatedly used. It is
not uncommon to construct a ten-story building by
using throughout the form work employed for the
first three stories. This fact should be borne in
mind in the design of reinforced concrete structures
because it is frequently cheaper to keep the columns
of the same dimension throughout in order to save
the cost of changing forms. That is more true now
than ever in view of the great increase in cost of
labor and the scarcity of materials. Where beam
and girder construction is used, consideration of
form cost as against the use of a slight increased
quantity of concrete will often determine whether
it would be more desirable to reduce the size of
section or leave it the same size as other corre-
sponding sections of the building.

Economy in form construction results from de-
vising ways and means to fasten sections together
and in position on the work so that the least
amount of nailing will be required. Every nail that
is driven home gives trouble when the forms are
taken down, and, because of careless handling, may
result in much injury to forms, not to mention in-
jury to concrete which has not thoroughly hard-
ened, from the hammering and knocking necessary
to dismantle forms. In many cases wedges,
clamps, ties, brackets and a variety bf fastening de-
vices other than nails can be used, thus consider-
ably reducing the labor to set and take down forms
and also resulting in prolonging their life for use
a greater number of times.

97

Safety Dependent on Form Construction

The safety of a reinforced concrete floor, as well
as that of the entire structure, may be jeopardized
by faulty form construction. Many of the failures
of reinforced concrete, if not most of them, can be
traced directly to weakness in the forms used, due
to faulty construction of their supports or the false
work. For example, if forms for beams and girders
are supported by struts of insufficient strength,
causing a collapse of the form in one part, the
probability is that the forms of the whole floor will
collapse with it and deposit its contents on the floor
below. A load suddenly applied in this manner to
the floor below might cause collapse of the whole
building, since the accident would probably take
place at a time when none of the concrete had at-
tained the strength ultimately to be realized.

In order that there may be no doubt regarding
the safety of forms, they should be carefully in-
spected before any of the concrete is placed. Up-
right supports and braces must be examined to. de-
termine that they are sufficiently strong to carry
the weight of the wet concrete. Frequently, false
work and braces are improperly placed and do not
have sufficient support. It is also not uncommon
to find forms braced against green masonry and
brick work and struts secured with a few wire nails
where they should have been notched into support-
ing timbers and well spiked in position.

Standardization of Panels

In the construction of forms, it is often possible
to standardize a set of panels that will permit of
considerable latitude in setting up, thus making
re-use of the same set of forms possible a large
number of times. Sometimes such panels are metal
lined with galvanized sheeting in order to prolong
their life and at the same time insure a better ap-
pearing finished surface to the work.

Wood Forms

Where wood forms are used most of the work
of cutting and erecting forms is done on the build-

98

ing site. However, for some classes of work such
as foundations for relatively small structures like
dwellings, standard panels are used and if carefully
handled may be re-used a number of times, On
account of the cost of form construction, any suc-
cessful attempt to standardize sections so that wood
forms can be used repeatedly is likely to prove
profitable. Some of the various so-called form sys-
tems which have already been mentioned are
adaptable to a variety of construction uses other
than the particular system of construction for which
originally devised.

The kind of lumber to use for form construc-
tion depends to a considerable extent on the kind
available and whether the material after first use is
to be again used in similar work; also, whether the
building is to have many floors of the same design
and construction or whether only two or three
stories. Ordinarily, good material should be used
in form work, for it permits good carpenter work
and also smooth, true concrete work. To support
forms it is the custom to use as cheap a grade of
rough, sound lumber as can be purchased. For the
sheathing, or that portion of the form in contact
with the concrete, it is best to use a good grade of
well seasoned hard pine because such material pos-
sesses both strength and grain of sufficient close-
ness to prevent the form boards from splintering
badly. Norway pine, when obtainable, is one of
the best materials. The hardwoods are too costly
and too expensive to work. The softer woods do
not permit of repeated use, although for exception-
ally fine surface finish and detail, it is sometimes
necessary to use soft grades of pine because of the
ease with which carpentry can be done on the
forms to reproduce the surface wanted.

If the forms are to be used once only, sheathing
is generally made up of 1-inch dressed material. If
they are to be used several times, the side and bot-
tom form boards of beams and girders are made of
either \y2 or 2-inch dressed planks. Shores and
supports for the centering generally consist of
rough 3 by 4-inch studding. Timbers as large as

99

4 by 6, 6 by 8, and 8 by 10 may be used to brace
and secure form work where the masses of concrete
to be supported are exceptionally heavy.

Sliding Forms

In some instances sliding forms are used in cer-
tain classes of construction, notably in the erection
of circular grain tanks or other buildings which it
is intended shall be truly monolithic throughout.
Such forms, as the name implies, are kept moving
continually upward as concrete is placed. In gen-
eral, sliding forms consist of wide outer and inner
panels, operated by means of jacks which derive
their support from vertical rods or pipes embedded
in the concrete. The use of sliding forms requires
continuous placing of concrete for twenty-four
hours daily so that the forms may be moved up-
ward slowly at a steady and uniform rate, thus pre-
venting concrete from adhering to them. In the
use of silding forms it is essential that at all points
the forms be kept in exact horizontal and vertical
relation to each other. These requirements indi-
cate that although the system is quite simple, ex-
perience and constant watchfulness must be on the
job to obtain the best results. Also the system of
jacking up the forms must permit of positive con-
trol and there must be no slipping of the jack on
its support.

Sliding forms are usually made fast to an upper
and lower wale, consisting of 2-inch planks with
overlapping joints. In circular concrete construc-
tion, one edge of these planks is cut to a radius of
the wall surface plus or minus the thickness of the
sheathing. Therefore, there is an inside and out-
side pair of wales cut to segments corresponding
to the curve of the outside and the inside of the
wall respectively. To these built up wales, 1-inch
sheathing) about four feet long is nailed usually
with triangular bracing between the wales to give
the forms required rigidity. The yokes are at-
tached at intervals to these forms and may be en-
tirely of wood, although the head piece is often
made of steel plates so as to insure little variation

100

in the separation of forms and .to give a rigid
member to take the lifting action of the jacks.

Jacks used are of several different types, some
of which are patented. Two types are common.
Both of these work on the jack screw principle. A
common type of jack consists of a hollow screw
fitted at its top with a turning head and at its bot-
tom with a device commonly known as a ratchet,
or "dog," for gripping a vertical jack rod which is
embedded in the concrete. The jack rod passes up
through the center of the jack, which in turn passes
through the threaded head piece of the yoke. By
turning the turning head with a bar, the yoke is
caused to move up, taking the forms with it. Suc-
cessive turnings of the jacks through the same
angle will thus cause every portion of the forms
to move the same distance. A strict regulation of
the amount of turning which each turning head is
given is absolutely necessary to correct operation
of the forms.

Another type of jack consists of a threaded rod
fitted with a collar which bears on a ly^-inch pipe
embedded in the concrete. The threaded rod
passes through the head piece of the yoke and is
fitted with a turning head. The pipe is made in
3-foot lengths, cut square at the ends and without
threads. The lower end of the threaded jack rod
extends down through the 3-foot length of pipe and
6 inches into the pipe below. This keeps all of
the 3-foot lengths of pipe in line, while the col-
lar bearing on the top of the uppermost pipe fur-
nishes a positive support to the jack. When the
forms have been raised the full distance of their
travel for one position of the jacks, the clutch is
released, the jack moved up and a short length of
rod or pipe, as the case may be, placed on top of
and in line with those already embedded in the
wall. The ratchet then engages the rod and the
work proceeds. When rods are used, the successive
short lengths are connected by sleeves.

Sliding forms have been used for a considerable
variety of structures. These include standpipes,
water tanks, grain tanks, grain elevators, mill

101

'ar-d. chimneys. The system is also adapted
to the construction of hollow concrete piers and
warehouses or walls, although it has so far been
but little used in such construction. When such
forms are used by experienced contractors in the
construction of mill and elevator buildings, window
openings can easily be provided for and cross
beams from one wall to another also can be con-
structed without special difficulty.

Dry Form Lumber Desirable

Form lumber should be free from shakes, rot
and knots. Knots and similar imperfections leave
their imprint on the finished surface of the concrete
and in addition weaken the lumber, hence the
forms. Air seasoned lumber is better than kiln
dried. The latter will swell and bulge at the joints,
while green lumber will shrink if not kept wet, re-
sulting in the opening of cracks through which
water carrying cement will leak when the concrete
is placed. Even for rough work, lumber that is
dressed at least on one side and two edges is best
for form sheathing so as to make the boards fit
closely together. The planed surface will also re-
duce the labor of removing and cleaning forms.
Tongued and grooved stock, as well as ship-lap is
often used for sheathing. Beveled edge stock is
preferred by some because if the lumber swells, the
edges will slip past each other without causing a
warping or bulging of the boards. Form sheathing
should be of uniform thickness to prevent uneven-
ness in the concrete surface.

Cost of Forms

The cost of forms varies within a wide range.
One of the most accurate methods of estimating the
cost of wood forms is to figure the board measure
of lumber and the hardware required, the carpenter
labor per thousand board measure to erect, the
labor of taking down and cleaning forms, and the
cost of transporting lumber to and from the job. A
certain percentage of the cost of form lumber
should be charged to the job. What this shall be

102

can be learned only from carefully compiled data
covering a number and variety of jobs that will dis-
close how long forms may be used repeatedly. The
amount of skilled and common labor required to
make, erect and dismantle forms, depends upon how
complicated they are and the conditions under
which the men work. The amount of carpenter
labor per thousand board measure of lumber for
form work is often difficult to estimate. A carpen-
ter experienced on concrete form work can accom-
plish more than one whose experience has been
confined to general building construction. Experi-
enced form carpenters bear in mind that forms
must, if possible, be designed and built to permit
salvage and further use, therefore, do no more cut-
ting of lumber than necessary. They also plan the
forms so that they may easily be taken down with
least damage.

Along with all other commodities lumber has
increased in cost. Consequently, it costs more to
make wood forms than it used to. For that very
reason greater care in making forms with respect
to cutting and fitting the various pieces as well as
greater care in erecting and dismantling forms is
likely to pay better than ever. It should be pos-
sible to use forms several times and the greater the
number of times they can be used, the lower the
percentage of original cost to be charged against
any one job. For certain classes of construction,
form lumber can be used ten times. Seldom should
more than twenty-five per cent of the first cost be
charged to one use unless there is an unusual
amount of cutting of stock lengths.

Wetting Forms

In dry, hot weather it is common to wet down
forms immediately before placing concrete in them.
This assists to prevent concrete from sticking to
the forms and also keeps the forms from absorbing
water from the concrete, necessary to its harden-
ing. Each time after taking down and before using
again, forms should be thoroughly cleaned of all ad-
hering concrete.

103

Centering and Falsework

The construction of centering and false work
for reinforced concrete bridges must be sufficiently
strong to carry the weight of the wet concrete of
the completed structure without deflection or move-
ment. All such form work must be securely
braced against failure from the pressure of con-
crete. The principal requirement, however, is that
the centering be so arranged that it may be readily
dropped away when the concrete has hardened suf-
ficiently to be self-sustaining and it is desired to
remove the forms. Probably the best method is to
use wedges of hardwood under main uprights or
under the false work supporting the lagging, then
these can be backed out, thus allowing the center-
ing to settle under them. Another method is to
use what is known as a sand box, which consists
of a tight metal box fitted with a plunger upon
which the uprights stand. The box is filled with
sand and in it is a small aperture which can be
closed with a screw plug or some other way. When
desired to drop the centering, the aperture is
opened, allowing the dry sand to flow out, thus
permitting the plunger and centering to settle.
Sometimes centering is built on screw jacks and
where several arch rings are to be built parallel
with each other, the entire centering is built on
trucks or rollers carried on a track. In this way
when one arch ring has been completed, the false
work may readily be shifted to the new position.

.

104

CHAPTER 6.
USE OF REINFORCING STEEL IN CONCRETE

Need for Reinforcement

Reinforced concrete is defined as a combination
of concrete and metal, preferably steel of certain
determined quality, the metal being so placed as
regards position and quantity that the concrete and
the metal both take and resist the strains which
they can best withstand.

Concrete is about ten times as strong in com-
pression as in tension. Plain concrete — that is,
concrete without any reinforcement in it — would
have to be unnecessarily massive to possess the
required strength as subjected to tension in con-
struction. As a matter of fact, it would be found
impossible to design most structures of concrete
were it not that steel is embedded in it to provide
the tensile strength which concrete lacks and at the
same time fully utilize its compressive strength. In
mass work where the load is placed immediately
upon concrete — that is, where the load is one of
compression entirely — reinforcement is seldom if
ever used, but great economy of design as well as
the great utility of concrete has resulted from
proper disposition of reinforcement in it.

Quality of Reinforcing Steel

Any quality of steel will not do for reinforce-
ment. Usually a certain quality is specified, that is
steel having a certain chemical composition and
given physical properties. Such steel, if properly
embedded in concrete of correct proportions and
consistency so that everywhere the concrete will
bond or adhere perfectly to the metal, takes the
pulling and bending strains because the adhesion
between the concrete and the steel prevents the lat-
ter from slipping in the mass. These facts make
it possible to use concrete in many ways that
would be impracticable were it not reinforced.

105

Position of Steel

In the design of concrete structures, the quan-
tity and position of steel are indicated on the plans.
It is important that no less a quantity be used than
called for and still more important that the position
of the steel as shown be strictly secured in the pro-
cess of construction.

The position of steel is determined by the na-
ture of the loads to which the structural member
or portion of the building is to be subjected and
also to insure that it is covered with sufficient con-
crete to protect it from prolonged exposure to fire
and from corrosion due to possible penetration
of moisture.

Piers

In piers, posts and columns the concrete takes
compression assisted by the steel, and the vertical
steel takes tension if any bending occurs.

Beams

In beams there are stresses of compression,
tension and shear. The concrete takes all the com-
pression and a limited amount of shear. The steel
is computed as taking all the direct tension and
assists the concrete to carry shear stresses.

Columns

It is customary to reinforce all columns whether
reinforcement is theoretically required or not. The
practice is to use at least four rods so disposed in
the column that their location corresponds to the
four corners of a square. In no case should the
steel be nearer the surface than one and one-half
to two inches, since it is desirable to prevent any
tendency of the vertical rods to buckle under ec-
centric stresses or working loads. It is also cus-
tomary to place occasional horizontal hoops or ties
around the vertical steel. Such hoops in the form
of wire ties are helpful in holding the rods in cor-
rect position while concrete is being placed. In
some systems of reinforcing columns, reinforcement

106

is shipped to the job practically assembled. The
same is true in part of reinforcement for certain
types of beams or girders.

Types of Reinforcements

In addition to plain round, plain square and
twisted square bars, there are various types of
deformed bars used for concrete reinforcement. In
general, the deformation consists of lugs or other
projections formed on their surface during the pro-
cess of rolling. The principal object of such de-
formation is to increase mechanical bond and to
safeguard against the effect of absence of mechan-
ical bond in places where concrete may not every-
where surround or be in contact with the steel.

In addition to steel bars of various forms, there
are many so-called metal fabrics or meshes used as
concrete reinforcement. The material commonly
known as "expanded metal" for example, is formed
by slotting sheets of steel having required thick-
ness and physical properties, then stretching or ex-
panding the sheet, thus opening the slots and con-
siderably increasing the area of the sheet. Some
types of expanded metal are particularly adapted
to exterior and interior plaster work such as stucco.
Some others are intended to be used so that they
will make actual forms unnecessary, even to secure
monolithic construction. For example, a steel
frame is set up, expanded metal or so-called metal
lath attached to each side of this frame, the space
between lath filled with concrete and finally both
outside surfaces plastered, thus giving a monolithic
reinforced wall.

Other types of mesh reinforcement may be
likened to woven wire fencing or to square mesh
fabric similar to that used for common screens.
These vary in weight per certain area due to the
weight of strands of wire used in forming the fab-
ric. Some such fabrics are woven, others are weld-
ed where the strands intersect or cross.

It makes little difference which one of these
forms of reinforcement is used in certain classes
of work, other than that perhaps in specific cases

107

some one type will be more economical or may be
otherwise used more advantageously. The principal
thing to observe is that the physical properties of
the steel and the net cross-sectional area of steel are
satisfactory and the material is in the proper place
to take all the tension to which it will be subjected.

Handling Reinforcement on the Work

Often on the job, reinforcing metal is carelessly
thrown about and allowed to become rusty and per-
haps covered with oil or other filth. Care should be
taken when placing it to make certain that it is free
from mill scale or scale in the form of rust. Either
of these can be removed by pickling in weak acid
or perhaps by brushing with stiff wire brushes.

Frequently some steel must be shaped on the job
to conform to the details of design shown on the
building plans. Various devices are used for bend-
ing steel, typical among which are Koehring bar
benders. These are made in two sizes. The smaller
will bend bars cold up to one inch square. The
bending die is two inches in diameter, giving a one-
inch radius to the inside curve of the bar at the
bend, and has roller-bearing journal. The guide
block is provided with a large roller, allowing the
bar to follow freely, in order to avoid fracturing
by too great tension. This roller reduces friction
to a minimum.

The large type will bend up to 134-inch round or
lJ4'mch square. The bending die is 3 inches in di-
ameter, which gives a IJ^-inch radius to the inside
curve of the bar at the bend, and likewise has roller-
bearing journal. This bender is provided with an
adjustable clamp, which automatically adjusts itself
to the thickness of the bar, and securely holds the
bar at one end. It is so constructed that the small
bars can be bent with direct leverage, and bars one
inch and larger can be bent with two men by using
the back gear attachment. The pinion is provided
with a ratchet lever, and this pinion engages the
gear segment on the main frame.

108

The bending point is central with the journal,
which gives it greatest leverage, and this combined
with the roller bearing journal and roller guide
makes it possible to bend the bars with least force.
Any size bar up to 1%-inch round can be bent
without making any adjustments. The bender also
affords advantages of counterbending, without re-
moving the bar or without making adjustments in
case a bar has been bent too much.

It is also necessary to have a device capable of
cutting bars as may be required. One of the most
efficient tools for this purpose is the Koehring bar
cutter, also made in two sizes.

In designing this bar cutter the primary object
was to provide a machine light in weight, conven-
ient to handle, effective in operation, and simple
in construction, so it will not get out of order.

The cutting jaws are so arranged that it be-
comes more powerful as the resistance increases in
advancing the cut, and so that the bar to be cut will
not be pushed away by the two knives in the cut-
ting action. When cutting, the two knives advance,
which makes a clean, square cut, and does not leave
fractured ends.

The cutters are built entirely of steel, and in-
clude handle for operating. With the No. 1 size one
man can easily cut a ^-in. square twisted or round,
and with the No. 2-A size two men can easily cut
a 1%-inch round or a 1 54-inch square twisted bar.

Stops are provided to prevent the bar from
twisting, and in cutting the various thicknesses,
care must be taken that the bar is placed at right
angle with the knives and that a spacing block is
placed between the bar and the stop post. If the
space between the bar and the post is not filled in,
it will allow the bar to twist while the knives are in
cutting action, and this will cause them to break
out. See that the bar is placed straight through
the opening at right angle with the blades, and
that a piece of wood or iron is placed between the
stop post and the bar.

