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UNIVERSITY OF CALIFORNIA.
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Accessions No. lf>5D J J . c/js.v M).
r u u J
ROADS AND PAVEMENTS
ALFRED PERKINS ROCKWELL, A.M., PH.B.
formerly Professor of Mining at the
Sheffield Scientific School and at the Massachusetts
Institute of Tecknvlogy,
f * OF THE ^ >V
V. OF ^f
JOHN WILEY & SONS.
LONDON: CHAPMAN & HALL, LIMITED.
JOHN WILEY & SONS.
BRAUNWORTH, MUNN A BARBER, PRINTERS AND BOOKBINDERS, NEW YORK.
OF THE *^ \.
_*^u4r w 1 ^ 1 t i^^
THIS contribution to the literature of Road Making
will, it is believed, be of service to all who are inter-
ested in the improvement of our highways both in the
city and in the country. It is partly the result of
personal observation by the writer, but is mainly a
compilation from the standard publications of Mon-
sieur A. Debauve, Ingenieur en Chef des Fonts et
Chaussees in charge of the Departement de 1'Oise, and
from the official documents of the French Government.
The writer desires to express his obligations to the
several friends who have aided him in various ways,
and more especially to M. A. Debauve, Ingenieur en
Chef des Fonts et Chaussees; M. F. Guillain, Inspec-
teur General des Fonts et Chaussees, Conseiller d'Etat ;
M. Boreux, Ingenieur en Chef des Fonts et Chaussees
et de la Voirie de Paris; and Prof. C. Frank Allen,
Massachusetts Institute of Technology, for courteous
assistance and valuable material.
ALFRED PERKINS ROCKWELL.
BOSTON, October 1895.
A perfect wagon-road 4
Material for roads, gravel n
Broken stone 12
Scale of quality 13
Quality of various rocks used 14
Quality used on Routes Nationales 15
Preparation, cleanness, size of stone 16
Mode of construction 17
Gravel road 18
Stone road 18
Roads with foundation 19
Tresaguet's method 20
Telford's system 21
Roads without foundation 23
Macadam's system 24
Thickness on Routes Nationales 26
Binding material 28
Reduction of bulk 30
Convexity, crowning 31
Resume of process of construction ... 33
Maintenance and repair 36
Patchwork repair 37
Repair of tracks and ruts 40
General recharging 41
Thickness of rechargings 43
Picking surface for recharging 44
Rolling ' 45
Watering during rolling . 46
Modified recharging 50
Scraping and sweeping 51
Typical French roads 51
Tree plantations 56
Cost of construction in the United States 59
Cost of construction in France 60
Cost of maintenance, Routes Nationales 64
Unit of travel 65
Pavements of Paris 69
Service of the public ways 70
Different classes of streets 71
Foundation for pavements 72
Different kinds of pavement 73
Block-stone pavement 76
Macadam pavement 81
Asphalt pavement 84
Asphalt sidewalks 88
Wood pavement 91
Cleaning and watering streets 98
Removal of house-refuse 99
Watering of streets 103
Width and convexity of Paris streets 104
Classification of French roads 106
ROADS AND PAVEMENTS IN FRANCE,
THE history of roads in Europe is interesting as be-
ing in short the history of civilization. The condition
of the means of communication reflects fairly well the
general state of society during the successive centuries.
The Romans, as every one knows, were the first
great road-builders. By means of their wonderful
system of permanent highways, reaching from Rome
to every part of the vast empire, and over which their
great armies moved, they held in subjection every prov-
ince and planted their civilization in the heart of each
conquered people. With the breaking up of the
empire and the invasion of the barbarians came a great
change in the conditions and requirements. The
necessity which created these great highways ceased
in a measure, and the roads were no longer maintained.
Such solid work was not indeed destroyed, but in time
it simply deteriorated from neglect.
Later Charlemagne did much to restore them to
2 ROADS AND PA VEMENTS IN FRANCE,
good order, as he, like the Romans, had large armies
to move rapidly over great distances.
Later again, under his weaker successors and still
more under the feudal system which followed, the
roads were almost entirely neglected, and their deteri-
oration was well-nigh complete. The feudal lords in
some cases, it is true, maintained them within their
several domains, but more often neglected them, and
in fact sometimes actually destroyed them, the better
to defend their territories against more powerful neigh-
bors. Moreover the state of society in the Middle
Ages did not demand good roads. Carriages for per-
sonal travel were but little used, as the great lords and
ladies travelled mostly in the saddle. General com-
merce counted for nothing, and what little survived on
land was hindered or destroyed by arbitrary exactions
and continual petty wars.
The recovery from this deplorable condition was
slow in coming. Not only the roads of the country
but even the streets of important towns were often
impassable at certain seasons. Even in the twelfth
century the only main roads in France were those
originally built by the Romans. Louis XIV. in the
latter part of that century made, it is true, some good
roads in the vicinity of Paris, but it was not till about
1775 that a genuine revival took place. Under
Napoleon I. road-building, as it is understood to-day,
had a great development both in France and in the
countries which he conquered. The famous road over
the Simplon Pass from Switzerland into Italy was
made by his orders in 1 800-6. From this time on
the progress has been great and continuous ; so that
to-day all Europe, with the exception of Russia, is
covered by wagon-roads, which are adapted to the re-
quirements of each district, and are models of dura-
bility and excellence.
ROADS AND PAVEMENTS IN FRANCE,
A PERFECT WAGON-ROAD
should have an easy grade, a surface hard, smooth,
even, and slightly convex to insure prompt and per-
fect drainage, be nearly or quite impermeable to water,
and at all seasons be, as nearly as practicable, free
from mud and dust.
Such roads are to be found in the best of our city
parks. They are rather costly to build, and are kept
in perfect order only by constant care. Such roads
are, however, common enough in all parts of Europe,
not simply as park roads and for pleasure driving
merely, but as the high-roads of general travel, run-
ning for hundreds of miles throughout the country,
connecting cities, towns, and villages, and giving easy
communication for general traffic. Long experience
and careful study have convinced the various govern-
ments that the well-being and prosperity of all parts
of the country, of rich and poor alike, depend in great
measure upon a well-considered system of highways,
built with great care and maintained always in good
order. The economy to each community of a good
wagon-road, whatever may be its cost, is no longer an
A PERFECT WAGfrN^-i&Ap, 5
open question in countries and districts where small
economies of all kinds are matters of anxious con-
sideration. Thoroughness of construction is a charac-
teristic feature, and a grade once established and a
road once built need rarely be changed.
The saving in wear and tear of wagon and harness
and the increased loads a horse can haul are perfectly
well understood and recognized by all who have prod-
uce or merchandise to carry to market. Two hun-
dred years ago good roads, if any existed then, were
built for the convenience and pleasure of the king and
his nobles ; to-day they are built to serve the interests
of general industry. The presence or absence of such
means of communication and the condition in which
they are kept are justly regarded in Europe as a fair
index of the degree of civilization of the community
In our own country the increased demand, within
the last few years, for improvement of the highways,
which has more recently taken shape in state legisla-
tion, is gratifying evidence of a growing interest in the
subject, that is likely to lead to good results.
With the hope of aiding the cause of highway im-
provement the writer contributes this little book,
mainly made up of an account of stone roads in
France, their mode of construction and maintenance,
and embodying to some extent the results of experi-
ence of some of the best French engineers. It is
chiefly compiled from the published books of Monsieur
O ROADS AND PAVEMENTS IN FRANCE.
A. Debauve,* Ingenieur en Chef des Fonts et Chaus-
sees, in charge of the Department of Oise, and from
the official reports of the Minister of Public Works.
As a matter of course, the methods and practice of
one country are rarely applicable in all their details to
another country, where many of the conditions of
population, climate, etc., are quite different. At the
same time all experience teaches something, either to
imitate, modify, or avoid ; and it seems probable that
we may learn something of value from the conclusions
reached by the highly educated and able engineers
who, one after another, have for more than a hundred
years had charge of the national roads of France. The
best and most economical method of construction and
maintenance, under existing conditions of climate and
population, has been their constant aim ; and the ex-
cellent roads of France to-day are the best evidence
of the faithfulness and skill of the French engineers in
The improvement of our own roads, which so many
of us earnestly desire, cannot be too carefully and
thoroughly studied. The best and most economical
method or methods of construction and maintenance,
the adaptation to the requirements of each region and
of each special case, with due regard to the amount of
present and future travel and to the money that may
* Manuel de 1'ingenieur des Fonts et Chaussees; Paris, 1873.
Instruction Generate pour le service courant; Paris, 1894. Dic-
tionnaire Administratif des Travaux Publics; Paris, 1892.
A PERFECT WAGON-ROAD. 7
be properly spent for the purpose, the nature of the
material to be used, the determination of grade and
width, and, above all, the permanent nature of the work,
are fundamental points to be carefully weighed before
decision. No detail is unimportant. It is hoped that,
on this subject at least, the period of temporary make-
shifts is over, so that work done, however incomplete,
may not need to be undone, but be the basis of
further possible improvement in the future.
We are no longer satisfied with the common dirt
road, which served a useful purpose when no better
was to be had ; and yet in some districts, where popu-
lation is sparse, it will still be the only practicable one.
In many cases it may doubtless be materially improved
at no greater outlay of money than the present annual
cost, and with much indirect advantage to those using
it. In its worst form and under the most unfavorable
conditions of climate and soil it is barely endurable
during eight or nine months, and is often nearly im-
passable for two or three months of the year. Its like
may be found in certain parts of Russia, where the
roads give easy communication only during four
months of summer and four of winter.
Between the two wide extremes of the perfect park
road before mentioned and the worst mud road lie all
possible degrees of goodness and badness.
Assuming, then, that the object is to get the best
practicable road under the circumstances in each case,
the various points to be considered, whether in build-
/-- s ! -
f ^ OF THE?
8 ROADS AND PA VEMENTS IN FRANCE.
ing a new road upon a new line, or in improving one
already built, may be conveniently grouped under the
following heads, viz. :
3. Mode of Construction.
A highway is a permanent work, and the laying out
and building of it is a matter of corresponding impor-
tance. The problem should be studied with an accu-
rate survey of the line of the road in hand, accom-
panied by full specifications and close estimates of the
amount of each part and kind of work to be done.
Such preparatory work is the only safe basis for
determining intelligently the several points at issue.
Without it the whole thing is a matter of guesswork.
Accuracy is always economical and guesswork costly
and wasteful. A shrewd contractor's guess allows a
very liberal margin to cover the unknown. It is the
duty of the engineer to define accurately the conditions
of the problem and eliminate the uncertainties, and if
he is a competent one his services are many times
worth his cost.
The advantages of an easy grade are too obvious
The standard adopted in France is :
National roads, not exceeding 3 in 100
Department " " " 4 in 100
Subordinate " " " 5 in 100
This standard is adhered to where practicable, but
obviously the rule is not absolute, and is very often
exceeded of necessity, especially in a mountainous dis-
trict, or where the travel is too light to justify an
excessive expenditure to keep the grade down to
A horse may be easily driven at a trot on a grade of
3 in 100, whatever its length, and on a grade of 4 in
100 for a short distance, but if the grade is steeper
than this he will naturally go at a walk.
