UC-NRLF
i
CONCRETE ROADS
CONCRETE
ROADS * 0
and Their Construction
BEING A DESCRIPTION OF THE
CONCRETE ROADS IN THE
UNITED KINGDOM, TOGETHER
WITH A SUMMARY OF THE
EXPERIENCE IN THIS FORM
OF CONSTRUCTION GAINED
IN AUSTRALIA, CANADA, NEW
ZEALAND AND THE UNITED
STATES OF AMERICA
'CONCRETE
SERIES
PUBLISHED BY
CONCRETE PUBLICATIONS LIMITED
4, CATHERINE STREET, ALDWYCH, LONDON, W.C.2
Price Eight Shillings nett
FOREWORD
ONE of the most pressing problems of the time in connection with
public works is that presented by the necessity for improved roads
to meet the demands of modern traffic conditions, which have resulted
from the enormous development of motor transport during recent
years.
The adoption of concrete is a serious attempt to grapple with
this problem, which really resolves itself into a search for the ideal
road, and so many of our thoroughfares and highways are insistently
calling for speedy reconstruction that the present would seem to
be an opportune time for approaching the question dispassionately
and without prejudice, examining it in the light of recent experience
and determining whether the time has not arrived for giving the
concrete road a fair trial in this country. True, our acquaintance
with modern traffic conditions has been brief, but, brief as it may be,
it is sufficient to form a clear indication of our future needs and to
serve as a guide for future methods.
Frequent reference has been made in the public Press to the head-
way made by concrete roads in America, where, owing to the wide
adoption of motor transport, the road question has assumed serious
proportions for years past. Thousands of miles of concrete road
are in use there, and something like 75,000,000 sq. yds. are in con-
templation during the present year. It cannot be supposed that
a nation so keen at weighing up the possibilities of a business propo-
sition would, after fourteen years' experience, continue to lay these
roads on such an extensive scale were they not entirely satisfied
as to their efficiency and economy. As might have been expected,
there were partial failures, particularly in America, in the early
days, but only in this way is progress attained — and the progress
has, indeed, been great, both in the United States and in the United
Kingdom — and even to-day, greatly as methods have improved,
no sane person would venture to say that concrete road practice has
reached finality.
vii
442886
viii FOREWORD
The experimental stage is, however, long since past ; we have
the advantage of American experience as well as our own to serve
as a guide for future practice, and, claiming as we do that the con-
crete road approaches more nearly to the ideal than any other, we
maintain that, as Mr. H. Percy Boulnois, M.Inst.C.E., said in his
report to the Roads Improvement Association, it should "be included
in the practice of road building, and should be given a better chance
in the future, than it has received in the past, to prove or disprove
its merits." Should this opportunity not be given, progress here must
inevitably be slow. But we believe it will be acknowledged that
the records we present of roads laid in the United Kingdom are suffi-
cient to show that this form of construction is quite sound, and that
from the point of view of efficiency the concrete road is entirely
justified ; while comparative figures have clearly proved that its
initial cost is little in excess of, and its ultimate cost is appreciably
lower than, that of any other type of road.
In the following pages particulars are given, as far as it has been
possible to obtain them, of the various concrete roads that have been
laid in this country up to the time of going to press, and the methods
adopted in their construction. Every effort has been made to pre-
sent a complete survey of the work done, and to this is added
the latest information obtained from the officials concerned with
regard to the condition of each road. It will be seen that these
communications are all strongly in favour of the concrete road,
and there is thus established a valuable summary of evidence from
those best able to form an opinion from the point of view of the road
authorities. A chapter has been devoted to roads in other countries,
for the account in which of the concrete roads in America we are
indebted to the courtesy of Mr. Thomas J. Harris.
For the chapter on mechanical devices as applied to concrete
roadmaking we have had the advantage of the services of Dr. A. B.
Searle, and our thanks are due to the various engineers and surveyors
mentioned who have willingly supplied us with information.
December, 1920. THE EDITOR.
CONTENTS
PAGE
CHAPTER I
CONCRETE ROADS IN THE UNITED KINGDOM
METROPOLITAN ROADS — Southwark — Deptford.
CHAPTER II
CONCRETE ROADS IN THE UNITED KINGDOM (continued) . 10
PROVINCIAL ROADS — Berkshire — Cheshire — Cornwall —
Devonshire — Essex — Hampshire — Kent — Monmouth-
shire— Northumberland — Somerset — Scotland — Ireland.
CHAPTER II [
CONCRETE ROADS IN INDUSTRIAL WORKS AND MILITARY
CAMPS . . . . .... 69
Port of London Authority — J. Baker, Sons and Perkins,
Willesden Junction — Empire Paper Mills, Greenhithe,
Kent — Factory at Southampton — Portsea Island Gas-
works, Portsmouth — Swindon, Great Western Railway
— Purfleet, Messrs. Jurgens, Ltd. — Belfast, Messrs.
Harland & Wolff— Hamilton Road, Belfast Harbour
Co mmissioners — London, Brighton & South Coast Rail-
way (Goods Yard) — Chisledon — Loch Boon — Cardiff,
Messrs. Lewis & Tylor, Ltd. — Tredegar, Powell
Duffryn Steam Coal Co., Ltd.
DC
x CONTENTS
PAGE
CHAPTER IV
CONCRETE ROADS IN OTHER COUNTRIES .... 99
New Zealand — Australia — Canada.
CHAPTER V
THE GROWTH OF CONCRETE ROADS IN THE UNITED STATES. 115
American Roads and their Development up to 1920.
CHAPTER VI
MECHANICAL DEVICES FOR MAKING CONCRETE ROADS. . 124
Appliances used for Preparing the Road-Bed — Preparing
the Concrete — Laying the Concrete — Tamping and Fin-
ishing the Concrete.
CHAPTER VII
CONCRETE KERBING ... . . . -. . 168
CHAPTER VIII
SUGGESTIONS FOR THE PREPARATION OF SPECIFICATIONS FOR
CONCRETE ROADS . . . . . . . * 177
CHAPTER IX
THE USE OF CONCRETE FOR ROAD ACCESSORIES . . 185
INDEX . . ..... . 195
LIST OF ILLUSTRATIONS
PAGE
ABERGAVENNY AND BRECON MAIN ROAD . . . , 54
ADAMS "LEANING WHEEL" GRADER . , , . 136
ANDREWS ROAD, GEORGIA . . . . • .120
BACKFILLER (GASTON) . , . . . . . .136
BARBER-GREENE LOADER ....... 149
BAXTER'S BALLAST- WASHING AND GRADING MACHINE . . 145
BRECON-ABERGAVENNY ROAD . . . . . .<• . 54
BRIDGE STREET, TAUNTON .. . , . . . 58
BROCKHAM STREET, SOUTHWARK ...... . 3
CANMORE STREET, DUNFERMLINE . . . .. 61, 63
CHISLEDON CAMP . . . . . .* . 91
CHTJRCHLAND ROAD, VIRGINIA . . . • >.' • .120
COAST ROUTE, SAN FRANCISCO TO Los ANGELES . .123
CONCENTRIC CYLINDER SCREEN . . . *. . .139
CONCRETE KERB LAID IN 1881 IN BRIGHTON . * . 171
CONCRETE KERB, PITCHER AND CEMENT PAVING LAID IN
BRIGHTON, 1878 . . . , -. *. . 171
CONSTABLE WAGON . . . . . . . 152
CRANE AND GRAB ........ 130
CROSS SECTION OF PART OF CONCRETE ROAD, SHOWING
SUGGESTED SECTION OF OUTSIDE EDGE WHERE NOT
SUPPORTED BY KERB ING . . . . . .183
CULVERT . .. . . . . . . 187
"DEVIL" DISINTEGRATOR . . . * . . 142
DOCK ROAD, SOUTHAMPTON ... . . .42
DOCK ROAD, TILBURY 35, 37, 40
DRAG-LINE EXCAVATORS 133
EPPING NEW ROAD, BUCKHURST HILL .... 33
ERIE SHOVEL 127
ERIE SHOVEL WITH GRAB 130
FOREGATE STREET, CHESTER 20
GLENGORMLY, BELFAST, CONCRETE ROAD AT . .66
GRAVESEND, ROAD NEAR 45, 48
xi
xii LIST OF ILLUSTRATIONS
PAGE
HALL'S DISINTEGRATOR . . ; . . . . 142
HAMILTON ROAD, BELFAST ...... 94
HEPBURN CONVEYOR . . . . . . .136
JUBILEE WAGONS . . . . . . 133
KERB AND CHANNEL IN THE BOROUGH OF AYLESBURY . .169
LADDER EXCAVATOR . 133
LAMP POST . .... . . . . 190
LOCH DOON CAMP . . 87
LONDON-DOVER ROAD, GRAVESEND .... 45, 48
LONGHOUGHTON ROAD, NORTHUMBERLAND . . .56
LOWER BRISTOL ROAD, BATH . . . . . . 58
LUTE TO PLACE CONCRETE, USE OF . . ' . . .161
MANHOLE . - . . . . . . . . 187
MARINE DRIVE, EXMOUTH . . . . . 26, 27
METHOD OF CONSTRUCTING SUBMERGED CONCRETE KERB IN
SURREY 174, 175
MILWAUKEE PAVER . . . . . . . . 164
MORRISON ROAD, COLORADO . : ' . . . . .117
MOULD FOR KERBS AT BRIGHTON . . .• ; . 173
MOUNTNESSING ROAD . . . . . . 31, 32
NEW KING STREET, DEPTFORD . . . . ... 7, 8
NEWPORT-CARDIFF ROAD . . . . . . .52
NEW SOUTH HEAD, WOOLLAHRA ROAD, SYDNEY . . . 103
NORTHBROOK STREET, NEWBURY . . . . 11, 13, 14
PADSTOW STATION . . . . . . . .23
PAVEMENT GUTTER IN THE BOROUGH OF AYLESBURY . .169
PIPES 190
PIPE -LINE EXCAVATOR . . . . . . .130
PORT OF LONDON AUTHORITY: ROAD IN COURSE OF CON-
STRUCTION AND FINISHED ROAD . . . . . 71
PRIESTMAN GRAB . . 127
PYRAMIDAL INTERLOCKED REINFORCEMENT FOR ROADS,
RAFTS, FLOORS, ETC., AS USED FOR THE PORT OF LONDON
AUTHORITY ........ 70
RANSOME ELEVATOR . . . . . . .152
RANSOME HAND -MIXER 152
RANSOME MIXER ........ 158
RANSOME SELF-CONTAINED MIXER . . . . .155
REX MIXER ......... 158
REX PAVER . . . . . . . . .160
ROAD-LAYING MACHINE USED BY THE PORT OF LONDON
AUTHORITY .... 166
LIST OF ILLUSTRATIONS xiii
PAGE
ROBERTS LANE, CHESTER ... .16
RUSTON AND HORNSBY EXCAVATOR . . . . .127
ST. KILDA ROAD, MELBOURNE 103, 106
SALT LAKE CITY, CONCRETE ROAD NEAR . . . .117
SELF-PROPELLING TEMPLATE AND TAMPER . .165
SIDMOUTH ROADWAY AND FOOTWAY ..... 27
SMITH HAND-MIXER . . . . . . .155
SPECIAL ROAD FORMS . . . . . . .161
STATION NAME PLATE . . . . . . .190
STEEDMAN STREET, SOUTHWARK ..... 3
TELEGRAPH POLE . . . . . . . .190
TEMPLATE 183
TORONTO -HAMILTON HIGHWAY ..... 109, 113
TOTNES-PAIGNTON ROAD .... Frontispiece and 30
TREE GUARD 187
TRENCH TAMPER . 139
VICTORIA MIXER . . . . . . . .158
VICTORIA MIXER WITH BUCKET DISTRIBUTOR . . .160
WHITEFRIARS, CHESTER . . . . . . .18
WINGET CHAIN SPADES . . . . . . .158
WINGET CRUSHER . . . . . . . . 139
WINGET MIXER 158
WINGET SELF-CONTAINED WAGON LOADER . . .149
WORKS ROADS : —
BELFAST : HAMILTON ROAD ..... 94
BELFAST : HARLAND & WOLFF'S SHIPYARDS . .94
CARDIFF: LEWIS & TYLOR 98
EAST CROYDON : LONDON BRIGHTON AND SOUTH COAST
RAILWAY GOODS YARD ...... 90
GREENHITHE : EMPIRE PAPER MILLS . . . .79
PORTSMOUTH : PORTSEA ISLAND GAS WORKS . 82, 83, 85
PURFLEET : JURGENS, LTD. ... 75, 95
SOUTHAMPTON : FACTORY ROAD ..... 79
S WIND ON : GREAT WESTERN RAILWAY . . .91
TREDEGAR: POWELL DUFFRYN STEAM COAL Co., LTD. . 98
WILLESDEN JUNCTION : JOSEPH BAKER, SONS AND
PERKINS 74
CHAPTER I
CONCRETE ROADS IN THE UNITED KINGDOM
A. METROPOLITAN ROADS
Southwark
Mr. Arthur Harrison, M.Inst.C.E., the Borough Engineer of South-
wark, has long been convinced of the value ot the concrete road,
and under his recommendation a stretch of concrete roadway
was laid as an experiment in Penton Place in August and
September, 1918. The success of this having been assured,
the Southwark Borough Council laid down a programme
for nine concrete roads, all of which have now been constructed,
and so satisfactory have they proved that a more extensive
scheme still has been decided upon, to include a total of twenty-
five roads and streets by the end of 1920. At the time of going
to press twenty-one of these have been completed.
Penton Place. Half of this roadway was laid in concrete as an
experiment in August and September, 1918, and the remainder
in 1919, being opened to traffic on December 19. Its length is
370 yds., and the area 2,680 super, yds. The traffic is described
as being part heavy and part medium.
Amelia Street. Length — 320 yds. ; area — 1,940 super, yds. ; opened
to traffic — July 14, 1919; nature of traffic — part heavy, part
medium.
Steedman Street. Length — 193 yds. ; area — 1,630 super, yds. ;
opened to traffic — August 16, 1919 ; nature of traffic — heavy coal
traffic in winter.
Warner Street. Length — 220 yds. ; area — 2,459 super, yds. ; opened
to traffic — October 1, 1919 ; nature of traffic — heavy.
Standard Street. Length — 186yds. ; area — 1,141 super, yds. ; opened
to traffic — October 21, 1919; nature of traffic — part heavy, part
medium.
1 B
: 2-": ;•• :.: ••:..: /;. .CONCRETE ROADS
Brockham Street. Length — 85 yds. ; area — 710 super, yds. ; opened
to traffic — November 6, 1919 ; nature of traffic — light.
Content Street. Length — 93 yds. ; area — 538 super, yds. ; opened
to traffic — January 10, 1920 ; nature of traffic — light.
Wadding Street. Length — 163 yds. ; area — 1,013 super, yds. ;
opened to traffic — January 10, 1920 ; nature of traffic — -medium.
Queen's Row. Length — 182 yds. ; area — 1,440 super, yds. ; opened
to traffic— February 12, 1920 ; nature of traffic— light.
Westmoreland Road. Length — 217 yds. ; area — 1,920 super, yds. ;
opened to traffic — March 26, 1920; nature of traffic — medium.
Trafalgar Street. Length — 340 yds. ; area — 3,000 super, yds. ;
opened to traffic — April 3, 1920 ; nature of traffic — medium.
Thurlow Street. Length — 533yds. ; area — 3,700 super, yds. ; opened
to traffic — June 3, 1920 ; nature of traffic — medium.
South Street. Length — 177 yds. ; area — 1,479 super, yds. ; opened
to traffic — June 26, 1920 ; nature of traffic — medium.
Wooler Street. Length — 80 yds. ; area — 573 super, yds. ; opened to
traffic — July 10, 1920 ; nature of traffic — light.
Avenue Road. Length — 80 yds. ; area — 614 super, yds. ; opened to
traffic — July 24, 1920 ; nature of traffic — fairly heavy.
Heiron Street. Length — 217 yds. ; area— 1,637 super, yds. ; opened
to traffic — August 7, 1920 ; nature of traffic — medium.
Deverill Street. Length — 275 yds. ; area — 1,890 super, yds. ; opened
to traffic — November, 1920 ; nature of traffic — medium.
Lawson Street. Length — 35 yds. ; area — 280 super, yds. ; opened to
traffic — November, 1920 ; nature of traffic — medium.
Lorimore Street. Length — 350 yd?. ; area — 3,010 super, yds. ; opened
to traffic — November, 1920 ; nature of traffic — medium.
Ralph Street. Length — 112 yds. ; area — 733 super, yds. ; opened to
traffic — November, 1920 ; nature of traffic — medium.
Theobald Street. Length — 200 yds. ; area — 1,206 super, yds. ; opened
to traffic — November, 1920 ; nature of traffic — medium.
The other roads to be laid in this borough by the end of 1920
are Alsace Street, Alvey Street, Hill Street, and Mina Road,
and 5,000 additional yards are to be laid in Westmoreland Road.
The general method adopted is the same for all, although Mr.
Harrison states that each street laid taught them something new,
and that, therefore, the whole scheme so far has been one of
continual progress, each road being an improvement in various
small details upon the one previously laid.
Construction. — The original roadway was of granite macadam,
FIG. 1.— Concrete road in Brockham Street, Southwark. The end of a
day's work. Note the planks by means of which the vertical edge is
formed.
\
FIG. 2.— Concrete road in Steedman Street, Southwark. This thorough-
fare has been open to traffic since August, 1919. Although the
photograph was taken soon after a heavy shower of rain, it will be
noticed that, with the exception of a few damp patches, the road
is already dry,
3
IN THE UNITED KINGDOM— METROPOLITAN 5
and this was excavated to a depth of 9 in.. The foundation,
which was found to be fairly solid, received no special prepara-
tion, and after being rolled was ready to receive the concrete.
The two -course method was adopted, the lower being 4 in.
thick and the wearing coat 2 in., the latter being laid before the
former had set, so that the whole might form one monolithic
structure. The concrete for the lower consisted of a 6 : 1 mixture,
and the material from the old macadam road was used as the aggre-
gate. The upper course was composed of a 3 : 1 mixture, the
aggregate in this case also being the material from the original
road, crushed, washed and graded from £ in. down.
By the use of the material from the old roadway a very consider-
able economy is effected by the elimination of costs for the purchase
and transport of new aggregate.
With a view to further economy, the Council, in 1919, purchased
a washing and grading machine which has already more than paid
for itself. (See Chapter VI.)
The reinforcement was placed 2 in. from the bottom, i.e., in
the middle of the bottom course. It consists of f in. rods simply
interlaced, like bedstead laths, and wired at the ends, succes-
sive lengths being joined to each other by being hooked together.
The method of laying alternate sections was not adopted,
but each day's work was finished off by a clear vertical edge as
shown in Fig. 1, against which the next day's work was butted
without the intervention of a joint filler of any description.
The reinforcement does not extend over these joints, so that each
section consists of a slab of reinforced concrete in itself.
The contour was formed by the use of pins, which were removed
as the work proceeded.
For finishing the surface, a special tool has been devised, which
consists of a metal plate 15 in. square, to which is attached a
handle fixed obliquely so that the tool can be operated from the
side of the road. The surface was rubbed over with this tool,
and parts of the road which were found to be too smooth were
roughened with a bass broom.
The joints were tarred first, and after an interval of some weeks
the whole road was coated with tar and sand. This gives a sur-
face which is not too smooth and which affords a good grip for
horses and wheels.
The traffic was kept off the road for about three weeks.
The roads in question are of varying character. Whilst not
6 CONCRETE ROADS
themselves main roads, several of them link up one main road
with another, and all, therefore, carry a fair traffic, which on some
of them may be described as heavy.
The average cost of the roads so far laid in concrete is 12 s. Qd,
per super, yard, which, having regard to the low maintenance cost,
compares very favourably with macadam, the maintenance cost
of which is very high in Southwark. The Borough Engineer is
of the opinion that macadam is quite unsuitable for town roads
and streets, and has the utmost confidence in concrete, which he
believes will in all cases ultimately be cheaper than any other
form of road construction.
It is noteworthy that the majority of the men employed for
this work were recently demobilized men who had never previously
done any work of this kind and were trained by the Engineer's staff.
Fig. 2 shows one of the roads open to traffic.
Latest Report. — In November, 1920, Mr. Harrison stated that
in two streets weaknesses appeared, but only over very limited
areas, and there was nothing which could be termed a failure.
The principal weakness was in Warner Street. This is thought
to have been due to want of care in curing. In Steedman Street
one weak place developed, the cause of which was believed to
be want of consolidation along the " joints " at the beginning
of the day's work.
All the other streets opened to traffic on the date named were
in excellent condition.
Deptford
New King Street. — This road was laid under the supervision of the
late Borough Surveyor, Mr. F. Wilkinson, A.M. I.C.E., and certain
features render the construction unique.
The length of the street is about 350 yds., and the average
width 16 ft. The traffic passing through this thoroughfare,
though it is not a main road, is said to be amongst the heaviest
in London, since the street leads to the entrance of the Supply
Reserve Department, and owing to the narrowness of the road,
which does not admit of any spreading out of the traffic, the
whole weight and impact is concentrated within narrow limits.
This constitutes a very severe test.
The two special features of this road are : —
1. Double reinforcement, one layer being placed near the top,
and the other near the bottom.
IN THE UNITED KINGDOM— METROPOLITAN 7
2. The dipping down of both concrete and the lower reinforce-
ment under the kerb and up on the inside as shown in Fig. 3 ;
the kerbs are of granite.
The lower reinforcement takes the stresses due to the weight
of the traffic in the usual way ; the object of the upper reinforce-
ment is to take the stresses due to the horizontal motion of the
traffic, the theory being that there is a tendency for the particles
of concrete in front of a moving wheel to be pushed forward, with
a reverse tendency in the case of the particles behind the wheel.
Between those two a tensional stress is set up, and it is to take
this stress, and so prevent cracks, that the upper reinforcement
is intended. It is also considered that the double reinforcement
METROPOLITAN BOROUGH OF DEPTFORD
Concrete Road
_ Borovqh £nqr/necr
F W/LKSHSO*. ff/IICE.. #/1i»Ei.
4« /t. C i
X -o-o-
'"^T
—°f u
1
M 1
BKC /V9
BofTom • /tne/0 £' - Bo/f»m
Depth of Concrete 9*
FIG. 3. — Transverse section of the concrete road laid in New King
Street, Deptford, showing the kerbs embedded in concrete.
renders expansion joints unnecessary ; these were, therefore,
not provided.
Construction. — No special foundation was prepared, as the sub-
grade of the original road was found to be sufficiently firm for
the purpose.
The road was constructed in two courses, a lower, 6£in., and
an upper, 2£ in. On account of the upper reinforcement it was
not possible to lay the surface coat before the concrete of the
lower had set ; the former was, therefore, laid 24 hours after the
latter, this being the earliest time at which the men could get
on to the concrete to place the second or upper reinforcement
in position.
CONCRETE ROADS
The lower reinforcement was first placed in position 2 in. from
the bottom. To keep it in place the mesh was stretched over a
2 -in. plank, and was supported elsewhere by portions of concrete
passed through a mesh. The wet mixture was then deposited
to a depth of 6J in. and left until next day. After an interval
of 24 hours the top reinforcement was placed and supported in
position £ in. above the surface of the lower concrete, and the
wearing coat put in to a depth of 2£ in. — J in. below thereinforce-
FIG. 4. — Concrete road under construction in New King Street,
Deptford. The reinforcement for the lower course, stretched over
a 2 inch plank to keep it in position, is seen in the foreground.
ment and 2 in. above it. Thus the depth of the concrete for the
whole was 9 in.
The surface was finished with a wooden float.
The amount of camber was 1 in 48, to obtain which a screed
was used. This, which was very shallow, remained in position until
the concrete had set. It was then removed, the trench extended
down to the first reinforcement and filled with the same mixture
as the wearing coat.
Unwashed Thames ballast graded up to 1 in. was used for the
lower course in the proportion of 6:1, and Mount Sorrel chip-
pings and sand 3 : 1 for the wearing coat ; the former passing a
f in. sieve. Fig. 4 shows this road in course of construction.
IN THE UNITED KINGDOM— METROPOLITAN £
It was not proposed to surface the road with tar, but to test'
it, at any rate for some months, as an unsurfaced concrete road.
An experiment was, however, being made in material in the fol-
lowing way with a view to ascertaining which treatment produced
the best results in point of wearing quality.
The length of the road was, for this experiment, divided into
four sections, in each of which a different treatment has been
adopted for the wearing coat, thus : — •
Section 1. Wearing coat plain 3 : 1 concrete.
Section 2. Same as section 1, but sprinkled with powdered
carborundum.
Section 3. Plain 3 : 1 concrete with a different brand of cement.
Section 4. Same as No. 3, but sprinkled with carborundum.
The carborundum was laid to prevent horses from slipping.
It was, of course, applied while the concrete was wet, and was
not tamped, but allowed to sink in by its own weight.
After the concrete had set sufficiently hard the surface was
covered with damp sand to a depth of 2 in. or 3 in., and the traffic
was kept off the road for a month.
The cost of this road was 17s. per super, yard, but now that
the men have experience in this form of work it is expected that
the next concrete road will be laid at a cost of from 105. to 125.
per yard.
The road has been open to traffic for eighteen months, and w'th
the exception of two or three small surface cracks and a pot-hole
at one of the joints, the road is in a good condition.
In a report, dated July, 28, 1920, the Borough Surveyor states
that this road was tar-sprayed for the first time on May 10,
1920. "It was treated with a very thin coat of tar and covered
with fine sand. The present condition is good."
Latest Report. — The Borough Surveyor, Mr. H. Morley Lawson,
in his report in November, 1920, on the present condition of
the road. . attributes the pot-hole, mentioned above, to careless
floating after the surface screed was removed ; this conclusion
was arrived at from the fact that all the other joints are perfect
and show little deterioration. The cost of repairing this pot-hole
will be small.
As before stated, the road takes all the heavy traffic going
to and from the Supply Reserve Depot, which is ever increasing,
and on account of the narrow width of the road the test to which
it will be submitted is severe.
CHAPTER II
CONCRETE ROADS IN THE UNITED KINGDOM
B. PROVINCIAL ROADS
Berkshire
Northbrook Street, Newbury. — Northbrook Street is the main
business street of Newbury, and, being part of the main road
between the Midlands and Southampton, bears a fairly heavy
traffic of a general character.
This road, which was laid in the spring of 1920, is 440 yds.
long, and the width of the roadway, from kerb to kerb, is 45 ft. ;
this enabled the reconstruction to be carried out in half widths
without undue inconvenience.
Construction. — The particulars of construction are as follows : —
Foundation. — The foundation is that of the original macadam
road, and is fairly well consolidated.
Course. — For the concrete road itself the one -course method
was adopted, and the thickness of the slab is 8 in.
Aggregate and Proportions. — The materials were mixed by hand
in the following way : A measuring box of one-third cu. yd.
capacity was employed, and this was filled,
Once with 2 -in. Glee Hill granite,
Once with 1-in. to £-in. Clee Hill granite, and
Once with sharp sand and flint grit.
This gives 27 cu. ft. of aggregate, to which was added 6 cu. ft.
of Portland cement, resulting in a 4£ to 1 mixture.
Reinforcement. — The subsoil here is peat, and it was solely
with a view to counteracting its effect upon the road surface that
reinforcement was employed. For a like reason the concrete
was treated as a slab, and the reinforcement placed 2J in. from
the under side.
10
IN THE UNITED KINGDOM— PROVINCIAL 11
FIG. 5. — The concrete road in Northbrook Street, Newbury, before
being opened to traffic.
FIG. 6. — The concrete road in Northbrook Street, Newbury, after
being opened to traffic.
IN THE UNITED KINGDOM— PROVINCIAL 13
Joints. — There are no transverse joints, the end of each section
being finished with a vertical face, and the concrete of the next
section butted up against it.
At the sides the construction presents a feature which appears
to be a novelty. Between the longitudinal edge of the road slab
which runs underneath the kerb (to which reference will be made
later) and the outer edge of the footpath foundation a space of
2 in. was left. This formed a groove or trench 2 in. wide and
8 in. deep, running under the kerb the whole length of the roadway
on each side, so that should there be any lateral expansion in the
concrete a 2 -in. space is provided in which such movement can
take place. This is seen in the section, Fig. 7.
FIG. 7. — Transverse section of the concrete road in Northbrook
Street, Newbury. On the right is a double kerb, necessitated by the
higher level of that side of the street.
Finish. — The surface was not floated, but tamped with a cam-
bered iron-shod screed, 2 in. by 9 in. The surface obtained is
very fine from the point of view of " grip " for horses and motor-
vehicles.
Surfacing. — Traffic was kept off each portion for one month,
and the road was tarred and gritted the day before being opened
to the public.
Camber. — A fall of 1 in 50 is allowed from centre to side, and
the flatness of the finished concrete portion, with its consequent
freedom from skidding, is very striking when compared with the
camber of the original road.