In shaping steel by bending, care should be

109

taken not to exert the bending strain suddenly or
violently, but rather gradually and uniformly to
prevent any fracture at the point of bend.

Makeshift Reinforcement Dangerous

No doubt concrete failures have resulted be-
cause of makeshift practices in reinforcing. Old
chain, wire cable and similar scrap material, which
seldom can be handled to advantage in the forms,
is quite likely to be ineffective even though the sum
total of metal used is greatly in excess of actual
requirements determined by design. Generally this
is due to the fact that once a strain of tension comes
on the concrete greater than it can bear the immedi-
ate help of reinforcement is lacking because the
steel or other metal was so placed as not to take
tension immediately.

It is necessary that the action of reinforcement
be continuous, and as in some classes of work bars
cannot be secured of sufficient length to extend be-
tween two desired points, it is necessary to splice
them. Splicing is usually done by lapping the bars
a certain number of times their diameter, roughly
50 to 60 times this diameter, at a point of least
stress. It is common where laps are necessary in
rectangular structures, to make them at or near the
center of one side rather than at or near a corner.

Examples

Two simple examples will serve to illustrate the
results obtained by hoop reinforcing of a column.
Make a cylinder of thin paper and fill it with sand.
The paper may be strong enough to hold the sand
if not disturbed, but if a load is put on top the paper
will burst and the sand will flow. If the shell of a
tin can, when top and bottom is removed, is used in
place of the paper cylinder, it will take considerable
load to burst the tin confining the sand. If, instead
of sand, the cylinder is filled with cement mortar or
concrete, it can be seen that the concrete will take
its full measure of load in compression and will
have the benefit of the encircling tin to prevent

no

crushing or failure when the safe compressive load
of the concrete has been approached or exceeded.

The principle of reinforcement in a beam can be
illustrated in a very simple manner. If a column of
concrete is made 6 by 12 inches in square dimension
and 10 feet long, then laid in such position that its
two ends only are supported, it corresponds to a
beam. Realizing that concrete is relatively weak
in tension, it can readily be seen that it would
easily be possible to make this concrete beam break
of its own weight by increasing its length suffi-
ciently between supports. The neutral axis in a
beam is the point where the character of stress
changes from tension to compression or from com-
pression to tension. In a beam of homogeneous
material, that is, one in which the tensile and com-
pressive strengths are equal, with symmetrical
cross section, the neutral axis will be midway be-
tween the top and bottom surface, or skin. At this
point stress is zero. At other points throughout
the section it will vary in amount and nature (ten-
sion or compression) with reference to the location
of the neutral axis.

It is not the purpose of this discussion to elab-
orate on the subject of reinforcing concrete since it
is a very technical one and requires a thorough
knowledge of engineering for a full understanding.

Frequently reinforcement is used in some parts
of structures not because an increase of structural
strength is necessary, but to prevent unsightly
cracks due to volume changes in the concrete from
changes in temperature, in other words, from ex-
pansion and contraction. Such reinforcement is
known as "temperature reinforcement."

111

112

CHAPTER 7.
NOTES ON SPECIFICATIONS

Specifications Should be Clear

Specifications for any construction work of im-
portance are necessary so that there may be a clear
understanding on the part of the contractor as to
the methods by which the work is to be carried on
to conform with the engineer's plan.

The first requirement of any set of specifica-
tions is that it shall be in such form as to present
only legal demands and afford legal protection to
all persons interested. This means that a specifi-
cation should be so worded as to be easy of inter-
pretation. It should not contain phrases or expres-
sions that by any chance might be given more than
one interpretation.

Technical terms and phrases must necessarily be
a large part of the text of specifications. Such
terms are well understood by the engineering and
contracting professions, yet it is possible to so refer
to technical subjects that a clear understanding of
them may be had by anyone who can read. It is
well in the case of some unusual terms or expres-
sions to append to the specifications, if necessary,
a glossary of terms that will define such words or
phrases in the light in which they are to be inter-
preted in reading the specifications.

Responsibility should be Clearly Defined

Specifications should not be drawn in such a way
as to release the engineer from responsibility justly
his. If for any reason there is wisdom in dividing
responsibility, the specifications should be so clear-
ly worded as to indicate what responsibilities rest
solely on the engineer or on the contractor, and
what responsibility is to be shared between them.

Another important requirement of specifications
is that they shall demand only methods that are

113

generally recognized as practicable — that is, no
unreasonable demands or requirements should be
made. Also, it is poor practice to write rigid speci-
fications if there is no intention of carrying them
out literally as written.

There probably never will be a piece of work
where minor adjustments will not be necessary
from time to time as the work progresses, but this
does not mean that the specifications applying are
not practical. Specifications should be so defined
that the contractor may know as nearly as possible
the grade or grades of materials he will be expected
to furnish, the quantity of work he will have to do
and as much other accurate, necessary information
as possible. They should be so drawn that neither
a superficial analysis of them, nor an attempt to
carry them out, will prove that they are at variance
with the plans on which they are based.

Features for Consideration

Among the various features of work that must
be given consideration in drawing specifications for
plain and reinforced concrete construction, are the
following :

Cement

Aggregates

Mixing water

Reinforcing steel

Proportioning, mixing, and placing concrete

Type of mixer to be used

Requirements for placing reinforcing steel

Methods of bending steel

Work done in cold weather

Form construction

Protection of concrete, both in cold and warm

weather

Removal of forms

Patching or repairing imperfect concrete
Provision for expansion joints

114

Inspection

Status of various men on the work as between

representatives of the engineer, contractor,

owner, etc.

It should be remembered that many large pieces
of work often involve changes of one kind or anoth-
er in the original plans. There should be a clause in
the specifications that will state how such changes
are to be handled by the contractor, particularly
with regard to additional or decreased compensa-
tion.

Often it has been the practice to arrange for the
arbitration of disputes in a way that was not always
equitable to either or any of the parties interested —
that is, the arbitration board provided for in the
specifications frequently included at least one mem-
ber likely to be partial to one or the other of the
parties most concerned.

From the very nature of concrete construction,
whether plain or reinforced, it is difficult to make
alterations in the work after it has progressed be-
yond a certain point. Therefore it is important
that provisions be made for continuous inspection
as the work advances, so that before any consider-
able amount of it at variance with specifications
can be finished it will be possible to correct faults.

Basic Principles in all Specifications

As nearly every piece of work has some features
peculiar to itself, specifications vary in accordance
with the particular job for which written. How-
ever, certain basic principles of concrete work are a
feature of every job. Therefore certain portions of
every specification are alike for all jobs. The ex-
tensions of, or additions to, a specification may be
almost without limit, yet should not be made with-
out some definite purpose in view.

Nearly all specifications that form the basis of
bids for certain pieces of work are accompanied by
explanatory notes, consisting of instructions and in-
formation for bidders. These items usually pre-

scribe the method of making a bid and how it
should be forwarded when ready for delivery to the
person or persons interested. If the bid is accepted,
the next step is the signing of a proper contract
which in its essentials states when the contractor
will commence the work and the time he will be al-
lowed for its completion. All specifications for
work likely to be subject to various delays beyond
reasonable control, should contain a clause outli-
ning the procedure necessary to obtain extension of
time on a contract.

On any job the first work usually involves more
or less excavation or other preparatory work. On
large jobs, contracts are usually let for various
parts of the work so the concrete contractor may
have nothing to do with excavation or other pre-
liminaries. If so, the contract should so state.

The first paragraph of a specification for con-
crete work involves the cement to be used. As a
rule, most specifications are too wordy in laying
down the requirements for the Portland cement to
be used on the job — that is, they go into such de-
tails as stating the specific gravity, fineness, time of
setting, tensile strength, chemical content, etc.
These requirements can be met by briefly stating
that the Portland cement used shall meet the re-
quirements of the latest Specifications and Tests
for Portland Cement of the American Society for
Testing Materials. If this is done, any of the well-
known brands of Portland cement, the manufac-
turers of which have subscribed to these specifica-
tions, may be relied upon to meet the demands of
any concrete construction.

Another objection to specifying in detail the
qualities that the cement shall possess, is that very
few persons, other than those whose experience in
sampling and testing cement has been acquired by
thorough laboratory work, are competent to under-
take cement testing. This fact has often been re-
sponsible for high grade cement being rejected on
the job. If for any reason it is desirable to test
cement, the work should be intrusted to a well-

11G

known, well equipped testing laboratory which spe-
cializes in such work.

Aggregates

The second item of the specification usually cov-
ers the subject of aggregates. These will consist of
sand and pebbles or of sand and some kind of
crushed stone, among which may be slag or other
materials of rock origin. If fine aggregate such as
stone screenings is to be used in place of sand, or if
cinders are to be used in place of other coarse ag-
gregate, the specifications should detail very care-
fully the quality of such materials and should give
field methods of determining their quality. Actual
tests on aggregates, like tests for cement, should
be made in some laboratory properly equipped for
such work.

The specifications for sand, usually referred to as
fine aggregate, are becoming more and more rigid,
and rightly so, since it has been proved that the qual-
ity of the sand affects the quality of the resulting con-
crete in a far greater degree than was once realized.

Proportioning Mixtures

The next item of specification should take up
the subject of proportioning mixtures. It should
go explicitly into the manner in which the several
ingredients are to be measured and mixed, so that
by no chance can the specification be interpreted to
mean that a 1:2 'A mixture and a 1 :6 mixture are
identical. Methods of measuring materials should
be definitely stated, as should the methods of mix-
ing them.

Type of Mixer

Engineers are in accord on the point that only
a batch mixer should be used. Specifications should
be specific in stating how and in what type of ma-
chine materials are to be mixed. The time of mix-
ing, or its equivalent in number of revolutions for
particular make of machine, should be carefully
specified and rigidly enforced.

117

Miscellaneous Paragraphs

Definite amount of water should be used for
each successive batch so long as materials are con-
stant in physical properties and moisture content.

The importance of the correct amount of mixing
water is another thing which has but recently been
thoroughly appreciated. A clause should describe
the consistency so clearly that any excess of water
will be avoided.

In reinforced concrete work, methods of placing
reinforcing steel and all practice involved in han-
dling and bending it where necessary to form it to
shapes shown on the plans, should be clearly stated
in the specifications.

On many jobs it is necessary to devote consider-
able space in the specifications to detailing methods
of making and erecting forms. A great deal of con-
crete work has failed to attain the strength that
might have been expected had proper attention
been given to form construction and all details con-
cerning erection, use and removal of forms.

Concrete work is often carried on during low tem-
peratures. In fact, during recent years, many large
contracting firms have practically specialized on
winter work. They have proved conclusively that
good concrete work can be done in cold weather.
But in anticipation of a certain contract extending
through a season when temperatures will be near or
below freezing, specifications should clearly define
how work should be handled under such conditions.

Much of the success of finished concrete work
depends upon carefully protecting the concrete for a
certain time after placed. This is true not only in
cold weather but also in extremely warm weather,
especially when hot, dry winds prevail. This latter
fact is seldom appreciated and the practice of protect-
ing concrete in warm weather is almost universally
neglected except in highway pavement construction.

There should be a clause in every specification
covering such protection as it is desired shall be
given the work for a stipulated period under cer-

118

tain conditions. For certain classes of work, the
time when forms may be removed should be defi-
nitely specified.

If surface finish other than that secured by plac-
ing the concrete in the forms is desired and the
same contractor is to attend to this part of the
work, the specifications should state the kind of
surface finish and how it shall be secured.

Sometimes concrete work is carried on under
specifications which require that proprietary prepa-
rations such as waterproofing mediums or floor
hardeners be used in some parts of the work. It
is not right to place entire responsibility on the
contractor for the success or failure of the work
as a whole, where the use of such mediums is made
a part of the specification. In these cases responsi-
bility should rest upon the manufacturer of the par-
ticular preparation and he should supply and en-
force the specifications governing, thus fixing re-
sponsibility for success or failure.

No specification should be longer than neces-
sary to cover all details of the work, yet far too
many specifications fall back on such expressions
as "Shall be done in a thoroughly workmanlike
manner" or "Shall be done to the satisfaction of the
engineer." These expressions are vague in defining
quality of workmanship and are sure to lead to al-
most interminable disputes on some occasions.

Considerable trouble on every concrete job of
any magnitude, where the job naturally comes un-
der the jurisdiction of local building ordinances, is
due to the fact that plans as well as specifications
frequently are at variance with building code re-
quirements. Such trouble can always be avoided
if specifications and code requirements are harmo-
nized before work is started.

119

120

CHAPTER 8.

ESTIMATING COST OF CONCRETE
CONSTRUCTION

Cost of concrete construction depends upon
many conditions. Cost of labor and materials
varies widely with locality.

In making estimates upon reinforced concrete
structures, cost may be closely approximated by
taking a unit price per cubic yard or per square foot
of floor surface from similar work recently complet-
ed under nearly or practically identical conditions.
Such unit price may be used for approximating the
cost of a proposed structure or piece of work. In
order, however, that such an estimate will approxi-
mate probable cost, the plans and specifications as
well as prevailing prices of labor and material must
be carefully compared with those of the structure or
job from which the unit prices are derived. Even
then it must be realized that such an estimate can
only be an approximation. It may, however, be a
very close one if the contractor has had consider-
able experience and throughout his experience has
made it a practice to carefully compile and analyze
cost data for the purpose of enabling close compari-
sons. Cost figures, based on one's own experience,
are much more valuable than those derived from
the experiences of others, as the latter relate to un-
known conditions of working, while the figures
which the individual compiles from his own experi-
ence relate to his way of working and the condi-
tions which he has met and with which he is there-
fore most familiar.

Estimating the cost of concrete construction
is in many respects different from estimating cost
of other classes of work. Naturally, experience in
handling a particular kind of job qualifies one to
estimate more closely on that kind of work than on
another kind with which one has had little or no
experience. Frequently the inexperienced contractor

121

has found out that the knowledge which he thought
he had acquired under the direction or guidance of
someone else, has not been so substantial as he
believed, in that he lacked the inside viewpoint and,
therefore, was unable to make careful analysis of
all factors affecting cost.

Items Entering into Cost

The following items enter into most work and
are therefore subject to detailed consideration be-
fore the preliminary cost of a piece of work can be
considered as complete:

Interest

Overhead expense

Bonds

Insurance

Employer's liability

Public liability

Fire insurance

Special risks

Freight on outfit to and from work

Moving in and out

Land damages

Camp and other buildings

Preliminary work

Cost of materials plus freight

Hauling materials

Supervision

Labor

Loss due to camp operation

Transportation of labor

Tools

Plant rental

Running repairs

General repairs

Specials

Machinery

Fuel and power

Weather

The subject of interest includes proper return on
the actual investment in equipment, as well as
money that must be paid to any source from which

122

financing for a job must be drawn. Certain jobs
can be financed with a sum not exceeding 10 per
cent of their total cost, providing the contractor
succeeds in making suitable arrangements for pay-
ment on account, as the work progresses. Finan-
cial standing and credit rating of a contractor regu-
late his activities, and limitation of these frequently
causes failure.

Overhead

Overhead expense is made up of a number of
items and should include salary allowance for mem-
bers of the organization, traveling expenses and
similar incidentals. Under overhead would also come
the maintenance of an equipment storage yard.

Bonds are necessary to safeguard the commun-
ity or individual owner with respect to faithful per-
formance of the work in accordance with the speci-
fication and contract.

Insurance

Insurance that must be provided is of various
kinds and includes protection from fire loss on any
combustible materials, safeguards against damage
to nearby buildings or structures, protection
against damage claims due to bodily injuries of em-
ployes and any other special risks against which
the contractor may be protected by underwriting.

Many contractors underestimate the amount of
freight or other transportation charges involved in
moving their outfits from one job to another.

Cost and Quantity of Materials Very Important

In making up an exact estimate, the cost of the
quantity of materials required can be accurately
determined by using the figures corresponding to
current market prices. The materials used in con-
crete construction may represent anywhere from 20
to 70 per cent of the total cost of the work. It
can readily be seen that in so large an item, errors
in estimating may affect profit considerably. The
contractor must also know that the materials de-
livered to him are up to quality and quantity re-

123

quired so that he will not be called upon to remove
or demolish a portion of completed work or secure
additional materials beyond those delivered in in-
sufficient supply.

In the case of practically all other building ma-
terials, finished products of known quality are sup-
plied to the contractor and he is simply a builder;
but in concrete work he is a manufacturer also, and
must be competent to correctly judge the quality
and suitability of materials entering into his work.

Labor costs can be estimated accurately only
when experience has proved the volume of work
which certain kinds of workmen or laborers may be
depended upon to perform in a given time or under
given conditions. Labor costs in erecting forms are
particularly difficult to determine, especially where
reinforced concrete construction is new to a locality
and the only carpenters obtainable have had little
or no experience with such class of work.

Speed of construction influences cost and in turn
is influenced largely by the availability of space and
labor. Frequently throughout a job a contractor
is confronted by a shortage of labor or unsatisfac-
tory labor. Competition of nearby work may make
it difficult for a contractor to maintain or retain an
efficient organization.

The uncertainties of transportation and its cost
affect the cost of work within a wide range. It
must, if possible, be arranged that there shall be an
uninterrupted supply of materials in order that the
work may progress without costly stoppages.

Weather Conditions

Weather conditions play an important part on
the cost of work. It is not possible to foretell when
storms or unfavorable weather may interrupt the
work, except that experience shows that more de-
pendable weather prevails at certain seasons of the
year than during other times. Late fall and early
spring are marked by unsettled weather, and if the
work must begin in or extend into either of these
seasons, calculations must be made on the inter-

124

ruptions that will result and the probable influence
in cost that they will have on the work.

A comparison of different classes of work will
show which factors most influence cost as among
various classes. In reinforced concrete construc-
tion, for example, cost of materials is secondary to
that of labor, while in plain mass concrete construc-
tion there is a larger cost for materials than for
labor. Some classes of work call for complicated
and therefore expensive form construction. On
other jobs forms represent but a relatively small
portion of the total cost.

Relation of Speed to Cost

Speed of the work is a factor in estimating cost.
The work may be carried on too rapidly at certain
points, thus causing congestion of labor and ma-
terials. For the same reason cost will be affected
favorably or unfavorably by a well or poorly bal-
anced construction gang. The mixer and associ-
ated equipment may be too small or too large for
the number of men working or there may be too
few or too many men for the equipment.

Often contractors must accept notes, bonds or
other commercial paper instead of cash in payment
for their work. The market value of such paper
should be definitely determined. When possible to
do so, arrangement should be made to dispose of se-
curities of this kind at a definite price before closing
the contract. Only by knowing what such securi-
ties will bring in cash can the contractor safeguard
himself in estimating. For example, if he is given
negotiable securities having a face value of $10,000,
which will bring only $9,000 cash, his estimate
must include an amount sufficient to cover such dif-
ference between face and market value of securi-
ties accepted as cash.