Steep grades limit so greatly the load a horse can
haul that, if the road is much used by heavily loaded
wagons, the greater cost of the longer line, with easy
grade, would often be sound economy in the long-
run. In fact, it may often happen that the extra cost
is by no means serious, and is of small account, in
view of the manifest advantages of the better grade.
This point should be most carefully studied in the
laying out of a new road. The errors of the past are
hard to correct.
The idea prevailed at one time, and unhappily was
largely acted on, that the main road between impor-
tant towns such, for instance, as the old stage
routes should be a straight line, going up and down
hill across the country, without regard to the in-
equalities of the surface. It may at first have been
10 ROADS AND PAVEMENTS IN FRANCE.
the most direct pathway or horse-track through the
otherwise trackless forest, or it may be a legacy of the
old Roman times, when the marching of armies was
more important than the movement of heavy loads of
produce or merchandise. Whatever its origin, the re-
sult to-day is, in too many cases, a road with grades that
ought to be modified to satisfy modern requirements.
Moreover, the straight line, with its steep ascents and
descents, is sometimes not even the shortest in actual
distance. But even if it be somewhat the shortest,
this, its only advantage, may be more than counter-
balanced by other considerations. It not unfrc-
quently is the case that a road winding along valleys and
around the hills is but 1/5 or 1/6 longer than the direct
road over the hills. It must also be remembered that
an ascent of 5 i n IO calls for an expenditure of force
in hauling, /;/ a given time, three times as great as if
the road were level ; or, if the force expended be the
same in both cases, then the time of ascent must be
three times as long. Yet a grade of 5 in 100 is con-
sidered moderate. The difference is still more strik-
ing when the grade is 6, 7, or 10 in 100. In fact,
all the arguments, the saving of time, the greater
loads that can be hauled, and the less expense of
keeping in order, are in favor of a line somewhat
longer, but nearly level or slightly undulating, as
against the direct line over the hills. The straight
line is only an abstract idea of no practical utility.
In many cases, however, there is evidently ho
MA TERIAL. 1 1
choice. It may be necessary to cross a range of hills
that are not cut by cross valleys, or the road must be
carried over the hill to serve the village on the sum-
mit, though even here the height should be sur-
mounted by a winding road with easy grade. But
where there is no such determining reason every con-
sideration of economy and public convenience favors
the longer line, winding with easy grades along the
An absolutely uniform grade is theoretically the
best for hauling, and on railways with steam or electric
power it is practically the best, but where horses are
used it is far from having the same advantages. Ex-
perience seems to show that nothing fatigues a horse
so much as a steady pull up a long uniform grade,
and that it is often better to vary the strain on the
collar by varying the grades. An alternation of
slightly ascending and descending grades is preferable
to a dead level, not only for the comfort of the horse,
but to secure more perfect drainage of the roadway.
A clay soil gives, perhaps, the worst possible road.
During a part of the year, when hard, dry, and
smooth, the road seems to answer all the essential
requirements, but at some seasons it becomes well-
nigh impassable for heavily loaded wagons, and is
endurable only when, in a sparsely settled region, the
12 ROADS AND PAVEMENTS IN FRANCE.
community is too poor to afford the cost of better
material brought from a distance. The wooden plank-
road, adopted in some parts of the West, was a tem-
Gravel, under certain conditions and when properly
used, answers most of the requirements. All which
passes under that name, however, is not equally good.
For this purpose it should be as free as possible from
clay or marl. In regions where it is abundant it is
the material naturally used on all country roads, and
nothing will replace it till the increase of population,
and consequent increase of use, demand a harder and
more durable substitute. A gravel road, like every-
thing else, wears out with use, and, in proportion to
the amount of travel, requires more or less frequent
renewal with fresh material-* What has been washed
off of it into the ditches should never be scraped back
on to its surface,
This, beyond question, is the best material. Its
cost, however, and the care needed for its proper use
limit its general adoption to cases where the amount
of travel or other special reason justifies a large ex-
penditure of money.
The choice of the kind of rock to be used is impor-
tant, though in the majority of cases there is practi-
cally but little choice, and the rock nearest at hand
must be the one used. The hardest and toughest is
the best, since roads made of it are more durable,
have a harder surface, diminish the resistance to be
overcome in hauling, and with an equal amount of
travel are less worn, and consequently are more easily
and cheaply kept in order.
The choice most frequently lies between an inferior
and cheaper rock close at hand, and a better but more
costly one brought from a distance. The better and
more expensive rock may prove more economical in the
long-run, but the cost and conditions in each case
must decide the question. The relative quality of the
different rocks available that is, their hardness, tough-
ness, mode of fracture, and fitness for this special pur-
pose should be first determined by careful tests in each
instance without regard to the name of the rock, since
rocks having the same general name vary very mate-
rially in fitness for this use. The better the quality,
the less proportionally is the wear, and the wear is
regarded as being in proportion to the amount of
Hardness, though most valuable, is not the only
thing, for the rock may be hard and tough and resist-
ant, or it may be hard and brittle and splinter easily
under the blows of heavy wheels, so that a somewhat
softer but tougher rock may prove in practice the more
In France a scale of quality from o to 20 has been
adopted, in which 20 stands for the best.
14 ROADS AND PAVEMENTS IN FRANCE.
* Following is a list of most of the varieties of rock
used, with the quality of each kind:
Porphyry varying from 10 to 20
Trap " " 16 " 20
Basalt " " 10 " 19
Quartzite " " H " 19
Gres quartzose " " 10 " 20
Flint " " 8 " 19
Quartz, " " 10 " 18
Serpentine " ' 12 " 18
Melaphyr " " 16 " 17
Diorite " " 13 " 17
Limestone " " 5 " 17
Gneiss " ' 5 " 17
Granite 4< 8 " 16
Millstone grit " " 6 u 16
Amphibolite " 4< 11 " 15
Schist " 4< 3 15
Mica schist " 6 " 13
Pudding-stone " " 4" 8
The wide variation in the quality of rocks classed un-
der the same name is noteworthy and instructive, and
the list is given here mainly to show it, for the fact is that
flint and limestone are by far the most commonly used.
The quality taken in connection with the cost of the
broken stone delivered on the road must evidently
determine the economy of using one rock or another.
* Mini^t^re des Travaux Publics. Routes Nationales, 1893.
Thus it would probably be economy to use trap of
quality 20 in preference to limestone of quality 8, even
if the cost of the former be double that of the latter.
In the year 1893 there were used in the repair of
the 22,000 miles of "Routes Nationales " about
1,702,000 cubic yards of stone. The general average
quality was 10.85. One fifth of the whole was of
quality 15 to 20, and one fourth was of quality 7 and
below. Evidently it was thought better economy to use
the inferior and cheaper stone near at hand rather than
the better and more costly from a distance.
As an instance, take the Department of Oise. They
1 . Flints, collected from the fields and quarries, the
quality of which varies between 8 and 13, averaging 1 1.
2. Limestone from quarries; quality, 8 to 9.
3. Millstone grit, compact; quality, 13 and up-
4. Porphyry; quality 20.
In the year 1893 there were used for repair of 250
miles of road in this Department, as follows :
Coat of Stone per
$0 6 to $i 8
i ^ 6^ ^
o 83 to i 48
Millstone Grit . .
) . (
I Q1 to 2 7^
2 ii to 3 54
The average travel was 227.8 units in the 24 hours.
1 6 ROADS AND PAVEMENTS IN FRANCE.
The quantity used was 72 cub. yds. per mile or
3 1 .60 cub. yds. per mile and 100 units. (See page 65.)
The stone of best quality and highest price was
used on roads in and about the large towns, where the
travel is heavy. The flint of medium quality and low
price was used on the greater part of the roads.
Preparation of the Material.
The cleanness of the stone is important. Soil, loam,
and even gravel or sand incorporated in the body of
a stone roadway are injurious to its solidity. Other
things being equal, the roadway is so much the better
the less fine material it contains; hence the need of
care to have the stone clean. That broken by the
crusher or by hand will naturally be free from, foreign
matter, but stones gathered in the fields and used un-
broken will nearly always have more or less soil or clay
adhering to them.
The size to which the rock should be broken depends
on its hardness and the special use intended. Pieces
3 to 4 inches in diameter are suited for the body of a
new road, where a heavy stone roller is used, more
especially if the rock is no harder than limestone ; but
if it be much harder, like trap, the standard size both
for new work and repair is 2J- inches in diameter.
Where a heavy steam-roller is not used, it may well
be i J to 2j inches. Absolute uniformity and regularity
of dimensions is practically impossible, desirable as it is ;
CONS TR UCTION. 1 7
but any considerable inequality in size is objectionable,
as it tends to cause unequal wear, and in time makes
the surface rough with protuberances. This is espe-
cially true when the harder rock is used. Pieces ap-
proximately cubical in shape, with sharp edges, are
better compacted under the roller and form a more
The simplest method of making a common dirt road
is evidently to plough a few furrows on each side,
where the ditches are to be, and scrape the material
toward the centre, rounding it up enough to cause
the rainfall to drain off as promptly as possible.
This is one degree better than no road at all, and in a
new country does well enough when dry, but during
part of the year the depth of mud on it depends mainly
on the richness or the clayey nature of the soil com-
posing it. The richer the soil the worse the road.
If the soil happens to be gravelly, and a thickness,
say of 3 to 4 inches, of gravel be put upon the road, the
result is quite different. But even a gravel road often
leaves much to be desired. The drainage is almost
always defective, no matter how high it may be rounded
up in the middle, and in fact the more it is crowned,
if the road be narrow, the worse it often becomes ; for
the inevitable tendency to form a single track along
the middle is increased, and the deeper the wheel-
1 8 ROADS AND PAVEMENTS IN FRANCE.
tracks the more they hold the water and prevent
proper drainage. A very moderate amount of atten-
tion might greatly improve such a road. The con-
struction of an ordinary gravel road is shown in Fig.
I. To keep such a road in perfect condition requires
considerable care. The frequency of renewal with
fresh gravel and the quantity required must depend
upon the amount of travel and consequent wear. The
FIG. i. GRAVEL ROAD.
vicious method of repair, so commonly used, which
consists in scraping every spring from the ditches the
fine mud which has been washed off from the road,
and in putting it back upon the road tends to ruin
what might otherwise be a very tolerable roadway.
Repairs should always be made with fresh gravel.
All of the methods employed in the building of stone
roads have one essential characteristic in common, viz. :
The upper layer of the roadway is made up of stone
broken into small pieces and compacted so as to form a
solid mass. This layer must be built and maintained in
such manner that wagon-wheels shall, under no circum-
ROADS WITH FOUNDATION. 1 9
stances, cut through it and penetrate the stone founda-
tion, if the road is built with one, or the ground below,
if the layer of broken stone rests immediately on the
The old Roman roads were, according to modern
ideas, unnecessarily thick and solid. Enduring as they
were, the great cost of such thick masses of masonry
would not be borne to-day. The modern road has
either no stone foundation at all or one of only
moderate thickness. In France the tendency has been
to do away with the foundation, and to reduce the
thickness of the upper layer, making it only so thick
as is necessary to give sufficient resistance ; in short, to
build less costly roadways and to maintain them in
proper condition by constant care.
The various methods employed resolve themselves
into two general classes : the one, roads with stone
foundation ; the other, roads without it. These have
been more or less modified by the whim of the engi-
neer, or by unusual requirements in special cases.