Footpaths. — The footways practically throughout the town
are of concrete, laid in situ in slabs 6 ft. wide with £-in. joints
formed with wooden strips, which are left in place. Those in the
main street have been down for 23 years and are in remarkably
good condition. In some cases the aggregate was composed
of gravel and in others of granite chips.
14
CONCRETE ROADS
Kerbs. — In Northbrook Street the kerbs (of concrete) were
laid in situ with £-in. joints, as in the case of the footways them-
selves.
A-? the original footpaths were being retained, an outer form
only was required for the kerb. This was placed in position on
the road slab and about four or five inches from the edge, so that
the outer portion of the kerb rests upon -the roadway itself.
Before placing the concrete for the kerb, a strip of tarred paper
was laid in the bottom of the trench formed by the edge of the
pavement and the outer form. This strip, which may be seen
FIG. 8.— Concrete road in Northbrook Street, Newbury, The kerb
is here seen under construction. In the foreground the strip of
tarred paper will be observed lying in the bottom of the trench.
The form is kept in position by spacers on the inside and blocks of
stone on the outside.
in Fig. 8, covered over the 2-in. space which has been mentioned
above and which acts as a longitudinal joint to the roadway.
The concrete was then placed in position up to the level of the
footpath, and finished off with a steel trowel. The appearance
of the finished kerb is very neat.
Cost. — The total cost cannot, at the time of going to press,
be given exactly, but is expected to work out at approximately
£1 2s. Qd. per super, yard. As prices rule to-day this is not high,
and in the present instance is regarded as eminently satisfactory.
16: : PI
1 CONCRETE ROADS
FIG. 9. — Showing metal reinforcement and the placing of the surface
concrete, Roberts Lane, Chester.
. 10. — View of completed road, Roberts Lane, Chester.
IN THE UNITED KINGDOM— PROVINCIAL 17
Northbrook Street has always been a bad roadway, and for 20
years prior to the war had cost £300 per annum in maintenance.
To-day, if retained as a macadam road, it would cost something
like £500 per annum.
The concreting of this road will cost somewhere about £5,000,
and as the interest on this at, say, 6 per cent., will amount to
£300 only, it will be seen at once that the contention of Mr.
S. J. Lee Vincent, A.M.I.C.E., the Borough Surveyor, that the
laying of a new concrete road is a sound commercial pro-
position, is borne out by actual figures.
It is anticipated that, when the present road has had time to
prove itself, other concrete roads will be laid in the borough.
Latest Report. — In December, 1920, the Borough Surveyor
stated that, in order to give a real concrete road a thorough test,
all top dressing was omitted with the exception of a thin coat of
refined tar and granite chippings. After seven months of heavy
traffic, the surface is in a thoroughly satisfactory condition.
Cheshire
Roberts Lane, Saltney, Chester. — One of the first reinforced concrete
roads to be constructed in this country was Roberts Lane, Saltney,
in the environs of Chester, laid in 1912, under the personal super-
vision of Mr. Matthews Jones, late City Surveyor. Briefly de-
scribed, this road, which is 950 ft. long and 20 ft. broad, was
excavated to a depth of 8 to 10 in. On top of the clay subsoil 2 in.
of cinders were placed to bind it, and on this 2£ to 3£ in. of concrete.
Across the road the reinforcement was then laid. Covering this
was concrete to a depth of 3£ to 4| in. The concrete was made
of five parts broken granite f in. to £ in. and sharp sand mixed
to one of cement. The road was closed for about three weeks,
and for part of the time was kept well watered. After being
opened for traffic, the road remained for nearly a year without any-
thing being done to it, when it was tar-sprayed and sprinkled with
granite chippings, at a cost of \\d. per yard. This treatment is car-
ried out once a year, so the cost of maintenance is a very light one.
The traffic on this road in 1913 was computed to be about
60 tons per day — not heavy — but undoubtedly this has increased,
and will still further do so as the property in and around this
district is developed. The original cost, including the excavation,
was 3s. lOd. per yard, and the cost of maintaining the surface has
already been mentioned,
18 CONCRETE ROADS
Latest Report. — When this road was inspected in the May of
1914, the surface was in perfect condition. In the spring of 1915
the tar-spraying, etc., was done, and when seen again in August,
1919, the surface was still in complete order, and there was not
the slightest sign of the dressing lifting in any way. On this
point it is well worth remembering that when the tar spraying
and chippings were first put down, the concrete was thoroughly
dry and hard.
FIG. 1 1 .—View of completed road, Whitef riars, Chester.
Whitefriars, Chester. — This road, which is 510 feet long and 15 feet
wide, was laid in August, 1914. It was originally a road made
with wooden blocks resting on a concrete foundation. The
foundation, having been broken up at different times for various
repairs, was not in good condition. Two inches of concrete were
put in, after which the metal reinforcement was placed across
the road, and upon the reinforcement a further 4 in. of concrete
was laid. This was a 6 to 1 mixture composed of four parts Welsh
granite, graded from \ to 1 in., two parts fine sharp sand and one
part cement. On completion the road was closed for three weeks,
kept well watered, and then opened to traffic. Somewhat later
it was tar-sprayed and granite chippings were put on. The cost
of this road, including excavation, was 6s. 3d. per yard super.
Latest Report. — Speaking at the Roads and Transport Congress,
held in London at the end of 1919, Mr. Matthews Jones, the City
Surveyor, stated that his Highways Committee had been so
satisfied with the results obtained that permission had been given
20
CONCRETE ROADS
FIG. 12. — Road in course of construction, Foregate Street, Chester.
FIG. 13. — A portion of completed road, Foregate Street, Chester.
IN THE UNITED KINGDOM— PROVINCIAL 21
to lay a further reinforced concrete road right through the main
thoroughfare of the City of Chester, namely, Foregate Street
and Eastgate Street. .
Foregate Street and Eastgate Street, Chester.— This street takes
all the through traffic from Manchester, Warrington and Liverpool
to North Wales, and, speaking roughly, there is not less than 1,500
tons of traffic passing over the roadway each day. Along the
centre of these streets is a double line of tramway track which
was concreted in at the same time. So far, only a portion of
the road has been completed and opened to traffic, but up to
now the results have been all that were anticipated. Very
careful observations are being made, and in the event of any
defect developing it will be possible, from the statistics obtained,
to find the cause and so remedy it in the future. The sanction
of the Local Government Board was received to do this work,
and the Road Board have shown their interest in the experiment
by granting the full estimated amount for carrying it out, viz.,
£5,000. The reconstruction of this road was estimated for early
in 1919, at a cost of lls. 3d. per super, yard, but up to now the cost
has been 12s. Qd per super, yard ; this is owing to the increase in
the cost of materials and of labour.
If this scheme proves a success, application will be made for
permission to deal with eight miles of roads' in Chester in a similar
manner. Mr. Matthews Jones stated in his paper that if the
eight miles of roads are reconstructed with reinforced concrete,
the estimated cost will be 13s. per super, yard, making a total of
£82,368. If the work were done with granite sett paving on
concrete foundation he could not, in Chester, estimate a lower
cost than 25s. per super, yard, or a total of £158,400 ; or, again ,
if it were done with tar-macadam, including a foundation, 17s.
per super, yard, or a total cost of £107,712.
The method adopted for laying this main street was as follows :
The concrete was mixed in the proportion of 5 to 1. The granite
used was of the following sizes : 1£ in., 1 in., f in., and \ in.
These were mixed in equal proportions. The concrete consisted
of 3£ of granite, \\ of clean sharp sand, to 1 of cement. When the
concrete surface had been completed— that is, after it had been
trammelled to the contour and allowed to set — the surface was
tar-sprayed and covered with i-in. granite chippings.
Our two illustrations, Figs. 12 and 13, show the road in course
of construction, and a portion of same after completion,
22 CONCRETE ROADS
Cornwall
PadstOW Station. — This road is on the Fish Quay at Padstow, on the
London and South-Western Railway, and was laid towards the
end of 1914. Its length is 107 ft. and width 20 ft.
Since it was thrown open it has so well stood the test of prac-
tical use that there is no sign of wear. In the formation of this
road there was first laid 2 in. of cinders, on this 3 in. of con-
crete, consisting of five parts of broken granite f in. and small
and sharp sand mixed, to one of cement. Across the roadway
on the top of the concrete reinforcement was placed. Covering
this was concrete of the same character as previously described
to a depth of 3 in., the surface being roughly smoothed over.
For three weeks the road was closed to traffic, and for the first
nine days the concrete was kept well watered.
The illustrations, Figs. 14 and 15, show the road in course of
construction and when finished.
Latest Report, November, 1920. — Mr. A. W. Szlumper, Chief
Engineer of theL. &S.-W. Railway, states that the present condi-
tion of the roadway is very good, and the cost of maintenance
since the road was opened has been nil.
Devonshire
The Marine Drive, Exmouth, is one mile in length and has a total
width of 65 ft., viz., carriage way 39 ft. 6 in., footpaths 5 ft.
6 in. and 20 ft. wide respectively.
The carriage-way is concrete 5 in. thick on a sand underbed
between concrete kerbs. Felt expansion joints were placed every
24 ft.
The reinforcement is placed 2 in. from the surface.
The concrete was composed of six parts of beach gravel, fine
and coarse proportionately, to one part Portland cement.
A trial portion was laid in May, 1915, and after six weeks was
tar-sprayed one coat. Traffic was put on three weeks later and
restricted to a width of 8 ft. of the carriage way in order seriously
to test the concrete. Considerably more than 1 ,000 tons passed
over this narrow portion between May and November, and there
was not the slightest sign of wear.
IN THE UNITED KINGDOM—
FIG. 14. — Padstow Station. Fish Quay road under construction.
FIG. 15. — View of finished road, Fish Quay, Padstow.
t .\CONCRETE ROADS
FIG. 16. — Marine Drive, Exmouth, showing the trial portion, with
concrete kerbs made on the site.
J
I
FIG. 17. — Marine Drive, Exmouth, during construction.
IN THE UNITED KINGDOM-
-jr,"
FIG. 18. — View of finished road, Marine Drive, Exmouth.
Fia. 19. — A reinforced concrete roadway and footway at Sidmouth.
IN THE UNITED KINGDOM— PROVINCIAL 29
The remainder of this road was laid and completed in September,
1916.
The photograph, Fig. 16, shows the trial portion referred to,
with concrete kerbs made on the spot.
Half a mile of this Marine Drive is an excellent example of
the application of reinforced concrete to engineering ends — the
piling of concrete reinforced with plain bars, the slope and parapet
also of concrete reinforced with expanded metal and faced with
limestone, and, as stated above, the roadway of reinforced concrete.
The engineer for the whole of the road construction and the
half mile of reinforced concrete sea defence was Mr. Samuel
Hutton, Engineer and Surveyor to the Exmouth Council.
Latest Report. — Mr. Hutton, reporting on the condition of this
road in November, 1920, stated that its present condition was very
good, and that the cost of maintenance during the whole period
since the road was laid has been less than £5, except for tar-
spraying, which averages Id. per super, yard per annum.
Although the question of expansion joints in concrete roads
is debatable, after three and a quarter years' experience Mr.
Hutton is not prepared to advise that they should be dispensed
with, since in this particular case the road, which is nearly 40 ft.
wide, has a southern aspect and is exposed fully to the sun's
rays.
The area so far laid is about 20,000 super, yards, and an extension
of another 6,000 yards in the immediate future is in contemplation.
This engineer finds that repairs can be done quite easily, and
is of the opinion that concrete roads will be more economical
than other types.
Totnes — Paignton. — An experimental section of reinforced concrete
road was laid in December, 1919, on the main road between
Totnes and Paignton.
The particular stretch was chosen owing to (1) its very damp
nature ; (2) no proper foundation ; (3) narrowness ; (4) The
fact of there being a convenient road where traffic could be
diverted, thus permitting the section to be dealt with being closed.
The road has a length of 100 yds., a width of only 16 ft., with
the addition of a 3 ft. wide footpath, and was excavated to a
depth of from 6 in. to 2 ft. in order to bring the bed to a gradient
of 1 in 42-5.
Before concreting was started all drains were laid, these being
placed under the footpath where possible.
30
CONCRETE ROADS
The aggregate used was composed of equal proportions of granite
broken to sizes H in., 1 in., f in. and | in. free from dirt and dust ;
the sand was washed River Dart sand. Cement was to the British
Standard Specification.
Frequent tests for voids were made, as a result of which the
proportion of material worked out at about 4| to 1. The mixture
was turned three times dry and three times wet, care being taken
that only sufficient water was added to bring the whole to a plastic
consistency. The centre of the road for a width of 12 ft. was
6 in. in thickness, the remaining 2 ft. on each side being 10 ins.
The reinforcement was placed 2| in. from the bed.
Very little ramming was done, the material bejng carefully
deposited approximately to required levels and floated with a
FIG. 20. — Road between Totnes and Paignton.
long wooden template run on screeds of wood. No joints
were provided for longitudinal expansion.
Over a week's frost was experienced whilst the work was in
hand, which necessitated a stoppage, the section completed being
covered with a layer of sand over which bags were placed. Care
was taken to leave the edge of the work stepped, rough, and
doubly reinforced/so as to form a good key when a recommence-
ment was made. No injury was done by the frost, nor is the
junction noticeable.
Five weeks after completion the surface was sprayed with
refined tar and the road opened to traffic.
IN THE UNITED KINGDOM— PROVINCIAL 31
A regular motor-bus service, as well as heavy traction engine
traffic, passes over the section daily.
Latest Report. — Mr. Andrew Warren, County Surveyor (Southern
Division) writing in November, 1920, stated : "The road is as good
to-day as when first reopened (January, 1920), and no com-
plaints have been received of its being slippery. The noise when
steel-tyred vehicles are running over the section is no greater
than when macadam was employed."
Essex
Mountnessing. — This road, which was laid in 1915, is one of peculiar
interest, inasmuch as the sides of it are composed of reinforced
concrete, whilst the centre track, a little over 11 ft., is of water-
bound macadam. Mountnessing is on the main road between
London and Colchester. The length of the section under notice
is about three-quarters of a mile, and the width 22 ft. 4 in.
The subsoil in this locality is clay, but as in early days this road
FIG. 21. — Section : Road at Mountnessing, Essex.
from time to time had been dressed with gravel it was on the latter
that the work of the new road was started. First of all the road
was excavated to a depth of 7 in., except at the side, where the
depth was 13 in. to provide for the kerb. A layer of 3 in. of ashes
was placed on the loose gravel, then l£ in. of concrete, on which
the metal reinforcement was laid, and on the top of this 3^ in.
of concrete. On either side of the road is a concrete kerb rein-
forced with one steel rod and sunk to a depth of 10 in. This
stands 3 in. above the surface of the road, and is 5 in. wide. The
kerbing was made and placed as the road progressed. The
width of the reinforced concrete on either side of the macadam
is 5 ft. 7 in., and supporting the macadam is a concrete abut-
ment running down from the level of the road to a depth of 8 in.
As regards the water-bound macadam, which extended to a depth
of 3 in., it is the old material scarified and a thickness of 2 in. of
new macadam rolled into it and water-bound.
The whole of the concrete was made up of three parts of crushed
ballast, graded so as not to exceed 1 in., one part of washed sand,
and one part of cement,
32
CONCRETE ROADS
FIG. 22. — -Road under construction, Mountnessing, Essex.
It should be observed that the first intention was to use the
reinforced concrete as a foundation for other material, but it was
afterwards decided that the concrete should be employed for the
whole thickness of this portion of the road, and this plan was
carried out. Some time after laying, the surface was covered
with a thin coating of tarred slag.
Fig. 21 is a diagram of the road, showing in a section from kerb
to kerb the position of the concrete, reinforcement, macadam, etc.
This work was planned and arranged with the approval of the
Road Board by Mr. Percy J. Sheldon, County Surveyor, and Mr.
Alfred Lyddon, late Deputy County Surveyor, Essex.
Latest Report. — Mr. Sheldon, reporting upon the road in
November, 1920, states that it is in very good condition, and the
cost of maintenance has been practically nil. The road carries
a very heavy traffic.
Epping New Road — Buckhurst Hill. — This road forms part of a
great highway which runs from London, through Woodford,
to Newmarket and Cambridge, and the portion which has been
laid in concrete is the Epping New Road at Buckhurst Hill. It
parries a weight of traffic of some 1,500 tons a day.
The stretch of concrete road originally designed was 500 yds.,
IN THE UNITED KINGDOM— PROVINCIAL
33
but owing to strikes and other labour difficulties, 235 yds. only
have been possible up to the present.
The Epping New Road at this point is 27 ft. wide, and since it
is a main road, the traffic could not be diverted ; one-half of the
width of the road was constructed at a time, the other half remain-
ing open for traffic.
Method. — The two course method was the one adopted at
FIG. 23. — The reinforced concrete road under construction
at Buckhurst Hill.
Buckhurst Hill, the lower course being 5£ in. in thickness, with a
wearing course of 2 in., making a total of 7£ in. At the channel
on each side to the width of a foot from the kerb the depth of the
concrete is 12 in.
The mixing was done by hand, and the upper course laid imme-
diately after the lower, so that the whole forms one monolithic
structure.
34 CONCRETE ROADS
For tho lower course local ballast was employed in the propor-
tion of 6:1, and for the wearing course granite chippings and
crushed granite graded from £ in. down, and mixed in the pro-
portion of 3 : 1.
The original road was macadam, and since the foundation has
proved to be thoroughly sound it received no special preparation
other than shaping and hand ramming.
The road is reinforced 1£ in. from the bottom.
No transverse joints were provided, the material at the com-
mencement of each day's work being butted against the vertical
edge left at the end of the previous section. Next to the kerbs
longitudinal joints filled with bituminous material have been
provided.
For purposes of surface drainage the road is shaped to a camber
of 1 in 50.
The surface was finished by being worked over writh a shaped
board or straight-edge until the mortar had been brought to
the top. When the concrete was thoroughly dry and hard it
was tar-sprayed.
After the concreting was completed the road was kept sprinkled
with water for several days ; the traffic was kept off for twenty-
one days in the warmer weather, and twenty-eight days during
the autumn weeks.
The surveyor for the county of Essex, Mr. Percy J. Sheldon,
M.Inst.C.E., under whose supervision the work was carried out.
reported as follows on the condition of the road.
Latest Report, November, 1920. — The cost of maintenance has
been nil, and very heavy traffic conditions prevail. The road has
been in use about five months.
Mr. Sheldon is convinced that there is no question as to the
strength and durability of concrete for roads, and that their
success and efficiency are only a question of workmanship.
It is interesting to note that all the bridges that are being re-
newed in the area administered by the Essex County Council
are being constructed in concrete, and there is every reason to
anticipate an extensive development of concrete roads within
the next few years.
Tilbury Dock Road. — The South Ward of Tilbury immediately
adjoining the huge dock of the Port of London Authority lies
well below the river level — the surface level being only four
IN THE UNITED KINGDOM— PROVINCIAL :}.">
Ordnance datum. The soil being alluvium for a depth of 40 ft.
before the ballast is reached, considerable trouble was formerly
encountered when erecting buildings or constructing roadways,
because of the unequal settlement of foundations.
The success which attended the erection of some cottages by
the use of reinforced concrete foundation. rafts caused the Council
to look to a somewhat similar form of foundation for remedying
the difficulties met within the heavily trafficked portions of their
road system ; instructions were therefore given their engineer to
prepare specifications for a trial length of concrete roadway with
suitable reinforcement.
The experimental section was laid down on the main Dock Road
during the months of September, October and November, and
opened to traffic at Christmas, 1917. It is 130 ft. long, 27 ft.
wide, and 7 in. thick.
<»**vryr
- -/?--»•
= SECTION-^
FIG. 24. — Reinforced concrete roadway, Tilbury.
The section is level longitudinally, with a cross-fall of 1 in 50.
It is on the main road leading from London to Tilbury Main
Dock, where the Cunard, Atlantic Transport, Orient, Peninsular
and other companies' large liners are berthed, and a summary of
traffic statistics shows " heavy traffic," there being more than
250 vehicles daily in addition to tractors.
Before the new roadway was laid down, the road paving had
consisted of water-bound macadam resting on about 1 ft. of hard
core.
The eastern end of the roadway being the turning corner of
ArrolTs Bridge leading to the Port Authority's property, the
heavy lorries in turning caused deep ridges to keep appearing,
and much nuisance from dust in dry weather ensued, to the annoy-
ance of inhabitants of adjoining property, with a large accumula-
tion of mud whenever the weather was wet.
The existing surface of the new carriage-way was excavated
36 CONCRETE ROADS
to an average depth of 7 in., except the portions adjoining exist-
ing kerbs, which were cut out to a depth of 12 in.
At this stage the gas and water companies' men visited the
site and satisfied themselves as to the necessity for any repairs
to their mains and services before the new work was com-
menced.
The concrete for the lower bed consisted of three parts of local
ballast to the following specification : 1 part of material
passing through a 1-in. screen and retained on ^-in. ; 1 part
of material passing through a f-in. screen and retained on a
I -in. ; 1 part of material passing through a |-in. screen and
retained on a 22 screen.
To this was added 1 part sand all through ^ in. screen, and 1 part
Portland cement, complying with British Standard Specification
for slow-setting cement.
The top-course concrete was 1| in. in thickness, and consisted
of one part best granite chippings graded from dust to -| in. One
part sand all through ^ in. screen, and one part Portland cement.
The concrete was mixed by hand to a plastic consistency, and
special attention was given to the placing of the top course, which
throughout the entire job was carried along simultaneously
with the putting in of the lower bed or base.
Transverse expansion joints were made in the concrete every
40 ft., and longitudinal expansion joints in the concrete alongside
the kerbs. These were provided for before the concrete was laid
by placing £-in, by 7-in. wrought boards of convenient lengths
and slightly greased with a hard lubricating grease ; the boards
were withdrawn when the concrete had set sufficiently to allow
their being removed without the arrises being destroyed, and the
expansion joints were filled flush with the finished surface of the
concrete with commercial soft pitch.
As soon as the lower course was finished, and while the material
^as still plastic, the reinforcement was placed upon it and slightly
pressed into it, the sheets of fabric being overlapped 4 in. at the
sides. While the reinforcement covered the whole area between
the expansion joints, in no case did it extend across them.
As the top-course concrete was laid the surface was immediately
struck off by means of a template resting on one kerb, and one
longitudinal screed, the template being moved over the surface
with a combined longitudinal and transverse motion. Any excess
pf material accumulating in front of the template was uniformly
IN THE UNITED KINGDOM— PROVINCIAL
37
FIGS. 25 and 26. — Views showing road
construction at Tilbury.
>urse of
40
CONCRETE ROADS
FIG. 27. — Road in course of construction, Tilbury.
FIG. 28. — View of finished road, Tilbury.
IN THE UNITED KINGDOM— PROVINCIAL 41
distributed over the surface of the new road except when near the
expansion joints, when the excess material was removed.
When the concrete had set sufficiently for a man to walk upon
its surface without in any way disturbing it, it was fenced
in and kept free from all traffic for twenty-one days, and the sur-
face was well watered by means of a watering can for the first
ten days and nights.
At each end of the new roadway a double row of 4-in. granite
setts on Portland cement concrete, 6 in. in thickness, was laid to
effect the junctions with adjoining surfaces.
Although owing to the increase in transport work at the docks
the roadway has had to bear a continuously increasing traffic,
the road after over a year's wear is as when laid down. The repairs
and maintenance have been nil, in the summer there is a com-
plete freedom from dust, in the winter an absence of mud, and
a very agreeable running surface is provided for vehicular traffic.
The cost of the complete work, including granite, ballast, cement ,
reinforcement, and granite setts at junctions with adjoining roads,
was IDs. 2^..'. per sq. yard.
Latest Report. — Mr. S. A. Hill-Willis, reporting on this road in
November, 1920, stated that since the road was constructed in 1917
it has been traversed by all types of heavy traffic in and out of
the Docks, and he is in every way satisfied with this trial length,
so much so that contracts have now been placed by the Tilbury
Urban District Council for 6£ miles of similar roadway in the
place of tar-macadam. A 50-ton Parsons trench excavator
recently passed over this road ; the rear wheels of the excavator
were shod with heavy steel studs, but in spite o^ the great weight
of the machine no injury was caused to the surface.
Hampshire
Southampton Docks. — This road was laid down at Southampton
Docks in the summer of 1917. It is 342 ft. long, 25 ft. wide,
and 6 in. thick, and has no paths or kerbs. It is level longitudin-
ally, but has a transverse camber of 4 in. (about ^ in. per foot).
The greater part is straight, but at one end it has a curve of about
100 yils. radius. It approaches one of the most important quays,
where vessels up to 20,000 tons are berthed, and consequently
has to sustain a fairly heavy traffic of all kinds. The ground in
this neighbourhood was reclaimed from the estuary some years
42
CONCRETE ROADS
ago, the filling consisting of broken chalk several feet in thickness
and overlying the original river mud. The site of the road had,
however, been in use for about twenty years, so that the ground
was fairly well consolidated. Before the new concrete was laid
down the road paving had consisted of water-bound ( macadam
resting on about 1 ft. of hard core, which again rested on the chalk
filling. The latter had settled so much that in places it was
necessary to raise the road as much as a foot. This was effected
by covering the old macadam with ashes, which were consolidated
by watering and rolling with a 10-ton roller, the surface being
finished off with a camber ready to receive the concrete. The
FIG. 29. — Reinforced concrete Dock Road, Southampton, for
London and South-Western Railway.
new pavement was made with Portland cement, and sea gravel
dredged from Langston harbour. As no machine mixer was
available it was all turned by hand three times dry and three
times wet to ensure good mixing. It was 6 in. thick in all, the
lower 4 in. being mixed in the proportion of 1 to 6. and the upper
2 in. in the proportion of 1 to 3. For this upper layer, the gravel
was all passed through a f-in. square mesh screen so as to avoid
the possibility of the road surface being pitted by the splintering
IX THE UNITED KINGDOM— PROVINCIAL 43
of large pebbles. In the lower layer of the concrete, and 2 in.
from its under surface, was placed one thickness of reinforcing
fabric.
While carrying out the work it was fortunately possible to divert
the traffic on to a temporary road. After rolling the base, the first
operation was to lay down the fabric, which was weighted and
kept from touching the base by 2-in. pebbles or pieces of brick
here and there. On the curved part of the road the fabric was
laid parallel to the straight part and sheared off at the. sides to
suit the curve. Immediately before placing the concrete, which
was of a moderately wet consistency . the base was w^ll watered.
A length of 12 ft. to 15 ft. only was started every day, so as to be
certain of finishing the whole thickness before evening. This ensured
the fine concrete on top being incorporated with the coarser concrete
below. Each day's work was finished off against temporary
timber templates fastened on pegs at the sides and ends, the sur-
face being formed by working a straight-edge longitudinally
backwards and forwards on the end templates. By this means a
fairly smooth surface was obtained and no rendering or touching
up was necessary. To prevent the possibility of the surface being
spoilt by rain at night, it was covered for twenty-four hours with
a tarpaulin sheet, which was supported so that it did not touch
the green concrete. After a length had been completed, the next
was omitted for a while, and the alternate length concreted.
Xo attempt was made to form any sort of expansion joint, the
concrete being simply shovelled up against the older concrete
face. The work occupied five weeks ; it was then left for another
five weeks — viz., till October 9, 1917. when the traffic was
turned on to it. As soon as weather conditions permitted (which
was in November, 1917), the whole of the surface was served with
a coat of hot tar, and dusted over with coarse sand.
Latest Report.— In November, 1920, Mr. F. E. Wentworth-
Sheilds reported that the road has stood the traffic exceedingly
well, and although, of course, a slight crack is visible at the
joint of each day's work, there is no sign of deterioration here
or elsewhere. What little wear there is is very even, so that
there are no pot-holes or malformations of a sort likely to become
intensified by further traffic. The surface is not slippery, and the
road has given general satisfaction, and is still in excellent con-
dition.
44 CONCRETE ROADS
Kent
On the Main London- Dover Road. — In the autumn and winter
of 1914-1915 a trial length of concrete road 300 yds. in length was
laid near Gravesend. During the time of its construction the
weather conditions were most unfavourable, and as it was on a
section of the highway from which the traffic could not easily be
diverted, it became necessary to make one-half of the length of
the road at a time. The original specification provided that the
concrete should be of a 6 : 1 proportion throughout, that is to say,
one part of cement to six of aggregate, including sand — certainly
not a rich concrete. That portion of the road laid in this manner
was, after its completion, tar dressed, probably before the con-
crete was properly set. Heavy traffic was put upon it in its early
days, and, in consequence, partial disintegration ensued. On
the other side, where a bed of 4| in. of 6 to 1 had been put in with
a metal mesh reinforcement above it, the authorities consented
to a richer concrete being used for the surface, and this consisted
of 1£ in. of 3 to 1.
This road was opened for traffic on March 15, 1915.
Nearly six years have elapsed since its construction, and the
section last-mentioned, which has never been tar-sprayed or
coated with any bituminous material, is still as good as when
it was first used, except for a few slight abrasions where the
transverse joints were put in.
The good condition of this part of the road has on more than
one occasion been referred to by Mr. H. T. Chapman, the County
Surveyor of Kent.