Cement requirements can be estimated accurate-
ly. It is, therefore, not necessary to increase the
quantity estimated other than to add a small sum to
actual cost per barrel to cover sack losses. The
percentage of sacks lost is largely dependent upon

125

the care received while in the hands of the user.
On many large jobs it is possible to adapt bulk ce-
ment to the work and avoid the temporary invest-
ment and the certain loss of some of this investment
when cement is used in sacks. It is always best to
have one or more men, as necessary, made respon-
sible for the careful handling and bundling of sacks.
Aggregates are sometimes sold by weight and
sometimes by the cubic yard, or a unit weight is
adopted and deliveries in cubic yards are converted
into equivalent weights. If aggregates or cement
must be transported and rehandled from trucks to
cars and cars to trucks, where there is likely to be
loss, there is also the cost of this transportation and
rehandling. There is also some wastage of materials,
particularly aggregates at the site of the work. It is,
therefore, safe to estimate 10 per cent over actual
figured aggregate requirements to cover such loss.

Cost of Water Should Not Be Overlooked

The probable cost of water is often overlooked.
Frequently there is no difficulty in arranging for a
sufficient supply. Within city limits, for example,
the necessary arrangements can be made with the
city water department for hydrant or similar con-
nection. The quantity of water required may safely
be figured at from 40 to 50 gallons per cubic yard
for concrete only. In addition to that there is the
water required for operating mixers, engines and
other equipment, for wetting down forms and
sprinkling concrete while hardening and for inci-
dental waste that may bring the estimated require-
ments up to 100 gallons per cubic yard of concrete
in place. The problem of water supply is often a
troublesome one on highway construction. Fre-
quently the supply must be hauled in tank wagons
or piped for long distances, and before estimating
cost of water, the situation to be met must be care-
fully analyzed. Hauling charges involve loading
and unloading of materials, including working as
well as waiting time of team and driver or motor
truck and actual time of truck in travel.

126

CHAPTER 9.

NOTES ON CONCRETE CULVERT
AND BRIDGE CONSTRUCTION

Culverts

The simplest form of concrete culvert is that
made of precast pipe. It is adapted to all sizes of
opening from 12 inches upward to the largest size
of pipe made, providing the largest size will other-
wise suit the situation. Good practice limits the mini-
mum size of waterway openings to 12 inches because
smaller sizes easily become choked with rubbish.

The box culvert is the most generally used of all
concrete culverts because for the head-room the
greatest area of waterway can be secured, and very
simple forms are required. As the name implies, it
is merely a long box with concrete top, sides and
bottom. It is in effect a small concrete bridge with
top slab acting as a floor to support the loads of
traffic. The slab must be reinforced with steel rods
or heavy mesh fabric. In building box culverts, a
concrete floor should be laid in the bottom of the
culvert. This is sometimes omitted and the sides
extended down a short distance into the stream
bed. It is always best to put the floor in to prevent
damage from undermining.

The arch culvert is different from the box cul-
vert in that the top is in the form of an arch in-
stead of a flat slab. There is no advantage in the
arch culvert for small spans. It requires little or
no reinforcing because the concrete takes all of the
load in compression. Form work for arch culverts
is more costly than for box culverts.

The area of waterway for culverts is shown in
the following table. These figures are given merely
as a guide from which an estimate can be made of
the approximate size of opening required. The area
of the waterway opening depends upon the water-
shed to be drained and the amount of rainfall which
must be taken care of from this area.

127

Table No. 13

SIZE OF WATERWAY REQUIRED FOR

VARIOUS AREAS TO BE DRAINED

(From Bureau of Public Roads)

Area Drained

Area of Waterway Needed (in

Sq. Ft.)

Steep Slopes

Rolling Country

Flat Country

Acres

10

5.6

1.9

1.1

20

9.4

3.1

1.9

30

12.8

4.3

2 6

40

15.9

5.3

3.2

50

18.8

6.3

3 8

60

21.6

7.2

4.3

80

27

8.9

5.4

100

32

10.6

6.3

125

37

12.5

7.5

150

43

14

8 6

200

53

18

10.6

300

72

24

15

400

89

30

20

Square Miles

1

127

42

25

2

214

71

43

3

290

97

58

4

359

120

72

5

425

141

85

7

548

183

109

10

716

239

143

15

970

323

194

20

1204

401

241

30

1630

543

326

50

2390

797

478

75

3240

1080

648

100

4020

1340

805

In the installation of concrete pipe culverts, the
pipe is laid in a carefully prepared trench, curved
at the bottom to fully support the pipe. Back-fill
and road cushions must be carefully placed and
compacted in layers so that the concentrated loads
of vehicles will be distributed over a large area and
not come directly over a small portion of the pipe.

For small box and arch culverts in stable soil,
the side walls usually constitute sufficient founda-
tion bearing. In soft or doubtful soil and for large
sized culverts, spread footings should be placed un-
der side walls. Often the culvert floor is considered
as the foundation footing. In such a case the floor,
which acts as a beam, should be reinforced in the
same manner as the culvert top, except that the
steel is placed in the upper part of the slab.

All flat slab or box culverts, regardless of size,
should be reinforced. As a rule, such reinforcing is

128

placed with its center point 1% inches from the bot-
tom of the slab, except in the case of the floor slab,
when it would be 1% inches from the top. Rein-;
forcing should be bent down and up into side walls
a suitable distance. Care should be taken to see
that it is held the required distance from the forms
by metal spacers or other devices so that it will be
in correct position in the concrete when the work is
finished.

Wing Walls

Wing walls are provided on bridges and culverts
to retain the road fill and prevent stream erosion.
Such walls, used in connection with concrete pipe
culverts, are generally built straight and parallel
with the road. The top thickness of unreinforced
end walls for pipe culverts should be not less than
12 inches and as a general rule the thickness at the
bottom should be 0.4 the height of the wall. The
foundation footing under the wall is usually made
6 to 12 inches wider than the wall.

End and wing walls for box or arch culverts are
either straight and parallel with the road or flared
at an angle to it. The flare type is more effective
in confining the road fill. Especially should it be
used on the upstream end of the culvert. End and
wing walls are frequently reinforced in the interest
of economy of concrete.

The concrete floor built in the bottom of con-
crete culverts assists in preventing choking of the
waterway and undermining of the foundation. A
vertical cut-off wall at each end of the floor, extend-
ing down 2 feet, is added protection against under-
mining. For very small culverts, the floor is made
continuous with the walls and thus acts practically
as a foundation. In larger culverts the floor is laid
usually as a 6-inch pavement between the walls in
order to properly distribute concentrated loads.

Road covering over all culverts should be 2 feet
for dirt or macadam. Owing to the better distribu-
tion of loads by concrete pavement, it will be suffi-
cient if the road slab proper is laid directly on the

129

top of the culvert. This allows a greater clear
height to the waterway, without altering the grade
of the road, than when the dirt or macadam road
cushion must be provided.

Since the upper part of the culvert top slab is
acting in compression, it should not be made part of
the concrete road. The additional thickness of the
road slab should be laid upon the culvert top. In
doing this, it is best to paint the top of the culvert
slab with something that will prevent bond between
it and the road slab. The road section over the
culvert should extend some distance on each side of
the culvert and be reinforced. In this way no joint
is formed at the side of the culvert and danger of
settling of the road slab at sides is avoided.

Concrete culverts are made the full width of the
road, including the shoulders. This is done by widen-
ing the road slab to the full length of the culvert.

Bridges

Most of the foregoing notes on concrete culverts
apply to concrete bridges. A bridge implies a larger
structure, although there is no line drawn to defi-
nitely state where the structure changes from the
classification of culvert to that of bridge.

The type of highway bridge to be selected for
any given location depends uppn length of span,
waterway opening required, foundation conditions,
etc. The flat slab bridge is probably the simplest
form and is specially adapted to short spans and to
the loads of ordinary highway traffic. It is merely
a concrete slab of proper thickness, suitably rein-
forced and resting on abutments. Reinforcement
usually consists of steel rods and requires little or
no fabrication before placing. Form work also is
simple. Essentially all that is required is a tem-
porary wooden floor upon which the concrete may
be supported until it has hardened sufficiently to
carry its own weight and that of traffic.

Where loads and length of span are such as to
require a heavier floor slab than common in the
ordinary type of flat slab bridge, the design changes

130

to a combination of girder and slab or girder, beam
and slab. Girders extend parallel to the road be-
tween abutments and support the floor slab which
can then be made relatively thinner. As the entire
structure is a monolith, concrete beams act as "L"
or "T" beams of which the floor slab is the upper
flange. This results in economy by reducing the
required size of beams. The beams, of course, are
suitably reinforced. Sometimes on long spans, large
concrete girders are used at each side with cross
beams between, supporting the floor slab. Rein-
forcement in this type of structure is more compli-
cated than in the types previously described.

In order to simplify the problem of reinforcing
and of form construction, steel "I" beams are some-
times substituted for concrete beams. The "I"
beam should be encased in concrete to prevent cor-
rosion. The concrete floor slab rests on the "I"
beams. In this type of construction it is conven-
ient to hang the forms to the lower flange and thus
eliminate the necessity of post supports for forms.

Concrete arches are suitable for locations where
good foundation and sufficient head-room exist.
Under such conditions the arch is economical.
Form work is more difficult and extreme care is
necessary to secure an unyielding foundation for
the abutments. Both plain and reinforced concrete
is used for highway arch bridges. In many cases
the arch can be designed so that it will not need
reinforcing. In other cases designing it for rein-
forcing will result in desirable economy of concrete.

Functions of Bridge Abutments

Bridge abutments have two functions. They
help to support the bridge superstructure and to
retain the fill of the approach. They may be either
of plain or reinforced concrete. If reinforced, they
allow considerable reduction in the abutment thick-
ness and a consequent saving in concrete.

Wing walls are needed for all highway bridges,
regardless of size. They prevent undermining and
erosion of the abutment and also add to the stabil-

131

ity of the abutment, as well as help to retain the fill
of the road and bridge approaches.

In the building of abutments, retaining walls and
wing walls, drainage should be taken care of by de-
positing against the back of the wall, a layer of
broken stone for the full height, connecting this with
weep holes or pipe extending through the wall.

Concrete for the ring of arch bridges may be
placed in two ways unless the structure is so small
that concreting can be finished in one day. The first
method is to concrete a section of sufficient width
so that the ring can be completed from abutment to
abutment in one continuous operation. One section
is completed each day or during a given period, un-
til the full width of the bridge is reached. The sec-
ond method is to deposit the concrete in transverse
sections, extending the full width of the bridge in a
manner similar to that after which masonry arches
are built. In this method, the surface of the con-
crete at the end of each day's work must be left in
a plane perpendicular to the form centering at that
point. In the larger arches built by the latter
method, there is some danger that the placing of
concrete at the haunches will cause the centering to
rise at the crown, thus distorting the true curve of
the arch. This danger is slight in small arches, but
can be guarded against by placing the keystone sec-
tion and the haunch at the same time, the weight
of the first tending to hold down the centering. In
placing concrete after either method, it should be
deposited first at both haunches and in equal
amounts on each side so as to load the forms equally.

Foundation Material of Utmost Importance

The stability of arch bridges depends in a great
measure on unyielding abutments and foundations.
The character of the foundation material is there-
fore of utmost importance. Rock, hardpan, and
hard and compact gravel, are suitable arch abut-
ment foundations. Piles are required when the soil
is yielding. Foundation footings must be carried
down sufficiently to prevent underscouring or un-

132

dermining by the current. Where necessary, they
should be protected by rip-rap. For very large mass
work it is permissible to use field stones in the con-
crete to effect a saving of materials. These should
not be thrown in the forms indiscriminately, but be
distributed carefully by hand during the placing of
the regular concrete mixture, so that they will be
evenly scattered throughout the mass.

In order to prevent seepage of water through
the joints in the arch ring, the ring must be thor-
oughly waterproofed. While well made concrete in
itself is sufficiently waterproof for this purpose, nev-
ertheless there are joints at the end of each day's
work which might allow seepage that would de-
tract from the appearance of the arch. To prevent
this the back of the arch and inner faces of the span-
drel walls are given a Ys-mch coating of coal tar
pitch. To dispose of surface water, broken stone
drains are provided to lead it away from the abut-
ment or to drain pipes extending through the
haunch of the arch near the springing line. The
road fill may be of broken stone, cinders or earth.
A minimum thickness of 2-feet of fill, well com-
pacted, should be provided at the crown.

If a permanent hard surfaced road is to be in-
stalled over the bridge, it is good policy to wait for
at least a year so that all settlement of the fill may
have subsided.

Carpenter Work on Bridge

Carpenter work required on average bridge
forms can easily be done by an ordinary carpenter.
It should be borne in mind that various members of
bridges are of considerable size and weight, there-
fore, forms should be strong and rigid to sustain the
heavy loads imposed by the fresh concrete. In or-
der that dimensions and shape of all members,
when finished, will conform exactly with the design,
every precaution should be taken to prevent distor-
tion of forms. Extra care expended on making and
erecting them will be repaid by the better appear-
ance of the finished work. Where necessary, plenty

133

of posts, well braced, should be used to support
forms and prevent them from sagging with the
green concrete.

The centering for an arch bridge is necessarily
more elaborate than for a simple flat bridge, yet the
carpenter work is well within the abilities of the
carpenter of average skill. Special attention must
be given to the wedges which provide for easy and
gradual lowering of the centering. Only good
quality lumber should be used for arch centering,
particularly for main supporting timbers and brac-
ing. Unless under exceptional circumstances,
forms should never be lowered from beneath arch
rings or floor systems in less than one month from
the placing of the last concrete. If the work has
been done under unfavorable conditions of temper-
ature, a longer time even may be necessary.

Table No. 14

TABLE SHOWING QUANTITIES OF MATERIALS REQUIRED IN
CONCRETE BRIDGES OF SPANS 8 FEET TO 24 FEET, ROAD-
WAY 20 FEET, AS SHOWN BY THE STANDARD PLANS OF
THE WISCONSIN HIGHWAY COMMISSION

Size

Excavation

Concrete

Reinf.
Steel
Pounds

8-foot span, 20-foot roadway
10 -foot span, 20 -foot roadway
12-foot span, 20-foot roadway
14-foot span, 20-foot roadway
16-foot span, 20-foot roadway
18-foot span, 20-foot roadway
20-foot span, 20-foot roadway
2 2 -foot span, 20 -foot roadway
24-foot span, 20-foot roadway

25 cu. yd.
30 cu. yd. " -
35 cu. yd.
35 cu. yd.
40 cu. yd.
40 cu. yd.
45 cu. yd.
50 cu. yd.
50 cu. yd.

42.3 cu. yd.
49.8 cu. yd.
56.5 cu. yd.
60.3 cu. yd.
68.6 cu. yd.
72.8 cu. yd.
81.4 cu. yd.
91.9 cu. yd.
98.2 cu. yd.

1910
2210
2720
3100
3540
3950
4540
5320
6360

134

CHAPTER 10.

CONVENIENT ESTIMATING TABLES AND
EXAMPLES OF USE

For convenience, concrete is usually mixed in
batches, each requiring one or more sacks of ce-
ment. The following table shows the cubic feet of
sand and pebbles (or crushed stone) to be mixed
with one sack of cement to secure mixtures of the
different proportions indicated in the first column.
The last column gives the resulting volume in cubic
feet of compacted mortar or concrete.

Table No. 15

Mixtures

Materials

Concrete cu. Ft

Cement

Sand

Pebbles
or
Stone

cement
in
Sacks

Sand
Cu.Ft.

Pebbles
or Stone
Cu. Ft.

Mortar

Con-
crete

1

1.5
2
3
1.5
2
2
2.5
2.5
3

3
3

4
4
5
5

1.5

2
3
1.5
2
2
2.5
2.5
3

3
3

4
4
5
5

1.75
2.1
2.8

3.5
3.9
4.5
4.8
5.4
5.8

The following table gives the number of sacks
of cement and cubic feet of sand and pebbles (or
stone) required to make one cubic yard (twenty-
seven cubic feet) of compacted concrete propor-
tioned as indicated in first column.

135

Table No. 16

Mixtures

Quantities of Materials

Pebbles

Cement

Sand

Stone or

Cement

Sand

or Stone

in Sacks

Cu. Ft.

Pebbles

Cu.Ft.

1.5

15.5

23.2

2

12.8

25.6

3

9.6

28.8

1.5

3

7.6

11.4

22.8

2

3

7

14

21

2

4

6

12

24

2.5

4

5.6

14

22.4

2.5

5

5

12.5

25

3

5

4.6

13.8

23

3

6

4.2

12.6

25.2

Example No. I

How much cement, sand, and pebbles will be
required to build a feeding floor 30 feet by 24 feet,
5 inches thick?

Multiplying the area (30 by 24) by the thickness
in feet gives 300 cubic feet, and dividing this by 27
gives 11-1/9 cubic yards as the required volume of
concrete. A one-course floor should be of 1 :2 :3
mixture, see Table No. 1 page 28. Table No. 16
shows that each cubic yard of this mixture required
7 sacks of cement, 14 cubic feet of sand, and 21 cubic
feet of gravel or stone. Multiplying these quantities
by the number of cubic yards required (11-1/9 gives
the quantities of material required, eliminating
fractions) as 78 sacks of cement, 156 cubic feet of
sand, and 233 cubic feet of pebbles or stone. As
there are 4 sacks of cement in a barrel, and 27 cubic
feet of sand or pebbles in a cubic yard, we shall
need a little less than 20 barrels of cement, 6 cubic
yards of sand, and 9 cubic yards of pebbles or stone.

Example No. II

How many fence posts 3 by 3 inches at the top,
5 by 5 inches at the bottom, and 7 feet long can be
made from one sack of cement? How much sand
and pebbles will be needed?

136

Fence posts should be of a 1:2:3 mixture.
Table No. 15 page 135 shows the volume of a one-
sack batch of this mixture to be 3-9/10 cubic feet.
The volume of one concrete post, found by multi-
plying the length by the average width and breadth
in feet (7 by % by %) is 7/9 cubic feet. By divid-
ing 3-9/10 by 7/9 we find that five posts can be
made from 1 sack of cement when mixed with 2
cubic feet of sand and 3 cubic feet of pebbles.

Example III

What quantities of cement, sand and pebbles are
necessary to make 100 unfaced concrete blocks,
each 8 by 8 by 16 inches?

The product of height, width and thickness, all
in feet (% by % by 4/3) gives 16/27 cubic feet as
the contents of a solid block. As the air space is
usually estimated as 33% per cent, the volume of
concrete in one hollow block will be % of 16/27 or
32/81 cubic foot; in 100 blocks the volume of con-
crete will bej5200==39.5— 1. 46 cubic yards, or 66%

81

cubic feet which being divided by 27 gives a little
less than \y2 cubic yards. Unfaced concrete block
should be 1 :2y2 :4 mixture, see Table No. 1, page 28.
Table No. 16 shows that each cubic yard of this
mixture requires 5-6/10 sacks of cement, 14 cubic
feet of sand, and 22-4/10 cubic feet of pebbles.
Multiplying these quantities by the number of cubic
yards required (1J4) gives the quantities of mater-
ial required as 8-2/5 sacks of cement, 21 cubic feet
of sand, and 33-3/5 cubic feet of gravel.

Example IV

How many 6-foot hog troughs 12 inches wide and
10 inches high can be made from 1 barrel of cement?