Roads with Foundation.
As early as 1764 Tresaguet, a French engineer, in-
troduced great improvements in the mode of construc-
tion, which ten years later were generally adopted in
France. Such stone roads as there were at that time
were 1 8 feet wide, and had generally a thickness of 18
to 22 inches in the middle and 12 to 16 inches on the
edges. Tresaguet considered this thickness excessive,
20 ROADS AND PA VEMENTS IN FRANCE.
and reduced it to 10 inches, but made it uniform for
the whole width of the roadway. The earth was ex-
cavated to the requisite depth for the whole width of
the proposed roadway, thus forming a broad shallow
trench, which was to receive the stone. Under the
earlier system the bottom of this trench was horizontal,
but Tresaguet gave it the same convexity that the
surface of the roadway would have when finished. On
this smoothly dressed bed, sloping from the centre to
the edges, the first layer of somewhat large stones was
carefully laid by hand on their edges, and as compactly
as possible; it formed thus a kind of rough pavement.
On top of this successive layers of somewhat smaller
stones were laid, also by hand, projecting points
broken off with a sledge and thoroughly pounded till
the mass was solid, care being taken to fill up the
spaces between the stones. This constituted the
foundation. Finally, the top layer, three inches thick
of stone broken to about the size of a walnut, was
spread uniformly over the surface. Tresaguet's sys-
tem, more or less slightly modified, was the one used
almost exclusively in France until about 1820, and
under it were built all of the roads now classified as
"roads with foundation." Of the 22,000 miles of
Routes Nationales in France, only about 9000
miles, however, are roads with foundation. Some of
the roads built under Tresaguet's system had, however,
a thickness of 16 to 20 inches, an additional layer of
stones, laid flat, being placed at the bottom, and on
TELFORD'S SYSTEM. 21
top of this layer stones on their edge, and so on to the
surface as above described. This additional layer was
required only when the ground was not thought suffi-
This is a modification of Tre"saguet's system, intro-
duced into England by Telford, an English engineer,
about 1820, and received with much favor. The
practical identity in principle of the two systems is
such that it is unnecessary to describe in detail the
whole construction. From the specifications for build-
ing a part of the Holyhead road we may learn Tel-
ford's early practice. The bed of the trench is hori-
zontal, and not rounding. The larger stones for the
foundation to be placed in the middle of the road are
9 inches deep, and at 9 feet from the centre 5 inches.
They are to be placed with their longest edge perpen-
dicular to the axis of the roadway, and their width at
the top is in no case to exceed 4 inches. All of the
projections of the upper surface are to be broken off,
and the interstices between the stones filled with small
fragments well rammed in. This foundation is then a
rough pavement having a convexity of 1/60. This is to
be covered with a layer, 6 inches thick, of hard stone,
so broken that the largest piece in its longest dimen-
sion can pass through a ring of 2\ inches interior di-
ameter. Four inches of this layer are to be spread
first, and after this sublayer has become quite solid
ROADS AND PA VEMENTS IN FRANCE.
and compact by travel the two remaining inches are
spread evenly over it. Finally, the whole surface is to
be covered with a coating, i inches thick, of good
gravel free from earth or clay.
Since that time the Telford method has been more
or less modified, but the characteristic foundation of
larger unbroken stones, supporting a thinner surface
layer of small broken stone, is essentially unchanged.
This method of construction, as oiten employed, is
shown in Fig. 2.
FIG. 2. TELFORD ROAD.
It will be noticed that the bottom layer of large
stones, which forms the foundation, rests upon a hori-
zontal bed of natural earth. The better construction
is to give to the surface of this bed the same convexity
or crowning as that of the finished road, thereby in-
suring better subdrainage of any water that may find
its way to that surface. The stone layer is conse-
quently of uniform thickness the whole width of the
The roads built in Essex County, N. J., by Mr.
James Owen,*C.E., are examples of this system. The
* Address on Highway Construction in New Jersey. By James
Owen, C.E. 1893.
ROADS WITHOUT FOUNDATION. 2$
earlier roads he built 12 inches thick, that is, 8 inches
of foundation and 4 inches of broken stone. Subse-
quent experience has led him to recommend for all
ordinary highway purposes a total thickness of 8
inches, that is, 5 inches of foundation and 3 inches of
stone broken to the size of I to 2 inches in diameter.
A thin layer of loam or clay is sometimes spread on
top of the foundation to fill the spaces between the
stones and give an even surface to receive the top
layer of small stones. After the small stones have
been brought to a somewhat even surface under a two-
ton roller a thin coating of loam is spread over them.
Other engineers disapprove of the addition of loam
or clay into the body of the roadway or upon the sur-
face, believing it to be a positive injury to the solidity
of the road. They advocate a heavier roller, as a
means of compacting the stone and of making the
roadway more enduring.
Roads without Foundation.
These are all made on the Macadam system more
or less modified. This system consists essentially in
doing away with a stone foundation of any kind, and
in replacing the two or three layers of the older system
by a single layer 6 to 10 inches thick, rarely less, of
small broken stone as nearly as practicable uniform in
size, which layer shall be impermeable to water.
The grea-t road over the Simplon Pass from Switzer-
24 ROADS AND PA VEMENTS IN FRANCE.
land into Italy, built by French engineers under the
orders of Napoleon I., was perhaps the first road of im-
portance built without a specially laid stone founda-
tion. The perfect solidity of the rocky bed rendered
such a foundation unnecessary. The roadway was
accordingly composed of small broken stone from bot-
tom to top without distinction of layers.
Macadam in England in 1816 appeared with his
method, and made such great improvement in the roads
put under his care that his system was generally
adopted in England, and for several years had no rival
till Telford and the advocates of roads with founda-
tion gained a share of popular favor.
Subsequently Macadam's system was introduced
into France, and gave such satisfactory results that it
became thoroughly established there, so that for many
years it has been used exclusively on all of the public
roads. All of Macadam's ideas were not accepted,
but the essential principles have been applied in the
construction of nearly all the modern French roads.
The ordinary method of construction of a macadam
road is shown in Fig. 3.
FIG. 3. MACADAM ROAD.
The thickness of the layer of broken stone is here
given as 10 inches. It is sometimes, though rarely,
MACADAM*S*&YSS&&^1>-- 2 5
more, and is oftener less, especially where the
natural foundation is exceptionally dry and solid.
The size of the broken stone is very generally 2-J
inches, but in some cases the lower part of the layer
may be made of stones 3 to 4 inches in diameter and
the upper half 2^ to ij inches in diameter.
Thickness. A stone roadway may be solid without
being very thick. The essential condition is that it
shall form a compact and impermeable mass, com-
pletely protecting the ground below from the effects
of moisture. The natural earth, when perfectly dry,
will resist sufficiently well the heaviest loads. It is
quite possible, using broken stone 2 inches and less in
diameter, to make a solid roadway that, when com-
pacted, shall be only four inches thick. There are
many old roads still in good condition, which have
been found on examination to have a thickness not
exceeding four inches. But such a road could hardly
be durable except under the most favorable conditions
of soil and climate. It might answer, if the ground
beneath were hard, gravelly, and naturally dry and the
travel light, but in the great majority of cases it would
not resist the frosts of many winters. A thickness of
less than 6 inches is not advisable ; that of 8 inches is
much better. This means the thickness of the finished
road after the stone, loosely spread, has become com-
pacted and solidified by persistent rolling or travel.
Experience seems to show that the harder the stone
the less the thickness required.
26 ROADS AND PAVEMENTS IN FRANCE.
In this connection the official * report on the pres-
ent condition of the Routes Nationales of France
may be of interest.
The 22,000 miles of Routes Nationales are peri-
odically examined with great care in order to ascer-
tain the actual thickness of the stone layer, and to
determine whether the roadway has been fully main-
tained by restoring to it annually fresh material to
replace that lost by wear, or whether it has been
allowed to deteriorate. Tests were accordingly made
in 1865, 1874, 1886, and 1891, and they were most
At intervals of 656 feet (2OO m ) along the road a
trench is cut, at right angles with the axis of the road,
from the middle to the outer edge of the stone layer.
This trench is about 20 inches (o m .5o) wide, and is
dug with the pick down to the earth below, or to the
stone foundation, if there is one, without penetrating
either, and the contents removed. The width and
depth of this trench are then accurately measured. A
perfect section is thus made of one half of the road-
way. These trenches are cut alternately on the right
and left sides of the axis of the road, so as to give
sections of the whole width without at the same time
interfering with travel. The general average of nearly
500,000 such tests, made in 1891, showed a thickness
of 5J- inches (o m .i3i). The average thickness of the
* Ministerc des Travaux Publics. Routes Nationales. Bondages
des Chauss6es en 1891.
THICKNESS OF STONE,
layer of broken stone of roads with stone foundation
was 4^ inches (o m .iO7) above the foundation, and on
roads without foundation 5$ inches (o 111 . 148). This
general average, however, by no means represents a
uniform thickness throughout the country. Thus in
different regions, and for reasons that are not apparent,
it ranges on roads without foundation from 3j- in.
(o'".079) to i of in. (o m .27o), and on roads with foun-
dation from 2\ in. (o l ".o64) to 8J in. (o lll .2i8).
The following table shows by percentages the rela-
tive number of miles of the different thicknesses:
Wit t h - With
Thickness of Stone
Fnn Foun -
S& d;uion -
p' r Per
cent. cent '
2 inches (o' n 05)
6 Q j. 16 80
in. (o in .o5) and
4 in. (o tn .ioi
" (o'Mo) and
6 " (o'M5)
" (o m .i5) and
8 " (o' n .2o)
" (o'".2o) and i
2 " (o m .3o)
15.12 6. ii
12 in (o m 30) .
401 T o o
U 4 I-,)*
From which it appears that two fifths of the total
length of the Routes. Nationals have a thickness
less than 4 inches, and 4 inches is the limit below
which it is thought unsafe to go. One eighth only
have a thickness exceeding 8 inches.
A comparison with the tests made in 1886 shows
that the general average thickness on the 22,000 miles
28 ROADS AND PA VEMENTS IN PRANCE.
was only 5/32 inch less in 1891 than in 1886. This
seemingly trifling difference, however, represents a
net loss of about 730,000 cubic yards of material from
the surface of the roads, and would seem to indicate
that that amount of broken stone was needed to re-
store the roads to the condition they were in five
As to what may be the condition, in this respect,
of the 300,000 miles of stone road variously classed as
departmental, communal, etc., the writer is unable to
say, as there are no official reports published or read-
ily accessible ; but it is assumed that they have been
built in the same general manner and on the same
principles as the Routes Nationales. It is certain,
however, that many of them lack the perfection which
characterizes the latter, and are not maintained with
the same care.
The stone layer, 6 to 9 inches thick, which forms
the solid roadway, inevitably contains a certain per-
centage of fine material intermixed with the broken
stone, even when none is intentionally added while the
road is being built. This, in an old roadway, is rarely
less than 33 per cent, and is often as much as 50 per
cent of the whole mass. In the best roads this so-
called binding material is formed in part by the crush-
ing of the stones or their grinding one against another
BINDING MAl^ERIAL. 2$
under the heavy steam-roller when the road is first
built, and in part by subsequent travel.