Latest Report. — At the Institute of Municipal and County
Engineers in July, 191 9, Mr. H. T. Chapman said that the portion
which was topped with 3 to 1 concrete was practically as good
as when laid, and there were no signs of disintegration or cracks,
except at the expansion joints, and we may further add that he
is of opinion that the description given above still holds good in
1920.
Monmouthshire
The Main Road from Newport to Cardiff. — The main Newport to
Cardiff road is probably one of the most heavily trafficked roads
in South Wales. This road, although specially treated, had never
been quite satisfactory, the poor subsoil being to some extent
IX THE UNITED KINGDOM-^PRO VINCI AL 45
FIG. 30. — A general view of the road.
FIG. 31. — A closer view of the good portion which has proved so
satisfactory.
ROAD NEAR GRAVESEND.
48
1 CONCRETE ROADS
FIG. 32. — A detailed view of one of the joints in the good portion of the
road, in order to demonstrate the undesirability of these.
I
FIG. 33. — A close view of the surface of one of the bays of good concrete,
which shows how level this remains after well over 5 years' wear. The
half of the road which was laid 6:1 is in the background, and the con-
trast between the two halves is very noticeable in the photograph.
ROAD NEAR GRAVESEND.
IN THE UNITED KINGDOM— PROVINCIAL 49
the reason : so that it was thought that, all things considered,
the position would give an excellent test of the possibilities of a
reinforced concrete road.
Owing to the absolute necessity of keeping the road open to
traffic, the length was treated in two portions. The width of
the road between kerb lines was from 24 ft. to 26 ft., and as the
width of the reinforcement was 7 ft., a 14 ft. width for the length
of 300 ft. was dealt with first, thus leaving the remaining width
open to the traffic.
The following specification was adopted : —
•'The thickness generally to be 6 in., laid in one course, with
the reinforcement placed about 2 in. above the bottom of the
concrete. The concrete to consist of one and a half of 2-in. local
limestone, one and a half of 1-in. stone, one and a half of
coarse sand to one part of cement. Transverse joints not to be
provided, but a longitudinal joint to be formed along the whole
length between the two portions of the road as laid. A strip of
thin tarred felting to be placed against the finished portion as
the work of laying the remaining portion proceeded ; thus the
two lengths would be absolutely independent of each other.
Where the concrete butts the kerb a clay joint of about f in. to
be made on both sides. At the end of the day's work an additional
strip of reinforcement 3 ft. wide to be built into the last portion of
the day's work about 2 in. below the top of the concrete, leaving
18 in. of the 3-ft. width projecting, in order to help the bond
with the next day's work. When completed the road to be
allowed to harden for at least three weeks before opening to
traffic, the surface being treated with tar and grit at the end
of this period."
After the work of scarifying and removing the old macadam
surface had been carried out to the required depth, the founda-
tion, which was not any too good, was* well rolled by a 12-ton
roller and made up in a few sunken places with hard, dry
filling.
Laying of Concrete. — The work of laying the concrete was car-
ried out exactly as specified, but it was found difficult to do this
economically owing to the somewhat confined space caused
through the necessity of keeping the one part of the road free
for traffic.
Before spreading the concrete the foundation was saturated
50 CONCRETE ROADS
with water in order that none should be drawn away from the con-
crete when placed into position, and while being spread the con-
crete was tamped down by shovel and rammer.
The surface was obtained by means of a shaped floater or tem-
plate 2 in. thick, 6 in. wide, and of a length sufficient to reach across
the portion laid. This was operated by two men, one at each end,
who gripped the handles provided for the purpose, and tamped
along the fresh surface until the ends of the floater rested upon
boards placed at the sides at the required level.
No other treatment was given to the surface, and the results
obtained are considered to be very satisfactory.
As regards the mixing of the concrete, great care was taken
that the proportions as specified were adhered to with each
batch. A gauge-box ^ cu. yd. capacity, with strips placed at
half depth, allowed the easy gauging of the 1| of large stone, 1£
of 1-in. stone, 1£ of sand, and the one part of cement ; the whole
was mixed by hand, and only sufficient water added to make
the mass into just a plastic state.
Each portion of the road when completed was allowed to stand
at least three weeks before being opened to traffic, and during
that time the surface was covered with fine sand to a depth of
1-in., and continually kept damp with water. Immediately before
opening to traffic the surface was brushed clean and allowed to
dry thoroughly before being covered with tar brushed in by hand
and gritted.
Previous to this, the concrete surface was carefully inspected,
and gave the appearance of being in excellent condition.
Weight of Traffic. — As with all new constructions, it is the
practical test which counts. This road has now been open for
over 12 months, and has during that time, especially owing to
the railway strike, carried excessive traffic. Two days after
the opening of the first portion laid, a very heavy traction
engine with three loaded trailer wagons, the whole weighing
at least fifty tons, passed over it ; also, six days after, a huge
piece of machinery which had to pass through the town during
the night, owing to its size, the weight upon one axle being
close upon twenty tons, was drawn over the new length of
concrete road. Coupled with this, the continuous heavy and
fully loaded motor-lorry traffic which used this road during
the railway strike, it being the main trunk road into South Wales,
has undoubtedly proved that this concrete road is well able to
IX THE UNITED KINGDOM— PROVINCIAL 51
carry any traffic which is likely to be brought upon it. Up to the
present, the surface has the same appearance as when first
opened.
Cost. — As regards the cost, this has been rather high.
The cost of labour and also the amount of material used are
given, as it may be some guide to those contemplating this mode
of construction.
Cost of removing existing macadam roadway and preparing
for concrete. Length, 300 ft. ; average width, 24 ft., equals
800 sq. yds. ; average depth, 6 in. : —
£ s. d.
Labour 56 10 9
Horse hire 35 8 5
Roller (scarifying and rolling) . . . 8 15 0
Watching and lighting . . . . . . 13 10 0
Supervision (say) . . . . . . .500
Total . . £119 4 2
This works out at 3*. per super, yard for preparing only.
There were 206 loads of useful material removed from the road
and 300 ft. run of 12-in. by 5-in. stone channelling — for which a
credit of £71 10s. is placed to the job.
Cost of reinforced concrete work : —
£ a. d.
Horse hire .......
Labour .......
Watching, lighting and fuel
2-in. stone (73 tons 10 cwt. 3 qr. at 12s.) .
1-in. stone (69 tons 2 cwt. 2 qr. at 12s. 3d.) .
Gravel and sand (86 tons 5 cwt. 1 qr. at 12s.) .
Cement (42 tons 14 cwt. 1 qr. at 74s. 9d.)
Use of timber for staging, etc.
B.R.C. fabric . . . . . .
Incidentals .......
Tar
Supervision (say) ......
Total . . .£675 3 10
For the 800 sq. yds. 6 in. thick laid this gives a cost per super,
yard of nearly 16s. lid.
52 CONCRETE ROADS
Taking the inclusive cost of the whole work and giving credit
for the salvaged materials : —
Cost of preparation
Cost of concrete work
Credit material
£ s. d.
. 119 4 2
. 675 3 10
Net total
794 8 0
. 71 10 0
£722 18 0
or per super, yard, nearly 185. Id.
This is a high figure, but irrespective of what has been said
above, there is no doubt that with better working facilities and
more extensive work the cost would be considerablv reduced.
FIG. 34. — The main road, Newport to Cardiff.
Latest Report. — This road was laid under the supervision of
Mr. Ivor F. Shellard, A.M.Inst.C.E., and Mr. H. Tremelling,
M.Inst.C.E. The present Borough Engineer reported in November,
1920, that " the road is still standing in good condition, the
only cause for anxiety being the longitudinal joint in the centre
of the road, which is being worn down rather badly.'
54
CONCRETE ROADS
I
FTOS. 35 and 36. — Brecon and Abergavenny Road, in course of con-
struction and partially completed.
IN THE UNITED KINGDOM— PROVINCIAL 55
Brecon and Abergavenny Main Road. — Work was commenced on
this road at a point near the Brecon boundary in September,
1919, under the supervision of Mr. S. A. Bennett, A.M.I.C.E.,
the County Surveyor, one-half width being laid at a time. After
about 100 yds. had been laid this portion was fenced off for
twenty-eight days, after which the traffic wras turned on to it while
the other half of the road was being constructed.
No longitudinal joint was made in the concrete, but a double
layer of the reinforcing fabric about 18 ins. wide was laid at the
centre of the road where the two halves met. Expansion joints
were provided, but instead of being placed at right angles to the
direction of the road, these were laid diagonally at intervals,
and were filled with bituminous material.
The concrete, which is 6 in. in thickness, was laid in one
course" and consisted of crushed furnace slag, graded from 2 in.
to \ in., sharp freshwater sand, and Portland cement, in the
proportion of 4£ slag, l£ sand and 1 cement.
Before being opened to traffic the surface was tarred and spread
with a |-in. coating of granite chippings.
On account of the water-logged subsoil, diagonal cross drains
were laid in the road, with 4-in. pipes, open jointed, the trenches
being filled in with 6-in. broken slag. These cross drains are
connected to a 6-in. longitudinal drain under the footpath, the
drainage water being discharged into watercourses.
The width of the roadway is 20 f t . , and the length so far completed
is about 800 yards.
The nature of the traffic over the road is both heavy and con-
tinuous, and consists of heavy steam tractors with trailers,
commercial motor lorries, and a frequent omnibus service, in
addition to the ordinary local traffic. Prior to the concrete
being laid, the road was constructed with most of the known pro-
prietary materials, but on account of the soft nature of the
subsoil it became almost impassable on account of corrugations
and depressions.
Latest Report. — The County Surveyor, reporting on the condi-
tion of the road in November, 1920, says: "So far the concrete
road has been a complete success, having withstood the traffic,
and showing no signs of disintegration or of any cracks."
56
CONCRETE ROADS
Northumberland
Longhoughton Road. — In May, 1920, the first reinforced concrete
road in Northumberland was commenced by the Alnwick Rural
District Council under the supervision of their Highway Surveyor,
Mr. Nicholas Bean. The road, which begins at the Longhoughton
railway station, is about a quarter of a mile in length and 24 ft.
in width. With a gradient of 1 in 18 this hill has always been
a source of trouble to the authorities, since, being the main outlet
of the Northumberland whinstone quarries, it has to bear very
heavy traffic, consisting mainly of steam wagons carrying loads of
five tons of stone between the quarries and the railway, and has
always had a tendency to "creep."
The concrete, which is 9 in. thick, was laid on a bottom of
whinstone setts and consists of 2| parts of Northumberland
whinstone chippings graded from 1 J in. to | in., and H parts of
f-in. chippings and coarse whinstone grit, to 1 part of Portland
cement. This aggregate is an ideal one for road work, being of a
very hard, dense nature.
FIG. 37. — Longhoughton Road, Northumberland, showing road-
making machine at work.
The Main North Road.— The first section of this road to be laid
in reinforced concrete is situated between Wideopen, about five
miles north of Newcastle, and Seaton Burn, a length of about
one mile. The road is practically level, the only gradient being
1 in 30.
CONCRETE ROADS
FIG. 38. — Lower Bristol Road, Bath.
FIG. 39. — Bridge Street, Taunton, laid June, 1920. Surveyor, Mr. D.
Edwaids. Length, 500 yds. ; width, 13 ft. 6 in. Traffic very
heavy.
IN THE UNITED KINGDOM— i>ROVINCS AX* V^ $%
The concrete, which was laid on the top of the existing road,
was mixed in the proportion of 3^ parts of crushed whinstone
H in. to | in., and 1£ parts f in., mixed with coarse whinstone
grit, to 1 part Portland cement.
The thickness of the concrete is 6 in., the reinforcement being
placed about 2 in. from the under side.
The cross-fall is about 1 in. to the channel, and the surface is
finished with tar paint and chippings.
As it was impossible entirely to close this main road, the con-
creting was done in half -widths, each section being opened to
traffic five weeks after completion. At the time of going to press
one-half of the road has been finished and is said to be standing
exceedingly well. It is the intention of the County Council,
who have acquired some of the most up-to-date road-making
plant, to layabout six miles of concrete road, and for this prepara-
tions are being made. The work is being carried out under the
direction of the County Surveyor, Mr. J. A. Bean, C.E., F.G.S.
Somerset
Lower Bristol Road, Bath. — In the first instance a length of 350
yds. of this road is being constructed in concrete, but upon com-
pletion of this section a further length will probably be laid.
The centre of the road is occupied by a tramway track, and
on either side of the road, which runs practically east and west,
are high buildings which exclude sunshine, with the result that
the road is hardly ever free from moisture.
The former road construction was hardwood paving, which had
become in a deplorable condition, and, in view of the parti-
cularly heavy traffic to which the road is subjected, it was felt
by Mr. D. Edwards, A.M.I.C.E., the City Engineer and Surveyor,
that the only solution was a concrete surface.
As the traffic could not be diverted and the width of the road
in its narrowest part is 29 ft., the work was carried out in half
widths.
The foundation is that of the original concrete, and so is well
consolidated.
The thickness of the new road is 6 in., and the reinforcement
was laid 2 in. above the bottom.
The aggregate consisted of Pennant stone, 1£ in. down to 1£
in. ; limestone, 1 \ in. down to 1 J in. ; fine stone chippings and
SJI^i'V".! « - tW CONCRETE ROADS
sand; and the proportions adopted were 1 part Portland cement,
1 part chippings, 1 part sand, and three parts stone. The amount
of water used was from 1 £ to 2 gallons for every 6 cubic ft. of the
materials taken separately, or, in other words, If to 2 gallons for
every cubic foot of dry cement.
A portion of the road was laid with Pennant stone and a portion
with limestone, with a view to comparison of results.
A batch mixer is used, and while being spread the concrete is
tamped with shovel and rammer and finished off with a floater
about 1 in. thick and 7 ft. long.
The finished work was covered with sand, which was watered
daily. The road was not opened to traffic until one month after
completion.
The surface was not treated in any way and thus this is a concrete
road pure and simple.
Scotland
Canmore Street, Dunfermline. — Canmore Street is one of the few
" level " streets found in the south side of a city where hills and
steep gradients predominate. Connecting, as it does, with the
centre of the town at its west end and with New Row at its east
end — the latter being the principal route to the lower railway
station, and very steep in that portion which lies between Canmore
Street and High Street — it has to carry a very heavy traffic.
During the summer of 1916 a motor-bus service was inaugurated
between the city and the dockyard at Rosyth, with its starting
point at the west end of Canmore Street. The roadway, wThich has
an average width of 15 ft. 6 in. between the kerbs, was originally
constructed of whinstone setts 7 in. deep, laid without a concrete
foundation, and soon gave way under the bus traffic, so much so
that within a very few months it became dangerous. The then
Burgh Engineer, Mr. P. C. Smith, submitted two schemes to the
Town Council : one to lift the setts, lay a concrete foundation,
and relay the setts, grouting the same with pitch ; and the other
to discard the setts and lay the roadway with 6 in. of concrete
reinforced with steel wire and surface sprayed with tar and
chipped. The latter was adopted.
The old setts having been removed and the surface brought
to the proper contour and level, 2 in. of concrete was laid down
and on this was spread the reinforcement. Two widths were
required to cover the roadway, and an overlap, averaging 8 in.,
IN THE UNITED KINGDOMS-SCOTLAND.
FIG. 40. — Road during construction, Canmore Street, Dunfermline.
FIG. 41. — View of finished road, Canmore Street, Dunfermline.
IN THE UNITED KINGDOM— SCOTLAND 63
was allowed ; on top of this another 2 in. of concrete of the
same proportions as the bottom layer was placed, and above this
was laid the finishing coat, 2 in. thick. The work was so carried
on that no layer was set before the other was superimposed
upon it. • . •
The two bottom layers consisted of three parts 1 \ -in. machine -
broken whinstone metal, two parts sharp sand, and one part
cement, while the finishing coat was of two parts £to 1-in. whin-
FIG. 42. — Road prior to reconstruction, Canmore Street, Dunfermline.
stone metal chips, two parts granite |-in. to dust, and one part
cement.
The surface contour was maintained by the putting in of pegs
every 4 ft. along the kerb line and at the crown of the roadway ;
on these were laid 1-in. laths from kerb to kerb, these being taken
up as the work proceeded.
When the surface was about three -quarters set it was gone over
lightly with a bass broom, thus securing a "key" for the tar
spray ; it was thereafter covered over with fine sand which was
kept moist for seven days and removed at the end of fourteen days.
On the work being completed, the surface — with the exception
64 CONCRETE ROADS
of 12 in. at the sides, which was finished smooth — was tar-sprayed
and chipped with f to £-in. whinstone chips. No expansion
joints were put in transversely, but along both kerbs were laid
J-in. white pine boards the depth of the concrete. It was intended
to remove these and fill the caviiy with pitch, but wet weather
interfered and the wood was left in.
The cost of the work, which included the removal of the old
setts, excavation, filling trenches for gas, water, etc., with 6 to 1
concrete, the concrete in the roadway, the fabric and the wood
slips along kerbs, was 105. 4d. per super, yard, and the tar-spraying
l%d. per super, yard.
Latest Report. — When the road was last inspected by the Burgh
Engineer in September, 1919, it was found by him to be in as good
a condition as on the day it was laid. He further reports that
the only maintenance necessary between October, 1916, and
the date of his leaving Dunfermline in 1919, was an annual tar-
spraying and chipping, which was carried out at an expense of
less than £5 per annum.
During the first year the road had to carry a heavy motor-
bus traffic, which was suspended in 1917. But apart from this
the road continued to bear a very heavy general traffic, including
that of traction engines, with no apparent detriment to the
surface. Mr. Smith states that from the experience gained in
Canmore Street, Dunfermline, he is quite prepared, should occa-
sion arise, to recommend the adoption of a similar construction
for roads of a like nature. He is satisfied that where the surface
is kept well covered with a coating of tar and chips, such a road
will last for many years and will repay the time and cost expended
upon it by a greatly reduced cost in annual maintenance.
The above report is borne out by the present Burgh Engineer.
Mr. R. Muir Morton, who, writing in November, 1920, stated that
': the condition of the road to-day is very satisfactory, and,
beyond requiring a new coat of tar, which it will receive in the
spring, no fault can be found with the surface of the road. The
work as it now stands is satisfactory and it is not anticipated that
any extraordinary expense will have to be incurred thereon for
a very considerable time."
Edinburgh
Blackwood Crescent. — That concrete roads are not the novelty
which is often supposed is shown by the fact that the concrete
CONCRETE ROADS
FIGS. 43 and 44. — Views showing the road at Glengormly, Belfast, during
construction.
IN THE UNITED KINGDOM— IRELAND 67
carriage-way of Blackwood Crescent, Edinburgh, 441 feet long and
33 feet wide, was laid in July, 1873.
The construction was a 4-inch base of 2-inch broken stone,
rolled, and a 5-inch coat of 1^-inch whinstone grouted with 1|
parts of fine riddled sea gravel and 1 part Portland cement, well
beaten down. No reinforcement was used, and the road has
never been surfaced with any other material.
The city road surveyor, Mr. James Sims, reporting on this
road on November 16, 1920, states that the surface is still in fair
condition and, what is very remarkable, the total cost of main-
tenance has been but £40 since the road was laid over forty-seven
years ago.
Gillespie Crescent, Edinburgh, was laid about the same period
and by a somewhat similar method.
Ireland
Glengonnly, Belfast, Antrim. — In August, 1915, a short length of rein-
forced concrete road (48 yds.) was laid in the Belfast Rural District
about four miles outside the boundary of the borough of Belfast.
This was one of three experimental lengths on a portion of the
Antrim main road where maintenance has always proved to be
difficult and expensive on account of the boggy nature of the
subsoil.
The width of the carriage way is 30 ft., and there is a footpath
6 ft. wide on the north-east side of the road, as well as a grass
verge of about the same width on the south west side.
The specification adopted for the work was the one used for
the Kent experimental length, with the exception that the con-
crete, instead of having a uniform thickness of 6 in., was made
7 £ in. thick at the middle of the road, reducing to 6 in. at the sides.
The road was laid in half widths, and each half width in 10-yd.
lengths.
After the foundation bed had been prepared a 2 -in. layer of
concrete was laid, and on this the reinforcement was placed longi-
tudinally, with 4-in. overlap where the separate sheets joined.
On account of the sheets overlapping, the reinforcement did not
come quite to the edge of the 30-ft. width of the concrete, but the
width outside the reinforcement was given an extra thickness
of 3 in. underneath, being 9 in. thick for a width of 12 in. The
68 CONCRETE ROADS
upper layer of concrete was laid immediately upon the fabric
and carefully tamped to bring it to the specified thickness, when
the surface was finished off by men who used contour boards,
which ensured that the surface had the proper form and cross -fall.
The concrete surface was then covered with a 2 -in. layer of damp
sand until the concrete had thoroughly set, and an interval of
fifteen days was allowed to elapse before traffic was permitted
on the new surface. The other half of the road was dealt with
in the same way, and when the full width of the concrete had set
and was thoroughly dry, the surface was tar-sprayed.
A traffic census on the Antrim Road near the Sandy Knowes
cross-roads, where this length was laid, gave a total of 416 tons
per day.
Latest Report, November, 1920. — Mr. D. Megaw, A.M.Inst.C.E.,
the County Surveyor, states that the length is at present in very
fair order and there has been very little expenditure on it since
it was laid, except the cost of tar-spraying each year : the road
is subject to heavy traffic.
CHAPTER III
CONCRETE ROADS IN INDUSTRIAL WORKS AND
MILITARY CAMPS
The Port of London Authority. — The system of reinforced concrete
roads introduced and developed by the Port of London Authority
presents many features of interest.
The road slabs are 9 in. to 10 in. thick, including a top wearing
crust of 2 in.
The method of reinforcement, designed and patented by Mr.
J. H. Walker, Assoc.M.Inst.C.E., of the Port Authority, was the
outcome of the difficulty foreseen in laying a satisfactory concrete
road upon the particularly soft ground of which the land in the
vicinity of the docks is composed. The reinforcement provides
for top and bottom layers of reinforcing bars combined and inter-
locked with zigzag diagonal tension members in such a manner
as to form a rigid mattress to which any additional bars may be
attached as required (see illustration).
The steel is delivered direct to the site from the rolling mills
in coils of ^ in. diameter wire and straight lengths of \ in. or
^ in. bars. The men quickly and economically bend and assemble
the bars on rough benches, which latter are moved forward as
the road progresses.
Very careful consideration was given to the question of rein-
forcement. The reasons for adopting such a type of double
reinforcement, with its accompanying great advantage of pro-
viding steel diagonal members to counteract the shear or diagonal
tension stresses, were as follows : —
(a) Economy.
(6) To provide two layers of reinforcement to meet the flexure
and contra-flexure stresses in the slab imposed by the
heavy rolling traffic,
(c) To eliminate the necessity for providing objectionable
expansion joints and to prevent the concrete from devel-
69
70 CONCRETE ROADS
oping contraction cracks due to variations in temperature
and amount of moisture in the concrete. The surface
of the roadway being exposed to great variations in
diurnal weather conditions necessitates steel reinforce-
FIG. 46. — Pyramidal interlocked reinforcement for roads, rafts, floors,
etc., as used for Port of London Authority roads.
ment near the surface of the concrete, whilst, due to
seasonal changes, a bottom layer of steel is also required.
The pyramidal diagonal bars being anchored in the
bottom layer of concrete also perform a very important
IN INDUSTRIAL WORKS AND MILITARY CAMPS 71
FIG. 46. — Reinforced concrete road in course of construction, showing
reinforcement and the road-laying machine covered with canvas.
FIG. 47. — Finished view of road for the Port of London Authority
at the Royal Victoria Docks.
74
CONCRETE ROADS
FIG. 48. — Reinforced concrete road at the works of Messrs. Joseph
Baker, Sons & Perkins, Willesden Junction.
FIG. 49. — Reinforced concrete road at the works of Messrs. Joseph Baker,
Sons & Perkins, showing the truck lines.
IN INDUSTRIAL WORKS AND MILITARY CAMPS 75
function in providing for any possible contraction of
the concrete by spreading this contraction over innumer-
able and practically invisible hair cracks.
(d) To provide a simple, cheap and practicable way of readily
assembling the steel, and to ensure that the reinforce-
ment, when laid, shall be in its correct position in the
concrete, and also to provide a framework to which any
additional bars can be readily attached when required
over trenches or other exceptionally weak places.
This system of constructing concrete roads was installed in
the Royal Victoria Docks in the winter of 1917-18, and has ful-
filled all expectations.
The proportions of the concrete, the methods of mixing, and
construction of the road may shortly be described as follows : —
The lower 7 in. consists of 6 of Thames ballast to 1 of Portland
cement, the top or wearing crust of 2£ of f-in. broken shingle,
and 1J of sand to 1 of Portland cement.
The construction of the road was as follows : After the road bed
had been excavated and graded, the reinforcement was laid there-
on, the bottom 2 in. of concrete was placed in position, and the
reinforcement lifted through it, by hooked bars, so that it rested
on the concrete. The remaining 5 in. of the bottom 7-in. coat
was then deposited. The top 2-in. coat was afterwards placed
in position, tamped and screeded by a specially constructed screed
worked by two men, which brought the surface to the actual
level and contour required.
A special feature in the making of these roads was the machine
for fixing, laying and screeding the concrete, which is briefly
described in Chapter VI, page 165.
Messrs. J. Baker, Sons & Perkins, Willesden Junction.— A con-
crete road was laid down at the works of Messrs. Joseph Baker,
Sons & Perkins, engineers, Willesden Junction, under the super-
intendence of Mr. S. W. Moscrip, the engineer.
Having studied the concrete roads of America and of this
country, and examined the question in all its bearings, Mr. VIos-
crip was satisfied that a concrete road was calculated to meet
more satisfactorily than any other the demands made upon it
by the heavy traffic which a road of this description has to carry ;
the company therefore decided to give this method of construc-
tion a trial.
76 CONCRETE ROADS
The foundation consisted of a mixture of clinker and ballast,
well rolled and consolidated. The kerbing, which was laid first,
is 1 ft. in depth, and is battered on both sides, being 6 in. wide
at the top and 9 in. at the bottom. The concrete for the road it-
self is 6 in. in thickness, and was laid in two courses, a lower course
of 4 in., consisting of a mixture of one part Portland cement and
five parts coarse material, and an upper layer of 2 in., consisting
of one part Portland cement, one part sand, and two parts pea
shingle, graded up to f in. diameter. The reinforcement consists
of steel mesh. Adopting the principle to which, where reinforce-
ment is used, recent experiments seem to point as being sound,
no expansion joints were provided. The concrete was laid in
alternate bays, and the material in the intervening spaces was laid
close up to the concrete already in position. The surface was
worked over by a trammel, shaped to the camber of the road,
and was afterwards finished with a wooden float. When the
concrete was sufficiently hard, the road was covered to a depth
of about 2 in. with ashes, which were kept constantly moist, and
allowed to remain for three or four weeks.
The road so far constructed is about 200 yds. in length and
24 ft. wide, and the result is satisfactory in every way. The sur-
face is even, but not smooth, and presents a " dead " face which
affords an excellent grip for horses and motor vehicles, and enables
each to work up to its maximum power ; and although some two
or three hundred tons of traffic pass over the road daily, there
is in it neither crack nor flaw. Indeed, so satisfied is the engineer
with the result of this experiment, that the company has in
contemplation the construction of concrete roadways throughout
the whole of its yards.
Latest Report. — Mr. S. Moscrip, the company's engineer, writing
in November, 1920, states : " The road has been in use now just
over three years and has cost nothing for maintenance or repairs.
When the concrete was thoroughly dry we gave it a good coat of
tar and sand and this has not worn off yet. Heavy loads up to
13 tons have been over the road in motor, steam and horse wagons.
" Messrs. Joseph Baker, Sons & Perkins are thoroughly satis-
fied with this kind of road construction and will certainly use it
in future extensions of their works."
Empire Paper Mills, Greenhithe, Kent.— This road forms the approach
to the Empire Paper Mills, Limited, at Greenhithe, and was
IN INDUSTRIAL WORKS AND MILITARY CAMPS 77
laid in the spring of 1918. The length which has been concreted
is about 800 ft., and the width of the road is 18 ft. between the
kerbs. Concrete kerbing, 6 in. thick, was first moulded in situ,
the mixture used being 3 of sand to 1 of cement. No reinforce-
ment was used for this kerbing, but to allow for expansion
joints were formed with deal strips £ in. thick, spaced every
12 ft. The concrete of the road was 6 in. in thickness, and con-
sisted of a bottom 4 in. of 6 : 1 mixture, and a finishing surface
2 in. thick of 3 : 1. It was reinforced throughout with metal
mesh, placed as nearly as possible 3 in. above the bottom — i.e.,
in the centre of the concrete. In order to reduce the number of
joints (which are a source of weakness in concrete roads), each
day's work was done continuously in one bay, and sufficient
space was left between one day's work and the next to allow of
the intervening bay being put in afterwards when those on each
side were set. One thickness of tarred paper was placed against
the ends of the completed bays before the intervening bay was
filled in. The reinforcement was placed so that it stopped 2 in.
from the end of each bay, and also 2 in. from the kerbing on each
side, in order to ensure that it was protected by concrete from any
risk of corrosion.