Use a 1 :2 :3 mixture, see Table No. 1 page 28.
Table No. 15 shows the volume of a 1-sack batch of
this mixture to be 3-9/10 cubic feet. As there are
4 sacks in 1 barrel, a barrel of cement would be
sufficient for four times 3-9/10, or 15-6/10 cubic
feet of concrete. The product of the three dimen-
sions, all in feet, gives the volume of one trough as

137

5 cubic feet. However, approximately 30 per cent
of this volume is in the open water basin or inside
of the tank, leaving 3-5/10 cubic feet as the solid
contents of concrete in one trough. Dividing
15-6/10 by 3-5/10, we find that 4 troughs (and a
fraction over) can be made from 1 barrel of cement
when mixed with 8 cubic feet of sand and 12 cubic
feet of pebbles.

Table No. 17

NUMBER OF SQUARE FEET OF WALL SURFACE COVERED

PER SACK OF CEMENT, FOR DIFFERENT PROPORTIONS

AND VARYING THICKNESS OF PLASTERING

Materials

Tc

tal Thickness of Plaster

Pro-

Vz-in.

X -in.

1-in.

1 i/4-in.

iVz-in.

portions

of Mix-

Sacks

Bush-

ture

Ce-
ment

Cu. Ft.

Sand

els
Hair*

Sq. Ft.
Cover-

Sq. Ft.
Cover-

Sq. Ft.
Cover-

Sq. Ft.
Cover-

Sq. Ft.

Cover-

ed

ed

ed

ed

ed

1:1

1

1

M

33.0

22.0

16.5

13.2

11.0

1:1%

1

1%

%

42.0

28.0

21.0

16.0

14.0

1:2

1

2

%

50.4

33.6

25.2

20.1

16.8

1:2%

1

2%

v&

59.4

39.6

29.7

23.7

19.8

1:3

1

3

y*

67.8

45.2

33.9

27.1

21.6

*Used in scratch coat only.

Note: — These figures are based on average conditions and may vary
10 per cent either way, according to the quality of the sand used. No al-
lowance is made for waste.

Table No. 18

MATERIALS REQUIRED FOR 100 SQ, FT. OF SURFACE
FOR VARYING THICKNESS OF PLASTER

Propor-
tions

Thick-
ness
(in.)

1:

1

1:

2

1:2 %

1:3

C.

(sacks)

Sd.
(cu.yd.)

C.

(sacks)

Sd.
(cu.yd.)

C.

(sacks)

Sd.
(cu.yd.)

C.

(sacks)

Sd.(cu.
yd.)

1

1V4
1%
IK

2

2.2
3.0
4.5
6.0
7.5
9.0
10.5
12.0

0.08
0.11
0.16
0.22
0.27
0.33
0.39
0.45

1.5
2.0
2.9
3.9
4.9
5.9
6.9
7.9

0.11
0.15
0.22
0.29
0.36
0.43
0.50
0.58

1.3
1.7
2.5
3.3
4.2
5.1
6.0
6.9

0.12
0.16
0.23
0.31
0.39
0.47
0.56
0.64

1.1
1.5
2.2
3.0
3.7
4.5
5.4
6.2

0.13
0.17
0.25
0.33
0.41
0.50
0.60
0.69

If hydrated lime is used it should be added in amounts of from 5 to
10% by weight of the cement.

Hair is used in the scratch coat only in amounts of % bushel to 1 sack
of cement.

These figures may vary 10% in either direction due to the character of
the sand.

No allowance is made for waste.

138

Table No. 19

QUANTITY OF CEMENT REQUIRED PER CUBIC FOOT AND
PER CUBIC YARD OF CONCRETE FOR VARIOUS
MIXTURES IN TERMS OF SACKS AND BARRELS

1 Cu. Ft.

Sacks of

1 Cu. Yd.

Bbl. of

Concrete

Cement

Concrete

Cement

1:1:1

.5404

:1:1

3.375

l:li/2:3

.2808

:1V2:3

1.895

1:2:4

.2220

:2:4

1.498

1:2 y2 :5
1:3:6

.1848
.1570

:2V2:5
:3:6

1.247
1.060

Table No. 20

MATERIALS REQUIRED FOR 100 SQ. FT. OF SURFACE
FOR VARYING THICKNESS OF COURSE

Thickness
Mix

C.

1 in.

St.

2 in.
Sd.

4 in.

Sin.

St.

Sd.

C.

St.

C.

Sd.

St.

C.

Sd.

1:2
1:1:1

:2:32
:2:4
:2V2:4
:2V2:5
:3:6

3.9

4.2
3.7
2.6

0.29
0.15
0.14
0.14

6. is

0.20
0.24

7.9
8.3
7.3
5.1

0.58
0.31
0.27
0.28

0.31
0.41
0.47

9^4
8.6
7.4
6.9
6.2
5.2

0.'64
0.55
0.64
0.57
0.58

i'.04
0.95
1.10
1.02
1.14
1.16

ii'.7

10.8
9.3
8.6

7.7
6.5

Q'.SO

0.69
0.80
0.72
0.73

i!so

1.19
1.37
1.27
1.43
1.45

Table No. 20

MATERIALS REQUIRED FOR 100 SQ. FT. OF SURFACE
FOR VARYING THICKNESS OF COURSE

6 in.

7 in.

8 in.

9 in.

Thickness
Mix

C.

Sd.

St.

C.

Sd.

St.

C.

Sd.

St.

C.

Sd.

St.

:1V2:3

14.0

0.78

1.56

16.4

0.91

1.82

18.7

1.04

2.08

21.1

1.17

2.34

:2:3

12.9

0.95

1.43

15.0

1.11

1.67

17.2

1.27

1.90

19.3

1.43

2.14

:2:4

11.1

0.82

1 64

12 9

0,Qfi

1 92

14 8

1 10

2 19

16 7

1 23

2 47

:2V2:4

10.3

0.95

1.53

12.0

1.11

1.78

13.8

1.27

2.03

15.5

1.43

2.29

:2V2:5

9.2

0.86

1.72

10.8

1.00

2.00

12 3

1 14

2 2Q

13.9

1.29

2.57

:3:6

7.9

0.87

1.74

9.2

1.02

2.03

10.5

1.16

2.32

11.8

1.31

2.61

Note: — Quantities expressed in the following units:

Cement sacks Sand cubic yard

Pebbles or Broken Stone cubic yards

139

Table No. 21

MATERIALS REQUIRED FOR 100 SQ. FT. OF SIDEWALKS AND
FLOORS FOR VARYING THICKNESS OF COURSE

Concrete Base

1:2:3

1:2:4

1:2 l/2 :4

1:2V2:5

Proportions

Thickness

C.

Sd.

St.

C.

Sd.

St.

C.

Sd.

St.

C.

Sd.

St.

2 i/2 in.

5.4

0.40

0.60

4.6

0.34

0.68

4.3

0.40

0.63

3.9

0.36

0.72

3

6.5

0.48

0.72

5.6

0.41

0.82

5.2

0.48

0.77

4.6

0.43

0.86

3%

7.5

0.56

0.84

6.5

0.48

0.96

6.0

0.56

0.89

5.4

0.50

1.00

4

8.6

0.64

0.95

7.4

0.55

1.10

6.9

0.64

1.02

6.2

0.57

1.14

4'/2

9.7

0.72

1.07

8.3

0.62

1.23

7.7

0.72

1.14

6.9

0.64

1.28

5

10.8

0.80|1.19

9.3

0.69

1.37

8.6

0.80

1.27

7.7

0.71

1.43

5V2

11.8

0.88

1.31

10.2

0.76

1.50

9.5

0.87

1.40

8.5

0.78

1.57

6

12.9

0.95

1.43

11.1

0.82

1.64

10.3

0.95

1.53

9.2

0.86

1.72

Wearing Course

Thickness
Inches

I4
2

1:1

1:1 Vz

1:2

C.

Sd.

C.

Sd.

C.

Sd.

3.0
4.5
6.0
7.5
9.0
10.5
12.0

0.11
0.16
0.22
0.27
0.33
0.39
0.45

2.4
3.6
4.8
6.0
7.2
8.4
9.6

0.13

0:19

0.26
0.33
0.40
0.46
0.53

2.0
2.9
3.9
4.9
5.9
6.9
7.9

0.15
0.22
0.29
0.36
0.43
0.50
0.58

Note: — Quantities expressed in the following units:

Cement sacks Sand cubic yards

Pebbles or Broken Stone cubic yards

140

CHAPTER 11.
FOUNDATIONS AND FOOTINGS

Before foundations and their footings are built,
it is presupposed that suitable tests by borings and
test loads have been made on the soil at the build-
ing site to determine its bearing value. In order to
sustain the weight of the structure to be placed
upon it, the foundations must be started on soil of
sufficient bearing capacity to sustain the proposed
superimposed load. Frequently to avoid excava-
tion to unnecessary depth the proposed load is dis-
tributed over a greater area of soil by starting the
foundation proper on a suitable footing.

When the excavation required for the building
having basement extending 40 or 50 feet below
grade passes through a firm stratum into softer ma-
terial or where any settlement at all would be con-
siderable, the foundations usually consist of wood
or concrete piles driven close together or of con-
crete piers extending to a lower stratum of hard
clay or to bed-rock. Where piles are driven close
together and do not bear on bed-rock, the soil is
compacted and skin friction together with slight
bearing at the foot of the piles sustains the super-
imposed load without any material settlement.
Concrete piers, on the other hand, do not depend
on friction except when it is impossible to carry
them down to bed-rock, in which case their sustain-
ing power is usually increased by increasing the
diameter of the lower section to form a bell-shaped
footing which gives additional bearing area.

Building codes in various cities specify the max-
imum load allowed on clay or other soils. For
clay, the allowable unit pressures go as high as
7,000 pounds per square foot for spread founda-
tions. Concrete piers are usually proportioned to
carry a load of 40,000 to 50,000 pounds per square
foot at the top. The load generally used for wood
or concrete piles seldom exceeds 20 tons per pile

141

but it will be found that in most cases long piles,
driven to refusal will carry safely 50 tons. Foun-
dations and footings are rarely or never reinforced,
dependence being placed on their mass for the re-
quired strength. There are, however, exceptions.

For small structures, it is frequently possible to
place the concrete for the foundation in the exca-
vated earth trench without using forms until
ground level is reached. This is true when the
earth is sufficiently firm to prevent caving of the
sides of the trench. However, when concrete is
placed under such conditions, workmen should be
cautioned against running wheel-barrows too near
the edge of the trench, thus resulting in earth
dropping into freshly placed concrete and causing
porous pockets in the mass. The best way is to
lay planks alongside of the trench. Also, in spad-
ing or tamping concrete for foundations where it is
being deposited in a trench without forms, care
should be taken not to knock down fresh earth into
the concrete for the reason above mentioned.
Sometimes, as in the case of excavations for a base-
ment or cellar, the concrete will need a form only
on the inside, the earth wall of the excavation serv-
ing in this case as the outer form.

Table No. 22

BEARING POWER OF SOILS

Supporting
Power in
Tons per Sq.

Ft.

Rock — in thick layers, in natural bed.

200

Clay — in thick beds, always dry

4

Clay — inthick beds, moderately dry

2

Clay — soft

1

Gravel and coarse sand, well cemented

8

Sand — compact and well cemented .

4

2

Loam soils . . . .

0.5

142

CHAPTER 12.
WATERPROOFING OF CONCRETE

Poor Concrete Responsible for Popular Belief
that Concrete is not Watertight

Much concrete construction that has been done
would give many the impression that concrete
could not resist the passage of water. This has
given rise to discussion as to the waterproofness
or watertightness of concrete.

Good Concrete Properly Mixed is Water Tight

Probably no concrete ever has been, nor ever
will be made that does not contain a considerable
percentage of voids. But for all practical purposes
concrete can be made watertight. The simplest
way of doing this is to so proportion well graded
materials that voids will be reduced to the lowest
possible minimum, and as existing, will not be con-
nected with one another so as to result in continu-
ous open channels through the mass.

The fact that concrete well made and properly
placed is essentially a watertight material, is proved
in many structures long used successfully as con-
tainers for water, oil or other liquids.

Thin sections of concrete are likely to contain
small fissures that will permit seepage. Also such
sections are almost invariably porous because of the
difficulty in placing thin sections of concrete in
forms to insure uniform density of the structure
throughout. However, countless structures such as
tanks, standpipes and other concrete receptacles for
fluids stand today as evidence that concrete can be
made watertight for all practical purposes.

Fundamentals for Watertightness

Primarily, several fundamentals govern the suc-
cess or failure to attain watertight concrete. These
fundamentals when observed or disregarded, as the

143

case may be, contribute to the success or failure of
the desired end. If mixtures are not properly pro-
portioned, if the materials of which they are pro-
portioned are not graded so as to reduce voids to
the lowest possible limit, if mixtures are too dry or
too wet, if, after placing, the concrete is not pro-
tected against too rapid drying out, the work will
not be watertight. It is necessary, of course, that
most uses of concrete in building construction shall
result in work that is watertight or waterproof be-
cause basement walls, floors and roofs fail in part
of their intended usefulness unless such an end is
attained.

Reinforcing steel must also be prevented from
rusting and this can only be done when the concrete
covering it is essentially impermeable to water.

Systems for Increasing Watertightness

There are three principal methods or systems
employed to increase the watertightness of con-
crete. They may be termed the "integral," "super-
ficial" and "membrane" methods. The first consists
in adding a material to the concrete when it is
mixed. The superficial method consists of coating
the concrete surface with . a preparation that will
adhere to it and remain attached. The membrane
method consists of putting on the concrete a coat-
ing distinct from it. While this coating may ad-
here to the concrete, it will not crack if the concrete
does, because of being a distinct and somewhat
elastic membrane, usually strengthened by felt or
other fiber cloth and impregnated with a mastic
asphaltic or bituminous material.

The three methods just summarized have ad-
vantages as well as disadvantages. For example, it
is impossible to use the integral method to prevent
water from seeping through concrete after the work
has been finished. In integral as well as in superfi-
cial methods o'f treatment, cracks developing in the
concrete would make the possible waterproofing
medium or method in these classes of no avail. In
the membrane as well as the superficial method,

144

care must be taken not to puncture the waterproof-
ing coat.

The three methods of waterproofing mentioned
are closely allied and there are various processes of
waterproofing on the market that are about halfway
between two of the methods. For example, when
melted paraffin is applied to a concrete surface with
a brush, as is sometimes done to increase water-
tightness, the treatment belongs to the superficial
method, though the paraffin may penetrate the con-
crete so far as to be classed as an example of the
integral method. Some paints may be classed as
belonging to the superficial methods though they
are elastic enough to bridge over very small cracks
that may develop in the concrete and thus come
within the membrane class.

There are a number of proprietary preparations
on the market, the use of which is urged by the
manufacturers in the interest of increasing the wa-
tertightness of concrete. Without approving or
condemning the claimed merits of any of these
preparations, it may be said that in no case will
their use be successful unless in proportioning, mix-
ing and placing the concrete and protecting it after
placed, all of the fundamentals of good concreting
practice are recognized.

One of the oldest processes of waterproofing
concrete is known as the Sylvester process. It
consists of applying powdered alum and soft soap
to the concrete. These materials combine chemi-
cally to form compounds that are insoluble in water
and fill the surface voids in the concrete with an in-
soluble, gelatinous mass. As a rule the Sylvester
process is applied by painting on the concrete two
separate solutions of alum and soap.

Asphalt and coal tar are used for waterproofing,
particularly the outside of foundation or basement
walls. They are applied hot with a mop. Several
coatings are usually applied.

145

146

CHAPTER 13.
PLACING CONCRETE UNDER WATER

When concrete must be placed under water, the
work should be done in such a manner that the
ingredients of the mix will not separate. Either a
tremie must be used — that is, a large pipe through
which the concrete is carried to a point near the
bottom of the water; or large buckets with hinged
bottoms, that can be lowered and from which the
concrete can be dumped with least disturbance.

When a tremie is used, the pipe is gradually
withdrawn and thus elevated upward as the mass
of concrete deposited is increased. The best results
are obtained by mixing the concrete moderately
dry, although when depositing by means of a pipe
or chute, the concrete is often mixed very dry. The
difficulty often encountered in placing concrete un-
der water usually results from lack of care to pre-
vent separation of materials. If the concrete is
thrown into the water or even allowed to settle
through it, separation of materials is unavoidable.

One common and inexpensive method is to
provide a closed rectangular wood chute or a circu-
lar metal one. This is placed with one end extend-
ing into the water and to the foundation in such
a manner as to prevent the concrete from flowing
out while the chute is being filled. When entirely
filled, it is raised slightly, thereby permitting the
concrete to gradually distribute itself and at the
same time permit additional concrete to be placed
in the chute, so that at no time can water enter.

In extensive work, a closed bucket with hinged
bottom is often used. In some cases concrete has
been placed under water in coarse jute sacks which
were lowered to the bottom of the foundation. This
method, however, is not dependable since frequent-
ly there is poor bond between different parts of the
foundation. When the concrete is to be deposited

147

from an airtight receptacle lowered into the water,
it should be mixed dry enough so that when the
gate or trap door of the bucket is opened, the ma-
terial will be discharged in a mass.

Cofferdams should be sufficiently tight to pre-
vent current of water through the pit and in other
respects the water should be quiet. The surface of
the concrete deposited must be kept as nearly level
as possible to avoid the formation of pockets which
will retain laitance and sediment. Where concrete
is not deposited continuously, all sediment should
be removed from the surface of the concrete by
pumping or some other means before concreting is
resumed. No mixture leaner than 1 :2 :4 should be
used when concrete is deposited under water.

148

CHAPTER 14.

NOTES ON SILOS, COAL AND MATERIAL
BINS AND GRAIN TANKS

As a rule all structures coming under the above
heading are circular in shape, the exception being
that sometimes coal pockets and other material bins
may be of rectangular form. However, because of
the development of circular forms for such con-

tstruction, the occasions where rectangular bins are
used are those largely governed by the location.
The circular type of structure is in general more
popular and becoming more common.

Certain essentials of construction are alike in
all of the structures mentioned. Because of the
pressure of contained contents all must be the sub-
ject of engineering design, principally to insure that
the concrete will be sufficiently reinforced to with-
stand internal pressure.

Reinforcement for any of the structures men-
tioned may be either rods or some one of the sev-
eral types of mesh fabric used as concrete reinforce-
ment. To illustrate the method of determining the
kind of reinforcement required for a monolithic
concrete silo for example, reference is made to an
accompanying table which shows the spacing of
horizontal reinforcing bars for silos of various in-
side diameters. Assume a silo 14 feet inside diam-
eter and 40 feet high as an example. For an inside
diameter of 14 feet, the table specifies */2 -inch round
rods. The column at the extreme left of the table
gives the distance from the top of the silo for in-
tervals of 5 feet. As the silo is 40 feet high, run
down the column to the line "35 to 40 feet," then
across to the column under "14 feet diameter."
This shows the spacing as 12 inches which means
that there must be a horizontal ring of %-inch steel
every 12 inches. This spacing applies to the first
5 feet above the floor. For the next 5 feet the spac-
ing changes to 14 inches. Spacing becomes great-

149

er as the top of the silo is approached and can be
found by simply following the 14- foot column to the
top. This method of determining the horizontal re-
inforcement applies to all sizes and heights of silos.