In some districts the practice has prevailed, and is
still adhered to, of mixing a certain percentage of fine
gravel as binding material with the broken stone at
the outset. In support of this practice it is urged
that a good roadway always contains at least 33 per
cent of fine material and that it is better to mix this,
at the outset, with the stone, rather than let it be
formed at the expense of the more costly stone.
This is, however, believed to be a mistake, and the
theory on which it rests a false one. Doubtless a
road containing 33 per cent of binding material may
be a good one, but it would be a better one if it con-
tained less. Some of the best engineers consider the
point now well settled, that, other things being equal,
a roadway is so much the better the less fine material
It is true that, where no heavy roller can be had,
the mixing of a moderate quantity of gravel with the
broken stones may seem desirable in order to bind
them the more quickly, but it is equally true that this
factitious solidity must always be at the expense of
the ultimate durability of the road. Hence no bind-
ing material should be mixed with the stone, but the
latter should be kept perfectly clean and free from all
foreign matter whatever. The passage of a lo-ton
steam-roller 40 or 50 times over a given point renders
all binding material superfluous, and compacts the
30 ROADS AND PAVEMENTS IN FRANCE.
stone so thoroughly that it becomes a mass nearly as
solid as the rock itself.
It is interesting to note that prior to 1830 neither
steam nor horse-roller was used, ordinary travel being
forced to gradually compact the loose stones. About
that year it was tried in England, and a few years
later was introduced into France.
When, however, the broken stone has been thor-
oughly compacted under the heavy roller, and not till
then, a layer of screened gravel, free from clay, 1/3
inch thick should be spread over the surface to fill up
the small interstices that may still be left at the top.
Clay or loam has sometimes been used instead of
gravel or sand. It makes an excellent surface at cer-
tain seasons, but in wet weather it becomes muddy
and in dry weather dusty. It is especially objec-
tionable when subjected to alternate freezing and
Reduction of Bulk.
Stones broken so as to pass through a ring 2-J inches
in diameter occupy, when roughly spread, about 55
per cent of the thickness of the layer, leaving 45 per
cent of vacant spaces between them. A layer there-
fore 6 inches thick would have 3.3 inches of stone and
2.7 inches of spaces. When completely solidified by
persistent rolling with a heavy roller the 6-inch layer
would be reduced to a thickness of less than 4 inches.
CONVEXITY OF ROAD. 31
The convexity, that is, the rounding up or crown-
ing, of the roadway may be stated either in its rela-
tion to the width of the roadway or as showing the
slope from the centre to the edges: thus 1/18 means
that a roadway 18 feet wide is i foot higher in the
centre than at the edges, which is the same as saying
that the slope from the centre to the edges is 4 inches
to the yard. The following table may be convenient
for reference :
i/iS = 4 inches to the yard.
1/24 =3 " " " "
1/30 = 2| " " " "
1/36 = 2 "
1/42 :rr if "
1/48 = l| "
1/54 = ij "
1/60 = i-l '*
1/66 = ly'j- " " "
1/72 = i " "
1/84= f " (( " <<
1/96= f " " "
The convexity given to the old roadways was ex-
cessive, the cross-section showing a slope from the
centre of 2j, 3, and even 4 inches to the yard. The
evident purpose was to promote good drainage and
thereby insure the solidity of the roadway ; but the
li " tl
" " "
32 ROADS A ND PA YEMEN TS IN FRA NCE.
fact is that water will drain readily from a surface
that may have but very slight inclination, provided
the surface is even. The important point is to keep
the surface even, and to prevent the formation not
only of ruts, but even of permanent tracks, since these
hold the water and prevent its proper drainage, how-
ever great may be the convexity of the roadway.
The more rounded the surface the greater is the
tendency of travel to keep to the middle, and a track
once begun is worn steadily deeper. If the roadway
be even and moderately crowned, wagons pass equally
well over every part of it, and no permanent tracks
will be made. Hence the surface should be such
that travel will use indifferently the whole width.
The less the convexity the more advantageous for
travel. The great secret of the maintenance of a stone
roadway in good order is to facilitate travel over its
Provided the roadway is kept in proper order, a
convexity corresponding to I inch to the yard is suffi-
cient for good drainage, and favors free circulation
over the whole width. This is the convexity pre-
scribed by Macadam, and is the one adopted on the
best English and French roads. This is of course
after the roadway has become thoroughly solidified
and reached its normal condition under travel. For
a newly-built road, however, and for ordinary stone
roads in general, a slope of 2 inches to the yard is
found best in practice.
The successive steps in the actual building of a
stone road are ordinarily as follows :
The grade is first determined, whether it be for a
road on an entirely new line or for an old one which
is to be made over. Next the width and convexity
to be given to it are decided on. Then follows the
preparation of the bed to receive the broken stone.
The essential conditions are that the surface of it
shall be well drained and that it shall be hard,
dry, and smooth, so that the stones, when^compacted
under the roller, shall not penetrate it. A few turns
of the roller over it are often advisable. Some engi-
neers, especially in England, spread a layer of gravel
2 to 3 inches thick before rolling, unless the ground
be hard and dry. As to whether the bed shall be
made horizontal or have the convexity of the finished
roadway, practice varies. If horizontal, the stone
layer is made thicker in the middle, where the wear
is inevitably greatest, in order to give the required
convexity. Otherwise the stone layer is of uniform
thickness throughout, and the convexity of the earth
bed gives drainage to any water that may find its way
there. But if the stone layer is as impermeable to
water as it should be, there would be none to drain
off. In view, however, of possible imperfection in
the work, the bed had better be convex.
Upon this bed is built the stone roadway, whether
34 ROADS AND PA VEMENTS IN FRANCE.
the Telford system with foundation, or the Macadam
system without foundation, be adopted. The latter,
as has already been stated, is the one exclusively used
in France to-day.
Under the Macadam system the stone layer con-
sists of stone, generally of one kind only, broken as
nearly as practicable to a uniform size. Sometimes
this is all spread at once and then rolled. If, how-
ever, the road is to be of standard thickness, it will be
more solid and durable if the total quantity be spread
in two layers, and the first is well rolled before the
top one is spread. This is especially true if a lighter
horse-roller is used instead of the heavy steam-roller.
If no roller at all is to be had, then ordinary travel
must do the work of compacting the stone, which was
Macadam's original method. Rollers were first used
in England about 1830. He spread 4 inches at first,
assuming that 10 inches in all of loose stone were to
be used, and when this had become sufficiently solid
under travel, a layer of 3 inches more, which is, in
turn, subjected to travel, and finally the top layer of
3 inches. At the present day, however, the great
convenience and advantage of thorough rolling is
fully appreciated. It not only brings the road at
once into perfect condition, but it consolidates far
better the mass of stone and makes the roadway the
compact, impermeable body desired.
The heaviest roller, within practicable limits, is
the best, and the greater the compression the more
solid is the roadway. The number of times a roller
must pass over a given point in order to secure
complete solidification varies much with different cir-
1. It increases in proportion to the hardness of the
stone. Assuming that the layer is 3 inches thick,
and that a 10- or 1 2-ton roller is used, 50 times are
sufficient with ordinary limestone, 50 to 75 times
with granite, and 90 to 100 times with porphyry or
2. It increases with the thickness of the layer to be
rolled, but not in proportion to the thickness.
3. It is more if the stones are dry than if they are
wet. Abundant watering at the moment of rolling
facilitates compression, transforms the loose stones
into a monolith, avoids the pulverization of the stone,
and is every way more economical. Great care must,
however, be taken to use the water in such way
and quantity as not to soften the ground beneath.
Where this is not exceptionally hard and solid it
would be better at first to roll dry.
When the rolling is nearly finished, and not till
then, a layer 1/3 of an inch thick of clean gravel is
spread over the surface, and the road is ready for
36 ROADS AND PA VEMENTS IN FRANCE.
IV. MAINTENANCE AND REPAIR.
The importance of keeping a stone road always in
good condition is so great from every point of view
that it would seem unnecessary even to mention it
were it not that in so many cases roads thoroughly
well made have been allowed to deteriorate simply
for want of moderate care and attention. It seems
hardly worth while to incur the necessary expense of
building a good road if it is to be so neglected. The
old adage, " A stitch in time saves nine," is emphati-
cally true of stone roads.
In the maintenance of such roads there are two
operations, viz., the use of the material to replace
that used up and the removal of mud and dust caused
by wear. If either of these is badly done, or not
done at the proper time, the roadway deteriorates.
There are also two quite distinct methods of repair.
A. That which, for want of a better name, may be
called patchwork repair. This is the older method,
and, though still employed upon nearly one half of
the Routes Nationales, is being replaced gradually by
the other method.
B. That by general recharging. This, the more
modern one, is favored where it can be applied, but it
necessitates the use of a horse or steam roller.
MAINTENANCE AND REPAIR. 37
A. PATCHWORK REPAIR.
This method consists essentially in restoring annu-
ally to the roadway a quantity of broken stone equal
to that lost by wear during the year, and this not by
spreading a layer uniformly over the surface, but by
repairing isolated spots or patches, where from wear
or other cause holes or depressions show themselves.
The intention is not only to keep the surface even
and insure perfect drainage, but also to preserve con-
stantly the normal convexity and thickness of the
When this method is faithfully carried out the
result is an excellent road, well maintained, but at
high cost. When, however, it is carelessly or ineffi-
ciently applied, as is not unfrequently the case on
less important country roads, the result is far from
satisfactory. The roadman there simply spreads the
broken stone, assigned to his section, at such points
as he thinks require it, and then leaves it to ordinary
travel to do the rest. This can never give a good
The obvious disadvantages of this method may be
diminished if the following precautions are carefully
observed: Notice the holes and depressions immedi-
ately after a heavy rain ; mark them by lines forming
rectangles around them ; pick the space within these
rectangles to a nearly uniform depth ; separate the
38 ROADS AND PA VEMENTS IN FRANCE.
stones from the fine material and pack them well
inside the space picked, adding more if required;
make them solid with the pounder, without the addi-
tion of any binding material ; repeat the pounding if
later any of the stones be displaced.
Evidently much labor must be expended to get
good results, for if the patches cover, say, a square
yard each, a roadman will hardly be able to use more
than \\ cubic yards of broken stone a day, and con-
sequently the length of road assigned to him must be
disproportionately small. This method is simple but
not economical, and should be used only where a
general recharging" is impracticable or unadvisable.
As, however, its adoption may be unavoidable,
some further details may be noted. The roadmen
have a tendency to frequently renew certain muddy
or wet places, such as the bottom of a valley or in a
dense wood, and especially on the flanks of the road-
way. Such points are often muddy, not because the
stone layer is too thin, for it not unfrequently is
thicker there than elsewhere, but because the drainage
is imperfect. The remedy is not to add more stone,
but to scrape away the mud. The flanks of the road-
way especially should be so treated, for they are
always less worn by travel than the middle of the
road, and any mud that may be there is largely ac-
cumulation of scrapings from the middle. The flanks
in any case must be kept clean, and this is generally
enough. If the roadway is not more than 16 feet
MAINTENANCE AND REPAIR. 39
wide these repair patches are needed only on the
middle 10 feet.