The number of vehicles passing over the road is not very great,
but they are of all classes, including large motor lorries and steel-
shod steam wagons. The illustration Fig. 50 shows this road
after completion.
The whole road is on a gradient from one end to the other, but
the gradient varies throughout its length. A cross-fall to both
kerbs of 1 in 50 was provided.
Latest Reports, November, 1920. — -According to a report from
the chief engineer of the above Company, Mr. D. T. Maclvor,
and a later report by an independent observer, the road has been
in use two years and is in as good condition as when first opened.
The method adopted for constructing this road, viz., by alter-
nate bays, has quite justified itself, and has demonstrated that it
is both unnecessary and undesirable to provide " expansion "
joints in a reinforced concrete road.
It is understood that the Empire Paper Mills Company is
highly pleased with this road, as, prior to its construction, great
trouble and expense had been experienced in keeping up the
macadam roadway, whereas the concrete road has cost nothing
for upkeep, and is not affected by the state of the weather.
78 CONCRETE ROADS
A Factory at Southampton. — Fig. 51 shows a concrete road laid
down at an important factory at Southampton. The road runs
the whole length of the main buildings, some 2.500 ft. in all.
During the construction of the factory, which was a Govern-
ment rolling mills, a hard core roadway had been formed approxi-
mately on the same lines as the new concrete road, for which
a good foundation had thus been prepared. Preparatory to
starting work on the concrete road, the top of the hard core
was picked over> screened, levelled and rolled. Concrete kerbs
which had previously been cast in moulds were then laid on a
concrete bed on either side of the new road, and served as forms
for the concrete.
The roadway itself is 10 ft. wide between the kerbs, with double
width passing-place, and consists of 6 : 1 cement concrete 10 in.
thick, laid direct on the hard core referred to. No reinforcement
of any kind was used, but the concrete was deposited in alternate
sections 10 ft. 8 in. in length and the full width of the road.
Upon this was laid a surface coat, 2 in. in thickness, consisting
of granolithic paving. When these sections had set, the inter-
vening portions were laid in a similar manner.
The traffic is of the heaviest and consists of motor wagons
up to 10 and 12 tons in weight with broad flanged metal wheels.
The Portsea Island Gas Works, Portsmouth. — The Portsea Island Gas
Light Company early in 1919 decided to lay a reinforced concrete
roadway in Green Lane, a public thoroughfare for the mainten-
ance of which the Company is responsible. The road, which
carries a fair amount of heavy traffic, including tractors, steam
wagons and motor lorries, was originally of water-bound macadam
but this had been repaired and patched many times, and its con-
dition was very bad ; a trial length in reinforced concrete was
therefore recommended. The eastern half of the road, extending
from the Gas Works entrance to the railway crossing, was put
down in concrete, the remaining half, over which the same amount
of traffic passes, being laid in water-bound macadam, in order to
obtain comparative results. The concrete portion measures
725 ft. in length and 22 ft. in width between the kerbs.
Manholes were provided where necessary at the crown of the
road, and gulleys were placed on both sides bedded in Portland
cement concrete foundations.
Work was commenced on the site in June, 1919, and as it was
IN INDUSTRIAL WORKS AND MILITARY 0? AMPS':
FIG. 50. — Concrete road, Empire Paper Mills, Greenhithe.
FIG. 51. — A concrete road at a factory in Southampton.
IN INDUSTRIAL WORKS AND MILITARY CAMPS 81
fortunately possible to divert the traffic, the whole of the road
was scarified to a depth sufficient to form a new bed, all surplus
material being screened and the recovered metal carted away for
vise on the second half of the road. A good solid foundation was
ensured by filling in, watering and ramming any soft places in the
bed; the latter being finally finished off to the required camber.
On the bed was laid the reinforcement — a metal mesh — a lap
of 4 in. being arranged at the junction of each width, and a lap
of 12 in. where one length ended and another began.
The aggregate employed was shingle dredged from Langs ton
Harbour, in the vicinity of the Works. This was mixed with
Portland cement in the proportion of 6 : 1 for the lower course of
4 in., and 3 : 1 for the wearing coat, the shingle for the latter all
passing a f in. screen.
On depositing the concrete the reinforcing fabric was lifted
and well shaken, and the concrete rammed to a depth of 2 in.
below the reinforcement, the position of which was thus uniformly
2 in. from the under surface of the slab. Great care was taken
that the upper 2 in. of fine concrete should be laid before the lower
layer had set, and the work was finished off each evening at a
straight edge placed transversely across the road. At the end
of each day's work a strip of reinforcing fabric some 3 ft. wide
was so laid across the road as to bond the two days' work together,
half the width being left projecting.
The formation of the correct camber was effected by the use
of two parallel screeds, placed one on each side of the road, and
a template faced with hoop -iron, which was dragged backwards
and forwards along the screeds after the laying of the concrete
in each section. This gave a very good surface.
Good progress was made by the above method, the average
rate of completion being about 30 ft. run per working day.
As the concrete was laid and the surface finished the work
was protected from the sun by means of corrugated iron supported
on poles. This temporary roof was moved daily to follow the
work, and was replaced by a layer of wet sand, which was kept
well wetted for three to four weeks after laying. Fig. 53 shows
the sub-grade in the foreground, the roll of reinforcing fabric, the
template and the corrugated iron protection.
When the concrete had thoroughly matured, the sand was
removed, and finally a coat of hot dehydrated tar applied, the
whole being dusted over with coarse sand.
82
CONCRETE ROADS
The road was opened for traffic six weeks after laying the last
batch of concrete, or twelve weeks after commencing the work.
The result has been considered very satisfactory, and up to
the present has been an entire success. A photograph of the
completed road is shown in Fig. 55.
In cost the concrete compares very favourably with the macadam
road, and a very large saving in maintenance charges is anticipated.
Benefiting by their experience with this trial length of road, the
company has since put down other concrete roads of greater
length inside the Works. The method of laying these roads and
their general construction are very similar to those of the trial
length, but one or two modifications have been introduced.
In the first place the new roads are formed with concrete
kerbs instead of stone, which forms the kerbing in the trial length.
ff+infot-c/'ng fabric' SECTION Of
FIG. 52. — Section through roads and border, Portsea Island Gas Works.
The layer of reinforcing fabric will project under the kerb and for
a distance of 6 in. beyond its outer edge, where the concrete
is formed into a step. This, it is thought, will reduce the stress
on the kerb, and, as an additional safeguard, a further strip of
reinforcing fabric 1 ft. 6 in. long has been laid through the body of
the kerb, as shown in Fig. 52.
The question of camber has required some attention. Many
concrete roads are laid with very little camber, 1 in 50 being often
specified for this purpose. Doubtless this will allow water to run
off provided the road can be kept reasonably clean, but a gas-
works yard is usually so muddy as to render the road leading
therefrom very needful of attention in this respect. A greater
camber was, therefore, given to the trial road — some 4 in. on the
total width of 22 ft., or 1 in 33, and this camber has been adhered
to in the new roads.
The work was carried out to the specification and drawings of
IN INDUSTRIAL WORKS AND MILITARY CAMPS 83
FIGS. 53 and 54. — Method of laying concrete in Green Lane,
Portsea Island, Portsmouth.
IN INDUSTRIAL WORKS AND MILITARY CAMPS 85
FIG. 55. — View of completed trial road at Portsea Gas Works.
Mr. T. Carmichael, the Gas Company's engineer and manager,
and, we understand, has resulted in remarkably fine thoroughfares.
Chisledon. — An interesting development of the use of concrete
for roads during the WTar was the making of a number of camp
roads, and the illustration, Fig. 59, shows a camp road at
Chisledon, about five miles from Swindon, where some concrete
roads were constructed during the War. Altogether there are
about two miles of these roads. The surface formation of the
roads is reinforced concrete, 6 in. thick. The roads comprise
different sections, one being 700 ft. long and 20 ft. wide. It was
originally intended that the concrete should be covered with as-
phalt or similar material, but eventually it was decided to leave
the concrete surface as it was. Another road was 15 ft. in width.
The concrete mix was 5£ to 1. The reinforcement was in the form
of electrically welded steel wire placed about 2 in. from the under
side of the concrete.
Loch Boon. — This road, which was laid in July, 1917, is about
700 yds. long and 16 ft. wide. It leads down to the loch from
a road which runs parallel to the side of the lake but some dis-
tance from it. The latter road is of macadam, and in some cases
had been filled in several feet in thickness, but was still subsiding,
86 CONCRETE ROADS
and it was for this reason that it was decided to try reinforced
concrete for the road down to the lake. The ground is boggy,
but was drained by a system of field drains and ditches. The
road was laid directly on top of the grass, which was fairly level,
and any small hollows were filled up with stones, but there was
no pitching and no rolling. It was understood at the time that the
road was entirely experimental, and nobody expected it to carry
the heavy traffic without showing some defects, although it was
hoped that it would be better than the macadam road. The
result has exceeded all expectations, as the road has carried all
the traffic in connection with dismantling the camp at the Loch
Doon Aerial Gunnery School and does not show the slightest
defect. The surface is coated with tar spray and granite chips.
The concrete, which is reinforced, is 7 in. to 9 in. thick.
London, Brighton and South Coast Railway Goods Yard, East Croydon.
— These roads, two in number, have been laid in the sidings which
are used mainly for the discharge of coal, with the result that the
traffic is of a very heavy order and comprises vehicles of all
descriptions up to heavy steam wagons.
The base of the new road was prepared by scouring off to the
required depth the top surface of the old road and consolidating
to shape with a 10-ton roller.
Before concreting, test blocks were made and were broken at 7
and 28 days, the results being found to be satisfactory.
The thickness of the concrete is 6 inches, and the proportions
adopted were 1 : 2 : 4, the larger aggregate being beach shingle
obtained from Newhaven Harbour.
The reinforcing mesh was laid 2 inches from the under surface
of the slab.
After the concrete had been laid, the surface screeded and the
material allowed to set, the road was covered with sand which was
kept wet for, approximately, three weeks, at the end of which
period the sand was removed, and the surface allowed thoroughly
to dry. It was then covered with a thin layer of tar and fine
granite chippings.
Fig. 57 shows the sub-grade prepared to receive the concrete,
and Fig. 58 is a view of the finished road.
The work was carried out under the superintendence of Mr. J.
Petrie, O.B.E., the district engineer.
The first of these roads was opened on 24th June, 1 920, and the
second on 29th September, 1920.
IX INDUSTRIAL WORKS AND
'CAMPS 87
CONCRETE ROADS
FIGS. 57 and 58. — Goods yard, East Croydon.
IX INDUSTRIAL WORKS AND
??:<: «1
FIG. 59. — Concrete road at Chisledon Camp.
PIG. 60. — A road at Swindon Works for the Great Western Railway
Company (laid partly in 1916 and partly in 1919).
CONCRETE ROADS
FIG. 61. — Road at Messrs. Harland & Wolff's Shipyards, Belfast. Laid
during 1919-20. Length laid up to November, 1920, about 2,000 ft. ;
width varying from 18 ft. to 30 ft. Traffic: heavy shipyard traffic.
FIG. 62. — Hamilton Road, Belfast — laid for the Belfast Harbour
Commissioners. Engineer, Mr. F, S, Gilbert, M.Inst.C.E.
IN INDUSTRIAL WORKS AND
FIGS. 63 and 64.— Road at Purfleet, at the works of Messrs. Jurgens
Ltd. Engineer, Mr. E. H. Simons. Laid in April, 1920. Length,
840 ft. ; width, 18 ft. Traffic : heavy factory traffic,
WORKS AND MILITARY CAMPS
FIG. 65.— Road for Messrs. Lewis & Tylor, Ltd., Cardiff, laid May, 1920,
Length, 164 ft. ; width, 16 ft. Traffic : Motor lorries.
FIG 66.— Colliery road for the Powell Duffryn Steam Coal Co., Ltd..
Tredegar. Engineer, Mr. W. J. Jones. Laid in April, 1920. Length,
240yds. by 13 ft. 6 ins. wide. Traffic: Very heavy motor lorries.
Present condition leaves nothing to be desired.
CHAPTER IV
CONCRETE ROADS IN OTHER COUNTRIES
New Zealand
PASSING now to the use of concrete for roads outside the United
Kingdom, the experience gained in New Zealand calls for attention,
and the following information is based on a paper read by Mr.
Walter E. Bush, M.Inst.C.E., City Engineer, Auckland, before
the Roads and Transport Congress held in London in November,
1919.
He stated his " belief in the future of concrete paving for climates
like that obtaining in Auckland, especially as motor traction would
tend more and more to replace horse traction in the future, and in
respect to a number of streets he gave alternative estimates for
paving such streets in compressed asphalt, wood block, stone setts
and concrete. It was not, however, until the latter end of 1915
that the City Council authorized him to put down the first cement
concrete pavement in the city, although cement concrete founda-
tions had been put under all paved streets.
" The measure of success met with in the first street has led to its
increasing use, and practically all streets that have since been per-
manently paved have been carried out in cement concrete.
"By March, 1919, some 35,000 yds. in all had been completed,
14,000 yds. were in hand, and an additional 135,000 yds. had been
authorized."
The following are some short particulars regarding three of the
streets laid in Auckland, according to information furnished by Mr.
Bush in his paper at the above-mentioned Congress : —
Little Queen Street. — This street is 423 ft. in length, and lying almost
due north and south, thus exposing it to the sun's rays for the
middle part of the day, which means that in summer-time the
surface temperature is often as high as 120° F., and may sometimes
exceed that. Its mean elevation is 9 ft. above sea level, and it
99
100 CONCRETE ROADS
serves the back or cart entrances of a number of warehouses and
works to and from which the traffic is of the heaviest description,
both two and three-horse lorries and also motor-trucks being
used, carrying the largest loads that the very flat grades on the
water front make possible, and it is also subjected to much
turning and twisting traffic from the fact that many of the ware-
houses have cart docks, and practically all unloading is done by
backing the lorries and trucks either into such cart docks or
against the kerb.
The street was prepared for paving by scarifying the water -
bound macadam, excavating to the required depth and preparing
and rolling the sub-grade to the required camber to receive a
uniform thickness of 8 in. of pavement, with a fall from the
crown to the channel of approximately 1 in 36.
Two-coat work was adopted, the lower six inches of 7 to 1
concrete and the upper two inches of 3 to 1 . The 7 to 1 concrete
consisted of five parts of clean beach shingle having a fair propor-
tion of sand, two parts of broken basalt between 1 in. and 2^ in.
gauge, and one part of Portland cement, while the 3 to 1 concrete
consisted of 2*25 parts of beach shingle, 0*75 parts of f in. gauge
basalt chippings and one part of cement. The top 2 in. was
laid immediately after the lower 6 in. had been roughly brought
to its proper shape, and while it was quite greeh, in order to
ensure that the whole 8 in. was practically homogeneous.
The surface was brought to a proper camber by a straight
timber template shod with steel, operated transversely to the
longitudinal axis of the street, from the centre to the channel,
on screeds of angle iron fixed to bars in the ground, after which
it was steel trowelled till it presented a wet, even surface ;
after setting had commenced it was lightly broomed to remove
glazing of any portion of the surface, and when setting had taken
place the concrete was covered with bags and kept wet for eight
or nine days.
It being midsummer, only three weeks were allowed before the
road was opened to traffic, and after nine months it was treated
with Calif ornian asphalt, brushed on hot and dressed with screened
beach shingle.
Prior to the application of the asphalt dressing the surface
showed slight signs of wear in one or two places where the shingle
had not been so good as in the remaining portions, a fact which
emphasizes the necessity of using only the best qualities of aggre-
IN OTHER COUNTRIES • . . : 1Q1
gate available in this class of pavement. This road was completed
in February, 1916.
Durham Street. — This was done with one-coat work 7 in. thick of
5 to 1 concrete, the traffic conditions not being so severe as in
the preceding road, and it was left untreated and has stood quite
satisfactorily since its completion in October, 1916.
Park Road forms a portion of Auckland's busiest traffic outlet,
and lies immediately eastward of the important reinforced concrete
viaduct known as Graf ton Bridge, which is surfaced with com-
pressed Neuchatel asphalt. The road was completed in July,
1917.
It carries mixed traffic, most of which is fast travelling, and
includes heavy petrol motor-wagons and chars-a-bancs, but no
motor-buses similar to those so common in London, the number
of vehicles counted being over 2,000 per day of ten hours.
The work was done in two halves to prevent stoppage of the
traffic, and was much delayed by difficulty in obtaining shingle
owing to bad weather, and this resulted in some shingle being
used which was not absolutely first class, and also in the street
being opened up for traffic sooner than was advisable. This
caused the engineer to cease using shingle for aggregate and to
substitute broken basalt and sharp sand.
The change was mado during the progress of the Park Road
job, which was a one-coat pavement of 5 to 1 concrete, 8 in.
thick, and the bays done with the basalt and sand aggregate
showed enough superiority to the rest of the work to justify the
alteration made.
With the exception of a short length of the basalt and sand
concrete, the whole surface was treated with a dressing similar
to that used on Little Queen Street.
In all the streets paved since 1917 the paving has been one-
coat work of concrete composed of clean basalt chippings and
screenings varying from IJ-in. gauge to "fines" mixed with
25 per cent, of sharp beach sand free from shell and gauged with
Portland cement in the proportion of 5 of aggregate to 1 of cement,
but prior to the concrete being laid the sub -grade is sprinkled
with 2 1 -in. clean basalt road metal as a measure of economy.
In all cases the sub-grade is carefully prepared and rolled solid,
and steel rod reinforcement is laid transversely over trenches
likely to cause trouble by subsidence.
102
CONCRETE ROADS
The cost per sq. yard, of pavement only, for the above thre6
streets worked out at 10s. and 9s. respectively.
In addition to the roads above described, it is interesting to
note the other works done to the end of 1919, as scheduled in the
accompanying table.
Kame of Street.
Length
in
Feet.
Area in
Square
Yards.
Thick-
ness in
Inches.
Cost per
Sq. Yd.,
Pave-
ment
only.
Date of
Comple-
tion.
Remarks.
Market Roads .
640
1,340
7
8/-
Mar., 1918
Untreated.
Exchange Lane .
140
155
4
• 5/3
Dec., 1917
Untreated.
Quay Street Ex-
530
3,828
8
9/-
Mar., 1918
Untreated.
tension
Intersected
by railway
sidings.
King's Wharf Rd.
605
2,351
8
9/-
May, 1918
Untreated.
Intersected
by railway
sidings.
Beach Road
1,896
12,801
8
—
May, 1919
Double-track
tramway.
Anzac Avenue .
2,347
9,909
8
—
—
Under con-
struction in
March,
1919.
Symonds Street.
3,100
13,427
'8
—
Sept., 1919
Double-track
tramway.
Total length, 10,453 ft. Total area, 49,372 sq. yds.
In addition to the above an area of over 2,000 sq. yds. in Pitt
Street, on which trial lengths of proprietary bituminous pavement
had been laid on a 6-in. concrete foundation and had failed, was
surfaced on the old concrete foundation with a rich concrete
(3 to 1), half of the area being an average thickness of 3 in. and the
remainder 3£ in. This was only completed in March. 1919.
Note. — The prices paid for labour and materials were as fol-
lows : Labourers 10s. Id., finishers and machine men lls. Id.
per day of 8 hours ; cement delivered 50s. per ton ; basalt chips
and screenings 10s. 3d., basalt road metal, 2^-in. gauge, 9s. 3d.,
and sand 10s. lid. per cu. yard.
Dealing with the question of concrete mixing, Mr. Bush expresses
himself strongly in favour of machine mixing.
Regarding joints he adopted the use of tarred paper, folded
IN OTHER COUNTRIES;
1D3
FIG. 67. — Western Motor Track, St. Kilda Road, Melbourne.
FIG. 68.— New South Head, WooMahra, Sydney.
lOu
CONCRETE ROADS
IN OTHER COUNTRIES 107
to form two thicknesses, and these were placed approximately
56 ft. apart, the length of bay laid being 14 ft., and four bays
a convenient length for a joint.
Out of 35,000 yds. laid, of which only 5,216 had been coated,
not a single crack had been discovered between the bays, and
only in Little Queen Street and Park Road, in which shingle
concrete was used, were there any noticeable signs of wear. The
tarred paper joints and those formed by the junction of two bays
are coated with asphalt and fine shingle.
Australia
In Australia some experiments in reinforced concrete road con-
struction have been carried out at Melbourne and Sydney in the
suburban areas, notably on the St. Kilda Road, Melbourne, and the
New South Head Road, Sydney.
St. Kilda Road, Melbourne (West side). — An extended, and what
may, so far, be called a satisfactory test with a reinforced con-
crete road has been made by the South Melbourne City Council
on the west side of St. Kilda Road on a section within the
council's jurisdiction. It was carried out under the supervision
of Mr. A. E. Aughtie, M.Inst.C.E., City Surveyor. Five different,
but conjoint, sections of the road were laid with steel mesh
reinforcement — longitudinal and transverse, and triangular —
supplied by two different makers, and with plain concrete, in
order that a comparative test might be made of their relative
values. In March, 1914, one chain of road was experimented
upon, 33 ft. being laid with plain concrete, and 33 ft. with con-
crete and longitudinal and transverse steel mesh reinforcement.
In June, 1915, 2£ chains of plain concrete road were put down ;
at the same time half a chain of concrete road with triangular
mesh reinforcement was laid. In March, 1916, half a chain of
concrete road with longitudinal and transverse mesh reinforce-
ment was constructed.
The reinforcement in the several instances mentioned was laid
in concrete 6 in. thick, while the plain concrete road was 6-8 in.
The concrete mixture for the various tests comprised four parts
of blue stone screenings two parts of sand, and one of cement.
The width of the road so treated is 24 ft., with 3 ft. of channelling
on either side. The surface of the various sections was tar painted
and sanded.
108 CONCRETE ROADS
Reporting on the test Mr. Aughtie said it had conclusively
shown that there had been absolutely no wear on the surface,
anql to all appearances it was as sound as on the day on which it
had been laid. A number of transverse cracks, however, had
appeared in the plain concrete road and at the junction of the
reinforced road, but very few had shown themselves in the latter.
Taking the reinforced sections as a whole, the cracks were of
a very minor nature and the structure gave evidence of durability.
New South Head Road, Sydney.— Some time ago the Woollahra
Council, Sydney, experimented with a section of the New South
Head Road, near Mona Road, Darling Point. There is a founda-
tion oi a depth of 6 in., consisting of concrete made in the following
proportions : — >S cu. ft. of H-in. blue metal, 8 ft. of f-in. metal, or
" shivers," 10 ft. of blue metal screenings, and 4 cu. ft. of cement.
Over this layer of ^concrete is laid the reinforcement. Above
this is the wearing course, which consists of a rich concrete
mixture of two parts of blue metal screenings to one of cement.
The length of road constructed was 160 ft., with expansion
joints 20 ft. apart.
Canada
The Toronto-Hamilton Highway.— This is one of the most interest-
ing examples of concrete road construction in Canada, and is
thirty-five miles in length. The former Engineer of the Toronto-
Hamilton Highway Commission, Mr. A. E. Wynn, has recently
stated that this road represents the best and most modern practice
in road building. For this reason we give some brief particulars
of its construction, together with illustrations.
The road is a link of the Provincial Government's scheme for
a system of main highways connecting the towns, and it carries
more traffic than any other road in Canada.
Its construction was undertaken in the autumn of 1914.
The specifications adopted very closely followed those of
Wayne County, Michigan, which is the pioneer district for concrete
roads. All work was done by day labour under the supervision
of the Commission's engineers.
The pavement itself had a standard width of 18 ft., with shoulders
IN OTHER COUNTRIES
109
FIG. 70. — The road before concreting.
FIG. 71. — View of finished road at Oakville.
THE TORONTO-HAMILTON HIGHWAY.
IX OTHER COUNTRIES 111
3 ft. wide on each side composed of the natural earth, gravel or
crushed stone.
The width was increased to meet local conditions, such as
through towns and villages. It was 24 ft. wide for a few miles
outside Toronto, and reached a maximum of 50 ft. wide through
the town of Oakville.
Materials and Method of hatidling them. — Only tested cement
of known quality was used. Before considering any stone for
use an inspector visited the quarry, and all details as to the methods
of handling, screening, output per day, etc., were recorded. A
sample of 100 Ib. was carefully selected from different points
in the quarry and shipped to the testing laboratory.
Here the following tests were made : —
(1) Resistance to wear — (2) Resistance to impact — (3) Specific
gravity — (4) Absorption — (5) Weight — (6) Granulometric analysis
—(7) Voids— (8) Cleanliness.
Most of the stone used was limestone or dolomite varying
in size from 1£ in. down, and had to pass the above tests satis-
factorily before being accepted.
All sands used were tested for cleanliness, grading and tensile
strength, and from the result of these tests certain sands were
decided upon to be used.
Every car-load of sand or stone was inspected before shipping,
and samples were sent in periodically to the laboratory to be tested
in order to be sure that they were up to specifications. On these
tests, too, was based the exact mixture to be used with a certain
aggregate.
The mixture adopted was nominally 1 cement, 1£ sand, 3
stone ; but this was checked up by the tests and was varied
slightly to suit different aggregates. When there was any change
in material the testing engineer gave to the field engineers the
correct mixture to be used and the amount of water required for
mixing.
At convenient points along the road material yards were built
alongside the railway, about eight miles apart. Xew spurs were
run into each yard. The cars of material were unloaded by a
clamshell bucket into large wooden storage bins with hopper
bottoms.
The material was then transported to any desired point along
the road by means of a narrow-gauge temporary tramway ; the
dump cars being loaded automatically from the storage bins,
112 CONCRETE ROADS
The track was laid on steel sleepers and bolted together in 20-ft.
sections, so that each section could be easily and economically
handled by two men.
The material was deposited along the road, behind the mixer,
in such quantities that as concreting progressed and the mixer
moved backwards there was always just sufficient material
on hand, with no waste or shortage.
Each train load carried cement , sand and stone in the desired
proportion, so that there was no delay in concreting due to in-
sufficiency of one of the materials.
The sub grade consisted of the natural soil, mostly sand. It
was rolled flat with a 10 -ton roller and thoroughly wetted down to
prevent absorption of moisture from the concrete. Side forms
for the concrete pavement were 6-in. iron channels, which were
accurately lined up and staked in place by instrument for some
distance ahead of concreting. Materials were mixed by half
cu. yd. mechanical mixers, steam-driven.
Water was pumped from the nearest available supply. The
amount of water used in mixing was accurately gauged by a
meter fixed to the machine and was varied to suit different aggre-
gates, but was kept constant for any particular aggregate. This
correct proportioning of water is very essential in road work and
is a point often overlooked. It ensures a uniform mixture and
is an important point in preventing cracks.
The materials were mixed in the drum of the mixer for a specified
time, and the concrete was then dumped out into a bucket which
travelled along a 20-ft. boom, to be deposited where required.
Construction of Road. — The cross section of the road was a
parabola, 6 in. thick at the sides and 8J in. at the crown, laid in
one course. As the concrete was deposited it was levelled off
by a template, handled by two men, and resting on the sido
channel forms.
Following up were the cement finishers, who worked from a
wooden bridge spanning the pavement. They floated up the
surface with wooden trowels, just sufficiently to bring the moisture
to the top.
No attempt was made to render the surface smooth, as a slight
roughness gives a better foothold, and too much trowelling will
bring the fine particles to the top, which would be liable to cause
dust.
All pavement was laid in 35-ft. sections. Between each section
IX OTHER COUNTRIES 113
was an expansion joint about £ in. wide, consisting of prepared
asphalted felt.
This felt was laid against the end form, which was set truly
in line and vertical, and the concrete was carried up to it. complet-
ing one section. Then concrete was laid the other side of the form,
and after setting a short time the form was taken out and the
space filled with concrete. To ensure the concrete being exactly
the same height on either side of the joint, a special trowel was used
with a groove to fit over the felt filler which projected above the
pavement about £ in.
After concreting followed the " curing."
The day after the concrete was laid it was covered with 2 in.
of dirt and was sprinkled with water daily for ten days.
After about four weeks the dirt was removed, the joint fillers
FIG. 72. — View of finished roacl, Toronto -Hamilton highway.
trimmed to within a quarter of an inch of the pavement surface,
and the road opened to traffic.
At intervals during concreting l-cu.-ft. blocks were made and
left along the road to cure in the same manner as the pavement.
They were marked according to their location and were afterwards
tested in the laboratory.
The pavement was not carried over culverts until after the
fill had thoroughly subsided, and was always reinforced with
wire fabric or ordinary fencing-wire, to prevent cracks.
I
114 CONCRETE ROADS
The pavement as a whole was not reinforced except over bad
places in the sub grade.
Building the 3 -ft. shoulders was the last operation, the material
employed being mostly that used for curing.
On the other hand, all culverts and bridges were built during
the winter under the severe climatic conditions that exist in
Canada. They were all constructed of reinforced concrete, the
longest spans being 125 ft.