Table No. 23

SPACING OF HORIZONTAL REINFORCING RODS FOR
SILOS OF VARIOUS INSIDE DIAMETERS

Distance

10-foot

12 -foot

14-foot

16-foot

18 -foot

20 -foot

in Feet

Diameter

Diameter

Diameter

Diameter

Diameter

Diameter

Down
from Top

%-inch
Round

jHi-inch
Round

Vz-inch
Round

Vz-inch
Round

V2-inch
Round

Vz-inch
Round

of Silo

Rods

Rods*

Rods*

Rods*

Rods*

Rods*

Inch

Inch

Inch

Inch

Inch

Inch

Top 5 ft.

24

24

24

24

24

24

5 to 10

24

24

24

24

24

24

10 to 15

24

18

24

24

24

24

15 to 20

18

16

24

18

18

16

20 to 25

16

12

18

16

14

14

25 to 30

14

10

16

14

12

12

30 to 35

12

9

14

12

10

10

35 to 40

10

8

12

10

9

8

40 to 45

9

7

11

9

8

7%

45 to 50

8

6'/2

10

81/2

7V2

7

*If square rods are used increase spacing 30 per cent, but in no case
should spacing be greater than 24 incnes.

Vertical reinforcement is needed in all monolithic
concrete silos. Usually this consists of % or %•
inch steel rods spaced 30 inches apart around the
circumference of the silo regardless of its size. In
this connection it should be mentioned that while
theoretically the center of the wall is not the exact
place where reinforcement should be placed in a cir-
cular structure, in designing for the reinforcement
a factor of safety is considered which permits plac-
ing reinforcement at the center of the concrete sec-
tion principally to facilitate placing of concrete. At-
tention also should be called to the necessity of se-
curely wiring horizontal to vertical rods, correctly
spaced at their intended location so that they may
not be misplaced while depositing concrete.

Usually concrete of three different proportions is
used in building monolithic silos. Requirements for
materials are given elsewhere under "Aggregates."
Table No. 1 page 28. A 1 :2% :5 mixture is generally

150

used for foundation and floor. For the walls a 1 :2 :4
mixture is used and for the roof a 1:2:3 mixture.

An accompanying table gives quantity of concrete
materials for monolithic silos of various diameters.

Table No. 24

QUANTITY OF CONCRETE MATERIALS FOR MONOLITHIC
SILOS OF VARIOUS DIAMETERS

These figures include footings and floor, but not roof. Walls 6 inches
thick. Continuous doors 2 feet wide. Figures are for sacks of cement
and cubic yards of sand and pebbles:

For Silo 30 Feet High

For Each Additional 5 Feet

Inside

in Height

Diameter

Feet

Cement

Sand

Pebbles

Cement

Sand

Pebbles

or Stone

or Stone

Sacks

Cu. Yd.

Cu. Yd

Sacks

Cu. Yd.

Cu. Yd.

10

116

11

18

16.0

1.5

2.4

12

140

13

21.5

19.2

1.8

2.9

14

164

15

25

22.5

2.1

3.4

16

188

17.3

28.7

25.7

2.4

3.8

18

212

19.6

32.6

29.0

2.7

4.3

20

236

22

36.5

32.3

3.0

4.8

In order to assist contractors in giving informa-
tion as to size of silo required, a table showing di-
ameter of silo necessary to feed various numbers
of animals and another showing the approximate
capacity of round silos are given.

Table No. 25

DIAMETER OF SILOS REQUIRED TO FEED
VARIOUS NUMBERS OF ANIMALS

Minimum number of each kind of stock to

Approxi-

be fed from each size silo

Diameter

mate

in Feet

Pounds to be

Fed Daily

Dairy
Cows

Beef
Cattle

Stock
Cattle

500-lb.
Calves

Horses

Sheep

10

525

13

21

26

44

48

75

12

755

19

30

38

63

69

252

14

1030

26

41

52

86

94

344

16

1340

34

54

67

112

122

446

18

1700

42

68

85

142

155

567

20

2100

53

84

105

175

191

700

151

Table No. 26

APPROXIMATE CAPACITY OF ROUND SILOS

Inside Diameter of Silo in Feet and Capacity in Tons

Height

OI

Silo

Feet

10 feet

12 feet

14 feet

16 feet

18 feet

20 feet

Tons

Tons

Tons

Tons

Tons

Tons

28

42

61

83

30

47

67

91

32

51

74

100

131

34

56

80

109

143

36

61

87

118

155

196

38

66

94

128

167

212

40

70

101

138

180

229

280

42

109

148

193

244

299

44

117

159

207

261

320

46

170

222

277

340

48

236

293

361

50

310

382

Bins for holding materials other than grain such
as coal, sand, etc., are sometimes built under trestles
and are filled by dumping into an opening in the
top, or by bucket, belt or screw conveyors. They are
emptied through gates at or near the bottom or by
dippers and grab buckets. Others are filled and
emptied in much the same manner as grain bins.

The average grain elevator provides for the fol-
lowing parts and operation:

1. A receiving shed where the grain is dumped
from wagons into chute ending in a boot at
the foot of the elevator. Usually a scale is
provided to weigh the grain as received.

2. The elevator is an endless chain or belt with
buckets which carry the grain to a head-
house where it is delivered by spout to the
bins. A belt conveyor is generally necessary
where there is a group of several bins.

3. When removing grain from the bin for ship-
ping, it is usually spouted from the bottom of
the bins into the boot at the foot of the ele-
vator and from there elevated to the work-
ing floor.

4. Elevators may or may not contain drying and
cleaning machines and other special machinery.

152

Lengths of rods used as reinforcement are gen-
erally such that splices must be made. The only re-
liable splice is to lap the ends enough to develop
bond. If the pieces are in contact there will be loss
of bonding area, amounting in the case of s.quare
bars to 25 per cent. For efficient bond the concrete
must everywhere completely surround the steel.
Lapped ends should have a clear space between
them of not less than twice the thickness of the
steel, the minimum distance being 1 inch regardless
of the thickness of the steel. This may be obtained
by placing a piece of steel or concrete between the
ends of the rods and wrapping around them some
soft wire to keep the ends separated while concrete
is being placed. Horizontal reinforcement is gener-
ally placed on the outside of vertical reinforcement,
merely because this is the easiest way to place it.

Accompanying tables show quantity of rein-
forcement required for bins of various diameter and
height, and capacity of circular bins and tanks in
bushels.

This table and the two following are based on
data contained in the text book known as "Walls,
Bins and Grain Elevators" by Milo S.Ketchum, pub-
lished by the McGraw-Hill Book Co., New York.

Figures given for quantities of reinforcement
required are theoretically correct but each bin or
tank should be the subject of special engineering
design so that the particular requirements in ques-
tion to be met will be accurately determined.

Circular Grain Tanks

Area of horizontal reinforcing steel in square
inches per foot of depth, and thickness of wall in
inches. Steel to be in center of wall.

Set ^4-inch rods vertically at approximately 6-
foot centers and %-inch rods between them at ap-
proximately 2-foot centers.

153

Table No. 27

CIRCULAR GRAIN TANKS— DIAMETER IN FEET

Depth

in

8

10

12

14

16

18

20

22

Feet

f

5

0.026

0.033

0.040

0.046

0.053

0.059

0.066

0.072

10

0.041

0.066

0.079

0.092

0.105

0.118

0.131

0.145

15

0.050

0.073

0.096

0.120

0.157

0.194

0.197

0.217

20

0.056

0.082

0.109

0.140

0.171

0.207

0.234

0 289

25

0.058

0.087

0.119

0.153

0.190

0.228

0.268

0.309

30

0.059

0.090

0.125

0.163

0.204

0.246

0.294

0.336

35

0.060

0.091

0.128

0.170

0.213

0.260

0.309

0.360

40

0.062

0.092

0.131

0.174

0.219

0.270

0.324

0.381

45

0.064

0.094

0.134

0.179

0.225

0.288

0.335

0.398

50

0.066

0.095

0.135

0.183

0.235

0.290

0.347

0.410

Thick-
ness

6"

6"

6"

6"

7"

7"

7"

8"

of wall

Square Grain Tanks

Upper figures give thickness of wall in inches.
Lower figures give area of reinforcement in square
inch per foot of depth. Center of horizontal steel
to be IJ^-inch from face of wall. Vertical bars
54-inch round or y2-mch square to be spaced 24-inch
centers (approx.)

Table No. 28

SQUARE GRAIN TANKS— DIMENSIONS IN FEET

Depth
in
Feet

8'x8'

10'xlO'

12'xl2'

14'xl4'

16'xl6'

18'xl8'

20'x20'

22'x22'

5

4"

4"

4.5"

6.0"

6.0"

6.5"

8.0"

85"

0.23

0.28

0.34

0.43

0.50

0.55

0.60

0.65

10

4"

5.5"

6.5"

8.0"

9.0"

10.0"

10.5"

10.5"

0.28

0.39

0 47

0.60

0.68

0.77

0.83

0.91

15

4.5"

5.5"

7.0"

9.5"

10.5"

11.5"

12.5"

14.0"

0.31

0.42

0.52

0.74

0.86

0.94

1.02

1.15

20

4.5"

6.0"

7.0"

9.5"

11.0"

13.0"

14.0"

15.5"

0.32

0.44

0.55

0.74

0.90

1.06

1.18

1.28

25

5"

6"

7.5"

10.0"

11.5"

13.0"

14.5"

16.0"

0.34

0.46

0.58

0.80

0.93

1.06

1.22

1.34

30

5"

6.5"

8.0"

10.0"

11.5"

13.5'

15.0"

16.5"

0.34

0.46

0.63

0.80

0.96

1.11

1.27

1.38

35

5"

6.5"

8.5'

10.5"

12.0"

14.0"

15.5"

17.0"

0.35

0.48

0.66

0.82

0.97

1.14

1.27

1.44

40

5"

6.5"

8.5"

10.5"

12.0"

14.0"

15.5"

17.5"

0.35

0.48

0.67

0.83

0.99

1.16

1.30

1.48

45

5"

6.5"

8.5"

11.0"

12.5"

14.0"

16.0"

18.0"

0.35

0.48

0.68

0.84

1.00

1.18

1.33

1.51

50

5'

6.5"

8.5"

11.0"

12.5"

14.5"

16.0"

18.0"

0.35

0.<?8

0.68

0.85

1.03

1.20

1.35

1.54

154

Table No. 29

CAPACITY OF CIRCULAR GRAIN BINS AND TANKS— IN
BUSHELS

Height

Diameter in Feet

10

12

14

16

18

20

22

24

10
15

631

946

910
1364

1238
1855

1616
2420

2042
3060

2525
3785

3060
4590

3550
5320

20

1212

1820

2475

3230

4090

5050

6125

7100

25

1578

2275

3095

4040

5100

6310

7650

8880

30

1892

2730

3715

4840

6125

7575

9180

10630

35

2208

3185

4340

5650

7145

8840

10700

12400

40

2525

3640

4950

6460

8170

10018

12240

14560

45

2840

4095

5570

7270

9190

11350

13780

16380

50

3158

4550

6195

8030

10210

12620

15300

18200

55

5005

6814

8888

11231

13882

16830

20020

60

5460

7433

9696

12252

15144

18360

21840

65

8053

10504

13273

16406

19890

23660

70

8672

11312

14294

17668

21420

25480

75

....

9293

12120

15315

18930

22950

27300

80

....

....

12928

16336

20192

24480

29120

85

....

13736

17357

21454

26010

30940

90

14544

18373

22716

27510

32760

95

19399

23978

29070

34580

100

20420

25240

30600

36400

lbushel=2150cu. inches=1.245 cu.ft. or I cu. ft. = 1728 cu. inches=
1 . 245 cu. ft. per bu.

Note: — Special bins should always be the subject of special en
gineering design.

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156

CHAPTER 15.

MECHANICAL EQUIPMENT— ITS STARTING
CARE AND OPERATION

The best equipment that it is possible to make
can be quickly ruined and its usefulness destroyed
by improper care and operation. Every contractor
desires to get the best possible results from his
equipment, and he hires the best obtainable opera-
tors to take care of his machines. At times, how-
ever, new men have to be broken in, and in order
that these men may have the benefit of the experi-
ence of others, we have compiled in this chapter
useful data as to the starting, care and operation
of Koehring Mixers.

Embodied in this will be found data that will
also be of interest and value to experienced oper-
ators. In addition, our Research and Engineering
Departments will be glad to answer any questions
submitted to them by operators, with a view to en-
abling them to secure the greatest possible output
from their machines under existing conditions.

Method of Unloading Mixer

Assuming that the car containing a Koehring
Mixer has arrived at the nearest siding to the work
and that the blocking has been removed, jack up the
mixer and put wheels, or multiplane tractors in
place. A runway of at least 20 feet long should be
built to make an easy grade. If an abundance of
railroad ties is available, one may build a close crib-
bing of them, and use 3" x 12" planks for runways.
If the ties are not to be had, heavier stringers may
be hauled to the siding, as they do not require as
much blocking as the above mentioned method.
After the runway is built, block the wheels of the
flat car securely, fasten block and tackle to the frame
of the mixer and to the draw bar of the car on the
opposite end from the cribbing. Use pinch bars un-
der the truck wheels and work the mixer gradually
onto the incline, lowering slowly by means of the

157

blocks and tackle. A Paving Mixer may also be
run off of car, and down runway under its own
power, if desired.

Assembling of Paving Mixers

The first step in assembling a Koehring Paver,
after unloading, is the placing of the overhead steel
frame, which should be put together as indicated
by the marks on the different parts. The tighten-
ing of bolts should be left until the framework is
completely assembled as it may be necessary to ad-
just some parts of it by means of drift pins. By
leaving bolts loose, the operation is made easier.
After all bolts are in place, see that lock washers
are on each, and then draw nuts up tight.

Next, load the charging skip of the paver on a
truck, back the truck to the mixer and fasten skip
in proper place. This method of attaching skip
eliminates much lifting and blocking, and saves
much time. The two skip cables are then led from
the grooved winding sheaves, over the small sheaves
near the top of the frame, to the cable brackets on
the skip. Care should be taken to have the same
tension on each cable to prevent twisting of the
skip. It is also important that the cable ends are
fastened securely.

Before the large sheave is &eyed on, all cable
should be run off and rewound to be sure that there
is no twist in it. This is extremely important as
the cable will continue to jump off the winding drum
if twisted. Next, be sure that the sheave fits within
1/32" of the bearing; then drive the key home.
When skip is on the ground the hoisting cable
should practically fill the large sheave and there
should be \y2 wraps on the winding drum. On the
14E Paver, in order that the cable may lead prop-
erly, the grooved winding sheave should be keyed
on at the end of the shaft and not close up against
the large sheave.

Next, load boom on truck, back truck to paver
and secure boom in place. As the boom support
cable is attached to boom, when shipped, it is a sim-

158

pie matter to hang it. Take cable off of sheave on
boom where it is attached, and get the slack needed
by turning the boom elevating hand wheel and then
slip over sheave which is attached near top of frame.

On the 10E, 21E and 32E, the delivery bucket
cable is reaved onto the grooved winding drum
when shipped from the plant, so all that is neces-
sary is to put it in the proper sheaves on the boom
and attach to cable clamps on bucket as shown by
blue print accompanying mixer.

On the 14E the cable must be re-reaved when
assembled on the job, as the idler sheave is removed
before mixer leaves the plant. To reave cable
properly, stretch it on the ground in line with
boom; take end nearest to mixer, lead it over top
of idler or tension sheave on operator's side, bring
it down in back of main winding grooved sheave
and then up again to idler sheave. Repeat this op-
eration until only two empty grooves remain on
idler sheave, then skip a groove and bring it down
in front of main winding sheave, then in front of
rear upper sheave on boom, and over top of lower
sheave. Then, take cable under boom and stop at
bucket, which should be placed in center of boom.
The other end of the cable is taken under the front
sheave on top of boom, through the boom hoist
bracket, over sheave on front end of boom, thence
back to bucket. The ends are then taken around
the shuttle and clamped in place. Be sure that cable
is started in top center groove of shuttle and carried
under the full length of shuttle before clamping.

Slack in bucket cable on the 10E and 14E is dis-
posed of by taking up nuts on the idler or tension
sheave hangers, and on the 21E and 32E by adjust-
ing sheave on the end boom.

Boom Erection and Adjusting Instructions

Erect boom and place pin (1) in position. Then
fasten support cable to support (2) and thread as
per diagram and fasten other end at (3). Next slip
assembled bucket and carriage on boom and bolt
stop blocks (4) in position.

119

Boom Details

SHUTTUE.,

Figure 1

Boom Details

Figure

161

Thread boom cable as follows:

Place end of long cable in winding drum (5) at
hole (A). Bend cable and clamp securely. Turn
winding drum (5) until half the grooves are filled.
Place end of short cable in hole (8) and lace other
half of drum. Thread as shown in diagram, BEING
SURE ENDS MEET IN CENTER OF BOOM
on under side of channels. Place ends in shuttle,
as shown in detail, and clamp. Slip shuttle into
carriage and bolt stop blocks (19) in position. To
tighten cable adjust bolt (6).

Adjust boom as follows :

See that both clutches (7) and (8) are in neutral
position. When in this position links (17) should
be in line. Adjustment may be made at (9) and
operating lever should be in neutral position in
plate (10). Brake should then be set by adjusting
bolt (18). Run bucket in, and if carriage hits
bumper (11) adjust nuts (12). Run bucket out and
if carriage hits stop blocks (4) adjust turnbuckle
(14). Carriage should never be allowed to strike
blocks (4) but to come as close as possible.

The door of bucket can be adjusted to suit con-
sistency of concrete and thickness of pavement to be
laid. To obtain proper opening, adjust angle (15).
If door does not close properly draw up on bolts (16).

Assembling of Construction Mixers

The same methods used in unloading the Paving
Mixer should be used for a Construction Mixer, and
the same principles apply to the hoisting cables for
the skip; but, instead of loading the charging skip
on a truck, the skip should be taken down off the
car and rolled into place at the side of the Mixer
where, raised on planks, it could be readily slid up
to place by means of bars.

Preparing to Start Mixer

After mixer is assembled, see that all grease and
oil cups are full, using a good grade of oil and No. 3
cup grease. Grease cups should be screwed down at
least twice a day, to keep all the bearings well lu-

162

bricated. Be sure to keep all cables lubricated with
good cable compound, and all gear teeth well lubri-
cated with a good graphite grease, but DO NOT
put grease on rollers or drum runway. The cable
clamps should all be gone over to make sure all nuts
are tight, as a loose clamp may cause trouble.

Before starting the engine, be sure that all
clutches are disengaged ; by so doing a bad accident
may be avoided.

Starting and Care of Boiler

After mixer is assembled, a slow fire should be
started in the boiler. Do not crowd the fire until
steam pressure shows on the gauge, indicating that
sufficient steam has been generated to protect the
top ends of the tubes; which, in full length tube
boilers are exposed to the hot gases. Hard firing
in getting up steam is almost certain to damage the
top ends of the tubes. This not only applies to fir-
ing the boiler the first time, but holds good for
every time a new fire is made.