Since this method contemplates the restoring for
the whole length of the road an amount of stone
equivalent to the annual wear, it is evident that more
must be added than just sufficient to fill holes and
The way sometimes adopted is to spread at once
on the many patches, the whole length of the sec-
tion, the year's supply of stone assigned to it, and
then leave it to travel to do the work of compacting.
Nothing could be much more objectionable. The
wagons avoid the loose stones as far as possible, and
the roadway suffers in consequence. The proper
way, assuming that no roller is used and that ordinary
travel must do the work, is to force travel to pass
over the whole surface by obstructing it in one direc-
tion and facilitating it in another. To effect this the
first patches may be made along the middle of the
road at intervals of about 50 yards, without reference
to any depressions there may be between. These
patches have the shape of elongated rectangles, about
The whole section having been gone over in this
way, the roadman commences again at the original
starting-point and makes new patches, checker-board
fashion, alternately on the right and left of the first
patches and midway in the space between them, care
4O ROADS AND PAVEMENTS IN FRANCE.
being taken to place them within the middle three
quarters of the width of the roadway.
On the third trip he makes new patches between
the second set, and so on, always observing the
Thus in five trips the whole central part of the
roadway has been covered, while travel has been in-
duced, without serious annoyance, to change direc-
tion five times and virtually to pass over nearly the
whole surface. When this has been well done the
roadway is perhaps good enough, but is never per-
fectly solid and even.
The pounder is an indispensable tool in making
good repairs, but the use of it is fatiguing, and is
often abandoned or neglected. A two-horse roller
is often used.
The cleanness of the stone added has already been
emphasized in the section on road construction. It
is equally important in repairs ; hence the mixing of
sand or gravel with it should not be allowed, for the
reasons already given. The objection applies with
even greater force to the use of clay or loam.
Repair of Tracks and Ruts.
Tracks and ruts are seldom found except on a
roadway that has been badly cleaned or badly re-
paired. The first step is to scrape off the accumu-
lated mud, dry as well as soft. Sometimes this alone
GENERAL RECHARGING. 41
will restore the road to tolerable condition, and unless
the wheel-tracks have worn into the stone, slight
obstacles may be placed, sufficient to turn the travel,
and thus gradually restore the even surface.
Inexperienced workmen may seek to remedy the
evil by filling the ruts with broken stone ; but this
rarely answers the purpose, for a new track will
speedily be formed by the side of the old one.
If, however, the track, after being scraped, appears
too deeply worn to be obliterated by the means
already suggested, nothing remains but to treat it as
a depression and thoroughly pound the stone in it.
This is obviously a costly operation, and should be
resorted to only to save the road from complete de-
The stone used for patch^vork repairs should be of
the same kind and degree of hardness as that of the
existing road. It should be neither harder nor softer,
or the road will wear unevenly. If softer, it is more
easily worn and tends to make holes. If harder, it
tends to produce little humps and to deepen the low
spots about them. Thus a hard trap should not be
used for patchwork repairs of a limestone road.
B. GENERAL RECHARGING.
This method presupposes the use of a horse or
steam roller, and consists in allowing the roadway to
wear away gradually until it has reached the minimum
42 ROADS AND PA VEMENTS IN FRANCE.
thickness compatible with sufficient resistance. When
this condition of wear has been reached, the whole
surface of the roadway is to be covered with broken
stone, sufficient to restore it to its normal thickness
and convexity ; and this layer should be as thoroughly
rolled as in the making of a new road.
The interval between two successive rechargings
must depend, other things being equal, upon the
amount of travel. It may be three or four or possibly
ten years. During this period the roadway, if entirely
neglected, would be covered with depressions and
holes, more or less serious. An even and conse-
quently uniform surface may be secured by means of
the ordinary patchwork repair, restricted solely to
this purpose, and with no intention whatever of re-
storing the annual wear. On roads where travel is
moderate such repairs are scarcely needed at all for
the first few years immediately following a recharging.
The advantages of this method are that it gives to
the public a good road at all times, and is economical
The disadvantages are, that a somewhat harder
stone is required, and that the normal convexity is
not maintained during the whole interval.
Stone roads, in fact, do not wear off uniformly
over the whole width. The middle portion is inevi-
tably most rapidly worn, and if the recharging is too
long delayed the surface becomes hollowed, and is
consequently not properly drained.
GENERAL RECHARGPNG. 43
In France the tendency is to substitute this method
for die older one, and in 1893 more than half of the
stone for repairs was used in general rechargings.
This method is used exclusively in general repairs of
the macadamized streets of Paris.
Thick ness of RecJiargings.
The thickness of stone to be added must depend
on the conditions in each case. Assuming that the
roadway, when new, had a thickness of 8 inches, and
that experience had shown this to be sufficient, so much
stone only need be added as will restore the layer to
its original thickness and convexity. As a road wears
it gradually loses its convexity, becomes flat, and
finally hollow along the middle if repairs are delayed
too long. The sides are comparatively little worn and
evidently require little or no fresh material. In gen-
eral, then, the recharging may be confined to the mid-
dle portion i^ to 2 feet from each edge of the roadway.
In the majority of cases, provided the wear has not
been allowed to go on up to the last possible limit, a
recharging which when compacted has a thickness of 4
inches is amply sufficient. If the wear is well within
this extreme limit an average thickness of 2|- to 3
inches of new stone may suffice, say 1/3 of a cubic yard
per running yard if the recharging is 12 feet wide, or
if it is only 9 feet wide, 24 cubic yards per 100 yards.
It is sometimes astonishing to see how, with even so
44 ROADS AND PAVEMENTS IN FRANCE.
slight a covering, an inferior road may be brought
into excellent condition, provided it is well rolled.
A recharging only 8 feet wide along the middle is
much better than nothing.
Picking of the Surface for Recharging.
When the surface of the roadway does not need
recharging for its whole width, the part to be covered
must be limited and defined by two furrows cut length-
wise of the road, in order to prevent the stone, which
may be added, from spreading under the roller, and
also to insure the better union of the edges of the new
layer with the undisturbed margin of the roadway.
These furrows should be carefully picked out. No
other picking is necessary. The practice of picking
up the whole surface of the width to be recharged
is common enough, but the utility of it is questionable.
Why destroy at considerable expense a portion of the
solid layer, which is already as thoroughly compacted
as it can be? Presumably the purpose is to insure a
perfect union of the new stone with the old body of
the road, but this can be effected quite as well in an-
other way and with far less expenditure of labor.
A vigorous scraping and sweeping will thoroughly
uncover the old surface. There is always a greater
or less thickness of mud or dust on a roadway. If
this is not removed it forms, after recharging, a thin
layer of material, as objectionable as clay, between the
old bed and the new a layer analogous to that which
GENERAL RECHARGING. 45
separates two successive beds of any sedimentary
formation. This layer should in any case be re-
moved, and can be by thorough scraping and
scratching with a stiff broom. If this is properly
done there is nothing to prevent the perfect union of
the new stone with the old solid road-bed. It is worse
than useless to set an army of men with picks to
break up this solid bed and do what had better be
left undone. A good stream of water from a hose
while the sweeping is going on aids greatly in the
perfect removal of the fine material.
This is an operation as essential in the recharging
as in the building of a road. It is just as important here
as there to compact the broken stone into a solid
mass and get rid of all cavities. By rolling, first, the
broken stones are crowded face to face, and lie as
closely together as their shapes will allow; second,
the edges and angles are to some extent crushed, and
the fine particles fill up the cavities. Of these two
results the first is evidently the better, and should be
facilitated as much as possible by diminishing the
friction between the stones. The ideal roadway will
be realized when they are so compacted that no cavi-
ties are left between them. This ideal may be ap-
proximately reached, when the stones are cubical and
of uniform size, by abundant watering before and
during the rolling.
46 ROADS AND PAVEMENTS IN FRANCE.
This watering is indispensable when a recharging
is made at a dry time on a hard foundation. In such
case the stones may well be deluged with water; the
compacting of them goes on more rapidly and per-
fectly, and their union with the old roadway is more
complete. The excess of water soon drains off, and
the road, after a few days of fine weather, becomes
exceptionally hard and solid.
At a dry time 350 gallons of water should be used
daily for every 100 running feet. During a wet time
k-ss watering is necessary, and the operation is conse-
quently more economical.
No binding material should be mixed with the
stones in a recharging any more than in the building
of a road. Here as well as there a perfect bind,
better and more enduring, may be secured by rolling
than by the use of gravel. Gravel may, however, be
advantageously used after the rolling has consolidated
the stones, spread as a layer not exceeding one third
of an inch thick, in order to fill the small interstices
that may be left in the mosaic.
Some have strongly advocated a method, which
consists in spreading on the old roadway a thin layer
of sand or sifted gravel before the recharging. Upon
GENERAL RECHARGING. 47
this the broken stone is spread, thoroughly watered,
and rolled. They claim that the sand or gravel be-
comes semi-fluid and is squeezed up among the stones,
and that it acts in the same way as a binding material
mixed with the stones. It certainly does favor the
more rapid packing of the stones in a certain way, and
is a less expensive operation than that recommended
above, but it cannot fail to impair the final solidity of
the road, and hence is not real economy. A recharg-
ing made with as much water as practicable and the
least possible quantity of binding materiaj will always
be the solidest.
The rolling of a new roadway, as has already been
stated, should be done in fine weather, when the sur-
face of the foundation soil is dry and hard.
The rolling of rechargings, on the contrary, may
better be done after several rainy days have helped to
clean off the old roadway and to soften somewhat the
The edges should first be rolled, and the centre not
before both edges have been somewhat compacted.
The first turn of the roller on the border should over-
lap about 8 inches on the old solid part. It will be
remembered that the furrow, cut with a pick, was in-
tended to narrow the part to be recharged, and was to
be cut in such way as to form a shoulder against the
thrust of the stone under the roller.
When one margin has been rolled the same operation
is repeated on the other margin, and so on pro-
48 ROADS AND PAVEMENTS IN FRANCE.
gressively toward the centre, care being taken that each
turn shall overlap about 8 inches of the part already
rolled ; the stone should be thoroughly watered during
the rolling. The rolling should be continued till the
mass is solid and does not undulate under the roller
or yield on the passage of a loaded wagon. Not till
then should the thin layer of binding gravel be spread,
not to penetrate into the body of the roadway, but
only to fill the interstices of the surface.
A small quantity of the stone should be reserved to
fill any depressions developed during the rolling and
to keep the surface even.
If the surface of the old road be in very bad condi-
tion, with many holes and ruts, these last may be
filled and pounded or rolled in order to prepare a
tolerably even surface for the recharging proper. In
the worst cases the recharging may be made in two
operations, the lower layer being of inferior and less
expensive stone. But in all cases the top layer should
be of the harder stone (if there is any difference), never
of the more tender, and under no circumstances an
indiscriminate mixture of hard and soft stone.
To insure perfect work the road should be watched
for some little time after a recharging and watered regu-
larly. Stones that may have become loose should be
removed ; any parts injured by some accidental cause
be pounded ; and by occasional sweeping all wheel-
tracks obliterated, in order that travel may be induced
to circulate over the whole width.
GENERAL RECHARGING. 49
The following is given by Monsieur Debaure as an
average cost, per cubic yard of material, of a recharg-
ing covering a width of about 10 feet, with an
average thickness of 2\ to 3 inches. This allows
8 to 9J cubic yards per 100 running feet. It
is exclusive of the cost of the broken stone and
gravel. It assumes the use of a hard stone, like trap
for instance, rolled dry with a zo-ton steam-roller.