Concrete was laid in very low temperatures with no ill effect.
The danger lies in using frozen material and in allowing the
concrete to freeze before gaining its initial set.
Maintenance so far has been a small item and is easily covered
by fines imposed upon motorists for speeding. The cracks are
cleaned out and filled with tar, heated to about 225° F. Coarse
dry sand is then sprinkled over, an excess of sand and tar being
used, and the traffic is allowed to iron it out.
Traffic along the road has far exceeded all estimates.
CHAPTER V
THE GROWTH OF CONCRETE ROADS IN THE
UNITED STATES
AMERICAN ROADS AND THEIR DEVELOPMENT
UP TO 1920
AT the close of the year 1909. there were six miles of concrete road
in all of the United States. At the close of 1919 there were 11,400
miles of concrete road. These mileage figures are based on the
actual yardage built, and since different roads are constructed of
different widths the usual road width of 18 ft. was used for the pur-
pose in hand. So the growth from practically zero to a mileage
that would span the continent from the Atlantic to the Pacific more
than three times shows how the popularity of these roads has in-
creased.
The study of the evolution of concrete roads cannot well be
carried on without at the same time taking note of the develop-
ment and use of .the automobile. In 1909 there were 127,731
cars in the United States, whilst at the end of 1919 a total
of almost 8,000,000 was reached, with an annual production
of nearly 2,000,000 cars. It will readily be seen that the develop-
ment of concrete roads and that of the motor driven vehicle
have been side by side. Carrying the motor-car figures a little
further, it is found that in the United States there is one car
for every fourteen persons, and automobile manufacturers expect
production for 1920 to be greatly increased. Motor-cars demand
a smooth, rigid road. It was not so with roads when the horse
was the motive power. Horse-drawn travel compacts dirt and
gravel roads, while motor traffic disrupts these same roads. The
speed of trucks and automobiles is at least five times greater than
that of the wagon and surrey,* likewise the cost of driving intricate
and expensive motor vehicles is correspondingly more expensive
on poor roads.
It is particularly interesting, as we bear in mind that concrete
roads and automobiles have developed side by side, to notice another
fact. Detroit, Michigan, is the centre of the automobile industry,
* A four-wheeled pleasure carriage (commonly two-seated), somewhat like a
phaeton, but having a straight bottom.
115
116 CONCRETE ROADS
and Wayne County, which contains the city of Detroit, is generally
recognized as the pioneer among counties throughout the entire
United States as a builder of concrete highways. At this point
it is fitting that recognition should be given to Mr. Edward N.
Hines, who, as chairman of the Board of County Road Commission-
ers of Wayne County, had the vision and foresight to anticipate the
need for hard roads, and who by great personal initiative was able
to convince voters and taxpayers that a comprehensive system
of concrete roads connecting the principal points in the county
should be built. At the outset considerable difficulty was experi-
enced in determining the proper width and thickness of the pavement.
It was a pioneering venture, and there were few rules or experiences
by which to guide their actions.
Many of the first concrete roads were much narrower than those
built since highway building experience has become more rounded.
Eighteen feet is now considered the minimum as a practical width
for country roads. This width gives an opportunity for trucks and
automobiles to pass with a good margin of safety at reasonable
speed, and in a large measure prevents road accidents.
The history of concrete roads, spanning as it does the short period
of a decade, may properly be divided into three parts. First, pre-
war construction, which commenced, as we have said, in 1909 and
continued until America entered the World War. Second, the
period of war construction, which took place from the date of the
entry of the United States into the world conflict until the signing
of the Armistice. The third period may be called the post-war
period of construction, which began at the signing of the Armistice
and continues until the present date.
The period of pre-war construction carries us largely through
the experimental and educational stage of concrete road-building.
From 1909 until 1911 actual construction was limited, and in those
two years less than 300 miles of road were built. During 1912 and
1913 considerable stimulus was felt, and from 1914 until 1917 the
construction of concrete roads throughout the United States was
carried on at a rapid rate. When a graph of the mileage by years
is plotted, the curve covering the last-named period becomes almost
perpendicular. In the four years ending in 1917, 5,000 miles of
18-ft. concrete roads were built. People were buying cars. Farmers
who at first had frowned upon self-propelled vehicles, and had
regarded them as a whim of the idle rich, had come to find out that
the car and the truck were valuable aids in carrying on their farming
GROWTH OF CONCRETE ROADS IN
FIG. 73. — A concrete road near Salt Lake City.
(2 1 miles long.)
FIG. 74. — Morrison Road, between Denver and Morrison, Colorado.
(About 1 mile long.)
FIG. 75. — Andrews Road, near Atlanta, Georgia.
(6,000 ft. long.)
FIG. 76. — Churchland Road, Xorfolk County, Virginia.
(Nearly 2 miles long.)
GROWTH OF CONCRETE ROADS IN UNITED STATES 121
operations. With the motor-car they could attend to more business
than ever before, and with the truck they were able to take care
of the increased business that came. Rural communities began to
want concrete roads. Now the farmers became consistent supporters
of concrete highways for their trucks and motor-cars.
Then came the entry of the United States into the World War.
The mobilization of 4,000,000 men for arms and the mobilization of
the remainder of the population for industrial work made labour
unavailable for continued road construction. Moreover, had labour
been available, material and transportation could not have been
furnished, since it, too, was diverted to war work. The country
at large had, as we have said, become educated to good roads, and
now came severe tests that were to prove the soundness of its logic
in asking for permanent roads. Particularly around army camps
and the roads traversed by military trains pavements were put to
the crucial test. Heavy pieces of artillery and endless trains of
heavy trucks carrying war supplies rapidly wore down all pavements
that were not of the highest class. Gravel and macadam roads
failed rapidly. Many other types that .were considered fair under
peace-time conditions gave way before the strain. It is interesting
to observe that where the army engineers reconstructed these military
roads they were usually built of concrete and successfully withstood
the severe punishment that our military establishments imposed
upon them. Reverting to the actual mileage constructed during
the war period, we find that J,533 miles of concrete road were built
in 1917 and 1,300 miles in 1918.
The situation, then, at the signing of the Armistice in November,
1918, was this : Before the war the popularity of the automobile
had created a widespread sentiment for good roads, and the heavy
punishment that roads received under war-time conditions proved
that concrete roads were better able to stand the stress than other
types.
After the war was over there was a strong, widespread sentiment
throughout the United States to build roads. The various States
and other road-building units gave large contracts, and in 1919
4,130 miles were built or contracts awarded. It was the premier
year for road construction. With hardly an exception every
State increased its mileage. The State of Illinois, which contains
the city of Chicago, voted $60,000,000 worth of bonds to build State
highways.
The same day that Illinois pledged itself to spend $60,000,000
122 CONCRETE ROADS
in improving its roads, the State of Pennsylvania voted a like amount.
The State of Michigan, which, as we have pointed out, was a pioneer
in road-building, voted $50,000,000 additional bonds in 1919.
This money will be used in extending its road system. During the
same year the State of California voted $40,000,000, Oregon
$10,000,000, and Alabama $25,000,000, in road bonds. During
the coming year Missouri will vote on the issuance of $60,000,000
worth of bonds, and Minnesota will vote on the issuance of
$100,000,000 worth of bonds, to be used in improving the roads in
the States named. This sentiment prevails in practically every
quarter of the United States, and bond issues totalling high into
the millions were passed, and all was in readiness for the greatest
era of road building in the history of our own or any other nation.
In 1920, $625, 000, 000 is available for road work, and the programme
will yet, in all probability, be much enlarged. But conditions were
such that the building had to be either curtailed or postponed.
Labour is very costly and at the same time extremely scarce even at
the high wage scale offered. Transportation facilities are to a large
extent disorganized and overworked. Their equipment is not
sufficient to take care of the present industrial needs of the country,
and manufacturers of cement and dealers in road materials find
themselves helpless to receive raw material or deliver finished
products.
A sketch of the concrete road in the United States wo\ild not be
complete without mentioning the roads built by the State of Cali-
fornia. As Wayne County, Michigan, was the pioneer county in con-
crete road-building, California stands out in bold relief as the first
great State building an extensive mileage of concrete road. California
builds her roads almost exclusively of concrete. In this State alone
are almost 2,500 miles of roads made of concrete. At the close of
1919 there was a thirty mile stretch of concrete highway known as
the " Ridge Route " in California opened to the public. The cost
of this road was something like $1,200,000, and it was estimated
by conservative State officials that with the heavy traffic that would
pass over this road the total cost of building would be absorbed in
less than 200 days by the saving in petrol, tyres and upkeep on
the vehicles passing over it.
As has been suggested, the entire people of the United States are
strongly in favour of good concrete roads. The term " concrete "
has come to be accepted as the general word designating all that
good roads should be. The Federal Government has made liberal
GROWTH OF CONCRETE ROADS IN UNITED STATES 123
appropriations to help to build roads where States and counties have
properly applied and their project has been accepted. The Federal
Government assists in building what is known as Federal Aid Pro-
jects. The platforms of the political parties have paragraphs endors-
ing the continuance of building good roads. There is no doubt
that of the roads to be built concrete will be strongly represented.
When conditions get back to normal, there is reason to believe that
the United States will carry on continuously a programme of road
building that will not stop until every important highway is paved,
and the lanes leading into these main routes will, if not paved, at
least be highly improved. It may truly be said that this is the
era of concrete roads in the United States.
Fro. 77. — Coast Route, San Francisco to Los Angeles, California.
CHAPTER VI
MECHANICAL DEVICES FOR MAKING CONCRETE
ROADS
THE construction of concrete roads in an economical and efficient
manner depends, to a very large extent, on the properly co-ordinated
use of a number of mechanical devices. It is, of course, possible
to make excellent concrete roads without the use of any machinery,
but the time required and the cost of such a procedure are excessive.
By the use of suitable machinery the drawbacks of hand labour are
avoided, the large number of men with wheelbarrows and shovels
are unnecessary, and a considerable amount of material as well as
time is saved. Consequently, the use of suitable machinery not
only reduces the cost of construction, but enables a much larger
area of roadway to be laid in a given time.
The mechanical devices used for constructing concrete roads may
be arranged in five groups : — •
1. Appliances used for preparing the road-bed.
2. Appliances used for preparing the concrete.
3. Appliances used in placing the concrete.
4. Appliances used in striking and tamping the concrete.
5. Appliances used in finishing the surface.
Appliances used for Preparing the Road-Bed
It is essential that the road-bed or foundation shall be properly
prepared or the concreted surface will not be durable. Hence
great care should be taken to ensure the bed being of the proper
width, shape and solidity. This is best secured by digging out
the surplus material by mechanical means, giving the bed the cor-
rect curve or camber by means of a grading machine, and rolling
or tamping the surface, if necessary, to increase its compactness.
Steam-shovels have long been used for quarrying and railway work,
but their employment for road-making is comparatively new. They
124
MECHANICAL DEVICES FOR MAKING ROADS 125
have now been modified so as either to remove a relatively thin slice
of material or to cut their way through a hill. When used for
levelling a rough piece of country — as in working a wholly new
road or in widening an existing one — steam-shovels are found to be
much cheaper and quicker than hand-digging, and far less super-
vision is required.
A British firm of steam-shovel manufacturers is Ruston
and Hornsby, Ltd., Lincoln, whose No. 5 Excavator (Fig. 78),
by reason of its remarkable mobility, wide range of move-
ments, ease of control and general utility is particularly suitable
for road-making. This excavator is capable of taking a maximum
depth of cut of 20 ft. without breaking the top down by hand,
and will also successfully deal with very shallow cuts for grading,
With the standard bucket-arms this machine can excavate a
trench to a depthof 6 ft., and, by the simple expedient of letting
out the jib ties and fitting slightly longer bucket-arms, up to
12 ft. The minimum bottom width of cut with 1 to 1 slopes is
12 ft., and the maximum height of open bucket door from rail
level 12 ft. 9 in., the maximum and minimum discharging centres
being 22 ft. and 15 ft. respectively.
Small revolving steam-shovels have been in use in the
United States for road-making with great success. The sizes
which are most popular are equipped with dippers of £ or f cu.
yds. capacity. Two such dippers full of material would com-
pletely fill the ordinary tip wagon or cart, while three dippers
would load a 2-yd. wagon or cart to its maximum capacity.
The shovels revolve through a full circle, permitting the ma-
chine to dig or dump at any angle and enabling them to operate
successfully in limited space. The latter feature is especially
valuable when it is necessary to build one-half of a roadway while
the other half is open for traffic. These steam-navvies will
excavate any materials which can be penetrated by picks and
shovels, and they are also valuable in handling properly blasted
rock.
The shovels have capacities in ordinary roadwork varying from
15 to 60 cu. yds. per hour, depending on the depth of cut, class of
material, and manner in which disposal of the material is organ-
ized.
Traction wheels are generally used on this class of navvy, but
any of them can be equipped with standard gauge car wheels, and
on some of the shovels continuous tread traction can be substi-
126 CONCRETE ROADS
tuted where desirable. It must, however, be recognized that the
use of any type of caterpillar traction, while it increases the speed
of the shovel in operation, makes moving of the shovel from one
job to another very much slower than is the case where ordinary
traction wheels are used.
These shovels are sufficiently light to be used for ordinary
street and road work without planking, although most of the
traction wheels are so arranged that cleats can be attached when
necessary.
Several of these machines, in addition to the customary fea-
tures of steam-navvies, are equipped with special devices for use
in shallow cuttings and for automatic levelling and grading work.
While these navvies are generally classed as " one man "
machines, it is usually desirable to provide an assistant to take care
of the firing of the boiler, keeping up the coal and water supply,
and generally assisting in operation. One or two pit men are
needed, depending on the type of machine, speed of the work, and
the care which it is necessary to give in cleaning and levelling up.
It must be recognized that the output from these navvies
depends almost altogether on the skill of the operator. A working
speed of from two to three dippers per minute can be obtained by
the average operator, although skilled men can obtain from four
to five dippers per minute with the same shovel working under
similar conditions.
Some navvies of the type mentioned above are the Erie Shovels,
manufactured by the Ball Engine Company of Erie, Pennsylvania,
and now sold in this country by Gaston Limited and by William
Muirhead, Macdonald Wilson & Co. Ltd., the Thew Shovel,
manufactured by the Thew Shovel Company, Lorain, Ohio, sold
in this country by the Allied Machinery Company, Ltd., and the
shovels manufactured by the Bucyrus Company of Milwaukee*
Wisconsin, sold in England by Messrs. George F. West & Co.
Cranes and Grabs. — For lifting large quantities of loose materials,
such as sand, aggregate and tipped earth, it is sometimes
cheaper to use a crane and grab than a steam shovel.
A firm of crane and grab manufacturers in this country is
Priestman Bros., Ltd., Hull, one of whose machines is shown in
Fig. 79.
A modification of the Erie shovel in which a grab is used instead
of a shovel is shown in Fig. 82. A similar crane and grab, made
MECHANICAL DEVICES FOR MAKING '
FIG. 78.— Huston & Hornsby No. 5 Excavator.
FIG. 79.
A Priestman Grab.
FIG. 80.
Erie Shovel.
CONCRETE ROADS
FIG. 81. — Crane and Grab.
FIG. 82.
Erie Shovel with Grab.
FIG. 83. — Pipe Line Excavator.
MECHANICAL DEVICES FOR MAKING ROADS 131
by Pawling and Harnischfeger Co., Milwaukee, Wis., and obtain-
able in this country from Gaston, Ltd., is shown in Fig. 81. This
machine is a complete portable locomotive crane with a lifting
capacity of 1 £ tons at 30 -ft. radius. It is driven by a petrol engine
and can travel under its own power at a rate of 1 mile per hour.
Drag-line Excavators are chiefly used on sticky soils or for lifting
loose materials, but they may also be employed for grading roads
of which the material is not too hard. As shown in Fig. 84, this type
of excavator has an inverted bucket or dipper suspended from the
boom by a rope and, on reaching the ground, this bucket is dragged
towards the machine till it reaches the limit of its journey ;
it is then lifted, the whole crane is swung round and the contents
of the bucket are discharged. By suitably regulating the suspen-
sion and drag lines, the bucket may be made to dig itself into the
ground to a convenient depth prior to its being drawn along
and a cut up to 8 in. deep obtained. The caterpillar wheels are
a special feature of the drag-line excavators made by Pawling and
Harnischfeger Co.
Trench Excavators. — As their name implies, trench excavators
are specially designed to make deep, but relatively narrow cuts,
chiefly for pipes for water, sewage and gas, and electric conduits.
Standard trench excavators are manufactured in various sizes
to cut trenches from 12 in. to 76 in. wide and in varying depths
to a maximum of 20 ft. at a rate of 6 in. to 40 in. linear per minute,
according to the nature of the ground and the size of the machine.
Trench excavators are commonly built in two classes, one
being known as the wheel type, the other the ladder type exca-
vator.
Wheel Type Trench Excavators are suitable for trenches not more
than 7 ft. 6 in. deep. They consist essentially of a vertical wheel
provided with a series of cutters around its circumference, the
wheel being mounted on a strongly trussed steel frame which
also carries the oil engine, hoist or conveyor for the excavated
material and the oil tanks.
The excavator should be provided with a steering gear, so that
either right or left-hand curved trenches of any radius may accur-
ately be cut, and a grade-control or lifting device should also be
provided, so that the trench is cut to the full depth and the bottom
is left at any desired slope or grade. In the wheel excavator
(Fig. 83) made by Pawling and Harnischfeger Co., the excavating
132 CONCRETE ROADS
wheels are of the open type, i.e., without an axle, and are arranged
to obtain the maximum depth of trench with the minimum
diameter of wheel.
Ladder Excavators are much more powerful and are capable of
digging to a much greater depth than wheel excavators. The
ladder excavator usually consists of two endless chains running
over an adjustable boom, the chains carrying a series of toothed
cutters and buckets. As the chain revolves these cutters penetrate
the ground slightly, and the material thus excavated is carried
upwards to be discharged as the bucket reaches the top of the
boom on to a chute or conveyor, which in turn transports the
excavated material to either side of the machine. It can be
dumped into a pile for backfilling or direct into tip wagons or
carts. Ladder excavators should have ample strength, since
excavating deep, wide trenches for sewer and similar projects
subjects them to constant heavy strains. Ladder excavators of
this type are manufactured by Pawling & Harnischfeger, and sold
through Gastoiis, Ltd. ; the Parsons trench excavators sold
through the Allied Machinery Co., Ltd. ; the Bucyrus sold through
Messrs. George F. West & Co. ; the Austin sold by the Austin
Machinery Company.
Backfillers. — -Where openings are made in roadways it is always
necessary to re-fill the trenches. This process — sometimes termed
backfilling — is often done in an unsystematic and inefficient
manner, and, consequently, is unnecessarily costly. Re-filling
trenches can be accomplished economically by a mechanical
backfiller such as is shown in Fig. 88, which consists of a scraper
attached to a light motor-driven crane with a supplementary
winding drum. The scraper is lifted and carried behind the pile
of earth or other material ; it is then lowered and dragged across
the hollow portion or ditch into which it discharges its contents,
and is then ready to be lifted back preparatory to repeating the
operation. Such a machine will re-fill a trench as rapidly as
twenty-five to fifty men moving the material a distance of 15 ft.
to 25 ft. The machine only requires one man for its operation.
In the backfilling of trenches it is of great importance that the
material should be thoroughly rammed or tamped, and although
this operation has up till now been chiefly performed by hand,
a machine for so tamping and trenching has been designed in
America and is actually in use in this country.
MECHANICAL DEVICES FOR MAKltfGT *tok&fe
FIG. 84. — Drag Line Excavators.
FIG. 85. — Ladder Excavator.
FIG. 86. — Jubilee Wagons.
FIG. 87. — Hepburn Conveyor
Fro. 88.— Backfiller (Gaston).
FIG. 89. — Adams "Leaning Wheel" Grader.
136
MECHANICAL DEVICES FOR MAKING ROADS 137
Wagons. — The excavated material should, wherever possible, bo
placed directly into wagons, those known as the Jubilee type
(Fig. 86), supplied by the Ransome Machinery Co. (1920) Ltd.,
being very convenient. '; Trains " of six or more wagons are
hauled away to the tip by a motor or locomotive.
Conveyors. — When circumstances do not permit the excavated
material to be placed in wagons direct from the excavator, it
should be conveyed on to one side of the road, well out of the way
of the workmen by means of a portable conveyor. Several suit-
able conveyors are on the market, the one shown in Fig. 87 and
made by the Hepburn Conveyor Co., Wakefield, being very satis-
factory.
Grading Machines. — Grading machines are used to ensure the
foundation of the road having the correct inclination and camber.
Xumerous machines for this purpose have been constructed in
various sizes to be operated by horse or mechanical traction. In
general they consist of a heavy frame mounted on four steel
wheels, the frame carrying a long blade. The position of the
blade is universally adjustable to any angle or depth, the useful
work of the machine being performed as this blade is drawn for-
ward along the work in such a way as to move the material from
the centre of the road to the side, or vice versa. In some cases,
larger type machines also are provided with scarifying attach-
ments so that macadam roads can be loosened up and re-graded.
Several successful machines are on the market, among these
being the Adams " Leaning Wheel ;' grader ; the Austin Giant
type ; and the Western Aurora type grader. Fig. No. 89 shows
an Adams grader making a cut almost the entire length of the
blade and delivering the earth just inside the left rear wheel.
Rollers and Tampers. — In order to consolidate the foundation
of a road, especially those parts which have been made by ''fill-
ing," rollers or tamping devices — operated by hand or power — •
are employed.
Hand and Horse-Operated Rollers are only suitable for the lightest
and smallest work. They are so well known as to need no descrip-
tion here, especially as their use is rapidly diminishing.
Steam Rollers are invaluable where great pressure is required for
compacting the foundation. They should be designed so as to
138 CONCRETE ROADS
secure the maximum pressure on the roller, whilst still retaining
sufficient " weight " on the rear wheels to ensure satisfactory
driving up steeply inclined gradients.
For road-making, a steam-roller should have sturdy construc-
tion and ample boiler capacity, with the boilers and cylinders
mounted so as to facilitate quick repairs.
The design should be as simple as possible, as such machines
work continually under adverse conditions and frequently in
Out-of-the-way places. In order that the roller may be stable,
its centre of gravity should be low, yet there should be sufficient
space above the ground to prevent the engine being damaged by
obstacles which the roller has failed to crush or by the machine
having to work on very irregular ground.
As steam-rollers are not required the whole of the time, it is
convenient to attach a belt to the fly-wheel and from this to drive
a crusher, screen or other machinery which can be operated at
intervals.
Motor Rollers in all sizes have been in successful use for a great many
years. They are manufactured in both the single and double
cylinder types, and some of them can be run on paraffin, the
advantages of the motor-rollers being that they can be operated by
one man, that keeping them supplied with fuel is less costly, and
that they do not require a constant supply of water.
Machines at present on the market are manufactured by Messrs.
Barford & Perkins, Peterborough, and the Austin Manufacturing
Company of Chicago.
Preparing the Concrete
The chief mechanical devices used in preparing the concrete are
crushers for the coarse aggregate, sand washers, screens, measuring
devices, appliances used for transporting the raw materials as well
as the concrete " slop," mixers and engines for the supply of power.
It is convenient to consider each of these separately.
Crushers should reduce the large lumps of stone or other material
used for coarse aggregate so as to produce angular fragments
of the required size. Machines which produce rounded pieces
are useless for road-concrete. Jaw-crushers and gyratory crush-
ers are the most satisfactory ; in the former the lumps are crushed
between two plates, one of which moves towards and away from
^MECHANICAL DEVICES FOR MAKI^
FIG. 90. — Trench Tamper.
FIG. 91.— A Winget Crusher.
FIG. 92. — Concentric Cylinder Screen.
CONCRETE ROADS
Fia. 93.
"Devil" Disintegrator,
FIG. 94.— C. E. V. Hall's Disintegrator.
MECHANICAL DEVICES FOR MAKING ROADS 143
the other, whilst in a gyratory crusher the material is broken
by the toothed faces of two cones between which it falls. The
crushing effect is obtained by a gyratory motion imparted to
the cone by the special gearing. Stamping mills and crushing
rolls are less effective, and edge-runner mills are quite unsuit-
able.
Jaw Crushers. — Among the commonest of this type of crusher are
the Blake-Marsden (made by H. R. Marsden, Ltd., Leeds)
and that made by Messrs. Winget, Ltd. (Fig. 91).
One example of this type of mill is the Heclon crusher made
by Hadfield, Ltd.
The crushers just described are suitable for coarse aggregate
but not for sand, as they are not economical when used to grind
a material to a fine powder.
Disintegrators or Cage Mills consist essentially of (a) a pair of cages
revolving in opposite directions, the material being broken be-
tween these cages and passing out between the bars, or (6) a ro-
tating shaft carrying loosely pivoted hammer-bars which rotate
like the spokes of a wheel and deliver a rapid series of blows on
the material contained on a grate until the material is crushed
small enough to pass through the grate. These disintegrators
(with various minor improvements) are made by several firms.
An illustration of the exterior of the " Devil " disintegrator made
by the Hardy Patent Pick Co., Ltd., Sheffield, is shown in Fig.
93, and an illustration showing an interior view of another disin-
tegrator made by C. E. V. Hall, Sheffield; is shown in Fig. 94.
Disintegrators are not suitable for grinding to a very fine pow-
der, but are very efficient for reducing hard lumps in sand, and for
producing a proportion of fine flour in the sand.
It is generally preferable to use crushers and disintegrators on
the site of the raw material and not in the roadway, though where
the latter course is preferred, the crushing machinery may be
mounted on a stout truck and driven by a portable engine. Care
should be taken, in selecting an engine for this purpose, to choose
one which is not readily damaged by the great and sudden varia-
tions in the power required. A little consideration will make it
clear that each time a hard piece of stone undergoes the crushing
process the pressure applied to it increases steadily until it exceeds
the maximum resistance of the stone, when the latter yields
144 CONCRETE ROADS
suddenly and the pressure being just as suddenly relieved the
engine will " race " badly until pulled up more or less suddenly
by the next piece of stone. This jerkiness of action is largely
inevitable ; it is much less serious in a steam-engine than in a gas,
petrol or oil-engine or an electric motor. If one of the last
four is used, it should be much more powerful than is strictly
necessary in order that it may not be suddenly stopped, and pos-
sibly damaged, by a stone of unusual hardness.
Where very finely powdered material is used, an entirely
different type of crushing apparatus is required ; this cannot
suitably be used on the site of a road, and such special material
— which is seldom required — should therefore be bought ready
for use.
Washers. — As the presence of some kinds of clay is detrimental
to the setting and hardening properties of concrete, and as it is
always desirable to wet both the fine aggregate and sand thoroughly
before putting them in the mixer, it is convenient to wash them
prior to use, though this process is often omitted on account of
its cost. Such washing consists essentially in stirring up the
material with a sufficiently large volume of flowing water to bring
the clay and " dirt " into suspension and to carry it away. Wash-
ing machines used for this purpose therefore consist of some form
of container fitted with agitators and some means of carrying
the sand forward in one direction, whilst the water, bearing away
the clay, etc., flows in another.
A considerable number of types of washers are used in various
industries, but they require adaptation before they can suitably
be used for the fine aggregate and sand used for concrete.
As all types of washers necessarily require very large volumes of
water, they cannot usually be employed on the site of a new road,
but are preferably erected on the site where the fine aggregate
or sand occurs or at some central site to which it is taken, treated
and then delivered in a washed state to the road-makers.
The Baxter Ballast Washer and Grader, illustrated in Fig. 95,
is, however, being used on the site by the Southwark Borough
Council, London.
Screens are essential for the production of a properly graded aggre-
gate, and failure to use them has, on several occasions, resulted in
MECHANICAL DEVICES FOR MAKING ROADS 145
the production of concrete of such low quality that its failure
to withstand the strains put upon it was inevitable.
The coarse aggregate should bo passed through a series of steol
cylinders, the perforations in which are arranged so as to form a
[series of sieves or riddles through which the material passes
consecutively, a portion of it being separated by each screen.
A commonly used device consists of a single cylinder, 6—14 ft.
in length, the circumference of which is divided into four or more
FIG. 95. — Baxter's Ballast -washing and Grading Machine, fitted with
petrol motor. The machine, which is taken from street to street as
required and connected to the nearest hydrant, was used by the
Borough Council of Southwark for washing and grading the material
from the old macadam roads.
sections, each of which consists of a series of perforations of defin-
ite size, the finest being at the entrance end of the cylinder. When
an ungraded coarse aggregate is passed through such a cylinder,
the smallest fragments pass out through the smallest perforations,
the remainder travel forward as the cylinder revolves, pieces of
increasingly larger size being separated until the largest " stones "
fall out at the exit end of the cylinder and are returned to the crusher
for further treatment. The chief objection to such an arrange-
ment is that the separation or grading is very inefficient. The
slope or inclination of the screening cylinder and the speed at
fc
146 CONCRETE ROADS
which it revolves impel the material much too rapidly through it,
with the result that, instead of all the pieces of aggregate of any
given size passing through the desired perforations, some of them
are carried forward and pass through larger openings. Even
when baffles are inserted in the cylinder the grading1 — though
better — is far from satisfactory.