During the first day's operation, do not keep the
water level in the boiler above the middle of the
gauge glass, as the water will, undoubtedly, foam on
account of the oil and grease on the plates. Blow
down the water glass several times a day but never
depend on it, as the opening may become choked,
keeping the water level apparently constant, while
the water in the boiler may actually be getting very
low. The water cocks are put in the boiler to use, and
are the only sure way of ascertaining the water level.

The boiler should be blown off well at the end of
the day to remove all grease. After this, sufficient
water should be carried in the boiler to show % °f
the way up on the gauge glass.

Keep a thin clean fire. This will give you 100%
more heat than a thick dirty fire, as the smoke from
a thick fire chokes up the tubes, and combustion
takes place not in the tubes but in the hood and
stack. Clinkers should be removed from the fire
box frequently and the ash box should be kept
clean. Doing so prolongs the life of the grates and
gives a better draft.

163

If at any time the boiler is to remain out of use
for a few days, place a cover over the smoke stack
to prevent water rusting out the tubes.

There will probably be injector trouble the first
day, due to clogging from scales from new pipes
and boiler. In such an event, take injector apart
and clean thoroughly.

The boiler tubes should be kept clean, as the soot
collected on them is a nonconductor of heat and
more fuel is required in order to keep up steam. As
often as is necessary, the tubes should be cleaned
with a scraper — the frequency will depend entirely
upon the fuel used and the carefulness exercised in
firing ; but they should be cleaned in the morning, at
least, before firing up, and during the day they should
be blown out every once in a while with steam.

Practically all feed waters contain more or less
scale forming substances which precipitate and form
incrustations in the water leg, on the flue sheet and
around the lower end of the tubes.

Frequently the contractor has to make use of
muddy water, and this also collects in the water leg
and on the lower flue sheet. This scale and mud, if
not removed by frequent cleansing, will become
firmly baked on the heating surfaces, retarding the
flow of the heat to the water and weakening the iron
from stresses due to unequal expansion. An accum-
ulation of scale 1/32" thick requires 10% more fuel;
1/16" of scale requires 20% more; y&" of scale re-
quires 30% more; and %" requires 60% more. By
keeping boilers clean, considerable fuel is saved.

Under usual conditions the boiler should be
blown off a little every day. It is a good plan, be-
fore stopping after a day's run, to pump in more
water than required while running. The next morn-
ing after firing is started and some ten to thirty
pounds pressure has been raised, open the blow-off
valve and blow the water down to the proper level.
If the water is very muddy, it is a good plan to re-
peat this at the noon hour. After the boiler has been
run for some length of time the boiler should be
blown down entirely and thoroughly washed. This

134

should be done at least once a week, and in case
of muddy water, it could be done to advantage
twice a week.

The boiler should not be blown down for wash-
ing while under steam pressure. The best time to
do it is when the steam pressure has just gone down,
but the water is still hot. Open the blow-off valve,
let all the water run out, remove the handhole
plates and wash out the boiler with a hose. To
properly do this, it is necessary that the water be
under pressure and that a properly shaped nozzle is
used. A good nozzle can be made of %" or %" pipe
having a short bend at the end so as to throw the
stream of water at right angles to its length and at
high velocity. If y2" pipe is used, the opening at
the end of the pipe should be drawn down a little
on a taper so as to give about a %" opening.

The boiler should also be scraped with a scraper
consisting of an elliptically shaped piece of iron,
which would fit the side of the boiler, and fastened
to a rod for handle. A very good cleaner can also
be improvised from a heavy wire with a piece of
chain secured to the end of it.

If the feed water contains ingredients such as to
form a hard scale, impossible to remove by wash-
ing, a boiler compound may be used to advantage
so as to reduce the scale to a muddy consistency
that can be washed out.

The best water obtainable should always be used
for the boiler. Where necessary to take it from a
road side sump, it is well to make two sumps and
use one as a settling basin; or barrels may be filled
and water drawn from them after the sediment has*
settled to the bottom.

Starting and Care of Steam Engine

After all grease and oil cups and lubricator are
filled, see that they are feeding properly. The oil
cup on the connecting rod when full should last five
hours; the lubricator should be adjusted to feed six
drops per minute. The engine being oiled and
enough steam in the boiler, see that throttle valve is

165

closed and drain cocks in cylinder and steam chest
are open. Open valve in steam line near boiler,
and the throttle valve just enough to blow out the
water in steam line, steam chest and cylinder. After
allowing the steam to pass through a few minutes,
turn fly wheel off dead center, open throttle slowly
until the engine starts running; then close drain
cocks and open throttle valve wide. To avoid
blowing out of gaskets, the nuts on the studs, hold-
ing cylinder head and steam chest cover in place,
should be tested and tightened up, if necessary.

When starting an engine in cold weather, lim-
ber it up by letting it run idle a little while before
placing any load upon it. When engine is started
run it slowly, having all cocks open. Many cylin-
ders are cracked by a sudden change in temperature.

In cold freezing weather, drain all water and oil
from the cylinder and lubricator when engine is
shut down for the night.

Gasoline Engine

For adjusting Fuller & Johnson Engine see their
instruction book.
To Start and Run Fuller & Johnson Engine

1. Tighten the grease cups on main bearings
and connecting rod and set feed on cylinder oil
cup. Oil small parts with squirt can.

2. Fill jacket and water cooling tank with clean
water. In the winter time the water should be
warm to assist the engine in starting readily.

3. Fill the starting reservoir with gasoline and
open the gasoline throttle to the starting mark (S).

4. Close the starting damper. (Handles in hori-
zontal position as shown in Fig. 2).

5. Close switch on battery. (If battery ignition).

6. Prime the cylinder through the priming cup.
Put in one-half to one priming cup full if the engine
is cold. The hotter the engine the less gasoline
required.

7. Attach the starting crank on the governor
side and give the engine a few quick turns. As soon
as the engine starts, open the starting damper and
adjust the gasoline throttle to the running mark (R).

166

167

Care of and Starting Waukesha Motor

See that fuel tank is full.

Inspect the spark plugs to see that none is
cracked or loose.

Test them for sparking. If you aren't getting
a good spark at every plug, look for carbon on the
plugs, or trouble with the ignition.

Look at your oil glass to see that your motor
won't run dry.

Be sure that the cooling system is not short of
water. An overheated motor will never give the
good results that a perfectly cooled one will. Be-
sides, if you are going where water is not right at
hand, it may take you half an hour or so to get the
water you need.

In other words, look your motor over from stem
to stern before you start, so that you can correct
any troubles in the easiest and quickest manner.

A motor that has good ignition, is well-oiled and
well-fueled seldom gives any trouble — but neglect
any one of these features, and troubles arise.

You can save yourself a lot of time, trouble, and
expense-^to say nothing of adding years to the life
of your motor — by careful inspection of all parts
before you start.

Owing to the presence of kerosene in some fuel,
which is destructive to the motors if not properly
vaporized, we advise that the following should be
given every attention.

1. At all times be sure of a good adjustment on
the carburetor. In ninety cases out of a hundred
the carburetors feed too much fuel.

2. See that the air intake of the carburetor re-
ceives hot air from the exhaust, as it is most im-
portant that the carburetor bowls remain heated to
assist in vaporizing the kerosene.

3. Although spark plugs cause little trouble
these days, they should be removed at least once a
week and have all the points uniformly adjusted no
further apart than 1/32" of an inch. Guard the ig-
nition wires; nothing tends to reduce the efficiency

168

of the motor more than poor ignition and carbure-
tion. Make every spark do its work.

4. Do not overload the crank case with oil. Add
oil several times a day and in this way retain a cer-
tain level at all times. Oil magneto once a week,
putting about two drops of sperm oil in each oil hole
with a match. Too much oil is as bad as not enough.

5. Drain the oil from the crank case at least
once a week if using high test gasoline, or every
third day when using the ordinary grade of gaso-
line. In doing this be sure to remove the four plugs
under each connecting rod oil pocket as well as the
large plug to the oil reservoir.

6. Keep the motor at its proper speed. Insist
on having a seal placed on your governor, and never
attempt to break it: it is one protection against
motor troubles.

7. Watch the adjustment of push rods. Keep
the valve seats in good condition. Any one cylin-
der working improperly will cause no end of trou-
ble in a short time.

8. Cut down the idling of the motor, as doing
this will reduce the dilution of the oil in the crank
case, and the carbonizing of combustion chambers
by at least 40%.

After the motor has been examined to see that
the plugs are clean and that it has plenty of gaso-
line and oil, retard spark on magneto; throw out
grounding switch; prime engine through the four
priming cups, putting about two priming cups full
of gasoline in each cylinder. Then the engine is
ready to crank. When engine is running, advance
spark. Before beginning to mix, see that there is
proper water circulation by raising the return pipe
in cooling tank.

To Get Out of Trouble

No matter whether you have a Fuller & Johnson
engine, a Waukesha engine, or some other make,
when trouble arises, consult the following TROU-
BLE CHART (reprinted by the courtesy of Stan-
ton & Van Vliet Company, Chicago, Illinois, pub-

169

lishers of 'Gas Engine Troubles and How To Rem-
edy Them' by J. B. Rathbun). Follow down the
column under the head of SYMPTOMS until the
description tallies with the actions of your engine.

Engine Will not Turn Over — Engine Stuck

1. Hot bearing or bearings seized.

2. Stuck piston due to overheated cylinder.

3. Water frozen to piston and cylinder (leaks).

4. Bolts rubbing on base or oil shields.

5. Friction clutch holding load on engine.

6. Broken gears wedging.

7. Water in cylinder due to leak in jacket.

8. Obstacle blocking wheels or gears.

9. Broken crank-shaft.

10. Dry bearings or rusted piston.

Starting Troubles

1. Fuel valve closed at tank (see that fuel
reaches engine).

2. No gasoline in tank.

3. Battery or magneto switch open.

4. Broken or disconnected battery or magneto
wire.

5. Dirty electrodes on make and break ignition
system.

6. Broken igniter spring on make and break ig-
nition system.

7. Weak batteries on either low or high tension
system.

8. Magneto not generating on either low or
high tension system.

9. Foul spark plug, high tension system.

10. Short circuit in wires or connection.

11. Defective spark coil on high tension system.

12. Defective timer.

13. Storage batteries.

14. No compression, indicated by engine turning
easily over center.

15. Carburetor trouble due to poor mixture.

16. Cold weather carburetor troubles.

17. High altitude.

170

18. Air leaks in cylinder between carburetor and
cylinder.

19. Vibrator on high tension spark coil may be
out of action.

No Power — Loss of Power

1. Fuel valve partly closed, may jar shut.

2. Air damper closed in air intake pipe; always
open the damper immediately after starting.

3. Compression relief cam may be left in
"starting" position. It should always be turned to
"run" as soon as engine is up to speed.

4. Throttle left in "starting" position.

5. Retarded spark will reduce power output;
always advance it to the proper point as soon as
engine is up to speed.

6. Advanced spark, when excessive, will cause
a loss of power, which will be accompanied by
heavy pounding.

7. Weak batteries reduce the spark and power.

8. Vibrator adjustment may be poor on high
tension spark coil.

9. Foul igniters on make and break system.

10. Foul spark plugs are a frequent cause of
power loss, especially with high compression.

11. Defective timer will cause power loss.

12. Misfiring is always accompanied by a loss
of power.

13. Clogged muffler filled with soot, or a clogged
exhaust pipe will cause power loss.

14. Long exhaust pipes or exhaust pipes with
many short bends will reduce power.

15. Magneto trouble will reduce the spark.

16. Lack of oil, especially in the cylinder will
cause compression leakage and power loss.

17. Hot bearings will cause the effects of an
overload and reduce the output.

18. Carburetor troubles are a very frequent
cause of power loss. "See Loss of Power."

19. Compression leakage is a very common and
persistent cause of power loss. Test for compres-
sion by turning engine over "center" on compres-

171

sion stroke: if it passes over easily leakage exists,
and must be stopped to prevent power loss and
waste of fuel.

20. Cold jacket water will reduce power; have it
leave jacket at 160 degrees F. on gasoline engines,
and 200 degrees F. with kerosene engines.

21. Valve out of time will cause power loss.

22. Warm intake air will reduce mixture in cyl-
inder.

23. High altitudes will reduce output of engine.

24. Worm cams, rollers and timing gears change
timing.

25. Valve opening too small causes back pressure.

26. Spring too stiff on automatic intake valve.

27. Magneto out of time.

28. Valves stuck in guides.

29. Valve gear worn.

Misfiring

1. Loose wires or dirty connections.

2. Swinging ground caused by poor insulation.

3. Broken wire.

4. Weak or exhausted batteries.

5. Poorly adjusted vibrator on high tension
system.

6. Foul spark plugs on high tension system.

7. Dirty electrodes on make and break system.

8. Moisture may cause short circuits.

9. Magnetos may cause misfiring.

10. Power loss is generally accompanied by mis-
firing.

11. Defective or short circuited spark coil.

12. Defective timer on high tension system.

13. Batteries may be weak.

14. Water in gasoline.

15. Valve gear worn.

16. Leaking exhaust valves are a common cause.

17. Poor mixture or poor carburetor adjustment.

18. Air leaks between carburetor and cylinder.

19. Valves out of time.

20. Leaking automatic intake valves.

21. Compression leaks.

172

22. Empty fuel tank.

23. Spark gap too large in spark plug.

Misfiring in One Cylinder

1. One cylinder may have a heavier carbon de-
posit.

2. One cylinder may have an air leak.

3. One cylinder out of time.

4. By timer having poor contact.

5. Loose wire leading to misfiring cylinder.

6. Sooted plug.

7. Magneto distributor foul with dust.
18. One vibrator stuck.

Sudden Stop

1. Ignition switch jarred open.

2. Fuel exhausted in tank.

3. Broken wire.

4. Loose connections or wires.

5. Carburetor nozzle clogged with dirt.

6. Fuel pipe clogged leading to carburetor.

7. Timer broken.

8. Defective magneto.

9. Hot bearings seize the shaft.

10. Defective igniter.

11. Water in gasoline.

12. Hot cylinder — Piston seized.

13. No oil.

14. Poor mixture.

Back-Firing

1. Poor mixture due to carburetor adjustment.

2. Retarded spark will cause back-fire.

3. Clogged carburetor nozzle or fuel pipe.

4. Leaky inlet valve on engine.

5. Air leaks in cylinder, or intake pipe.

6. Wide open throttle at full load.

7 On low speed may be caused by opening of
the auxiliary air valve on the carburetor.

8. Valves out of time.

9. Defective timer on high tension system.
10. Weak batteries.

173

Irregular Running

1. Broken wire.

2. Dirty timer.

3. Sticking coil vibrator, high tension system.

4. Worn make and break mechanism (loose
joints).

5. Loose timer control rods.

6. Water in gasoline.

7. Clogged carburetor nozzle.

8. Weak exhaust valve spring (broken springs).

9. Air leaks between carburetor and jcylinder.
10. Worn cams or cam shaft on multi- cylinder

engine as well as a twisted shaft or loose gears.

Overheating in Cylinder

1. Retarded spark.

2. Mixture too rich.

3. Lack of oil in the cylinder.

4. Poor water circulation due to the jacket.

5. Poor compression.

6. Insufficient valve lift.
7 Clogged exhaust pipe.

8. Clogged muffler.

9. Clogged radiator.

10. Defective circulating pump.

11. Tight piston.

12. Lime deposits in cylinder.

13. Overload on engine.

14. Closed water supply valve.

Pre-Ignition or Deep Pounding in Cylinder

1. Too much lubricating oil forms deposit.

2. Rich mixture forms a deposit in combustion
chamber.

3. Overheated cylinder, especially in air cooled
engines.

4. Sharp edges in combustion chamber.

5. Deposit in cylinder.

6. Deposits in kerosene engines are usually
formed by running with a cold cylinder or by hav-
ing the intake air too cold.

174

Smoke

1. Black smoke is caused by too much gasoline,
or too rich a mixture.

2. Light colored smoke is caused by an excess
of oil fed to the cylinder.

Engine Gradually Slows Down and Stops

1. Weak or exhausted batteries.

2. Poor mixture due to carburetor adjustment.

3. Overload on engine.

4. Magneto slipping or governor out of order.

5. Overheated bearings.

Excessive Vibration

1. Engine crankshaft may not be perfectly
balanced.

2. Twisted cam shaft may change valve timing
and cause an uneven application of power.

3. Uneven wear on cams or push rods may give
an uneven application of power.

4. Defective timer may fire the cylinders at un-
equal periods.

5. Carburetor not situated at equal distances
from the cylinders may be the cause of vibration.

Cam Shaft Rattle

1. Caused by retarded spark.

2. Loose cam shaft bearings or gears.

3. Loose cam rollers or pins.

Wheezing Scraping Sound

1. Broken piston rings.

2. Dry piston due to lack of oil.

3. Vibration of auxiliary air valve on carburetor.

4. Tight piston.

5. Overheated cylinder.

6. Fly wheel scraping on metal shields.

Knocking and Pounding — Regular

1. Ignition too far advanced.

2. Pre-ignition.

3. Overheated cylinders.

4. Loose bearings.

175

5. Loose connecting rod bearings.

6. Loose fly wheel.

7. Loose counterweights.

8. End play in crank shaft.

9. Broken valve stem.

10. Broken circulating pump.

11. Wear on cam shaft and cams.

Irregular Knock

1. Loose electrical connections.

2. Loose piping or rod on engine.

3. Pre-ignition.

4. Defective commutator or timer.

Speed Variation

1. Due to misfiring.

2. Water in fuel.

3. Irregular supply of gas.

4. Magneto slipping.

5. Defective fuel pump.

6. Defective governor.

7. Wear on valve gear.

8. Defective timer.

9. Loose electrical connections.
10. Poor mixture.

Adjustment of Friction Clutches

Unnecessary slipping of the friction clutch, caus-
ing undue wear on the friction blocks E should be
remedied at once by making adjustments in the
following manner:

1. Loosen lock-nut A on set screw B.

2. Loosen set screw B.

3. Strike set screw B lightly with a hammer to
loosen copper disc C which has been forced into
threads of master disc 65.

4. Turn adjusting ring 63 to the right about
one-quarter of a turn to adjust for ordinary wear
on blocks E. Try the clutch by pushing in spool
70 with lever or hand wheel. If the clutch should
be too tight, i. e. does not lock, turn adjusting ring
63 to the left slightly.

5. When proper adjustment has been made
TIGHTEN SET SCREW B, making sure that
copper disc C is in place first, and then tighten
lock-nut A.

CAUTION: Be sure that the fifth instruction
has been complied with before operating the ma-
chine.

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Figure 4

Removing Clutches

When for any reason it becomes necessary to
remove a clutch, where it is impractical to remove
the housing H first, proceed as follows :

1. Loosen lock-nut A on set screw B.

2. Loosen set screw B.

177

Figure 5
Main Shaft and Clutch Assembly 14E Paver

178

Figure 5
Main Shaft and Clutch Assembly 14E Paver.

179

3. Strike set screw B lightly with a hammer to
loosen copper disc C, which has been forced into
threads of master disc 65.