The cost would be about 20 per cent less if rolled
wet and if a softer stone were used. The average
wages of an ordinary roadman are from 65 to 70 cents
Picking the furrows and preparation i
Spreading the broken stone. 7
Finishing off and spreading gravel 4
Cost of water and watering , 13
Rolling, oiling, and small repairs of roller. 13
Wear of roller and large repairs 5
A lO-ton steam-roller can effectively roll in a day
328 running feet (100 metres) of such a recharging
as above indicated. The cost, if a horse-roller were
used, would be about 30 per cent greater.
In the Department of Oise, under M. Debaure's
charge, 130,000 cubic yards of broken stone are used
annually for general rechargings.
50 ROADS AND PAVEMENTS IN FRANCE.
After a very severe winter or following an excep-
tionally heavy travel a roadway may have become very
uneven, full of holes and ruts, and quite out of order,
while the stone itself is not much worn. The time
for a regular recharging has not yet come, and yet
heavy repairs are demanded immediately. Recourse
in such case may advantageously be had to a modi-
fied recharging, with use of the roller. From 4 to
8 cubic yards of stone per 300 feet of length, corre-
sponding to about 1/6 to 1/3 of a regular recharging,
may be spread at once where needed along the middle
of the road and in the low spots, the edges of these
spots having first been picked. Wet weather is availed
of for this operation, and the roller is passed about a
dozen times at most over the stone.
This operation, if well done and at a favorable season,
gives excellent results, and restores to good condition
a roadway that in appearance is nearly ruined. This,
however, should be regarded only as a remedy in an
emergency, and is not to be substituted for the sys-
tem of general recharging. But it is infinitely better
than the method of patchwork repair, as generally
applied. These patclies, when made all at one time,
in a large number of spots, cause great annoyance to
travel, and almost never effect an improvement com-
mensurate with the expenditure.
TYPICAL FRENCH ROADS. $1
Scraping and Sweeping.
The removal of mud and dust as soon as it is
formed is necessary to keep the roadway in perfect
order, and the roadway suffers just in proportion as
this is neglected. In no other way can the formation
of tracks be so well prevented, and the complete
drainage of the surface insured.
Typical French Roads.
The following sections of typical French roads,
taken from Debaure's treatise, shows the methods of
construction adapted to different conditions of topog-
raphy and travel :
Fig. 4 is a section of the type of road in the
Department of Seine-et-Oise, and is regarded as a
good one where there is considerable travel. The
macadamized portion is 16^ feet wide, with paved
edges each about 3 feet wide ; the sidewalks are
about 6 feet wide, with a slope of I in 20. The
convexity of the macadam is 1/40, or nearly 2 inches
to the yard from centre to edge.
XOADS AND PA VEMENTS IN FRANCE.
Fig. 5 is the type of roads in the Department of
Bas-Rhin. The width of macadam is 19 j feet, with
a gravel or grass margin on each side6 ^ feet wide.
The ditches are 5 feet wide at the top and 20 inches
deep. The macadam is unnecessarily wide, 16^ feet
Lao".! -20 -20*:. 6-7-"--- -- 1 9-10-
being amply sufficient. The convexity is 1/50, or i|-
inches to the yard.
Fig. 6 represents a type in the Department of
Loiret. The macadam is 16^ feet wide, with gravel
edges each 20 inches wide, and raised margins of
turf 6 feet wide. The drainage into the side ditches
is effected by means of small cuts at short intervals
TYPICAL FRENCH ROAJJb.
through this turf margin. The convexity is 1/50, or I ^
inches to the yard.
Fig. 7 is a section of one of the ' ' Routes Nationales ' '
in the Department of Haute- Vienne, where the road
is built upon an embankment. The macadam is 19^-
teet wide ; upon one side a footway 3 feet wide is
-1--3V-11- O'l0- -"- -9-10- lj-_
raised 18 inches above the edge of the macadam.
The drainage is by pipes or uncemented but covered
stone drains passing under this sidewalk. The con-
vexity of the roadway is 1/40, or nearly 2 inches to the
---5-8-'---'-20 L 2(P ----- 5-' --------- 8-3-"- ----- '- ------ &'s- ---- - 1 ---- -5- Igo'Uo- ---- -7-3-" -----
Fig. 8 represents a departmental road in the
Department of Eure. The width of the stone portion
is i6J- feet, with gravel or turf margins each 5 feet
wide. The total width, including ditches, is 33 feet.
ROADS AND PA VEMENTS IN FRANCE.
The stone roadway is formed of two layers, each 6
inches thick ; the bottom layer is of large stones, and
the top layer of broken stone 2\ inches in diameter.
The convexity is about 1/36, or 2 inches to the yard.
Fig. 9 represents a road of the first class in the
Canton Vaud, in Switzerland. The width of the
macadam is 1 5f feet, which will allow two carriages to
pass, with margins each 3 feet wide of gravel. The
convexity is 1/40, or nearly 2 inches to the yard. The
slopes of cuts and embankments are generally I of
height to i^ of base. Slopes steeper than that would
be gullied, and difficult to maintain.
Fig. 10 is the section of a country road in the
Department of Indre-et-Loire. The macadam is 10
TYPICAL FRENCH ROADS. 55
feet wide, flanked with a margin on each side of 5
feet of gravel or turf. For roads of this kind 10 feet
of macadam is quite sufficient. A width of 13 feet,
which width is often adopted, has the disadvantage of
being unnecessarily great for one carriage, and yet not
enough for two. The convexity is 1/20, or 3^ inches
to the yard, which is excessive.
$6 ROADS AND PAVEMENTS IN FRANCE.
IN a country so thickly populated as France the
economical use of all available land is a matter of im-
portance, arid the desire to utilize the margins of high-
ways, which would otherwise be waste land, by the
growth of trees has been one reason why the planting
of trees upon the borders of most of the public country
roads has received so much attention and care. But
the reasons, equally strong there and of greater weight
in our country, are the agreeable shade which trees
give to the traveller during summer, and the influence
they have in preserving the roadway during periods of
dryness. In hilly and mountainous districts, where
the deep winter snows cover everything, the trees are
especially useful in marking the line of roadway.
It is therefore not surprising that tree-planting on
the highways has for a century been the subject of
royal decrees and legislative enactments, determining
the kinds of trees to be planted, manner of planting,
care of them, penalties for injury to them, etc. For
instance, in 1851 it was ordered that the trees planted
should be of species appropriate to the soil and climate,
and as far as practicable those that would have a
marketable value, such as elm, ash, oak, and chestnut
TREE PLANTATIONS. 57
among the harder woods of slow growth, and among
the softer woods poplar, plane, sycamore, and acacia.
Certain kinds, such as fruit-trees, walnut, wild cherry,
and apple, were to be always excluded.
In 1880 the report of the engineers was adverse
upon certain plantations of cherry, walnut, pear, apple,
almond, chestnut, and mulberry trees, upon the ground
that the fruits were stolen and the trees injured.
Forest trees were preferred.
The utility of shade-trees in preserving the surface
of the roadway during the dry heat of summer is the
more evident where the material of which the road is
built is quickly drained. One result of the constant
care bestowed upon the main highways at the present
day is that they are solid and perfectly drained, and in
the majority of cases suffer more injury from dryness
than from moisture. Hence shade-trees are of special
value on long stretches of level road in an open
country swept by drying winds. On the other hand
shade-trees should not be planted in low, wet places,
or where the roadway is not readily dried.
The method of planting is influenced by the width
of the road. Many of the old. Routes Nationalcs
were laid out originally over 65 feet wide, where to-day
a roadway of 16 feet width is amply sufficient for
present travel. The turf margins are in such cases
frequently planted with a double row of trees upon each
side of the roadway. As a general rule, when the
roads are 50 feet or more in width, two rows, 10 feet
58 ROADS AND PAVEMENTS IN FRANCE.
apart, are planted on each margin, the trees in each
row being 33 feet apart, placed alternately.
On roads, which are from 33 to 50 feet in width, one
row only is planted on each margin with trees 33 feet
COST OF CONSTRUCTION. 59
COST OF CONSTRUCTION.
Statements of the cost of building roads, unac-
companied by full details of the conditions in each
case, have only a general interest. Not only are the
elements which make up the cost different in differ-
ent countries, but they are by no means the same
in all parts of the same country, or even of the same
The amount and kind of travel to be provided for,
the importance of the road and its width, the grading
required, the special engineering obstacles to be over-
come, the cost of broken stone, the local wages of
labor and other similar considerations necessarily
modify very materially the cost in each case. It is
one thing in New England, where gravel is abundant
and good rock near at hand, and quite another on the
broad prairies of the West.
This, then, being understood, the following state-
ments of cost are given for what they may be worth
as general indications :
60 ROADS AND PA VEMENTS IN FRANCE,
Mr. James Owen* states, as the result of many
years' personal experience in building roads on the
Telford system in New Jersey, that "roads built in
the manner I have described [6 to 8 inches thick in-
cluding the stone foundation] cost in Essex County,
N. J., 60 to 80 cents a lineal foot, 16 feet wide,
according to their thickness and distance the material
has to be hauled, including foundations of quarry-
stones. This would be $3000 to $4000 a mile. By
using local stone for foundation and local help in haul-
ing, and as much as possible local labor, and also re-
ducing on many of the local roads to 14 feet and even
12 feet, I think the cost throughout the State [Massa-
chusetts] might be placed at $2500 per mile, provided
due economy and wise administration are secured."
The following figures are compiled from the returns
published by the Minister of the Interior:
CJtem ins Vicinaux. f
During the period of six years, from 1881 to 1886,
inclusive, there were built, under the operation of the
* Address on Highway Construction in New Jersey. By James
Owen, C.E. Pub. of the Mass. Soc. for Promoting Agriculture,
f See Appendix, "Classification of Roads in France."
COST OF CONSTRUCTION,
law of March 12, 1880, 25,994 miles of stone road at
a total cost of $57,404,789. They are subdivided
into three classes:
Class of Road.
de grande communication. .
d'interet commun . . .
5 08 1
2 ^OQ I 6
II 7^2 8^2
qe 470 177
These general figures cover the whole cost of the
roads, excepting for bridges, culverts, and such struc-
tures. They include not only the cost of the road-
way proper, but also the expenditure, whatever it may
have been in each case, for grading and the right of
way, where necessary. Unfortunately the reports do
not show separately these special expenditures, or the
cost of different parts of the work, labor, material, etc.,
and hence do not admit of as complete an analysis as
would be desirable. Such as is possible is given
The returns are from 86 of the 87 Departments
into which France is divided, and give the number of
miles of each class of road built and the total cost in
each one of the Departments. The range of cost is
very great. Thus in 6 Departments all of the roads,
aggregating 400 miles, were built at a cost of not ex-
ceeding $800 a mile. In 13 Departments 310 miles
62 ROADS AND PAVEMENTS IN FRANCE.
cost approximately $5600 a mile, and in 3 Departments
380 miles cost about $7200 a mile.
Obviously the conditions of every sort must have
been exceptionally faverable in the first case, and very
exceptionally unfavorable in the last two cases.
Between these extremes are all grades of cost, but the
returns show that
Chemins de grande Communication.