To avoid this serious objection, Messrs. Johnston and Chapman
Co., U.S.A., supply a screen which consists of three or more con-
centric cylinders (Fig. 92), arranged so that the outermost ones
have the smaller perforations. By this means the largest pieces
are separated first, and no pieces can pass to the next section of
the screen unless they are of the proper size to do so. Such an
arrangement has the further advantage of only allowing the smaller
pieces to come into contact with the finer portion of the screen,
so that these can be made of thinner metal and they are not so
rapidly spoiled by wear and tear.
Rectangular screens are occasionally employed — chiefly for
small quantities and for relatively crude grading. If properly
arranged, however, a series of rectangular screens can be made to
work with remarkable efficiency especially for the finer aggregates,
and with little or no expenditure of power. Rectangular screens
may be of two kinds, horizontal or inclined, the latter being usually
more satisfactory and requiring less labour. An excellent type
of inclined screen is the " Newaygo " screen made by Messrs.
Sturtevant Engineering Co., Ltd., which consists of a sheet of
perforated steel plate inclined at an angle of about 45 degrees and
arranged so that it is vibrated by a number of hammers which
rotate on shafts above the sieve and periodically strike raised
projections on the sieve provided for the purpose, thus keeping
the apparatus constantly in u state of vibration. The material
is supplied to the uppermost end of the sieve by means of a screw
conveyor, and as it falls down the incline the small particles pass
through the perforated plate whilst the coarser ones run down
either into a box below or on to a coarser screen. The vibration
of the screen prevents the holes in the sieve becoming clogged,
unless the material is very sticky.
In some cases, several screens of varying fineness are suspended
one below another, so that the material passing through one sieve
passes on to a finer one below it, and so on until the whole
of the material is satisfactorily graded, when it may be mixed
in the required proportions.
MECHANICAL DEVICES FOR MAKING ROADS 147
Elevators are particularly useful for lifting the road-materials
from the ground level to trucks, etc., and where sufficiently large
quantities are involved. Their use is much cheaper than that
of hand-shovels. These elevators consist essentially of an end-
less band or its equivalent, on which is mounted a series of slats
or buckets which carry the material. If the height to which
the material is to be lifted is not great, a plain band-conveyor will
suffice, but for greater angles of elevation buckets are preferable.
A self-contained wagon loader, supplied by Messrs. Winget, Ltd.
(Fig. 97), will fill a 3-ton lorry in twelve minutes. It is specially
designed for filling trucks and wagons with sand, gravel, crushed
stone and similar materials, and is driven by a 2^-h.p. petrol or
benzol engine, or, if desired, by electric motor.
The belt-conveyor made by the Hepburn Conveyor Co., Ltd.,
Wakefield, shown in Fig. 87, is equally useful where an elevator
of this type can be used.
The addition of two rotary discs (as in the loader supplied
by the Allied Machinery Co.) (Fig. 96), converts a bucket elevator
into a self-feeding machine and so greatly enhances its value in
road-making. The two horizontal steel discs set close to the
ground revolve inwards towards the conveyor.
Transporting the Materials. — The raw materials, consisting of stone
or gravel, sand and cement, are usually brought to the roadway
in motor-lorries, wagons or carts. Where the materials must be
dumped in the roadway, these should preferably be of the self-
tipping type, so as to reduce to a minimum the labour required in
emptying them.
Among the large number of tipping wagons available the
" Constable " Patent Side-Tipping Wagons (Fig. 100) of Messrs.
Tuke & Bell, Ltd., may be mentioned. During the operation
of tipping, an angle of 50 degrees is obtained, which is sufficient
to eject any class of material. The door on the side of the body
automatically remains in its normal position and out of the way
of the material being tipped. The load is discharged in 90
seconds.
The material tipped on the side may be transported in wagons
or carts ; or an automatic feeder and conveyor system, such as the
Barber- Greene Loader (Fig. 96) may be employed for this pur*
pose.
148 CONCRETE ROADS
It is convenient when reloading materials on the site to use
wagons, carts or boxes which also act as measures.
It is of the greatest importance that the transporting, propor-
" tioning and distribution of the materials should be effected
systematically and with a minimum of labour, as it is easy,
through carelessness or absence of suitable appliances, to spend
a double amount of money on these portions of the work.
Keeping Aggregates Clean. — One of the essential but too often
neglected features in constructing concrete roads is the. delivery
of clean aggregate to the mixers. Engineers rightly insist on the
use of clean stone, sand and cement ; therefore, wherever possible,
the material should not be dumped on the sub-grade or on the
side of the road, since in re-handling it to the mixer it is quite
possible that a considerable amount of sub-grade or shoulder
material may become mixed with the aggregate.
This may largely be avoided by combining the measuring and
delivery of the stones, sand, etc., with the transportation of the
material direct from the source of supply to the mixer. In most
road jobs this can be accomplished by placing the material for a
complete batch in specially constructed boxes or carts. These
boxes or bodies can be built, or can be obtained from manufac-
turers in several sizes; the material is automatically measured to
ensure accurate proportions, and so that they can be easily dumped
directly into the mixer or into the mixer loading skip.
In addition to ensuring the cleanliness of the material, this
method of charging the mixer is usually much more economical
than dumping the material on the grade ahead of the mixer, since
it eliminates a double handling of all material.
A fixed measuring hopper is supplied with Ransome Mixers
(supplied by the Ransome Machinery Co., Ltd., London).
The hopper is of such dimensions that it contains the requisite
quantity of aggregate to form the batch in each size of machine.
The door is operated by a hand-lever. Every Ransome Mixer, un-
less otherwise specified, is also despatched with a water-measuring
tank attached.
Various mechanical measuring devices suitable for concrete road
materials are on the market, though most contractors will find the
divided wagon previously mentioned, or separate "boxes," quite
satisfactory and free from great liability to error or serious
MECHANICAL DEVICES FOR MAKING ROADS 149
FIG. 96. — Barber-Greene Loader, supplied
by the Allied Machinery Co., Ltd.
FIG. 97.— Winget Self-Contained
Wagon Loader.
152
CONCRETE ROADS
FIG. 99. — Ransome Hand Mixer.
FIG. 98. — Ransome Elevator.
FIG. 100.— Constable Wagon.
MECHANICAL DEVICES FOR MAKING ROADS 153
misuse ; they do not require any power, such as is always the
case with mechanical measurers.
The Measurement of Water is most satisfactorily effected by means
of a tank of the required capacity which is fixed at a suitable
height above the mixer, and is so arranged that a definite quan-
tity of water — neither more nor less than is required — is delivered
on opening the tap. An ordinary water-saver syphon tank with
a ball- valve, controlling the feed is excellent for the purpose, as
it delivers the water with the utmost rapidity and can be refilled
automatically from a larger tank without any trouble. Water-
measuring tanks fitted with taps are often troublesome, and the
delivery of the water is usually too slow.
The water tank used in connection with a concrete mixer should
be of ample size, yet not excessively large. For the size of mixer
most suitable for road work, a tank delivering 17 or 18 gallons is
satisfactory.
Elevators. — The cement, aggregate and sand must usually be lifted
from the ground level to a short distance above the inlet of the
mixers. If the material is transported by means of a conveyor
no further arrangement for raising it is needed, but in other cases
some form of elevator is desirable. Such elevators may conveni-
ently form a part of the mixing plant. The use of an elevator
reduces the cost of charging the mixer and, under certain condi-
tions, increases the output by reducing the time required to charge
the mixer. The advantage is very marked when the mixer is
located at a considerable elevation above the level at which the
aggregate, etc., is delivered.
Many elevators which have been in use in the past are primitive
and crude in design and arrangement, but several more recent
designs are quite satisfactory. Among the latter is the Ransome
Elevator (Fig. 98), which consists of an elevating skip of rectangular
form to avoid undesirable clogging when discharging its contents.
The skip is controlled by a single lever, by the use of which all
operations of lifting, discharging, lowering and steadying during
its descent are controlled.
Mixers. — The machines used for mixing concrete are arranged in two
classes, according as they are operated by hand or mechanical
power.
Hand-Mixers are chiefly useful for small repairs, as they are very
154 CONCRETE ROADS
portable and essentially "one-man" machines. A convenient
machine (Fig. 99) for this purpose is made by the Ransome Ma-
chinery Co., Ltd. ; it has a capacity of about 2 cu. ft. and an output
of 2-2^ cu. yds. per hour. The mixer is of such dimensions that
a standard navvy barrow can be readily placed beneath the drum
in order to receive the batch when discharged.
In the " Smith Hand mixer " (Fig. 10 1 ) made by Messrs. Stothert
and Pitt, Ltd., the mixed concrete is discharged on to a board placed
ready to receive it, or into wheelbarrows. In the latter case it is
advisable to remove the wheels, placing the machine on timbers
sufficiently high to allow wheelbarrows to pass underneath and
receive the charge. When desired, the mixer can be placed so
as to discharge its contents into a trench, and being portable can
readily be moved along as the work progresses, discharging each
batch exactly where required. Two men are required to drive
this mixer, which has a capacity of 3-3| cu. ft. of unmixed material,
and an hourly output of 2£-3| cu. yds. of concrete.
Power -driven mixers have replaced the hand -driven machines
for all except the smallest jobs, as they not only mix a larger
quantity of concrete at a time with greater certainty, but
they can be arranged to discharge it precisely at that part
of the road where it is required. Power-driven concrete mixers
are of two chief types, (a) continuous and (6) batch mixers. Con-
tinuous mixers are seldom satisfactory for road-making, as the
conditions are not usually favourable ; batch mixers should,
therefore, be used in most, if not all, cases. In a batch mixer,
definite measured quantities of all the ingredients are placed in a
hopper or skip provided for the purpose, and this quantity of
material—termed the batch— is introduced into the mixer, in
which is added a definite and proper quantity of water. When
the process of thoroughly incorporating the ingredients is com-
plete the mixed material is then completely discharged from the
mixer, which is ready to receive the next measured batch
which has, meanwhile, been prepared in the hopper or skip
previously mentioned.
Mixers which are especially adapted for road-making have been
developed to a very satisfactory and economical point. The
introduction of the material into the mixing drum usually requires
its elevation to a considerable height ; therefore, most of the
satisfactory road mixers are equipped with some type of power-
operated elevator. They are also equipped with means for
MECHANICAL DEVICES FOR
FIG. 101.— Smith Hand Mixer.
1083
FIG. 102.— Ransome Self-Contained Mixer.
158
. ^CONCRETE ROADS
FIG. 103. — Ransome Mixer.
FIG. 104. — Victoria Mixer.
FIG. 105. — Rex Mixer.
FIG. 106.— Winget Mixer. FIG. 107.— Winget Chain Spades.
MECHANICAL DEVICES FOR MAKING ROADS 159
mechanically distributing the concrete after the mixing is com-
pleted. This is accomplished by means of a pivoted chute into
which the material is dumped from the mixing drum. A wider
range of distribution can be effected by means of a boom and
bucket arrangement. These booms are maae in varying lengths
to 25 ft. A bucket attached to an endless rope is drawn in towards
the mouth of the mixing drum and receives its charge; the wind-
ing gear is then reversed and the bucket drawn out along the
boom to the point of discharge, where an automatic trip arrange-
ment causes the bottom doors of the bucket to drop open. As the
boom is pivoted so that it will swing through 1 80 degrees, a very
large area can be covered. Since road work requires that the
mixer should be moved frequently as the work progresses, it has
been found advisable on most paving mixers to arrange for power
traction derived from the engine which operates the mixing drum.
Certain types of mixers are also arranged so that from the same
source power is derived for steering the machine during the
moves.
Mixers of the above type can be supplied by the Ransome
Machinery Co. Ltd. (Figs. 102 and 103), by Messrs. Stothert &Pitt,
Ltd. (Figs. 104 and 108), Messrs. Gaston,Ltd. (Figs. 105 and 109),
and by the Allied Machinery Co., Ltd. (Figs. 113 and 114).
The "Winget" Mixer, which has a capacity of 3 cubic feet,
has been fitted with special mixing arms (in place of the chain
spades illustrated in Figs. 106 and 107) for wet concrete, and is as
suitable for road work as for site concrete and Drench concreting.
Laying the Concrete
The mechanical devices employed in laying the concrete on the
roadway include : (i) The forms or shuttering boards which pre-
vent the material from flowing outside the prescribed limits and
also determine the thickness of the layer of concrete ; (ii) distribu-
ting devices used for applying the concrete to the road surface ;
(in) the devices used for spreading the concrete.
The forms or shuttering boards are held in position by clamps
of any convenient pattern. As wooden forms easily warp, they can
only be used a limited number of times and are more costly than
appears at first sight, it is usually more economical in every way
to use steel forms, such as the Blaw forms, made in America, but
which may be obtained in this country. These are shown in Figs.
110 and 112.
160
CONCRETE ROADS
FIG. 108. — Victoria Mixer with Bucket Distributor.
Tamping and Finishing the Concrete
In the United States, a self-propelling template and tamper (see
Fig. 115) is sometimes used. This is now being introduced into the
United Kingdom by the Allied Machinery Co., Ltd. At the front of
the machine is a strike-off board which levels up the concrete, leaving
the surface about half an inch high, a power-driven tamping-bar
then consolidates the concrete, and a power-driven belt finisher at
the rear of the machine smooths up the surface to a trowel finish.
The surface of a concrete road may be finished with a wooden
float or trowel applied by hand, the workman kneeling or lying on
a suitable "bridge."
FIG. 1U9.— Rex Paver.
MECHANICAL DEVICES FOR MAKING ROADS 161
FIG. 110. — Special Road Forms.
FIG. 111. — Use of Lute to place Concrete
FIG. 112. — Special Road Forms.
M
164
CONCRETE ROADS
FIG. 113. — The Milwaukee Paver, showing method of loading.
FIG. 114. — The Milwaukee Paver, showing method of discharging.
MECHANICAL DEVICES FOR MAKING ROADS 165
It is, however, preferable, when a sufficient length of roadway is
constructed to justify the expense, to mount the bridge on end
wheels, and to provide it with a simple propelling mechanism.
A particularly effective arrangement developed by the Walker-
Weston Co., Ltd., 7 Wormwood Street, E.C.2, used in construct-
ing concrete roads at the Victoria Docks of the Port of London
Authority, is so arranged that once the road-bed is graded and the
reinforcement laid thereon there is afterwards no necessity for any
machines or men to stand on the road formation (see Figs. 116 and 117).
It consists of a light timber framework structure completely spanning
FIG. 115. — Showing self-propelling Template and Tamper.
the whole width of the road, and carried on either side on a bogie
mounted on rails. One bogie mounted on a track of 4 ft. 8£ in.
gauge carries an electrically-driven concrete mixer, and also an
electric motor driving a pair of friction winches. The bogie on
the other side of the road is mounted on a 24-in. gauge track
and carries the other end of the framework. This framework
is covered over with tarpaulin, and its interior can easily be
lighted or heated so that work can proceed, if necessary, by day
and night, and also in frosty weather. To the under side of the
ridge of the framework structure is attached a cableway actuated
by friction winches, by means of which the concrete skip is conveyed
from the concrete mixer to any part of the road under the " tent."
Boards laid opposite each other, transversely across the " tent,"
form a platform or bridge on which stand the two men who work
166
CONCRETE ROADS
the strike board for smoothing the concrete surface. Roads 30 ft.
wide are " struck " or screeded in three strips, and when screeding
the crown or centre strip, each end of the board rests on two fixed
FPJWfrtG COYE&eD MTH CJNV/iS
3 /DEL ELS: VA 77 o/y .
FIG. 116. — Road-laying machine used for concrete by the Port of
London Authority.
angles carried transversely across the base of the " tent " and parallel
to the longitudinal axis of the road. These angles are easily adjusted
FIG. 117. — Reinforced concrete road in course of construction, showing
the Road -laying Machine in use.
and fixed to the correct height to enable the board automatically
to strike off the surface to the correct level. The strips of road
on each side are treated in a similar manner, with the exception that
MECHANICAL DEVICES FOR MAKING ROADS 167
the gutter-end of the board rests on a board fixed to pegs in the ground
and graded to the levels required for the gutters.
Some engineers prefer to finish the surface by rolling, using a
roller made of light sheet steel 8 in. diameter and 6 ft. long and
weighing about 70 Ib. The roller has a handle of such a length
that the operator can stand at one side of the road and push or
draw the roller completely across it, or two ropes may be attached
to the shaft of the roller, so that it may be drawn across the road by
a man on each side of the latter.
The roller should not cross the road at right angles, but at such
an angle that it advances about 2 ft. along the road at each crossing.
It is usually necessary to roll the surface three times in this manner.
An alternative method consists in drawing a belt of rubber or
rubber-faced canvas at least 2 ft. longer than the width of the road
and 8-12 in. wide, to and fro and longitudinally across the surface.
The belt should be moved in strokes about 12 in. in length, across
the road, the movement along the road longitudinally being very
slight. In a second, similar application of the belt, the strokes should
be quite short — only about 4 in. — and the movement along the road
much greater than before.
A popular method of finishing road surfaces in the United States
is a combination of the two processes just described.
REINFORCEMENT NOTES.
The roads at the following places mentioned in this volume were
reinforced with the British Reinforced Concrete Engineering Com-
pany's Fabric: Abergavenny, Bath, Belfast (3), Buckhurst Hill,
Cardiff, Chester (3), Chisledon, Deptford, Dunfermline, Gravesend,
Greenhithe, Loch Doon, Longhoughton, Melbourne, Mountnessing,
Newbury, Newport-Cardiff, Portsea Island, Purfleet, Southampton,
Swindon, Sydney, Taunton, Tilbury, Totnes-Paignton, Tredegar.
The Expanded Metal Company's Rib Steel Reinforcement was used
in the following roads : Roberts Lane, Chester ; Marine Drive,
Exmouth ; Fish Quay, Padstow ; and on the sea front, Sidmouth.
Triangle Mesh was employed in the B road Portsea Island Gas
Works, and Goods Yard, L.B. & S.C. Ry., East Croydon.
The Walker-Weston Patent Pyramidal Interlocked Reinforcement at the
Royal Victoria Dock (Port of London Authority).
The other roads were reinforced on non-proprietary systems.
CHAPTER VII
CONCRETE KERBING
CONCRETE kerbing and channelling have been used extensively in
many of our counties, and the practice adopted by surveyors in
Surrey, Brighton and Aylesbury, may serve as a useful guide as to
the method for making kerbs of concrete.
Aylesbury. — Mr. W. H. Taylor, Borough Engineer and Surveyor
of Aylesbury, gives the following account of concrete kerbing in
his district : —
The Aylesbury Corporation have made concrete kerb and chan-
nelling for the past eight years. The kerbs are 5 in. by 10 in. by
3 ft. long, and the top face is chequered to give a good foothold.
At the commencement the kerbs were cast in wood moulds, but
after a time the moulds became warped and iron moulds were
obtained.
The channel-blocks are 9 in. by 4 in. by 15 in. long, and the upper
face is slightly dished. They are cast in wood moulds face down-
wards.
The materials used for making both the kerb and channel-
blocks are one of Portland cement to three of Clee Hill granite
chippings J in. to dust. In mixing the materials, great care is
taken, as it has been found from experience that this is most
essential, or the results are not so good.
The aggregate is measured and well mixed with the cement both
before and after the water is added. As the moulds are being
filled the material is rammed gently by means of a small wood
rammer, and if this is done a good surface is obtained.
Many thousand yards have been laid and the first length is
still excellent.
168
CONCRETE KERBING
169
FIG. 118.— Concrete kerb and channel in the Borough of Aylesbury
Section.
Fio. 119. — Concrete pavement gutter in the Borough of Aylesbury.
170
CONCRETE ROADS
Pavement Gutters. — During the War it was found impossible to
obtain iron pavement gutters and therefore experiments were
made with concrete gutters. They are cast in a wood mould
with a 3-in. iron pipe running through the mould. If care is
taken in the casting and when being fixed they are found equal
to iron gutters. Fig. 119 shows a gutter of this type.
Brighton. — In 1878 the Corporation commenced making concrete
kerb and " pitchers," and the first street was laid with concrete
kerb and pitchers in that year. Since that date many streets have
been laid with that material.
The kerbs and pitchers have been made in the Corporation's
own stores in iron moulds by hand and without pressure, the
kerbs 30 in. by 11 in. by 5 in., and pitchers 18 in. by 6 in.
by 4 in. They have been found to be a very useful and cheap
substitute in the case of roads having ordinary traffic. They
were at first made with beach shingle and cement, 3 parts shingle,
1 part sand, and 2 parts cement, but afterwards, owing to the
slippery nature of the shingle, granite was substituted. These,
with granite, were made at a cost of Sd. per foot lineal, against
Purbeck stone at Is. 3d., and granite at Is. Qd.
Concrete slabs were also made by hand, and the first were laid
in 1881 in one of the busiest streets of the town and are still in
existence ; York stone laid adjoining has been replaced on two
occasions.
FIG. 120.— Moulds for kerbs at Brighton.
CONCRETE KERBING
171
FIG. 121. — Concrete kerb and pitcher, and cement paving laid in 1878,
in Brighton.
FIG. 122. — Concrete kerb laid in 1881 (and cement paving laid later),
in Brighton.
CONCRETE KERBING 173
Concrete has been much used in Brighton. The wall at the
south side of Marine Parade was built in lime concrete by a local
builder in 1830-1834. This wall, in places, is 50 feet high, has a
batter on the face of 1 in 6, is 2 ft. thick at the top, and the back
is vertical. This cost about £100,000.
The first cement concrete groyne for sea defence was built in
1865, and at the present time all the wooden groynes have been
removed and concrete groynes substituted.
Surrey. — Mr. Alfred Dryland, M.Inst.C.E., late County Surveyor
of Surrey, now of Middlesex, has furnished us with the following
interesting details and illustrations of the method adopted by
him : —
The first kerb put down in Surrey was a reinforced concrete
submerged retaining wall or abutment to the carriage-way, and
was evolved from considerations of, and investigations into, the
apparent weakening of the road crust at the sides by movement
or " creep " in the cross-fall direction where the roadside wastes
were soft or the ditches unpiped, and was primarily intended to
remedy such defects as arose from this cause. The kerb was
laid in situ and was 9 in. deep by 4 in. wide and reinforced with
two steel rods £ in. diameter in the positions shewn in Fig. 123.
The kerb was put down to levels to coincide with the finished
top or carpet coat of the carriage way when laid. A trench
8 in. wide was excavated to required depths and 9 in. by 2 in. deal
shuttering held in place with iron road-pins was fixed in proper
position four inches apart. Concrete composed of four parts
clean crushed ballast to pass half -inch mesh sieve, two parts clean
sharp sand and one part British Standard Specification Portland
cement (all measures by bulk) was deposited between the shutters
and tamped and trowelled off on top and the reinforcing rods
inserted in their proper positions as the work proceeded. The
shutters were painted with soft soap and were allowed to remain
for three days, when they were removed without difficulty and with-
out detriment to the concrete kerb, which was immediately cov-
ered over with a small mound of earth and left to set for at least
28 days. Where the ground was sufficiently deep and compact
and could be cut in a straight regular face, no shuttering was used
on the back face. At bends or curves in the road 9 in. by 1 in.
shutters were used to obtain an easy sweep. The kerb was con-
tinuous and being practically submerged, and therefore not liable
to great changes in temperature, no expansion joints were con-
174
CONCRETE ROADS
FIG. 123. — Method of constructing submerged concrete kerb in Surrey.
sidered necessary, this conclusion being substantiated by the
total absence of cracks, damage, or movement so far as obser-
vations can detect. This retaining kerb performs its functions
successfully and is one to be recommended in rural areas where
building developments are slow. For use upon main roads and
others in districts where, in anticipation of housing schemes, foot-
paths are essential in the completed road, an elaboration of this
kerb was adopted, and is designed not only to retain the road
crust but also to keep traffic within the boundaries of the carriage-
way and form an edge to the footpath. It is shown in Fig. 12 4.
The trench in this case is dug 9 in. wide and generally to a depth
of fourteen inches below the intended path level, and a layer of
concrete 9 in. wide and 5 in. thick composed of five parts ballast
to pass a 1-in. mesh sieve, two parts broken clinker and ashes,
one part clean sharp sand, and one part Portland cement, is laid
iii the trench. The shutters, which are again 9 in. by 2 in.,
planed on one face, and coated with oil or soft soap, are
secured in position on this bed of concrete to show 5 in.
between faces. The reinforcement is fixed in the line of neutral
axis on a vertical plane in order to resist as far as possible
reversals of normal stress which undoubtedly occur, and although
not in conformity with theory, it was contemplated that in this
position it would oppose the necessary tensile resistance to any
bending and unbalanced stresses brought to bear upon it in any
direction and avoid the cost of two lines of reinforcement. It
consists of a strip of " Exmet " expanded metal f-in. diamond
mesh 9 in. wide, cut in lengths of about 16 ft. for convenient
handling. To ensure continuity of the reinforcement an overlap
of about 2 in. is arranged at each join, but to provide for expan-
sion of the concrete, joints are made at every 15 to 18 ft. by intro-
ducing a layer of tarred felt into the cross section of the kerb.
This is slit and passed over the reinforcement. Five to one con-
crete is then poured in to such a height as will bring the kerb
CONCRETE KERBIXG
175
to road level, and above the road level a three to one concrete con-
sisting of one part £ in. crushed ballast, one part |-in. to dust
granite chippings (to give "case hardening"), one sand and one
Portland cement, is added and tamped against the shutters and
smoothed off on top. To eliminate the sharp angular edge a
chamfer is trowelled on the kerb about one inch wide, or to effect
the same purpose a hard wood fillet can be nailed to the front
shutter. On gradients where traffic in many instances uses the
kerb to form a "drag" upon the vehicle, a protecting steel strip
is embodied in the kerb immediately below the chamfer. It is
FIG. 124. — Method of constructing concrete kerbs in Surrey.
\\ in. by & in., and is secured every 2 ft. by bent wire nails as
shown in Fig. 124.
The nails are countersunk into the steel and are finished flush,
so that no " bite " can be got of them by wheels, which would
cause damage difficult to repair.
It is essential when removing the shutters to cover over the kerb
for at least a month to ensure thorough setting, as it is subjected
to a considerable amount of grinding and buffeting from the wheels
of vehicles. Many miles of this kerb have been laid and give
every appearance of proving entirely successful, both from a
constructional and financial point of view, the cost at present
prices being little more than one-third the cost of granite. For
this class of work a gang of eight men is required, and, when experi-
enced, 50 to 60 yds. per day can be averaged. The shutters can
176 CONCRETE ROADS
be used many times over, and by hooping the ends before use the
life of the boards is greatly increased.
Integral Kerb. — Where concrete footpaths are laid, a method more
recently adopted is that of forming the kerb in situ as part
of the footpath itself. This is done by erecting a planed 3-in.
plank along the kerb line in a trench, the kerb and paving
being laid together with a joint every six feet. In this
method the greatest care is required in the alignment of the
planks. They must be very rigidly supported with stakes, or
bulging will occur. The cost is rather less than when the kerbing
is moulded separately.
There are many other examples of concrete kerbing which could
be mentioned, as this class of work has been carried on for many
years. In Gravesend and Northfleet, for instance, concrete kerbs
were put down more than thirty years ago.
CHAPTER VIII
SUGGESTIONS FOR A FORM OF SPECIFICATION
FOR CONCRETE ROADS
IN submitting the following suggestions, it must be clearly under-
stood that they are put forward more in the light of a useful guide
when drawing up a specification for making concrete roads, than
laying down any hard and fast formula.
There will always be found, from time to time, certain conditions in
road construction requiring special treatment, and undoubtedly these
are matters which will naturally engage the close attention of the road
engineer, surveyor or contractor in charge of the work. It may be
stated, however, that the suggestions set out have been compiled after
much study and observation of concrete road work in this country, and
in addition, valuable aid has been rendered by those who have had
considerable experience in the most modern and successful methods
of concrete road-making in America. These notes are, therefore,
presented in the full belief that they will be found reliable and
instructive in framing the definite principles of a specification.
Materials
1. Cement. — The cement shall be supplied by a British manufacturer
of repute, and shall comply with the requirements of the British
Standard Specification for cement in force for the time being.
It shall be of the " slow-setting " quality as defined in that
specification. Conditions as to testing, delivery and storage
shall be agreed between the vendor and purchaser.
2. Aggregates. — Great care shall be taken in the selection of the
aggregates. The actual materials to be used must depend upon
local circumstances, subject to the following limitations : —
No natural deposits of sand and gravel shall be used without
washing, screening, and grading to comply with the conditions
hereinafter laid down.
Jf crushed stone is used it shall be screened, graded, and, if
177 N
178 CONCRETE ROADS
necessary, washed, to comply with the conditions hereinafter laid
down.
No aggregate shall be used which is not hard and tough, or
which is laminated, and upon crushing breaks down into flat or
elongated particles. Soft or porous materials, such as broken
brick, breeze, etc., shall be prohibited.