4. Unscrew adjusting ring 63 and remove same,
together with toggle links 71, toggle yokes 72 and
spool 70.

5. Remove from plate 60 and friction plate 74.

6. Remove pins F from adjusting ring and
toggle links and replace adjusting ring 63 on master
disc 65, as shown in Fig. 4.

7. Scratch a locating mark on shaft at edge of
master disc 65 to insure proper replacement of disc.

8. Insert two or three bolts (three if you have
a three-link adjusting ring) in the slots of the ad-
justing ring 63 and through a plate placed over the
end of the shaft as shown in Fig. 4.

9. Be sure that pins D in housing H are in line
with slots S in master disc 65.

10. Draw up nuts on bolts and strike occasional-
ly with a hammer on plate as indicated in Fig. 4 in
order to start the disc 65.

11. In cases where the housing can be removed
first, the master disc 65 can be driven off.

12. When replacing clutch parts, locate master
disc 65 by mark previously scratched on shaft, see
that it is keyed tight and be sure that set-screw B
is tightened before operating the machine.

Toggle links 71, toggle yokes 72 and pins F,
and J should be replaced by new ones when they
become worn to such extent as to cause improper
operation of the clutch.

Adjustment of Hoist Brake

On all Koehring Mixers, the basic principle of
adjustment is to first adjust the clutch, and then
adjust the brake to suit. While the design of levers
is somewhat different on the various mixers, the
following general method of adjustment of the
brake on the 14E and 21 E Pavers applies to all the
machines. For reference see Figure 5.

In case set screws (7) and (8) have been dis-
turbed, after mixer has left the factory, to adjust

180

properly — Pull lever (6) down and loosen nuts (14)
and (15).

Adjust set screws (7) and (8) so that centers of
(9), (10) and (11) are approximately in line when
clutch (18) is engaged. Release clutch (18) with
lever (1) and move back to extreme limit. Tighten
nut (14) until tension pulls clutch (18) forward
*4 ", then tighten nut (15).

Readjust lever (6) by adjusting nut (13) until
lever (6) locks brake band, then tighten nut (12).

After the brake is adjusted, adjust the knockout
at (16) or (17).

Lever ^Operation
General : —

While the lever arrangement is somewhat differ-
ent on the various mixers, the same operating prin-
ciples apply to all machines, whether they be
Pavers, Heavy Duty Mixers or Dandie Mixers.

As, on account of the propelling features, the
lever arrangement is somewhat more complex on
the pavers, it is described in detail:

10E Paver

Refer to Figure 6 page 182 for reference.

When starting mixer disengage gasoline engine
clutch (not shown) or stop steam engine. Then
disengage traction clutch with lever (1) ; shifting
lever (2) must be in neutral position. Next, engage
drum drive gear with lever (4) and engage gasoline
engine clutch (not shown) or start steam engine.

To hoist charging skip, engage hoisting clutch
with lever (6).

To stop hoisting of skip, disengage clutch with
lever (6) and apply brake lever (7).

If, however, the skip is raised to charging
height, it will be stopped automatically providing
the adjusting screw is set properly in the knockout.

To lower bucket, release brake lever slightly.

To move mixer, hoist and lock charging skip
clear of the ground, then :

(a) For low Speed Ahead — Lever (2) must be

in neutral position.

181

®

11

Disengage traction clutch with lever (1).
Next, shift lever (3) to left hand notch. Then,
engage clutch with lever (1).
To brake, throw out traction clutch with lever
(1) and apply brake lever (5))

(b) For reverse traction — Disengage traction
clutch with lever (1), having lever (2) in neu-
tral position. Then, shift lever (3) to. right
hand notch and engage clutch with lever (1).
To brake, throw out traction clutch with lever
(1) and apply brake lever (5).

(c) For high speed ahead — With gasoline en-
gine clutch disengaged or steam engine stopped
and lever (3) in neutral position, engage trac-
tion clutch lever (1) and throw out drum drive
gear with lever (4). Then shift lever (2) from
left hand hole to right hand hole and engage
gasoline engine clutch or start steam engine.
To brake, make sure that traction clutch lever
(1) is engaged. Then, throw out gasoline en-
gine clutch or shut off steam and apply brake
lever (5).

14E and 21E Pavers

For reference see Figure 7 pages 184 and 185.

To hoist skip, engage drum drive clutch with
lever (2) then engage hoist clutch with lever (1).

To lower skip, disengage clutch lever (1) half-
way and when skip nears ground, apply brake with
lever (1).

To hold mixer when operating on a grade, ap-
ply and lock brake lever (4).

To,1 hoist batch box with derrick — Engage
clutch (7) with lever (6) ; raise batch box higji
enough to clear skip, next apply brake with level
(6) swing batch box over skip and dump material.
After batch box is empty, to lower box on car
reverse operation.

To operate power discharge — Engage clutch
(B) with lever (18) to discharge. To reverse
swinging chute, engage clutch (A) with lever (8).

To move mixer, hoist skip to clear ground,
then lock with lever (13).

183

NOT PUT pRE*§£ CN p^v. R'JN.'.^S

Figure 7
Main Shaft and Clutch Assembly 21E Paver.

184

flj

TEERiNG WHEEL

u

Figure 7
Main Shaft and Clutch Assembly 21E Paver.

185

(a) For slow speed forward, be sure brake lever
(4) is disengaged; disengage clutch lever (3);
turn shifting wheel (5) until L is at arrow, then
engage clutch with lever (3).

(b) For reverse traction— Be sure brake lever
(4) is disengaged; disengage clutch with lever
(3) ; turn shifting wheel (5) to the left until R
is at arrow, then engage clutch with lever (3).

(c) For high speed ahead— Be sure that brake
lever (4) is disengaged; disengage clutch with
lever (3) ; next disengage drum drive clutch
with lever (2) ; turn shifting wheel' (5) to right
until H is at arrow, then engage clutch with
lever (3).

(d) To work brake for all traction speeds — dis-
engage clutch with lever (3) then apply brake
lever (4).

When mixer is to be removed with teams or
tractor instead of its own power, remove driving
chains from rear wheels, disconnect steering rod,
by removing cap from front ball socket, and be
sure to wire the rod up well.

To apply brake under the above conditions, pull
on brake lever near rear wheels.

Instructions for Operating Steering Mechanism

on 21E Paver— With Full Length

Multiplane

Straight Ahead

When traveling straight ahead leave steering
wheel (A) in neutral.

Slight Turn

Turn wheel (A) quickly in; desired direction
until you feel a sudden stop. After proper course
is obtained, quickly turn wheel (A) back to neu-
tral.

Sharp Turn

Turn wheel (A) quickly in desired direction un-
til you feel a sudden stop. Continue to turn wheel
until no more movement can be obtained and hold

186

firmly until proper course is obtained; then re-
verse wheel back to neutral.

Adjustments and Greasing

If brake drum sticks apply a few drops of oil
on lining.

Grease cups (H) and (K) should be turned
down freely twice a day; on a long travel 4 to 6
times daily.

If lever (B) goes over center without setting
brake hard enough, loosen nut (D), remove pin
(L), adjust clevis (E) until you obtain 1/16" clear-
ance ibetween brake shoe (G) and brake drum (F)
on both drums.

Replace pin (L) and tighten nut (D).

Loosen nut (C), remove pins (M) and (N), ad-
just! rod (P). When rod (P) is properly adjusted,
lever (B) must be in neutral and 1/16 clearance
maintained between each brake shoe and brake
drum. Insert pins (M) and (N) and tighten
nut (C).

187

VIEW' SHOWING, ONE
A ITS BRAKE APPLIED

Steering Mechanism with Full Length Multiplane on 21E Paver.

188

Water Control Essential to Dominant
Strength Concrete

Successful concrete construction is only possible
when the quantity of mixing water is systemati-
cally controlled. Uniformity of water content in
each batch means uniform strength of concrete.
Without knowledge of the aggregates to be used,
the weather conditions under which the work is to
be carried on, and the amount of water in the sand,
it is impossible to set a definite figure as the quan-
tity of mixing water required per cubic foot or
cubic yard of concrete. If a porous aggregate, such
as crushed blast furnace slag, is employed, sufficient
water must be added not only to hydrate the ce-
ment and wet the surface of the sand but to be ab-
sorbed by the coarse aggregate ; while with a hard
dense gravel less water is required.

With a given aggregate, known weather condi-
tions and a particular type of work, there is one
quantity of water which satisfies the requirements.
This amount may change from day to day but will
not change from one mix to the next.

Adjustment of Water Tank

In the design of the water measuring tank two
requirements have been kept constantly in mind.
First, that the measuring device be easily adjust-

189

ed, and second, that the tank when set deliver the
same quantity of water to each batch of concrete,
measuring it automatically even though the oper-
ator be giving his attention to some other part of
the mixing operation. Further, the foreman or in-
spector should be able at a glance to determine the
quantity of water passing into the mixer.

The Koehring Water Measuring Tank fulfills
these requirements. It is constructed without floats
or intricate parts and can be quickly regulated and
adjusted without the use of a wrench or special
tools. Simple in design, staunch in construction,
it is a dominant factor in the manufacture of Stand-
ardized Concrete.

The tank is filled by attaching a supply hose at
nipple D, Fig. 8, and turning handle of three-way
valve, into position C, Fig. 8. With the handle in
this position, water will flow into the tank, the air
escaping through check valve E, which automati-
cally closes, when the tank is filled.

Discharge of water from the tank into the
drum is accomplished by turning three-way valve
handle into position C2, Fig. 8.

The following table gives the amount of water
discharged from the tank for each setting of the
regulating handle:

Set-

Discharge

Discharge

Discharge

Discharge

Discharge

ings of

fron 12x24

from 12x33

from 16x34

from 18x40

from 18x50

Valve
Han-

Tank

Tank

Tank

Tank

Tank

die

Gal.

Lbs.

Gal.

Lbs.

Gal.

Lbs.

Gal.

Lbs.

Gal.

Lbs.

1

1.2

3.5

1.3

10.75

2.1

17.5

6.4

53.0

5.7

47.5

2

1.4

11.5

1.7

14.5

3.0

24.75

7.5

62.75

7.1

59.5

3

1.8

15.25

2.7

22.5

4.3

35.5

9.7

81.5

9.7

81.0

4

2.4

20.0

3.5

29.0

6.2

51.25

12.6

105.75

13.6

113.0

5

3.3

27.25

4.7

39.0

8.3

69.0

16.5

137.5

18.0

150.0

6

4.2

35.25

5 9

49.25

11.2

94.0

20.0

167.0

22.2

185.5

7

5.2

43.5

7.6

63.25

14.0

117.0

24.3

203.0

29.2

243.5

8

6.2

52.0

9.0

75.25

17.5

145.5

29.0

240.75

35.3

294.5

9

7.8

64.75

10.8

90.0

21.0

175.25

34.0

284.5

42.2

352.0

10

9.2

76.5

12.7

106.0

24.1

201.0

38.0

317.0

48.5

404.25

11

10.0

84.0

14 1

117.5

27.1

226.0

41.5

345.75

53.5

446.5

12

10.9

91.0

15.1

126.25

28.5

235.7

43.5

362.75

57.3

478.0

In starting up mixer, the segment on the handle
B should be set with latch A in notches (4) or (5)
and then moved backward or forward to regulate
to the proper amount of water required.

190

If tank does not fill fast enough, do not blame
the water measuring system but rather look for the
trouble in the supply line. See if there is sufficient
water pressure and be sure that the supply line or
any part of; it is not smaller than the supply open-
ing at D.

The tank should be occasionally drained during
the working season in order to remove sediment,
which, if allowed to accumulate, will cut the bronze
plug and cause trouble. IT MUST ALWAYS BE
DRAINED AT NIGHT AND WHEN NOT IN
USE IN COLD WEATHER, in order to prevent
damage to parts by freezing.

Mixer on Work

After mixer has been taken to the work, we
suggest putting one or more wheelbarrows full of
stone in the drum and running the mixer for half
an hour or more, thus scouring it thoroughly and
removing all roughness. The revolutions of the
drum should be tried out. The best results are ob-
tained at the following revolutions per minute:
No. of Mixer R.P.M.

104S 17

10S, 14S, 214E, 10E and 14E 16

107S, 21S and 21E 15

28S and 32E 14

The pickup buckets, discharging directly upon
the swing chute, also give the quickest discharge at
the above stated revolutions. At a lower speed a
certain amount falls off the buckets before reach-
ing the proper height and at a greater speed some
of the concrete is carried over the swinging chute.
It is advisable, upon starting a new mixer, to
use one-half the normal crew the first day, in order
to allow the operator to become acquainted with
his machine and to make minor adjustments of the
clutches.

After running the machine a couple of days,
remove all slack from cables, as new cables stretch
with use. This eliminates the jerks by which they
are sometimes broken.

191

After running a week or so, all nuts should be
drawn up, as the new bolts may stretch, leaving
the nuts loose.

Operating MIXER TO INSURE MAXIMUM
Yardage

The operator should throw in the hoisting
clutch, then when the skip has reached the elevation
where it is ready to charge drum, start the water
flowing from the measuring tank. As automatic
knockouts are on all Koehring Machines the skip
will stop when reaching the proper height. After
skip has been lowered the operator should close the
three-way valve when the water stops flowing. 'He
can tell this by watching the gauge glass on the
water tank. When concrete has been mixed the re-
quired length of 'time, has been dumped, and three-
fourths of the concrete is out of the drum, the skip
should be started up again. By the time it has
reached the charging position the drum is empty.
Then reverse the tilting discharge chute so that it
can aid in mixing the next batch. The operator
will have time to run bucket out on the boom and
dump it while the batch is being mixed and the
skip is being loaded.

Keep Mixer Clean

When contractors finish concreting at noon and
in the afternoon, it is advisable to put a few wheel-
barrows of stone in the drum and scour it for a few
minutes. By doing this a clean drum is assured at
all times.

To help instill in the minds of the crew pride in
their work and to secure a maximum of output, the
machine should be kept as clean as possible, both
on the inside and on the outside. The outside may
be kept clean by brushing off the machine each
night before shutting down and coating the drum
and other parts with oil, which will prevent the ce-
ment from sticking. The oil drained from the
crank case can be saved and used for this purpose.

192

In coating the drum and other parts of mixer
with oil, care must be taken that no oil gets on the
runways of either the drum or the boom.

The Proper Method of Putting Aggregate in

Skip to PREVENT CONCRETE CLOGGING

on Blades

Cement should never be put in skip first, as it
retards the flow of material when skip is elevated,
thereby making it necessary to hold it in that posi-
tion for a longer time to clean itself. As the ce-
ment is last to leave the skip, some of it will stay in
the sub-chute until pushed into the drum by the
next batch, and some will pack on the inside of the
drum head on the charging side, building up a ring
around the drum opening. There should always be
at least J4 °f *he stone or gravel in skip before ce-
ment is dumped, as this will aid the flow of material
and also prevent the cement hanging in the sub-
chute.

It is very important that the water be admitted
at the proper time ; that is, when the material starts
to roll into the drum, so the material and water will
enter the drum at the same time to avoid clogging.
This also increases the mixing efficiency.

Shutting Down Mixer for Winter or Prolonged
Period, When Machine Will not Be in Use

Drain all water from the boiler and steam en-
gine or gasoline engine, and also from piping and
water tanks. Pour about one gallon of .cylinder oil
into the boiler and a quart of oil into the tanks.
Fill again with water, then drain. It would be well
to add a little whitelead to the cylinder oil, — just
enough to give it a little body.

If mixer is equipped with steam power, remove
hood from boiler and clean the tubes out thorough-
ly 1 with a wire brush and swab carefully with oiled
waste or rags. Cover the top of the boiler with
canvas and tie it down securely, then coat inside
of fire box with heavy oil, and paint oryoil the out-
side of the boiler.

Whether gasoline or steam engine is used, take

193

off cylinder head and coat inside of cylinder with
whitelead and oil.

All hard working machinery, especially concrete
machinery, must wear ; therefore examine the entire
machine carefully and try out all working parts and
replace with new parts those parts, if any, which
are worn enough so as not to work properly.

By overhauling the mixer and replacing all
worn parts, when mixer is shut down, no delay will
be occasioned by having to make repairs when
ready to re-start the mixer in the spring. This
should not be neglected, for worn machinery de-
creases results and increases delays and conse-
quently labor, and possibly will necessitate extra
hours at night for the operator "when the mosqui-
toes are biting at their best."

After machine has been thoroughly, inspected
and overhauled/ coat all bright parts on mixer with
heavy machine oil or, preferably, cylinder oil con-
taining a good heavy body of whitelead. Give bal-
ance of mixer* a good coat of paint.

Grease all bearings carefully and turn machin-
ery over a few times to insure that the insides of
bearings are thoroughly coated. Take off cables
and clean thoroughly with kerosene, then pass
through a bath of warm lubricant. The following
makes a good mixture:

One part freshly slacked lime.

Four parts fine or coal tar.

One-half part powdered graphite.

Heat up and thoroughly mix together.

Clean traction chain thoroughly with kerosene,
then give it a good coat of heavy oil.

If possible, house the mixer or cover it with
tarpaulin in order to protect it from the weather.

When starting up again after a prolonged shut
down, it will, of course, be necessary to clean off all
surplus grease and then follow the same procedure
as used in starting of a new machine.

Ordering Parts

When ordering new parts for a mixer, the con-
tractor should be sure to give the size and number

194

of his machine. This he will find on the nameplate
attached to the frame. The part and pattern num-
ber he will find in the repair part book which ac-
companies each mixer.

Ordering Clutch Parts

When ordering new parts for clutches, state
specifically whether parts are wanted for —
Drum or main drive clutch.
Charging skip hoist clutch.
Traction clutch.

Boom clutch or auxiliary hoist clutch.
AND ALWAYS GIVE THE NUMBER OF
YOUR MIXER.

(Illustration)

Part No. 65, master disc for charging skip hoist
clutch on mixer.

Size No

Get these numbers from nameplate on your mixer

Or

. Mixer No

code word of part code word of HP clutch

This will eliminate mistakes and will enable us
to give our customers prompt service.