Number of miles built in 86 Departments is 3486|.
No. of Percentage of Approximate
Depts. 3486f Miles. Cost per Mile.
17 43 $1600
7 7 2400
1 8 20 3200
8 7 4000
4 6 4800
7 5 S^oo
Chemins a" Interet Commun.
Number of miles in 86 Percentage of
Departments is 5081. 5081 miles.
22 45 l6o
13 j 22 2400
17 21 3200
2 I 4000
4 2 4800
6.. 2 5600
COST OF CONSTRUCTION^Q^ 63
CJiemins Vicinaux Ordinaires.
Number of miles in 86 Percentage of
Departments is 17,416. 17.416 miles.
7 ... ii 1300
17 37 1600
15 1 8 2000
16 17 2250
ii ii 2550
5 3 2900
5 3 3200
From which it appears that nearly one half of the
whole number of miles of each class cost approxi-
mately $1600 a mile, that being the average cost per
mile in each one of 56 Departments.
64 ROADS AND Psi VEMENTS IN FRANCE.
COST OF MAINTENANCE.
These are maintained by the national government.
The annual appropriation covers expenditure of every
kind for ordinary and extraordinary repairs and im-
provements, and is apportioned among the 87 depart-
ments, generally in proportion to the number of miles
taken in connection with the amount of travel.
Great care is taken to ascertain what this travel is,
in order to insure an equitable distribution of the
appropriation. * Once in six or seven years a com-
mission of competent officials of the Bureau of Bridges
and Roads thoroughly investigates the question. Their
labors extend through twelve months, and their report
is full of elaborate and carefully analyzed details. The
choice of the several posts of observation is evidently
one of the most difficult and important parts of the
work. The 23,500 miles (including 1500 miles of
block-stone pavement) are divided, according to cir-
cumstances, into sections of two to ten miles each, but
averaging four and one half miles. The posts of ob-
* Ministere des Travaux Publics. Routes Nationales. Recense-
roent de la Circulation en 1888.
COST OF MAINTENANCE. 65
servation were (in 1888) 4734. The point was to de-
termine the amount of travel that passes over each
section during each twenty-four hours of the year. It
was assumed that an exact record of what passed each
post during 28 days, selected out of the twelve months,
would give a fair average. Accordingly the record was
made every thirteen days from January 3d to Decem-
ber i Qth, thus giving seven days and each day of the
week in each quarter of the year.
The "unit" adopted to express the amount of
travel was each horse harnessed to a loaded wagon,
and in order to reduce all the observations to this
standard unit the following values were given, viz. :
1. Each horse hauling a public vehicle or a cart
loaded with produce or merchandise I
2. Each horse hauling an empty cart or a private
3. Each horse, cow, or ox unharnessed, and each
4. Each small animal (sheep or goat) J/S
The results of these extended observations were
accepted as giving a very close approximation to the
actual amount of travel, as affecting the wear of the
The official report gives the average travel in each
Department. Excluding a few Departments where the
travel was quite exceptionally large or small, it
ranged generally between 100 and 400 " units " in the
66 ROADS AND PA VEMENTS IN FRANCE.
twenty-four hours. The general average of all Depart-
ments was 170.6 "units."
It is generally assumed that, where the conditions
are the same, the wear of the roadway is in direct
ratio with the amount of travel, but the conditions
may vary considerably. A mountain road subjected
to the wash from heavy rains and melting snows may
easily lose more material from its surface and dete-
riorate more rapidly with little travel than a much-
frequented road in a level country.
The quality of the broken stone used in different
districts influences very materially the quantity re-
quired for repairs. As has already been stated, in a
scale of quality from o to 20, the general average of
all Departments is 10.85. ^ n two f the Departments
the average quality is only 6.40 and 6.90, and in four
it is, respectively, 16.23, 16.33, 16.65, an d 16.95.
Considerable quantities of qualities 3 and 4 are used.
It is evidently thought good economy to use to so
large an extent the inferior but cheaper material near
at hand, rather than the better but more costly one
brought from a distance.
TOTAL AVERAGE COST, LABOR AND MATERIALS.
From the Official Reports it appears that there are
in France 321,803 miles of stone roads of the various
classes, upon which the annual expenditure for main-
tenance, including improvements and repairs, is ap-
proximately $31,551, 860.
COST OF MAINTENANCE. 67
iu;i Annual Annual Cost
les - Total Cost. per Mile.
Routes Nationales 72.009 $43335 $ 22 5 During year 1893
Routes Departmentales.. 16,188 2,794,723 172 1 Annual average
Grands Vicinaux 128,522 15,835.100 123 i- for three years,
Petits Vicinaux 155,093 8,488,537 55 j 1886,1887,1888.
These figures represent the outlay for materials and
for labor on the roadway proper. About 45 per cent
must be added thereto to cover expenditure for water-
courses, sidewalks, planting of trees, and for general
General Averages for Year 1893,
Number of miles 22,009
Average travel in 24 hours, " units" 170.6
Broken stone, including 7^ per cent of binding
gravel, per mile and 100 " units," cubic
Quality of stone, scale o to 20, average 10.85
Average cost of stone, per cubic yard $1.17
" " of binding gravel, per cubic yard. 0.36
Labor cost per mile and 100 " units " 30.71
" " " cubic yard of material used 0.63
Average wages of roadmen per day 0.55
Total average cost per mile and 100 " units:"
The Average Cost of Stone.
The average cost in the several Departments that
68 ROADS AND PA VEMENTS IN FRANCE.
make up this general average varies very considerably,
and seems to depend as much on the proximity of the
quarries and cheapness of quarrying as on quality of
stone. The average in 12 Departments was, severally:
$0.53 per cubic yard of quality. . . .No. 8.04
.. " 7.19
.. " 10.47
.. " 9.70
... " 9.25
... " 6.40
... " 13.80
... " 16.33
... " 16.95
... " 10.91
.. " 14.25
Average Cubic Yards per Mile and 100 "Units"
The average consumption in some departments is as
low as 26 to 30 cubic yards, and in others as high as
60 to 65 cubic yards. This wide divergence in quan-
tity used is due in part to differences in the quality of
the stone used, the inferior stone wearing out faster;
but aside from that there are differences the reasons
for which are not stated in the reports.
The writer was unable to obtain corresponding de-
tails and analysis of expenditures for the maintenance
and repair of the Routes Departmentales, Grands Che-
mins Vicinaux, and Petit s Chemins Vicinaux.
< < < ( <
tt < < < <
0.73 " "
< < < < < <
n < i n
< < < < < <
< < < < < <
< < < < < <
< i < < <
2.78 " "
tt ( < (
PA VEMENTS OF PARIS. 69
PAVEMENTS OF PARIS.*
The excellence in general of the street pavements
of Paris and the intelligent care bestowed upon them
by the government and the highly educated body of
engineers more immediately in charge justify a careful
study and a somewhat detailed account of the mode
of construction and maintenance of the several kinds,
the conditions to which each is suited, as well as the
reasons for the adoption of one or another, and in
general the conclusions reached after many years of
experience and experiment.
The simple facts that the area of the street pave-
ments exceeds 10,500,000 square yards, in addition
to 8,288,000 square yards of sidewalks, alleyways,
etc., all under the same direction, and that the expen-
diture for the year 1893, exclusive of the salaries of
officials and the cost of new constructions, amounted
to $4,910,000, are sufficient to indicate the great im-
portance of the subject.
The "Service of the Public Ways" is primarily
under the Prefet of the Seine, who represents the
* The greater part of what relates to the Pavements of Paris is
derived from " Notes a 1'appui du Compte des Depenses de 1'Ex-
ercice 1893," by Monsieur L. Boreux, 1'Ingenieur en chef de la
Voie publique, and from other official documents furnished by
him to the writer.
?O ROADS AND PAVEMENTS JN FRANCE.
national government, but is specially under the
direction of the Board of Public Works of Paris, and
immediately in charge of an engineer-in-chief of the
Fonts et Chaussees. Under him are eight engineers
of the Fonts et Chaussees, each of whom has the
responsible charge of one of the eight sections into
which the twenty wards (arrondtssements) of Paris
are divided. The engineer-in-chief has under his
immediate command 15 superintendents, 22 overseers,
17 assistants, and 2 office-boys. Under the eight sec-
tion engineers there are in addition 108 superintend-
ents, 1 1 1 overseers, and 99 assistants.
Each section is subdivided into six districts, each
under the immediate charge of a superintendent and
one or more overseers or assistants, according to the
importance of the service.
In all of the sections excepting one the street-clean-
ing is under the direction of the district superin-
The figures are unfortunately not at hand to show
accurately the total number of workmen of all classes
employed in the street service, but in 1893 the num-
ber was considerably more than 5000, of whom 3500
were engaged in street-cleaning.
The engineer-in-chief has executive control, since
August i, 1892, of
i. All new constructions, and the maintenance of
existing highways (streets, sidewalks, alleyways, etc.) ;
PAVEMENTS OF PARIS, 71
2. The cleaning and watering of these public ways.
Under the first head are embraced
(a) Block-stone pavements and the working of the
quarries belonging to the city ;
(fr) Macadam pavements and the steam-rollers, in-
cluding the shops for the repair of the rollers ;
(c) Asphalt pavements;
(</) Wooden pavements, including the purchase and
preparation of the wood ;
(e) Bridges, foot-bridges, and the various construc-
tions connected with the care of the public ways ;
(/) Control of the cements, the laboratory for test-
ing materials, and the collecting of statistics relating to
the public ways;
(g) Sidewalks, alleyways, improved surfaces, etc.,
and the supervision of the establishments for the prep-
aration of powdered asphalt and of bituminous mastic ;
(//) The laying out of roads for private owners.
The cleaning of the streets includes the watering,
sweeping and removal of mud, removal of snow and
ice in winter, removal of house refuse, and the man-
agement of the shops for the repair of material.
These shops serve also for the repair of the steam-
rollers and tools used in paving, but 60 per cent of
the expense is chargeable to street-cleaning.
Different Classes of Streets.
From the point of view of maintenance and control
the streets are divided into "Classified" and " Un-
72 ROADS AND PA VEMENTS IN FRANCE.
classified." The former are public highways in every
sense, and are public property. The adjacent proprie-
tors are charged in the first instance with the whoie
cost of the first pavement. After the street has been
accepted as a public way it is maintained at the public
The "unclassified" streets are private ways, and
are wholly maintained at the cost of the adjacent
All of the wood, asphalt, and a portion of the
block-stone pavements of Paris are laid upon a specially
prepared cement-concrete foundation, which, under the
same conditions, is the same for all.
By the requirements of the contracts the concrete
must be composed of two parts by measure of pebbles
and one part of sand, with which the cement, generally
Portland, must be mixed in the following proportions,
by accurate measurement and weight :
Pebbles, by measure I cubic yard
Sand, " " i "
Portland cement, by weight 420 pounds
None of the pebbles must be more than 2^ inches
nor less than 3/4-inch in diameter; they must be made
perfectly clean by abundant washing. The sand must
be free from all earthy matter and be screened so as to
contain no grains less than 1/12 nor more than 1/6
inch in diameter. The Portland cement is thoroughly
tested before being accepted.