All aggregates used shall be clean and free from clay, dust,
vegetable and other foreign matter. Care shall be taken that the
aggregate is not contaminated with mud, etc., after delivery
to the site of the work.
Coarse Material. — For one-course roads no aggregate shall be
used which will not pass through a screen having square openings
of 1 in. ; but for two-course roads the bottom course may contain
aggregate the largest stones in which will pass through a If -in.
square opening. None of the coarse material shall pass through
a J-in. square opening. The grading from the maximum to the
minimum sizes shall be regular, and no material shall be used which
contains a large proportion of stones of approximately one size.
Sand or fine material shall all pass through a J-in. square open-
ing, but not more than 10 per cent, by weight shall pass a sieve
having 50 meshes per lineal inch. The grading from the maximum
to the minimum sizes shall be regular, and no material shall be
used which contains a large proportion of particles of approxim-
ately one size.
Representative samples of the approved coarse material and
sand shall be retained by the surveyor in charge of the work,
and all deliveries shall be required to conform strictly to such
samples.
3. Concrete. — The average compression resistance of not less than
three test pieces of the concrete shall not be less than will comply
with the following formulae : — •
When 4 weeks old :— C 1 = 2,800—200 V, and
When 13 weeks old :— C 3 = 3,600—200 V, where
C 1 and C 3 = compression resistance in Ibs. per sq. in.
V= Volume of sand and coarse material per volume
of cement.
For determining the compression resistance, tests shall be made
on cubes or cylinders of not less than 6 in. each way. The prepara-
tion, setting and maturing of the test pieces shall, as far as possible,
conform to the conditions that will pbtain in the actual execution
of the work, provided that care must be taken to see that the
conditions for all test pieces are as uniform as practicable, and
that none of them is exposed to frost during setting and maturing.
The compression resistance of any test piece which gives such a
SUGGESTIONS FOR FORM OF SPECIFICATION 179
low result as to indicate a faulty specimen shall be eliminated
in arriving at the average of the results for any test.
4. Water. — The water" shall be fresh and clean, and shall be taken
from a public drinking water supply or from other source of known
purity.
5. Reinforcement. — All metal for reinforcement shall be free from
oil, paint, excessive rust, or coatings of any character which will
tend to destroy the bond with the concrete. The metal shall
develop an ultimate tensile strength of not less than 60,000 Ibs.
per sq. in., and withstand bending when cold 180 degrees around
one diameter and straighten without fracture.
6. Joint Filler. — Joint filler must be an elastic waterproof material,
which will not lose these properties under extremes of weather
conditions.
Preparation of the Existing Surface
7. Foundation. — The preparation of the foundation will necessarily
vary with local conditions, and must be determined by the sur-
veyor in charge of the work. Any necessary embankments or
fills shall be executed to the satisfaction of the surveyor, and shall
be thoroughly consolidated, so that there is no possibility of settle-
ment at any point. Any soft or weak places must be excavated
and filled up with hard stone or other suitable material, so as to
obtain solidity equal to the remainder of the surface. The sur-
face shall be finally rolled to the required contour with a roller of
not less than 10 tons in weight. It should be noted that the use
of concrete for the road cannot be assumed to do away with the
necessity for a good and even foundation over the whole surface.
The surface thus prepared shall be regular and may be flat, or
with a slight cross fall as may be specified by the surveyor.
When the road is not supported by kerbing on either side,
a channel may be dug, longitudinally, immediately inside the
edge of the prepared base, so that the concrete when placed has a
cross section at this point as shown in Fig. 125.
Immediately before the concrete is placed, all foreign matter
shall be removed from the prepared surface, which shall then be
thoroughly watered.
8. Drainage. — -Where local conditions require, a suitable drainage
system shall be provided to the satisfaction of the surveyor.
180 CONCRETE ROADS
Concrete
9. Proportions. — The coarse material and sand shall be used by
volume in such proportions, one to the other, as are found by
trial with several mixtures of the same total quantity measured
separately, but of varying proportions, to give the least volume
of concrete when mixed with the prescribed quantity of cement
and tamped into a mould of known capacity.
For one-course roads not more than 5 parts of coarse and fine
aggregate, mixed as provided, to one of cement shall be used.
Generally speaking, where severe traffic conditions are likely to be
met, the concrete for a one-course road should be in the proportions
of 1 part of cement to 1 ^ parts of fine aggregate and 3 parts of coarse
aggregate. For two-course roads not more than 8 parts of coarse
and fine aggregate, mixed as provided, to one of cement shall
be used for the lower course, and not more than 3 parts of fine
aggregate to one of cement for the upper or surface course.
10. Measuring the Materials. — The method of measuring the
materials for the concrete, including water, shall be one which will
ensure uniform proportions at all times. The cement shall be
taken by weight on the basis that 90 Ib. is equivalent to a volume
of one cu. ft.
11. Mixing. — The concrete shall be mixed in a batch concrete mixer
of an approved type. The mixing shall continue until the in-
gredients are homogeneous and plastic throughout. The drum
shall be completely emptied after mixing each batch.
12. Consistency. — The quantity of water to be added to the concrete
shall be such as to secure a plastic mixture which can be easily
worked, and so that only light tamping shall be necessary to con-
solidate when placed in position. Care shall be taken to pre-
vent an excessive amount of water being used, and the concrete
shall not be so sloppy as to cause a separation of the coarse aggre-
gate from the mortar during handling and laying.
Any concrete which has partially set before being placed in
position shall not be used. To avoid waste from this cause, all
concrete which is mixed ready for placing in position imme-
diately before the dinner hour or other stoppage of the work shall
be placed and finished before stopping. Under all circumstances
as little time as possible shall elapse between the mixing of the
concrete and placing and finishing.
SUGGESTIONS FOR FORM OF SPECIFICATION 181
Placing the Concrete
13. Weather Conditions. — So far as is practical, all work should be
clone during the summer months, but in the event of concrete
roads having to be laid when the thermometer is below 39° F.,
care shall be taken that the sand and stone shall be heated before
being introduced into the mixing drum, or that an intense heat
shall be brought to bear on the concrete during the mixing process.
During such weather conditions, after material is put in place on
the road, care should be taken that it is thoroughly protected,
preferably by tenting with canvas under which steam pipes or
braziers shall be introduced to ensure that the temperature of the
concrete will remain above freezing point until the concrete has
had time thoroughly to set.
The concrete shall be deposited over the whole width of the
road at one and the same time, except in cases where it is impossible
to divert the traffic for the time being. The sides of the road,
where there is no kerb, and the end of each day's work, shall be
supported by a wooden or metal form sufficiently strong
and properly supported to resist straining out of shape
under the pressure of the concrete. All mortar and dirt shall be
removed from forms which have been previously used, and the
forms shall be greased or oiled before any concrete is deposited
against them. The side forms shall remain in place until the
concrete is set sufficiently hard to permit of the removal of the
forms without damage to the edges. In removing the form at
the end of the previous day's work, in order to resume operations
the next day, very special care will have to be taken to see that
the concrete is not damaged, and, furthermore, in beginning the
deposition of concrete special care must be taken with the tamping
of the concrete to see that the previous day's work is not disturbed
or damaged in any way. This will, inevitably, be one of the most
critical points in the road and will merit the very closest attention
and supervision. If desired, joints filled with material complying
with paragraph 6 may be provided between each day's work,
but shall not exceed J in. in thickness. The value of these joints,
however, is not proved, and they undoubtedly introduce weak
points into the road. Longitudinal joints similarly filled may
also be provided alongside the kerb or channelling (if any) if
desired.
14. Thickness. — The total thickness of concrete for both one and
two-course roads shall be specified, and it will be found that, under
average conditions, a total thickness of about 6 in. will probably
be sufficient. The surface course of two-course roads shall be
approximately 2 in. thick.
182 CONCRETE ROADS
When a two-course road is being laid the upper course or wear-
ing surface shall be spread on the lower course immediately after
the latter is deposited and before it has begun to set.
15. Consolidation. — Immediately after being placed in position in
a roadway, the concrete shall be struck off to approximate grade
and camber and shall then be thoroughly consolidated to eliminate
all voids and all surface moisture. This consolidation is to be
effected by tamping or punning the surface of the concrete, either
mechanically or by hand, or it may be done by rolling. In no
event shall any tamping device be used which necessitates a
penetration below the concrete surface.
16. Surface. — Failing the use of a mechanical tamper, the wear-
ing surface shall be struck off to the finished contour by means of
a double template, of which a suitable type is shown in Fig. 126.
This template shall be drawn over the concrete with a com-
bined longitudinal and transverse motion, so as to produce
a surface free from depressions or inequalities of any kind, and
this surface shall not afterwards be disturbed by floating off or
in any other way. The finished surface shall have a cross fall only
sufficient, in the judgment of the engineer or surveyor, to ensure
that the surface water will pass off the roadway quickly, and shall
not vary more than £ in. from true shape. It will be found that,
at the most, a cross fall of 1 in 60 will be sufficient.
No cessation of work of more than an hour's duration shall
be permitted, except at the end of a completed bay.
In cases where it is impossible to divert the traffic and the con-
crete has to be laid on one-half of the road at a time, the edge of
the concrete in the centre of the road shall be left with a rough verti-
cal edge, and immediately before filling in the concrete for the
second half this edge shall be thoroughly swept, watered, and
painted with a thin coat of neat cement and water in equal pro-
portions. The concrete shall then be applied immediately.
17. Reinforcement. — The concrete may be reinforced with steel
reinforcement of a type approved by the surveyor. When, in
the opinion of the surveyor, reinforcing is necessary, such rein-
forcing should be equivalent to 0-05 square inch per foot width of
the concrete. In cases where one-half of the roadway is laid at
one time, the reinforcement should be carried beyond the centre
edge of the concrete first laid so as to provide a positive connection
between the two halves.
i
s-«
184 CONCRETE ROADS
Curing and Protection
18. Watering Surface. — The surface of the concrete shall be sprayed
with water as soon as it has sufficiently hardened to withstand
pitting, and shall be kept wet until covered as hereinafter provided.
The surface of the concrete shall be covered within 24 hours
with clay, earth or other easily obtained material, which shall be
kept thoroughly wetted for a period of at least 10 days.
When sunshine, a drying wind, or other conditions make it
desirable, in the opinion of the surveyor, the freshly laid concrete
shall be protected by canvas laid on a wooden framing or other
covering until set sufficiently to be watered and protected as
prescribed.
19. Opening to Traffic. — Under the most favourable weather condi-
tions the concrete road shall not be opened to traffic until at least
twenty-one days after it is laid, and when the weather is cool or
wet this period shall be increased for such additional time as may
be necessary in the opinion of the surveyor.
Where the road is constructed in two halves owing to the
impossibility of diverting the traffic, the traffic should not be
concentrated on to the first half which has been concreted until at
least thirty-five days after completion, or longer where weather
conditions make it desirable in the opinion of the surveyor.
CHAPTER IX
THE USE OF CONCRETE FOR ROAD ACCESSORIES
Introduction. — In reviewing the constructional methods of the past,
nothing, perhaps, will be found to be more striking than the large
and ever increasing variety of uses to which concrete, during
recent years, has been applied for the production of articles and
structures of a permanent nature which were formerly made of
timber, brick, iron or steel. The reason for this is undoubtedly
to be found in the improved methods of making and handling
concrete, which have resulted in a fuller appreciation of its superi-
ority for many purposes, over other materials of which it is rapidly
taking the place.
Structures or articles made of wood, iron, or steel, soon begin
to deteriorate, and unless paint or other preservative is used
will depreciate very quickly. Concrete, on the other hand, not
only requires no paint or preservative of any description, but
actually improves with age, becoming stronger and stronger
over a long period of years.
Thus it will be seen that, although the initial cost of concrete
may, in some cases, slightly exceed that of other material, this is
more than compensated for by its great durability and low cost of
maintenance.
If any evidence were wanting as to the efficiency and economy
of concrete, it would be found in the extensive way in which the
great railway companies and some municipal bodies have adopted
this material for a large variety of uses, and for which purpose
they have laid out and equipped their own concrete yards. In this
connection special mention should be made of the work being done
at Taunton by the Great Western Railway Company, who were
the pioneers of this type of construction ; at Exeter by the London
& South-Western Railway Company ; at York by the North- Eastern
Railway Company, and many others which might be quoted.
Excellent examples of this class of work may be seen at the Per-
manent Exhibition of Concrete Products which has been installed
185
186 CONCRETE ROADS
at 143 Grosvenor Road, London, S.W.I, by the Concrete Utilities
Bureau of 35 Great St. Helens, London, E.G. 3.
No book on concrete roads would be complete without some
suggestions with regard to numerous accessories to roadways
which might well be made of concrete, and the following hints are
submitted in the hope and belief that they will be of interest to the
reader.
Pavements. — Modern requirements demand that the ideal footpath
or pavement shall be smooth without being slippery, even, durable,
clean and unaffected by climatic conditions. These requirements
are met in a striking manner by concrete, provided that the
material itself is of the first quality, and that the job be carried
out in an intelligent and workmanlike manner. Little, however,
need be said here about concrete footpaths, since these, either in
the form of slabs or concrete laid in situ, are rapidly replacing
those of other materials, and they have been so long before the
public that their strength, durability and general efficiency have
been convincingly proved.
Kerbs and Channelling. — This subject, a very important one, has
been fully dealt with in Chapter VII.
Fig. 127, showing a tree-guard for pavements, illustrates another
use for concrete as a substitute for iron. As will be seen from the
photograph the tree-guard is in the form of lattice work, each
bar of which is reinforced by a single steel rod.
Reference has already been made in Chapter VII to the pavement
gutters produced in concrete by the Aylesbury Borough Council.
Culverts. — In connection with rural roads concrete culverts are
coming into general favour. If constructed in situ, they should
be built during the dry season, if possible, or the water may be
diverted during their construction by building a dam above the
culvert and conveying the water away from the work by means
of temporary troughs or pipes.
A method often adopted is that of employing pre-cast culvert
blocks or half-pipes, which, when cemented together, form the
culvert. No reinforcement is used in structures of this nature.
Fig. 129 is an illustration of this type of culvert.
Sewer Pipes and Water Mains. — Considerable economies can be
effected and increased efficiency secured by the use of concrete
sewer pipes and water mains. These are being adopted here and
in various parts of the world with great success.
Concrete pipes are usually made either in vertical iron moulds,
or are cast on the centrifugal method in horizontal moulds.
USE OF CONCRETE FOR ROAD ACCESSORIES 187
FIG. 127. — Tree Guard.
FIG. 128. — Manhole.
FIG. 129. — Culvert.
190
CONCRETE ROADS
i
JB&
I
FIG. 131. — Station Name-plate.
FIG. 130.— Tele-
graph Post.
FIG. 132.
Lamp Post,
FIG. 133.— Concrete Pipes.
USE OF CONCRETE FOR ROAD ACCESSORIES 191
The advantages of concrete over iron for pipes are the low initial
cost, and the fact that concrete does not corrode. Modern scien-
tific research suggests that the corrosion of iron pipes is largely
due to electrolysis ; in a properly made concrete pipe in which
the reinforcement is completely embedded this danger is eliminated,
with the result that the life of such pipes is indefinite.
In order to avoid disturbance of the concrete roadway, in all
cases where it is possible to do so, sewer pipes, gas and water
mains and electric conduits should be laid under the pavement
where they would be more accessible, and a minimum of inter-
ference with the traffic would be caused when repairs were
necessary.
Manholes and Inspection Chambers. — Fig. 128 shows a concrete man-
hole. This, of course, could be moulded in situ, but a more con-
venient form of construction is that adopted in the case of the
manhole shown in the illustration ; that is to say, a series of pre-cast
concrete rings which, when the excavation has been made, are
lowered into position, one on top of the other until the surface is
reached, the joints being grouted if necessary according to circum-
stances. It will be seen at once what a saving of time is effected
by this method over the old practice of bricking up the manhole.
Inspection chambers may be constructed in the same way with
pre-cast concrete blocks.
Fence Posts and Gate Posts. — The value and importance of good
fencing are appreciated by all who are responsible for the enclosure
of land and who know from experience what constant attention,
time and expense are required in order that the fences may be
kept in proper condition.
The material most commonly used for fencing is wood, but this
is not only high in price and increasingly difficult to obtain, but,
used for this purpose, it has a short life, is expensive to maintain,
and is not fireproof. For these reasons, wood is being rapidly and
extensively replaced by concrete since this material meets all the
demands made upon it. The reinforced concrete post is reason-
able in first cost, it may be made on the spot if so desired, local
unskilled labour can be used in its construction, it may be moulded
to any design, is hard and strong, does not decay, requires no
painting, is fire-resisting, and with ordinary usage is practically
everlasting ; indeed, after a period of years when a wooden post
would have to be renewed, the concrete post is stronger than when
it was first put into the ground.
The utility and the economy of concrete for this purpose are
demonstrated by the fact that this form of fencing is being adopted
to an increasing degree by municipal bodies ; and those who travel
192 CONCRETE ROADS
by rail must have been struck by the great and growing mileage
of concrete fence posts which are rapidly replacing wooden ones
along the lines of practically all the companies. These facts
point to the suitability of concrete fencing for rural highways.
Telegraph and Telephone Poles, Electric Light Standards and Trans-
mission Poles. — Concrete, owing to its great strength and dura-
bility, forms an efficient substitute for iron or wood in the making of
telegraph and telephone poles, electric light standards and trans-
mission poles. In early days when poles of this description were
made solid their great weight was found to be a disadvantage, but
with improved methods of moulding and reinforcing these articles
are made much lighter and their adoption is being rapidly
extended. In addition to their low initial cost, the advantage of
course lies in the fact that concrete does not decay as wood does,
nor does it require painting, which is necessary in the case of the
iron pole in order to prevent corrosion.
Lamp Posts. — Concrete being in its wet state a plastic material, is
one which can be moulded to any shape. It is not surprising,
therefore, that artistic lamp posts may be fashioned of concrete,
and if properly made and suitably reinforced are an effective
substitute for the iron post. This is a direction in which municipal
authorities might, with advantage, adopt a method of construc-
tion which is at once efficient, economical and pleasing to the eye.
Examples of concrete lamp posts may be seen at the Permanent
Exhibition of Concrete Products to which reference has already
been made.
An example of a concrete telegraph post and of a lamp post
made by the L. & S.-W. Railway Company, are shown in Figs.
130 and 132.
Street Name Plates. — Street name plates can be made with advantage
in concrete. It is not generally known that concrete can be made
in any colour. In the case of the railway station name boards
which are now being made of concrete, the lettering is of permanent
black concrete on a light-coloured concrete background, so that
no paint is required, and all that is necessary to keep the name
plate clean and legible is an occasional wash. If this type of
sign has been found to be satisfactory in the case of railway
station name boards, why should it not be adopted for street name
plates, which are easily made and if moulded on glass are perfectly
smooth and polished ?
Road Signs. — Since concrete has been found suitable for railway
gtation name plates, it can also be readily adapted for road signs,
USE OF CONCRETE FOR ROAD ACCESSORIES 193
whether in the form of direction posts or of the various cautions
and danger signals adopted by the Automobile Association and
Motor Union. These, as we have suggested, could be made entirely
of concrete. Black letters on an approximately white ground
would be sufficiently clear to the passing motorist, and the
economy effected by the use of a material which needs no expense
for upkeep should appeal to the authorities who have control of
these road signs.
INDEX
Aggregates, 177
Coarse Material, 178
Amelia Street, Southwark, 1
American Roads, 115
Anzac Avenue, Auckland, N.Z.,
102
Appliances used for Preparing
Road-Bed, 124
Avenue Road, Southwark, 2
Backfillers, 132
Baker, Sons & Perkins, Willes-
den Junction, 75
Beach Road, Auckland, N.Z., 102
Blackwood Crescent, Edinburgh,
64
Brecon and Abergavenny Main
Road, 55
Brockham Street, Southwark, 2
Canmore Street, Dunfermline, CO
Cement, 177
Chisledon, 85
Concrete, 178, 180, 181
Consistency, 180
Measuring the Materials, 180
Mixing, 180
Proportions, 180
Consistency of Concrete, 180
Consolidation, 182
Content Street, Southwark, 2
Conveyors, 137
Cranes and Grabs, 126
Crushers, 138
Culverts, 186
Curing and Protection, 184
Opening to Traffic, 184
Watering Surface, 181
Deverill Street, Southwark, 2
Disintegrators or Cage Mills, 143
Dock Road, Tilbury, 34
Drag-Line Excavators, 131
Drainage, 179
Durham Street, Auckland, N.Z.,
101
Electric Light Standards, 192
Elevators, 147, 153 •
Empire Paper Mills, Green-
hithe, 76
Epping New Road, Buckhurst
HiU, 32
Exchange Lane, Auckland, N.Z.,
102
Factory Road, Southampton,
78
Fence Posts and Gate Posts, 191
Finishing Appliances, 160
Foregate and Eastgate Streets,
Chester, 21
Foundation, 179
Gate Posts, 191
Glengormly, Belfast. 67
Grading Machines, 137
Hand and Horse-operated
Rollers, 137
Heiron Street, Southwark, 2
Inspection Chambers, 191
Integral Kerb, 176
Jaw Crushers, 143
Joint-Filler, 179
Keeping Aggregates Clean, 148
Kerbing :
Aylesbury, 168
Brighton, 170
Surrey, 173
Kerbs and Channelling, 186
195
196
INDEX
King's Wharf Road, Auckland,
N.Z., 102
Ladder Excavators, 132
Lamp Posts, 192
Lawson Street, Southwark, 2
Laying the Concrete, 159
Little Queen Street, Auckland,
N.Z., 99
Loch Doon Road, 85
London, Brighton and South
Coast Ry. Goods Yard, East
Croydon, 86
London-Dover Road, Graves-
end, 44
Longhoughton Road, Northum-
berland, 56
Lorimore Street, Southwark, 2
Lower Bristol Road, Bath, 59
Main North Road, Northum-
berland, 56
Manholes and Inspection Cham-
bers, 191
Marine Drive, Exmouth, 22
Market Roads, Auckland, N.Z.,
102
Measurement of Water, 153
Measuring the Materials, 180
Mixers, 153
Mixing, 180
Motor Rollers, 138
Mountnessing Road, Essex, 31
New King Street, Deptford, 6
Newport-Cardiff Road, 44
New South Head Road, Sydney,
108
Northbrook Street, Newbury, 10
Opening to Traffic, 184
Padstow Station, 22
Park Road, Auckland, N.Z., 101
Pavements, 186
Penton Place, Southwark, 1
Placing the Concrete, 181
Consolidation, 182
Reinforcement, 182
Surface, 182
Placing the Concrete —
Thickness, 181
Weather Conditions, 181
Port of London Authority, The,
69
Portsea Island Gas Works, 78
Preparation of the Existing Sur-
face, 179
Drainage, 179
Foundation, 179
Preparing Concrete, 138
Proportions, 180
Quay Street Extension, Auck-
land, N.Z., 102
Queen's Row, Southwark, 2
Ralph Street, Southwark, 2
Reinforcement. 179, 182 .
Reinforcement Notes, 167
Road Accessories, 185
Road Signs, 192
Roberts Lane, Saltney, Chester,
17
Rollers and Tampers, 137
St. Kilda Road, Melbourne, 107
Screens, 144
Sewer Pipes and Water Mains,
186
Southampton Docks, 41
South Street, Southwark, 2
Specification, Suggestions for, 177
Standard Street, Southwark, 1
Steam Rollers, 137
Steam-Shovels, 124
Steedman Street, Southwark, 1
Street Name Plates, 192
Surface of Concrete, 182
Symonds Street, Auckland, N.Z.,
102
Tamping and Finishing the
Concrete, 160
Telegraph Poles, 192
Telephone Poles, 192
Theobald Street, Southwark, 2
Thickness of Concrete, 181
Thurlow Street, Southwark, 2
Toronto-Hamilton Highway, 108
INDEX
197
Totnes-Paignton Road, 29
Trafalgar Street, Southwark, 2
Traffic, Opening to, 184
Transmission Poles, 192
Transporting the Materials, 147
Tree Guards, 186
Trench Excavators, 131
Wa tiding Street, Southwark, 2
Wn irons, 137
Warner Street, Southwark, 1
144
Water, 179
Water Mains, 186
Watering Surface, 184
Weather Conditions, 181
Westmoreland Road, Southwark,
2
Wheel Type Trench Excavators,
131
Whitefriars, Chester, 18
Wooler Street, Southwark, 2
ENGINEERING NOTES. DECEMBER 15th 1920.
In an interesting article on
REINFORCED
CONCRETE ROADS
The subject is referred to in the following
manner : —
" The adoption of reinforced concrete in the con-
struction of roads, although never taken up with the
same enterprise in this Country as in the United States
and Canada, is becoming more general, and amongst
road engineers the opinion is gaining ground that if
efficiently constructed of proper materials a reinforced
concrete road is capable of proving very durable even
under the heaviest of traffic and can also be made to
present a surface upon which the necessary tractive
effort is reduced to a minimum, which is an important
matter relative to modern methods of motor trans-
port. . . ."
ADVERTISEMENTS
Patent Double-
Layer Interlocked
Reinforcement
for Concrete Roads
and
Foundations.
This System is used by
THE PCRT CF LONDON AUTHORITY,
THE COUNTY BOROUGH OF EAST HAM,
MESSRS. HARLAND & WOLFF, LTD.,
MESSRS. WATNEY, COMBE, REID & Co., LTD.,
THE LONDON & NORTH WESTERN
RAILWAY Co. ETC., ETC. :: ::
Apply for Designs and Estimates to the Manufacturers and Patentees:
THE WALKER-WESTON COMPANY, Ltd.,
Empire House, 7 Wormwood Street, London, E.C.2.
ii •
ADVERTISEMENTS
:GIEMT
YjT/E supply the complete
• plant for the con-
struction of roads from
grading to the finished sur-
face.
For twenty-five years our
engineers have been con-
stantly improving labour
aiding machinery for mak-
ing concrete roads, giving
special attention to those
details which produce a
better concrete.
For grading or regrading
roads, the THEW STEAM
NAVVY, also the AUS-
TIN and WESTERN
ROAD GRADER, DRAG
and WHEEL SCRAPERS .
For handling the material,
AUSTIN GYRATORY or
JAW CRUSHERS, SCREENS, ELEVATORS and BINS. LAKEWOOD HAUL-
AGE OUTFITS for conveying materials to the LAKEWOOD PAVING MIXERS and
FINISHING MACHINES— these are all in successful use throughout the country. These
machines offer ideal methods for mixing, placing and finishing concrete ; the concrete being
thus thoroughly mixed, consolidated and given a finished surface with assured precision.
We maintain a staff of experienced constructional engineers who can give you unbiased advice
as to the methods best adapted to each job. At your request they will call upon you and arrange
for a cinema demonstration, showing all these machines under working conditions. Special
catalogues describing each machine will be forwarded to you upon request. SEND FOR YOUR
COPY NOW.
STOCKS OF ALL MACHINES CARRIED IN LONDON FOR IMMEDIATE
DELIVERY.
ALLIED MACHINERY CO., Ltd.
132 QUEEN VICTORIA ST., LONDON, E.G. 4
Telephone : Telegrams :
City 4253 (three lines). "Alydmachin, Cent. London."
ADVERTISEMENTS
Construction Machinery.
We can supply the following lines of up-to-date Con-
struction Equipment, many of which are particularly adaptable
to Road Construction.
1. "ERIE" Revolving Steam Excavating Shovel
fitted with special mechanical grading device, and
. convertible to Locomotive Crane, Drag Line, Grab,
etc.
2. " INSLEY " Quickshift Counterweight Chute Con-
crete Placing Plant, Buckets, Towers, Hoists,
Chutes, etc.
3. " INSLEY " Mast Hoist Bucket Plant for placing
concrete on comparatively small jobs.
4. "BLAW" Steel Forms for every type of concrete
work, including BLAW special Road Forms.
5. " BLAW " Grab and Dredge Buckets for handling
all kinds of material.
6. "REX" Concrete Paving Mixers, all sizes, also
" REX " Building Mixers.
7. " P. & H." Power Traction Tamping Machine.
8. " P. & H." Power Traction Backfiller.
9 . ' *P. & H.' ' Wheel and Ladder Type Trench Excava-
ting machines, all sizes.
10. " J.D.ADAMS & CO." Adjustable Leaning Wheel
Road Grading Machines.
11. " NOVO " Petrol and Paraffin Engines, 1£ H.P.
to 15 H.P. units, Pumping, Hoisting, Compressor,
Saw Bench outfits, etc.
Catalogues and full details furnished on request.
GASTON LIMITED,
Construction Machinery Department,
20 Bishopsgate, LONDON, E.G. 2.
Telephone : London Wall 3040
Telegrams: "Gastonorge, Led. London."
IV
AD VERTISEMENTS
CUT YOUR COSTS
AT THE START
THE "WINGET
WAGON-
LOADER
PAYS FOR
ITSELF
Height :
1 1 ft. 6 ins.
Width :
3 ft. 6 ins.