195

INDEX

Page
Aggregates

Chapter 7 — Notes on Specifications 117

Aggregates — Acceptability of

Chapter 2 — Materials Entering Concrete 31

Aggregates — Concrete Aggregates

Chapter 2 — Materials Entering Concrete 23

Aggregate Control

Chapter 1 — Field Operation in Concrete Construction. . . 19

Aggregate — Effect of Aggregate on Fire Resistive Qualities
of Concrete

Chapter 2 — Materials Entering Concrete 30

Aggregate — Effect of Mineral Properties of Aggregate
on Strength of Concrete

Chapter 2 — Materials Entering Concrete 31

Aggregate — Effect of Physical Properties on Quality of
Concrete

Chapter 2 — Materials Entering Concrete 25

Aggregates. Tests on

Chapter 2 — Materials Entering Concrete 27

Aggregates, Washing

Chapter 2 — Materials Entering Concrete 30

Amount of Concrete to be Placed

Chapter 1 — Field Operation in Concf etc Construction ... 11
Assembling of Construction Mixers

Chapter 15 — Mechanical Equipment — its Starting, Care

and Operation 162

Assembling of Paving Mixers

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 158

Balancing of Plant

Chapter 3 — Concrete in Highway Construction 54

Basic Principles in all Specifications

Chapter-7 — Notes on Specifications 115

Beams

Chapter 6 — Use of Reinforcing Steel in Concrete 106

Boiler, Starting and Care of

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 163

196

INDEX— Continued

Page

Boom Erection and Adjusting Instructions

Chapter 15 — Mechanical Equipment — Its Starting,

Care and Operation 159

Bridges

Chapter 9 — Notes on Concrete Culvert and Bridge Con-
struction 130

Bridge Abutments — Functions of Bridge Abutments

Chapter 9 — Notes on Concrete Culvert and Bridge Con-
struction 131

Capacity of Mixing Plant

Chapter 1 — Field Operation in Concrete Construction. . . 21

Careful Planning Means Economical Completion of
Project

Chapter 1 — Field Operation in Concrete Construction ... 9

Careful Supervision over Proportioning and Mixing
Necessary

Chapter 4 — Miscellaneous Notes for Superintendent or

Foreman 87

Carpenter Work on Bridge

Chapter 9 — Notes on Culvert and Bridge Construction . . 133

Centering and Falsework

Chapter 5 — Forms for Concrete Construction 104

Clean Sand

Chapter 2 — Materials Entering Concrete 24

Clutches — Adjustment of Friction Clutches

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 176

Clutches — Removing Clutches

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 177

Coal and Material Bins

Chapter 14 — Notes on Silos, Coal and Material Bins and

Grain Tanks 149

Cold Weather Work

Chapter 3 — Concrete in Highway Construction 54

Chapter 4 — Miscellaneous Notes 88

Colorimetric Test

Chapter 2 — Materials Entering Concrete 24

Columns

Chapter 6 — Use of Reinforcing Steel in Concrete 160

197

INDEX— Continued

Page
Concrete Base in Highway Construction

Chapter 3 — Concrete in Highway Construction 35

Control of Amount of Mixing

Chapter 1 — Field Operation in Concrete Construction .... 20

Cos tof Forms

Chapter 5 — Forms for Concrete Construction 102

Cost — Items Entering into Cost

Chapter 8 — Estimating Cost of Concrete Construction .... 122

Cost — Cost and Quantity of Materials very Important

Chapter 8 — Estimating Cost of Concrete Construction 123

Cost — Relation of Speed to Cost

Chapter 8 — Estimating Cost of Concrete Construction 125

Cost of Water Should not be Overlooked

Chapter 8 — Estimating Cost of Concrete Construction 126

Culverts

Chapter 9 — Notes on Concrete Culvert and Bridge Con-
struction 127

Curbs in Highway Construction

Chapter 3 — Concrete in Highway Construction 36

Cost — Cost and Quantity of Materials very Important
Chapter 8 — Estimating Cost of Concrete Construction. . . 123

Curing

Chapter 1— Field Operation in Concrete Construction ... 16

Curing in Highway Construction

Chapter 3 — Concrete in Highway Construction 55

Curing

Chapter 4 — Miscellaneous Notes for Superintendent or

Foreman 90

Curves in Highway Construction

Chapter 3 — Concrete in Highway Construction 36

Design — Effect of Design of Mixer on Quality of Concrete

Chapter 1 — Field Operation in Concrete Construction ... 17

Design of Pavements

Chapter 3 — Concrete in Highway Construction 35

Drainage

Chapter 3 — Concrete in Highway Construction 38

198

INDEX — Continued

Page

Effect of Aggregate on Fire Resistive Qualities of
Concrete

Chapter 2 — Materials Entering Concrete 30

Effect of Design of Mixer on Quality of Concrete

Chapter 1 — Field Operation in Concrete Construction. . . 17

Effect of Physical Properties of Aggregate on Quality of
Concrete

Chapter 2 — Materials Entering Concrete 25

Engines

Gasoline Engine

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 166

Steam Engine, Starting and Care of

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation . 165

Engine — To Start and Run Fuller & Johnson Engine

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 166

Engine Trouble

Chapter 15 — Mechanical Equipment — Its Starting, Care
and Operation

Engine will not Turn Over — Engine Stuck. .170

Starting Troubles 170

No Power — Loss of Power 171

Misfiring 172

Misfiring in one Cylinder 173

Sudden Stop 173

Back 'Firing 173

Irregular Running 174

Overheating in Cylinder 174

Pre-Ignition or deep pounding in cylinder. .174

Smoke 175

Engine gradually slows down and stops .... 175

Excessive vibration 175

Cam shaft rattle 175

Wheezing scraping sound 1 75

Knocking and pounding — regular 175

Irregular Knock 176

Speed variation 176

Falsework — Centering and Falsework

Chapter 5 — Forms for Concrete Construction 104

199

INDEX— Continued

Page
Features for Consideration

Chapter 7 — Notes on Specifications 114

Finishing — Forms and Finishing

Chapter 3— Concrete in Highway Construction 53

Forms

Chapter 4 — Miscellaneous Notes for Superintendent or

Foreman 85

Forms — Care in Manufacture of Forms

Chapter 5 — Forms for Concrete Construction 95

Forms — Contractor Responsible for Forms

Chapter 5 — Forms for Concrete Construction 95

Forms — Cost of

Chapter 5— Forms for Concrete Construction 102

Forms — Dry Form Lumber Desirable

Chapter 5 — Forms for Concrete Construction 102

Forms — Form Economy

Chapter 5 — Forms for Concrete Construction 97

Forms — Forms and Finishing

Chapter 3 — Concrete in Highway Construction 53

Forms — Sliding Forms

Chapter 5 — Forms for Concrete Construction 100

Forms — Wetting Forms

Chapter 5 — Forms for Concrete Construction 103

Forms — Wood Forms

Chapter 5— Forms for Concrete Construction 98

Foundation Material of Utmost Importance

Chapter 9 — Notes on Culvert and Bridge Construction. . 132

Foundation and Footings

Chapter 11 141

Gasoline Engine

Chapter 15 — Mechanical Equipment — Its Starting,

Care and Operation 166

Grain Tanks

Chapter 14 — Notes on Silos, Coal and Material Bins and

Grain Tanks 153

Handling Materials

Chapter 3 — Concrete in Highway Construction 39

200

INDEX— Continued

Page
Harmful Materials

Chapter 2 — Materials Entering Concrete 25

Haulage Units

Chapter 3 — Concrete in Highway Construction 64

Hoist Brake— Adjustment of Hoist Brake

Chapter 15 — Mechanical Equipment — Its Starting, Care

Construction 180

Instructions for Operating Steering Mechanism on 21 E

Chapter 15— Mechanical Equipment etc 186

Insurance

Chapter 8 — Estimating Cost of Concrete Construction. . . 123

Joining New Concrete to Old

Chapter 4 — Miscellaneous Notes for Superintendent or

Foreman 91

Keep Mixer Clean

Chapter 15 — Mechanical Equipment etc 192

Lever Operation

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 181

Maintenance of Concrete Pavements

Chapter 3 — Concrete in Highway Construction 56

Materials of Construction in Highway Construction

Chapter 3 — Concrete in Highway Construction 36

Materials — Cost and Quantity of Materials Very Impor-
tant

Chapter 8 — Estimating Cost of Concrete Construction. . . 1 23

Mechanical Equipment

Chapter 3 — Concrete in Highway Construction 38

Method of Making Void Determination

Chapter 2 — Materials Entering Concrete 27

Mineral Properties of Aggregate — Effect on Strength of
Concrete

Chapter 2 — Materials Entering Concrete 31

Mixer — Effect of design of Mixer on Quality Concrete

Chapter 1 — Field operation in Concrete Construction. . . 17

Mixer

Keep Mixer Clean

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 192

Mixer Most Important Piece of Plant

Chapter 1 — Field Operation in Concrete Construction. . . 12

201

INDEX— Continued

Page
Mixer on work

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 191

Mixer Plant

Chapter 3 — Concrete in Highway Construction 47

Mixer — Type of Mixer

Chapter 7 — Notes on Specifications 117

Motor — Care and Starting Waukesha Motor

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 168

Notes on Silos, Coal and Material Bins and Grain Tanks

Chapter 14 149

One and Two Course Construction

Chapter 3 — Concrete in Highway Construction 34

Ordering Clutch Parts

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 195

Ordering Parts

Chapter 1 5 — Mechanical Equipment — Its Starting, Care

and Operation 194

Organization of Crew

Chapter 3 — Concrete in Highway Construction 53

Operating Mixer to Insure Maximum Yardage

Chapter 15 — Mechanical Equipment-^Its Starting, Care

and Operation 192

Overhead

Chapter 8 — Estimating Cost of Concrete Construction. . . 123

Panels — Standardization of Panels

Chapter 5 — Forms for Concrete Construction 98

Pavers

Chapter 15 — Mechanical Equipment — Its Starting, Care
and Operation

No. 10E Paver 181

No. 14E and 21E Paver 183

Piers

Chapter 6 — Use of Reinforcing Steel in Concrete 106

Placing Concrete in Forms

Chapter 1 — Field Operation in Concrete Construction ... 15

202

INDEX — Continued

Page
Placing Equipment, Character of

Chapter 1 — Field Operation in Concrete Construction. . . 13

Placing Concrete Under Water

Chapter 13 147

Planning — Careful Planning Means Economical Com-
pletion of Project

Chapter 1 — Field Operation in Concrete 9

Plant, Balancing of

Chapter 3 — Concrete in Highway Construction 54

Plant, Character of

Chapter 1 — Field Operation in Concrete Construction ... 12

Plant — Remainder of Plant Around Mixer

Chapter 1 — Field Operation in Concrete Construction ... 12

Preparing to Start Mixer

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 162

Proper Method of Putting Aggregate in Skip to Prevent
Concrete Clogging on Blades

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 193

Proportioning Mixtures

Chapter 7 — Notes on Specifications 117

Pump and Water Line

Chapter 3 — Concrete in Highway Construction 49

Quality of Concrete Desired

Chapter 1 — Field Operation in Concrete Construction ... 14

Quality of Concrete not Dependent on Cement Atone

Chapter 2 — Materials Entering Concrete 32

Receipt of Materials and Plant for Handling

Chapter 1 — Field Operation in Concrete Construction ... 10

Rehandling Materials

Chapter 3 — Concrete in Highway Construction 45

Reinforcement — Handling Reinforcement on the Work

Chapter 6 — Use of Reinforcing Steel in Concrete 108

Reinforcement — MakeshiftReinforcement Dangerous

Chapter 6 — Use of Reinforcing Steel in Concrete 110

203

INDEX — Continued

Page
Reinforcement — Need for Reinforcement

Chapter 6 — Use of Reinforcing Steel in Concrete 105

Reinforcements — Types of Reinforcements

Chapter 6 — Use of Reinforcing Steel in Concrete 107

Reinforcing Steel — Examples, of Reinforcing Steel in
Concrete

Chapter 6 — Use of Reinforcing Steel in Concrete 110

Reinforcing Steel — Position of Steel

Chapter 6 — Use of Reinforcing Steel in Concrete 106

Reinforcing Steel — Quality of Reinforcing Steel

Chapter 6 — Use of Reinforcing Steel in Concrete 105

Remainder of Plant Around Mixer

Chapter 1 — Field Operation in Concrete Construction. . . 12

Responsibility Should be Clearly Defined

Chapter 7 — Notes on Specifications 113

Sampling Sand

Chapter 2 — Materials Entering Concrete 26

Safety Dependent on Form Construction

Chapter 5 — Forms for Concrete Construction 98

San J or Fine Aggregate

Chapter 2 — Materials Entering Concrete 23

Shoulders in Highway Construction

Chapter 3 — Concrete in Highway Construction 36

Shutting Down Mixer for Winter or Prolonged Period
When Machine Will Not be in use

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 193

Silot

Chapter 14 — Notes on Silos, Coal and Material Bins and

Grain Tanks 149

Sliding Forms

Chapter 5 — Forms for Concrete Construction 100

Specifications Should be Clear

Chapter 7 — Notes on Specifications 113

Starting and Care of Boiler

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 163

204

INDEX — Continued

Page
Steam Engine— Starting and Care of

Chapter 15 — Mechanical Equipment, Its Starting,

Care and Operation 166

Steering Mechanism — Instructions for Operating
Steering Mechanism on 21 E Paver — With
Full Length Multiplane

Chapter 15 — Mechanical Equipment — Its Starting,

Care and Operation 186

Strength

Chapter 1 — Field Operation in Concrete Construction ... 17

Surface Finish — Concrete Surface Finish

Chapter A — Miscellaneous Notes for Superintendent or

Foreman . 91

Tables—Use of

Chapter 3 — Concrete in Highway Construction 51

Tests on Aggregates

Chapter 2 — Materials Entering Concrete 27

Two Course Construction

Chapter 3 — Concrete in Highway Construction 34

Type of Mixer

Chapter 7 — Notes on Specifications 117

Uniform Strength Demands Uniform Consistency of
Concrete

Chapter 1 — Field Operation in Concrete Construction . . 15

Unloading — Method of Unloading Mixer

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 157

Voids

Chapter 2 — Material Entering Concrete 26

Voids — Method of Making Void Determination

Chapter 2 — Materials Entering Concrete 27

Washing Aggregates

Chapter 2 — Materials Entering Concrete 30

Water Control

Chapter 1 — Field Operation in Concrete Construction ... 20

Water Control Essential to Dominant Strength Concrete

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 189

205

INDEX— Continued

Page
Water Line — Pump and Water Line

Chapter 3 — Concrete in Highway Construction 49

Water Tank — Adjustment of Water Tank

Chapter 15 — Mechanical Equipment — Its Starting, Care

and Operation 189

Watertightness — Fundamentals for Watertightness

Chapter 12 — Waterproofing Concrete 143

Watertightness — Good Concrete Properly Mixed is
Watertight

Chapter 12 — Waterproofing Concrete 143

Watertightness — Poor Concrete Responsible for Popular
Belief That Concrete is Not Watertight

Chapter 12 — Waterproofing of Concrete 143

Watertightness — System for Increasing

Chapter 12 — Waterproofing Concrete 144

Weather Conditions

Chapter 8 — Estimating Cost of Concrete Construction.. .124

Wetting Forms

Chapter 5 — Forms for Concrete Construction 103

Wing Walls

Chapter 9 — Notes on Culvert and Bridge Construction . . 129

Wood Forms

Chapter 5 — Forms for Concrete Construction 98

206

INDEX TO TABLES

Page
Table No. 1

Table of Recommended Mixtures and Maximum Aggre-
gate Sizes 28

Table No. 2

Table Showing Cubic Yard Weights in Pounds, Equiva-
lent Weight in Tons, and Fractional Number of Cubic
Yards Per Ton 33

Table No. 3

Thickness for Light Traffic Roads and Streets 37

Table No. 4

Thickness for Heavy Traffic Roads and Streets 37

Table No. S

Minimum Quantity of Storage Required for Economic
Operation of Highway Project 44

Table No. 6

Cars of Materials Required Per Day and Per Month for
Three Sizes of Paver. 44

Table No. 7

Trackage for Economiral Operation 44

Table No. 8

Capacity of Material Bins 45

Table No. 9

Size of Pipe Required for Varying Length Head 50

Table No. 10

Cubic Yards of Concrete Per Linear Foot and Per Mile

of Pavement 58

Table No. 11

Quantity of Material Required for Roads, Streets and
Alleys 60

Table No. 12

Maximum Safe Load for Wood Columns 86

Tmble No. 13

Size of Waterway Required for Various Areas to be
Drained 128

207

INDEX TO TABLES— Continued

Page
Table No. 14

Table Showing Quantities of Material Required in Con-
crete Bridges of Spans 8 Feet to 24 Feet, Roadway 20
Feet, as Shown by the S.tandard Plans of the Wisconsin
Highway Commission 134

Table No. 15

Table Giving the Cubic Feet of Sand and Pebbles (or
crushed stone) to be Mixed With One Sack of Cement to
Secure Mixtures of the Different Proportions, and the
resulting Volume in Cubic Feet of Compacted Mortar or
Concrete. 135

Table No. 16

Table Giving the Number of Sacks of Cement and Cubic
Feet of Sand and Pebbles or Stone Required to Make One
Cubic Yard ftwenty-?even cubic feet) of Compacted Con-
crete 136

Table No. 17

Number of Square Feet of Wall Surface Covered Per Sack
of Cement, for Different Proportions and Varying Thick-
ness of Plastering 138

Table No. 18

Materials Required for 100 Sq. Ft. of Surface for Varying
Thickness of Plaster 138

Table No. 19

Quantity of Cement Required Per Cubic Foot and Per
Cubic Yard of Concrete for Various Mixtures in Terms of
Sacks and Barrels 139

Table No. 20

Materials Required for 100 Sq. Ft. of Surface for Varying
Thicknes of Course 139

Table No. 21

Materials Required for 100 Sq, Ft. of Sidewalks and Floors
for Varying Thickness? of Course 140

Table No. 22

Bearing Power of Soils 142

Table No. 23

Spacing of Horizontal Reinforcing Rods for Silos of Vari-
ous Inside Diameters 150

Table No. 24

Quantity cf Concrete Materials for Monolithic Silos of
Various Inside Diameters .. 151

INDEX TO TABLES— Continued

Page
Table No. 25

Diameter of Silos Required to Feed Various Numbers of
Animals 151

Table No. 26

Approximate Capacity of Round Silos 152

Table No. 27

Circular Grain Tanks — Area of Horizontal Reinforcing
Steel in Square Inches Per Foot of Depth, and Thickness
of Wall in Inches. Steel to be in Center Wall 154

Table No. 2S

Square Grain Tanks — Thickness of Wall in Inches and
Area of Reinforcement in Square Inch Per Foot of Depth . . 154

Table No. 29

Capacity of Circular Grain Bins and Tanks in Bushels .... 155

Table No. 30

Table of Wages . . 156

209

LIST OF ILLUSTRATIONS

Page
Koehring Paver with distributing spout 2

Koehring Construction Mixer with steam engine,

boiler and power charging skip 4

Koehring Paver with full length multiplane traction

and distributing boom and bucket 6

Spread Your Concrete This Way with a Koehring

Paver 8

Koehring Crane Excavator 40

Installation Plan — Koehring Steam Pump 48

Koehring Dandie Mixer equipped with power charg-
ing skip and solid rubber tires 84

Koehring 28S Heavy Duty Construction Mixer 112

An interesting picture, showing complete plan of road
building operations, from material bins to the

finished concrete road , 120

View of bridge under construction 146

Boom details 160

Boom details 161

Line drawing showing Fuller & Johnson Gasoline

Engine 167

Adjustment of friction clutches, Fig. 4 176

Main shaft and clutch assembly 14E Paver, Fig. 5 178

Main shaft and clutch assembly 14E Paver, Fig. 5 179

Gear assembly and control, 10E Paver, Fig. 6 182

Main shaft and clutch assembly, 21E Paver, Fig. 7. .. 184

Main shaft and clutch assembly, 21E Paver, Fig. 7 185

Diagram showing steering mechanism full length
multiplane on 21E Paver 188

210

INITIAL FINE~OF 25 OEKTS

LD 21-100m-7/33

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