Length :
11 ft.
T I ERE'S a handy self-contained wagon loader which will fill a three
•*• ^ ton lorry in twelve minutes, and can soon be made to pay for
itself. A small non-collapsible type of Elevator, specially designed for
filling trucks and wagons with sand, gravel, crushed stone and similar
materials, it is light as well as strong, and easily moved about. The
total weight is 18 cwt. It is driven by a 2\ h.p. petrol or benzol
engine; or, if desired, by electric motor.
WINGET LIMITED
Head and Registered Office:
WINGET HOUSE, 24u Grosvenor Gardens,
Westminster, S.W.I.
Foundry and Engineering Works :
THE CAPE, Warwick.
_.. ...TRADE
ADVERTISEMENTS
!|l!llll!!!lllll!l!llllllllll!lllllll!llllllll
™E teAL IN
LAST ;QBOVB CONCRETE
WORD ipSbS^p' MIXERS
WINGET'S
3 CUBIC FEET MIXER
FOR
CONCRETE ROADS
HPHE powerful arms of the " Winget " 3 cubic ft. Mixer — specially
•*• adapted to road work and all wet concrete mixing — economise
the use of cement and thoroughly mix every particle of aggregate.
" In a day's work," writes one well-known Contractor, " We are able
to place more concrete with this small mixer than we are with the
half cu. yd. steam-driven .... Mixer."
JV/IOREOVER, the "Winget" Mixer can be readily moved from
1V1 point to point, thus obviating, or reducing to a minimum, the
barrow run generally necessary when a mixer is used in a fixed position.
IT can be driven by benzol or petrol engine, electric motor
1 or belt.
WINGET LIMITED
Head and Registered Office :
WINGET HOUSE, 24u Grosvenor Gardens,
Westminster, S.W.I.
Foundry and Engineering Works:
THE CAPE, Warwick.
.... .TRADE ,^%
VI
A D VERTISEMENTS
TIDNAMS, LTD.,
a WISBECH.
Concrete
Specialists,
Manufacturers of Tidnams* Patent
Reinforced Concrete Fencing and Gate Posts
as supplied to the Admiralty, War Office, Road Board, the principal
Railway Companies, and most of the County, Town and District Councils.
Fencing
on the
Market.
The
Cheapest
and Best
ALSO MAKERS OF
Reinforced Concrete Posts for Building purposes.
Storey Posts and Main Posts of Farm Buildings to receive Concrete Walling.
Concrete Telegraph Poles, Railway Signal Posts, Sleepers and Seat Blocks,
Lamp Standards and Guide Posts.
Reinforced Concrete Window and Door Heads, Steps, Sills and Coping.
Cattle Pens, Mangers, Cattle Troughs. Complete Pigsties.
Beams and Girders for Bridges, etc.
CATALOGUES ON APPLICATION.
Sole Proprietors of GRIMSHAW'S PATENT STRAINING RATCHETS FOR WIRE FENCING.
Works: WISBECH and ARLESEY (Beds). Head Office: WISBECH.
Telegrams: "Tidnams, Wisbech." Telephone: 187 Nat., Wisbech.
ADVERTISEMENTS
vn
EXPANDED METAL
FOR
Concrete Roads and Foundations
UXBRIDGE ROAD, ACTON, MIDDLESEX.
EXPANDED STEEL-CONCRETE FOUNDATION TO ROADWAY.
Middlesex County Engineer, MR. A. DRYLAND, M.Inst.C.E.
LITERATURE, PRICES AND SAMPLES ON APPLICATION.
The EXPANDED METAL Co., Ltd.
PATENTEES and MANUFACTURERS OF EXPANDED METAL
YORK MANSION, PETTY FRANCE, WESTMINSTER, S.W.I.
Works :-WEST HARTLEPOOL.
Vlll
ADVERTISEMENTS
ECONOMY
In the construction of roads. Re-
inforced concrete is undoubtedly
the most economical material obtain-
able either for the wearing surface
or the foundations, and Triangle
Mesh is the cheapest and most
efficient reinforcement.
ONE OF TWO REINFORCED CONCRETE ROADS AT CROYDON
GOODS YARD, L.fi. & S.C. RAILWAY.
Full particulars, prices and specifica-
tion for the construction of roads and
foundations free on application —
INDENTED BAR
AND
CONCRETE ENGINEERING Co., Ltd.
QUEEN ANNE'S CHAMBERS, WESTMINSTEfi, S.W.I
Telephone : Victoria 1642.
Telegrams: "Patinbar, London."
ADVERTISEMENTS
SELF - SENTERING
EXPANDED METAL
SELF-SENTERING DECKING OVER CULVERTS-
NOTE SIMPLICITY OF. TEMPORARY STRUTS.
FOR ROADS,
BRIDGE DECKING,
CULVERTS,
SEWERS,
FOOT PATHS.
XN^V/"SX^/WXX
WRITE FOR PARTICULARS TO
SELF - SENTERING EXPANDED
METAL WORKS, LTD.,
24 Cannon Street House,
Cannon Street, E.C.4.
ADVERTISEMENTS
Road Reinforcement
THE whole durability of a road lies in its foundation,
the function of which is to spread the wheel-load
over an area that will preclude all possibility of a
depression of the ground as the load passes over. Con-
crete roads reinforced with Johnson's Steel Wire Lattice
have been proved to provide the best highways for all
modern traffic conditions. They are the ideal roads for
heavy, continuous traffic ; providing a foundation of a
lasting resiliency to ensure hard, even wear. They are
economical in cost, upkeep, and material, requiring
only 6 to 8 inches of concrete against 12 to 14 inches
of massed concrete for ordinary roads.
Reinforced Concrete Road Foundations are more
economical and more satisfactory than plain concrete.
Johnson's Steel Wire Lattice Road Reinforcement effects
considerable economies in first costs for labour and
materials. Johnson's Steel Wire Lattice is delivered in
the form of a complete fabric, ready for laying, in handy
rolls of varying lengths and meshes.
Johnson's Reinforced Concrete
Engineering Company, Limited
LEVER STREET, MANCHESTER.
LONDON, LIVERPOOL, MIDDLESBROUGH, GLASGOW.
Lattice System
ADVERTISEMENTS
XI
Devolving
Shovels
Type "B" Erie Shovel on Road Work.
Why the ERIE Shovel pays fine profits on road work
BIG OUTPUT.— Erie Shovels excavate 500 to 600 cu. yds- per day, or more,
work- In shallow cuts from 6 in. in depth, through hard material such as old ma
i ordinary bank
..._ dam,300to400
cu. yds. per day, or more, leaving a perfectly level floor bottom.
TRAVELLING ABILITY.-The superior digging ability of the "ERIE" is backed up by real
travelling ability. It is far ahead of other shovels in both respects- The " ERIE " climbs a 25%
gradient under its own power and is easy to steer straight- It is fitted with broad Traction Wheels,
crowned and rounded at the edges.
WIDE CUTS. — A floor bottom 35 ft- wide can be excavated in one operation and wagons can be
loaded 23 ft. from centre of shovel, or on an 8 ft. bank.
LABOUR SAVING.— The "ERIE" will do the work of 50 men, thus effectively solving the
present labour shortage.
An unequalled Steam-
Shovel
Compared with hand
labour, any good Steam
Shovel will prove to be
a Money Saver. BUT
there is a lot of difference
in Shovels — a difference
which may amount to
as much as 30 or 40 per
cent, of your profits-
BEFORE You BUY, IN-
VESTIGATE CAREFULLY.
GET THE FACTS. CHOOSE
THE BEST STEAM SHOVEL
Convertible to Locomo-
tive Crane
Write for Catalogues which give details of the Type " B " j-cu. yd. capacity.
NOTE— We can give early delivery.
For Road work the automatic grading apparatus ensures a uniformly even foundation.
Sole Concessionaires for the Sale of "Erie" Shovels in the British Isles:
WM. MUIRHEAD, MACDONALD WILSON & CO., LTD.
Engineers and Public Works Contractors
41 PARLIAMENT STREET, WESTMINSTER, S.W.1
'Phone : Victoria 537 three lines; Tel. Address : Amplitude, London.
xii ADVERTISEMENTS
EMPIRE STONE
ARCHITECTURAL DRESSINGS.
STAIRCASES.
FOOTWAY PAVING SLABS.
GRANOLITHIC PAVING, ETC.
REINFORCED CONCRETE CON-
STRUCTION.
CONCRETE FENCE POSTS.
DIRECTION POSTS.
CONCRETE KERBS & CHANNELS.
EMPIRE STONE Co.
THANET HOUSE,
231 STRAND, LONDON, W.C.
ALSO AT
NARBOROUGH, WINCHESTER HOUSE,
LEICESTERSHIRE. VICTORIA SQ., BIRMINGHAM
Gerrard 8152. T. J. MCDOWELL, Managing Director.
ADVERTISEMENTS
xni
BIG Mixers are essential on big jobs, and during the last
10 years we have supplied leading contractors in all
parts of the world with Mixers up to 80 cubic feet capacity.
Illustrated below is our smallest size machine — The Victoria
H.M. Mixer — which for portability, efficiency and economy is
unequalled.
The scope of the H.M. Mixer is far beyond that of many small
machines, and when fitted with a 2 B.H.P. petrol or paraffin
engine it is capable of a very considerable output.
This Mixer is designed for either hand or power drive and can
be used wherever concrete is required. The machine can be
moved about freely from one part of the job to another — one-
man can handle it on the level and two men are sufficient on
rough and uneven tracks.
The H.M. Mixer has a low feeding position and this feature
saves a considerable amount of time and labour in filling the
machine.
If you have experienced the need of a really efficient, portable
Mixer of this nature write to-day for our catalogue M.D. 105.
(MIXER DEPARTMENT)
ll.VICTORIA ST., LONDON S.W1
" The Small Machine
wilh a Large Output."
xiv ADVERTISEMENTS
Illlill
[CONCRETE!
is now used in all forms of con-
struction: in important engineering
undertakings, housing, roads, on the
farm and estate and in the garden.
If you are interested read
I CONCRETE ANDl
I CONSTRUCTIONAL 1
! E N G I N E E R I N G 1
The officially appointed Journal of the
Concrete Institute.
ISSUED MONTHLY,
Annual Subscription post free anywhere, 2 1/-. |
Specimen Copy Post Free, 1/6.
FROM—
CONCRETE PUBLICATIONS, Ltd.
4 CATHERINE STREET,
ALDWYCH, W.C.2
nil
ADVERTISEMENTS
xv
THE TONKIN MIXER— Capacity 60 tons per day
MIXES
Sloppy, Wet.
Semi-Dry, or
Damp Con-
cretes, Facing
Materials,
Mortar, Grout,
o r Compo.
equally we 1 1,
and is specially
adapted for
mixing Ta r
Macadam for
Roads.
, Full particulars
from
the Offices.
608 SALISBURY HOUSE, LONDON WALL, E.G. 'Phone No. : London Wall 1931
Practical demonstrations can be given at any time by appointment.
THE "AUSTRALIA" PATENT
CONCRETE
BLOCK MAKING
MACHINE
is unrivalled in efficiency,
simplicity and price, is
strong, durable, fool-proof
and easily portable.
Approved by the Ministry of Health-
May be inspected in operation at
any tirre at the works,
LAVIE MEWS,
PORTOBELLO ROAD
(WEST END), W.10
Size of Block 24 x 12 by any
thickness up to 4i inches.
Output by one unskilled
worker, ONE per Minute.
Full particulars from
607, Salisbury House,
London Wall, E.C.2.
ADVERTISEMENTS
HOLLOWAY BROS. (London), LTD.
Contractors tor ^ferroconcrete IRoafcs ano JBrtfcges*
BRIDGE WHARF, GROSVENOR ROAD, WESTMINSTER, S.W.I,
SHARP, JONES 6 Co.
PARKSTONE, DORSET.
Patentees and Manufacturers of the
AQUATITE MANHOLE BOTTOM
Complete Concrete Manholes, of any depth,
with Step-irons ready fixed, supersede Brickwork
and save much time in construction.
We hold immense stocks of
ROCK-CONCRETE TUBES
from 15 inches to 6 feet diameter for
CULVERTS UNDER ROADS,
SURFACE - WATER DRAINS,
STORM-WATER and SEWERS.
THE OLDEST FACTORY OF CONCRETE TUBES IN
THE EMPIRE. - - - ESTABLISHED 45 YEARS.
Telegrams: "Henry, Bournemouth." TelephDne: 406 Bournemouth.
ADVERTISEMENTS
xvii
END OR EITHER SIDE TIPPING BODIES OR TRAILERS
THE "CONSTABLE" TIPPING WAGON FOR SAND, GRAVEL, BALLAST, ETC.
Only one man required for tipping the heaviest loads,
the discharge of which is effected in 90 seconds.
Either-side door in the case of the side tip, and the end door in the case of an
end tip, on the body being raised, is released and remains in its normal
position out of the way, avoiding all obstruction to the material being
discharged, and allowing a perfectly free outlet. The material is tipped
entirely clear of the wheels.
The Constable Tipping Bodies have been supplied to , or are on order for,
the following Councils amongst others: —
Barrow. Glasgow (4). Maidstone. Bedfordshire.
Bo'ness. Hull. Manchester. Cumberland.
Brighton (8). Kettering. Newport. Dumbartonshire.
Cheltenham. Leeds. West Ham. Dumfriesshire.
Croydon. Leicester. Wood Green. Stirlingshire.
Derby. Lerwick. Aberdeenshire. Warwickshire.
Liverpool. Ayrshire.
The British Government and the Government of France.
Please send for Booklet No. 21
TUKE & BELL, LTD., LICHFIELD, AND
n LINCOLN'S INN FIELDS, LONDON, W.C.2
Hi ADVERTISEMENTS
WILLIAM GRIFFITHS & CO.,
LIMITED.
Hamilton House, Bishopsgate, London, E.C.2
ESTABLISHED NEARLY A CENTURY.
ENGINEERS & CONTRACTORS for the construction
of ROADWAYS & TRAMWAYS
including CONCRETE FOUNDATIONS.
QUARRY OWNERS AND STONE MERCHANTS.
QUARRIES at GUERNSEY, GRIFF (Leicestershire),
KIT HILL (Cornwall).
PITCHINGS, KERB, MACADAM, AND GRANITE CHIRPINGS
FOR REINFORCED CONCRETE IN- SITU PAVING, ETC.
DIRECT IMPORTERS OF PAVING TIMBER.
Telegrams : "Griffiths, Stone, A\e., London." Telephones : 2496-2497, London Wall.
Wilson Lovatt & Sons, Ltd.
Clarence Street,
:: WOLVERHAMPTON. ::
Telegrams :— •• Lovatt, Wolverhampton." Telephone :— 1130 (2 lines).
Government Contractors.
Every class of Engineering' Public Works executed.
ALL CLASSES OF RAILWAY AND ENGINEERING WORKS.
DRAINAGE, SEWERS, WATER MAINS, ETC.
BUILDINGS OF ALL DESCRIPTIONS.
ALL CLASSES OF REINFORCED CONCRETE WORK.
CONCRETE AND MACADAM ROADS.
ADVERTISEMENTS xix
Telephone: WOODFORD 557.
W. & C. FRENCH,
Public Works Contractors,
BUCKHURST HILL,
ESSEX.
FERRO-CONCRETE ROADS & BRIDGES.
Licensees for the Hennebique System.
FOUNDED 1840
Stuart's
Granolithic Co., Ltd.
63 LINCOLN'S INN FIELDS,
LONDON,
AND AT
MANCHESTER, BIRMINGHAM AND EDINBURGH.
'Grams: "Granolith." 'Phone: 5268 Hoi.
xx ADVERTISEMENTS
Patent Victoria Stone
OVER 50 YEARS' WEAR IN LONDON.
Large stocks of well matured paving for immediate
delivery in sizes to suit any footpath.
Kerb and Channelling also stocked in large quantities.
All kinds of Architectural Stonework suitable for
Housing Schemes can be supplied.
Works:—
STRATFORD MARKET, ESSEX, and
GROBY QUARRIES, LEICESTERSHIRE.
The Patent Victoria Stone Co., Ltd.
11, 12 & 13 HAMILTON HOUSE,
BISHOPSGATE, E.C.2
Telegraphic Address : Victoria Stone, Ave., London. Telephone : London Wall 2866.
CONCRETE
COTTAGES
Small Garages and Farm Buildings
Deals exhaustively with materials
and methods of construction
DESIGNS for COTTAGES
Numbers of Illustrations and Plans
5/- NET. By Post 5/9
FROM
CONCRETE PUBLICATIONS, LTD.,
4 CATHERINE STREET, ALDWYCH, W.C.2.
ADVERTISEMENTS
xxi
FOR
PERFECT
CONCRETE
use the
brands
PORTLAND
CEMENT
manufactured by
THE ASSOCIATED PORTLAND CEMENT
MANUFACTURERS, LIMITED.
THE BRITISH PORTLAND CEMENT
MANUFACTURERS, LIMITED
MARTIN EARLE& COMPANY, LIMITED
THE WOULDHAM CEMENT COMPANY,
LIMITED.
'FERROCRETE'
Specially prepared
for concrete
specialists.
T"
Correspondence to be addressed to the selling organization :
THE CEMENT MARKETING COMPANY LTD.
8 LLOYDS AVENUE, LONDON, E.G. 3.
Telephone: Avenue 5690. Telegrams: "Portland, Fen, London."
xx
ADVERTISEMENTS
By Appointment to
H.M. King George V.
By Appointment to
the late King Edward VII.
LEAD SEALED
PELICAN BRAND
OF
EARLE'S CEMENT
m
ROBSON'S
PORTLAND CEMENT
MANUFACTURED BY
G. & T. EARLE, LIMITED 1
(Established over a Century)
WILMINGTON, HULL.
!
I
|
I
ADVERTISEMENTS
xxni
The SOUTH WALES PORTLAND
CEMENT and LIME CO., LTD.,
PENARTH, SOUTH WALES
ESTABLISHED 1888.
CAPACITY 3,000 TONS WEEKLY
Cement Works:—
PENARTH. MITCHELDEAN.
BRIDGWATER
Lime Works:—
PENARTH.
BRIDGEND.
Telephone : PENARTH 299, 300. Telegrams : " CEMENT, PENARTH."
BRIDGWATER, 142. "CEMENT, BRIDGWATER.'
BRIDGEND, 112. "LIME, BRIDGEND."
Manufacturers of —
BEST PORTLAND CEMENT
ABERTHAW LIME— LUMP & GROUND.
ARTIFICIAL STONE
Brands—
SEVERN— DRAGON— COLOSSUS
Our Cement is guaranteed to readily comply with all the requirements of
the BRITISH STANDARD SPECIFICATION of AUGUST, 1920.
Our DRAGON BRAND PORTLAND CEMENT— medium or slow setting
—is remarkably quick hardening and is pre-eminently suitable for RE-
INFORCED CONCRETE WORK. Being especially well ground it has an
unusually large percentage of flour, and is very economical in use.
ON ADMIRALTY AND WAR OFFICE LISTS.
xxiv ADVEBTISEMENTS
THE
Stone Court Chalk,
Land & Pier Co., Ltd.
STONE COURT,
GREENHITHE, KENT.
Telegrams: " Stone Court Co., Greenhi the." Telephone: Dartford 150
Pure White Chalk
(Block or Small).
Washed Pit Ballast and Sand
Crushed to the following Grades :
PIT BALLAST - 1 in. down.
3 •
SAND -' - - I in. ,','
WASHED and CRUSHED PIT BALLAST and SAND IS
HARD, ANGULAR and WELL GRADED, and MAKES the
BEST AGGREGATE FOR CONCRETE.
Deep Water Loading Jetty on River Thames,
and Rail connection to S.E. & C. Rly.
London Office:
SOGresham Street, Bank, London, E.C.2.
ADVERTISEMENTS
Unique (Bolleetion
When in London
DO NOT FAIL
to pay a visit to the
PERMANENT
EXHIBITION OF
Concrete Products
at 143, Grosvenor Road, S.W.I
(Near Vauxhall Bridge).
OPEN DAILY (Saturdays excepted), 10 a.m. to 4 p.m.
ADMISSION FREE.
This collection, the only one of its kind in the King-
dom, comprises over 300 examples illustrating the
great variety of ways in which Concrete can be
employed by Municipal and County Authorities and
Railway Companies, in Public Works, and also on
the Estate and Farm, and in the Home and Garden.
This Exhibition has been arranged by
THE CONCRETE UTILITIES BUREAU
35, Great St. Helens, London, E.C.3.
Tel.: Avenue 5422,
XXVI
ADVERTISEMENTS
The World's Most Efficient and Durable
CONCRETE MIXERS
In models & sizes to profitably meet all needs
Ransome Special Road Concrete Mixer, which eliminates the faults of all the other
Road Mixers and has advantages of its own. This is the RELIABLE Road Mixer.
VY^HEN purchasing Concrete Mixers remember this :
Ransomes are the largest manufacturers of Quality
Concreting Equipment in Europe, and the efficiency and
substantiality of Ransome Equipment make Ransome
Mixers preferred all over the world by the most experi-
enced users. For safety's sake, for efficiency's sake, for
economy s sake, have a genuine British Ransome. The
Ransome may cost a little more, but it outwears two or
three of the cheap imported kind, and turns it out better,
quicker and cheaper all the time !
Write for these Catalogues :
No. 7. Special Road Concrete Mixer.
No. 151. General Concrete Mixers.
No. 13. Concrete Hoisting and Placing Plant.
No. 11. Concrete Tip-Carts.
RANSOME MACHINERY CO. (1920), LTD.
Dcpt. V. 14-16 Grosvcnor Gardens, LONDON, S.W.I
Telephone : Victoria 8060. Telegrams : Ransomaco, Sowest, London.
Contractors to the principal Governments, Public Bodies and
Industrial Concerns of the World.
INDEX TO ADVERTISEMENTS
PAGE
Allied Machinery Co., Ltd. ...... ii
Associated Portland Ceriient Manufacturers, Ltd. . . xxi
"Australia" Patent Concrete Block-Making Machine . xv
British Portland Cement Manufacturers, Ltd. . . . xxi
Cement Marketing Co., Ltd. ...... xxi
Concrete and Constructional Engineering . . . xiv
Concrete Cottages ....... xx
Concrete Exhibition ....... xxv
Concrete Utilities Bureau ...... xxviii
Earle, G. & T., Ltd xxii
Empire Stone Co., Ltd. ....... xii
Expanded Metal Co., Ltd. ...... vii
French, W. & C xix
Gaston Limited ........ iii
Griffiths, William, & Co., Ltd xviii
Holloway Bros. (London), Ltd. ..... xvi
Indented Bar and Concrete Engineering Co., Ltd. . . viii
Johnson's Reinforced Concrete Engineering Co., Ltd. . x
Martin Earle & Co., Ltd xxi
Muirhead, Wm., Macdonald Wilson & Co., Ltd. . . xi
Patent Victoria Stone Co., Ltd. ..... xx
Ransome Machinery Co. (1920), Ltd. .... xxvi
Self-Sentering Expanded Metal Works, Ltd. ... ix
Sharp, Jones & Co. ....... xvi
South Wales Portland Cement & Lime Co., Ltd. . . xxiii
Stone Court Chalk, Land & Pier Co., Ltd. . . . xxiv
-Stothert & Pitt, Ltd xiii
Stuart's Granolithic Co., Ltd. ..... xix
Tidnams, Ltd. ........ vi
Tonkin Mixer Co. ........ xv
Tuke & Bell, Ltd ... xvii
Walker-West on Co., Ltd i
Wilson Lovatt & Sons, Ltd. ..... xviii
\\~iiiget Limited . . . . . . . iv, v
\\Ouldham Cement Co., Ltd. .... . xxi
xx vii Q
XXVI 11
ADVERTISEMENTS
The Concrete
Utilities Bureau
Is an organization formed for the purpose of rendering assistance
free of charge to those in need of information or advice on the
subject of CONCRETE.
The function of this Bureau is to bring before the notice of
cement users and the public generally, the very large number of ways
in which Concrete may be usefully, economically and successfully
employed, especially with regard to what may be termed its smaller
uses ; it is not intended, however, to take the place of, or enter into
competition with either the architect or the engineer by giving technical
advice such as a client would expect from his professional adviser.
Enquiries addressed to the Bureau, either personally or by letter,
will receive prompt attention.
The following illustrated pamphlets, containing detailed instructions,
may be obtained, post free, on application : —
CONCRETE.
7. Poultry Houses andPiggeries.
8. Farm Buildings.
9. Troughs and Wells.
10. Greenhouses, Garden
Frames and Root Cellars.
11. In the Home.
12. Blocks.
1 3. General.
14. Its Artistic Possibilities.
1 . Introductory.
2. How it is made.
3. Tanks and Cisterns.
4. Paths and Pavements, Kerbs
and Gutters.
5. Fence Posts, Gate Posts and
Walls.
6. Floors, Feeding Floors and
Footpaths.
THE CONCRETE UTILITIES BUREAU
35, GREAT ST. HELENS, LONDON, E.C.3
Tel.: Avenue 5422.
ANALYSIS OF ADVERTISEMENTS
Architectural Stone Work.
Empire Stone Co., Ltd.
Patent Victoria Stone Co., Ltd.
Cement.
Associated Portland Cement Manufacturers, Ltd.
British Portland Cement Manufacturers, Ltd.
Cement Marketing Co., Ltd.
G. & T. Earle, Ltd.
Martin Earle & Co., Ltd.
South Wales Portland Cement & Lime Co., Ltd.
Wouldham Cement Co., Ltd.
Concrete Fencing and Posts.
Empire Stone Co., Ltd.
Tidnams, Ltd.
Concrete Kerbs and Channels.
Empire Stone Co , Ltd.
Patent Victoria Stone Co., Ltd.
Concrete Machinery
Allied Machinery Co., Ltd.
"Australia" Patent Concrete Block-Making Machine Syndicate.
Gaston Limited.
Ransome Machinery Co. (1920), Ltd.
Stothert & Pitt, Ltd.
Tonkin Mixer Co.
Winget Limited.
Concrete Publications.
Concrete and Constructional Engineering.
Concrete Cottages.
Concrete Utilities Bureau.
Concrete Tubes, Drain Pipes, Sewers, etc.
Sharp, Jones & Co.
Contractors.
W. & C. French.
William Griffiths & Co., Ltd.
Hollo way Bros. (London), Ltd.
Muirhead, Wm., Macdonald Wilson & Co., Ltd.
Stuart's Granolithic Co., Ltd.
Wilson Lovatt & Sons, Ltd.
Direction Posts.
Empire Stone Co., Ltd.
Tidnams, Ltd.
xxix
xxx ANALYSIS OF ADVERTISEMENTS
Elevators, Hoisting and Placing Plant.
Allied Machinery Co., Ltd.
Gaston Limited.
Ransome Machinery Co. (1920), Ltd.
Winget Limited.
Manholes.
Sharp, Jones & Co.
Mixers.
Allied Machinery Co., Ltd.
Gaston Limited.
Ransome Machinery Co. (1920), Ltd.
Stothert & Pitt, Ltd.
Tonkin Mixer Co.
Winget Limited.
Paving Slabs, etc.
Empire Stone Co., Ltd.
Patent Victoria Stone Co., Ltd.
Stuart's Granolithic Co., Ltd.
Reinforced Concrete Construction.
Empire Stone Co., Ltd.
Holloway Bros. (London), Ltd.
Self-Sentering Expanded Metal Works, Ltd.
Stuart's Granolithic Co., Ltd.
Walker-Weston Co., Ltd.
Wilson Lovatt & Sons, Ltd.
Road Material, Aggregate, etc.
Stone Court Chalk, Land & Pier Co., Ltd.
William Griffiths & Co., Ltd.
Road Plant.
Allied Machinery Co., Ltd.
Gaston Limited.
Muirhead, Wm., Macdonald Wilson & Co., Ltd.
Ransome Machinery Co. (1920), Ltd.
Winget Limited.
Road Reinforcement.
Expanded Metal Co., Ltd.
Indented Bar and Concrete Engineering Co., Ltd.
Johnson's Reinforced Concrete Engineering Co., Ltd.
Self-Sentering Expanded Metal Works, Ltd.
Walker-Weston Co., Ltd.
Steam Shovels.
Allied Machinery Co., Ltd.
Gaston Limited.
Muirhead, Wm., Macdonald Wilson & Co., Ltd.
Tipping Wagons and Carts.
Allied Machinery Co., Ltd.
Tuke & Bell, Ltd.
Ransome Machinery Co. (1920), Ltd.
Printed in Great Britain by
Butler & Tanner
Frcme and London
THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW
AN INITIAL FINE OF 25 CENTS
WILL BE ASSESSED FOR FAILURE TO RETURN
THIS BOOK ON THE DATE DUE. THE PENALTY
WILL INCREASE TO SO CENTS ON THE FOURTH
DAY AND TO $1.OO ON THE SEVENTH DAY
OVERDUE.
ADD 1 fV irvotr
ArK 17 iv35
•V!, : ,.- ,-» ,.
cDec'49'^
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YC 69439
V
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