PA VEMEKTS OF PARIS. 73
The concrete must be made on movable beds as
near as possible to the point where it is to be used,
the pebbles, sand, and cement being mixed dry with
shovels in such way as to insure an intimate mixture.
Water is added, and the concrete shovelled at once on
to the ground prepared to receive it. It is then
brought up to grade and the surface made even.
After not less than three days a coating of cement
and sand about an inch thick is spread, and the sur-
face made perfectly smooth and even. This mixture
is in the proportion of 760 pounds of Portland cement
to a cubic yard of sand.
This concrete foundation has uniformly a thickness
of 6 inches, including the cement coating. In ex-
ceptional cases, where the bad condition of the earth
below demands it, the foundation is made 7 or 8
Maintenance of Street Pavements.
It is assumed that the wear of a pavement depends,
first, on the number of vehicles using it; second, on
their weight ; third, on their rate of speed. These
three causes act simultaneously in wearing the pave-
ments of Paris to a degree not exceeded in any city of
the world. The effect of the numerous three-horse
omnibuses is specially noticeable. Their weight, which
amounts to 12,000 pounds when fully loaded, their
speed varying from 54 to 6^ miles per hour, and their
frequent stops, all combine to make them a very
f ~ OP THE
74 ROADS AND PAVEMENTS IN FKANCE.
destructive agent. The speed of the public cabs has
also sensibly increased within the past fifteen years.
Different Kinds of Pavement.
Area Jan. i, 1894. Per cent.
1. Block-stone 7,541,258 sq. yds. 71.5
2. Macadam 1,724,632 " " 16.3
3. Asphalt 402,394"- " 3.8
4. Wood 886,236 " " 8.4
10,554,520 * 100. o
All of the pavements of Paris fifty years ago were
either cobble-stone, block-stone or macadam, the for-
mer in those sections where travel was heaviest, and
the latter where travel was relatively lighter. As
travel increased in the streets with macadam pave-
ment the wear and consequent cost of maintenance
increased proportionally, until in any given street it
became evidently more economical to substitute the
more costly but durable block-stone, with its moderate
annual cost of maintenance, in place of the macadam,
with its rapidly increasing annual outlay for repairs.
To-day 71 per cent of the street pavement of Paris is
of block-stone, and 16 per cent is of macadam.
The desire, however, in certain sections and streets
for a pavement which would obviate the noise of the
one and the mud and dust of the other has led to the
introduction first of asphalt and later of wood. The
experiments with asphalt date from 1837, but it was
PA VFMENTS OF PARIS. 75
not until 1855 that the mode of construction in use
to-day was first applied.
The first wood pavements were laid in 1881.
On the 1st January, 1894, the asphalt pavements
represented 3.8 per cent and the wood pavements
8.4 per cent of the whole pavement of Paris.
The tendency to-day is to substitute asphalt and
wood, mainly the latter, for block stone and macadam,
especially for macadam. In certain outlying parts of
the city macadam will still be retained, and in others,
from the nature of the traffic, block stone will still
be preferred, but the use of wood is decidedly on the
On the 1st January, 1894, the total area of pave-
ments of all kinds was 21,516 square yards greater
than on January I, 1893; but the area of the block-
stone pavement had during the year decreased
31,215 square yards and that of macadam 25,000
square yards, while that of wood had increased 77,381
square yards, and during the year 1894 it had fur-
ther increased more than 124,000 square yards.
The area of asphalt had increased during the year
1893 only 2800 square yards.
Wood pavement is obviously the favorite one. Its
advantages as compared with block stone and mac-
adam have already been stated ; it is smooth, noise-
less, agreeable to drive over, easily kept clean, and is
rapidly relaid when worn out.
Asphalt has all of these advantages, but has the
disadvantage of being rather more slippery when wet.
76 ROADS AND PAVEMENTS IN FRANCE.
Its use is in general restricted to narrow streets, less
open to the sun and winds.
Wood is in general laid on the broader streets, to
which the sun and winds have free access.
Neither asphalt nor wood is considered a suitable
pavement for streets where the grade exceeds 4 feet
in 100. This condition is the more necessary in
Paris, where all horses at all seasons are shod smooth
a local custom, the reason for which is not apparent,
as there seems to be no law requiring it, It un-
doubtedly diminishes the wear on both asphalt and
wood, but necessitates the sprinkling of sand or gravel
wherever the surface becomes slippery from any cause.
I. BLOCK-STONE PAVEMENT.
The area is 7,541,258 square yards. It is main-
tained partly by contract, and partly by the city
directly with the force of the street department.
The number permanently employed in this work is
about 444, divided into 75 gangs (" brigades "), com-
prising together 43 inspectors, 84 foremen, and 317
ordinary paviors. The wages per 'month of 26 days
of 10 hours each are as follows
Inspectors of the first class $33
" " second " 31
Pavior of the first class 29
" " second " 28
Helpers (five classes) $25 to 28
BLOCK-STONE PA VEMENT.
Construction and Maintenance.
All wholly new pavement is laid by contract.
The maintenance includes
1. Reconstruction with the substitution of new stone
for old ;
2. Large repairs, which consist in taking up the
old pavement and in repaving with selected blocks
that are more or less worn ;
3. Small repairs in such spots as require them.
The reconstructions and large repairs are all made
by contract. In the case of reconstruction the old
: : ;5:
'^,' ' '
5 : - ;: ;
; J Vv
1 '-' ';-.-'
blocks are carefully sorted, the best are reserved for
large repairs elsewhere, and the others are piled in
the yards to be recut, or to be discarded entirely if no
It is considered necessary that not less than 1/35 of
7 ROADS AND PA VEMENTS IN FRANCE.
the entire area of block-stone pavement should be
reconstructed every year with new stone.
All of the older pavements were laid upon the
earth, bedded in a thin layer of sand. Within a few
years, however, a certain area has been laid upon the
concrete foundation already described, in a layer of
sand not exceeding 3 inches thick.
The results have been so satisfactory that the gen-
eral adoption of this cement-concrete has been limited
only by its cost. In 1894 rather more than 1/22 of
the entire block-stone pavement was on concrete foun-
Kinds of Rock and Dimensions.
The standard dimensions now approved are a
length \\ times the width and a uniform depth of
6J- inches; thus the sizes 6'x 4", 7" X 4f", 8" X 5f,
all 6^ inches deep, are accepted.
There are five kinds of rock used the porphyritic
granite of the Vosges Mountains, the porphyry from
Belgium, and three varieties of a granular quartzose
rock (gres quart zites], more or less compact.
The Belgian porphyry is but little used at present,
hard and durable as it is, because it tends to become
polished and slippery under wear. This is a point
of more importance perhaps in Paris than elsewhere,
since all horses there are shod perfectly smooth at
The Vosges granite and the hardest of the quartz-
BLOCK-STONE PAVEMENT. 79
itzes have given the most satisfactory results, but the
softer quartzites have been most used in the past as
being the least costly. The city owns and works
some quarries, but relies on them mainly as a means
of determining the proper cost of the stone and of de-
feating any combination of the contractors.
Nearly all of the stone used is furnished by con-
tractors, who are required to deliver it in one or other
of the eleven depots or yards where it is to be stored.
A sufficient force is employed to receive it, and at
the same time to rigorously inspect each block and to
reject all that are deficient in quality of stone, exact-
ness of dimensions, or perfection of cutting.
Contract for Laying Block-stone Pavement.
All of the contracts covering the block-stone pave-
ments of Paris extend over the same period. The
last were , for 2^ years and expired July I, 1895.
The form of the contract was the same in all, but in
general the paving of each of the twenty wards
(arrondissenients) was the subject of a separate bid
and contract, and no more than two contracts were
awarded to any one bidder.
The probable expenditure under each of these
eighteen contracts is stated before the bidding, but
this is not made binding upon the city as a condition
of the contract.
The contract is very full and specifies in great
detail the materials to be used, the kind of work that
80 ROADS AND PAVEMENl'S IN FRANCE.
may be required, the manner in which it shall be done,
etc. Attached to it is an elaborate schedule of prices
of the different kinds of labor, of the several materials
used (except paving-blocks), of recutting old blocks,
of all excavations, etc. The several bids are made at
a greater or less discount from this schedule of prices,
which discount applies to every item of the schedule.
In the last contracts this discount ranged from 24 to
38 per cent, averaging about 33 per cent.
The contractor must do the work, whatever may be
required, at the time ordered.
The rate of work (new or reconstructions) must be
50 linear feet a day, whatever the width of the street.
In addition five days are allowed for preparatory
work if the pavement is to be laid in sand simply,
and twelve days if to be laid on concrete foundation.
The penalty is $4 a day if the work is not com-
pleted within the prescribed time. If the delay is
more than five days, the engineer may complete the
work at the expense of the contractor.
The process of reconstructing an old pavement is
very simple. The contractor removes the old pave-
ment and carts the blocks to the proper yard to
be sorted. He receives and transports the new
blocks to be laid. The old sand is picked and fresh
sand added as may be required. The new blocks
are placed in position and remain uncovered till in-
spected and approved by the superintendent or over-
seer. The joints are then filled full with dry sand
MA CAD AM PA VEMENT. 8 1
by thorough brushing. The whole surface is well
pounded with a paving- beetle weighing about 75
pounds. A top layer i inches thick of sand is
spread, and by means of water and brooms all joints
are carefully filled. This process is continued till
water flows over the surface without penetrating any
of the joints.
If the pavement is to be laid on a concrete founda-
tion, the earth upon which the foundation is to rest
must always be previously pounded, watered, and
puddled with care. The city may roll it at its own
expense. The contractor lays the concrete founda-
tion as described on page 72. Upon this foundation
a 3-inch layer of sand is spread in which the blocks
are bedded. The joints are sometimes filled with a
fluid mortar of Portland cement and sand instead of
simple sand alone.
II. MACADAM PAVEMENT.
The area of macadam pavements is 1,724,632 sq.
They are maintained almost entirely by the city
directly with the force of the street department, the
material only being furnished by contract, delivered
either in depots or on the street where required.
The number of men permanently employed is 886,
comprising 6 inspectors, 69 foremen, and 81 1 ordinary
roadmen. In addition some 230 assistant roadmen
are more or less permanently employed, as occasion
82 ROADS AND PAVEMENTS IN FRANCE.
The wages per month of 26 days of 10 hours each
are substantially the same as those given on page 76.
The roadmen are in gangs of 10 or 12 under a fore-
The mode of construction and repair of a macadam
pavement has been already described (pages 24-50) in
sufficient detail, and it is only necessary here to note
the special application of it to the streets of Paris.
The system of ''general recharging," that is, of re-
storing to the pavement, at intervals of three or four or
perhaps ten years, the material lost by ordinary wear,
has been substituted for the older system of "patch-
work repair." The latter is now used only for the
filling of holes and the preserving of an even surface.
A recharging of about 4 inches thick is preferred as
being done under the best conditions, but circum-
stances may necessitate one of 2 to 3 inches, or one
even of 6 to 7 inches.
The work of repair is spread through nine months
of the year in order to give steady employment to
the force and to fully utilize the steam-rollers. To
this end, every spring and autumn a well-considered
"plan of campaign" is determined upon to be carried
out by the several engineers.
The city owns five steam-rollers, two of which
weigh about 58,000 Ibs. each, one about 63,000 Ibs.,
one 40,000 Ibs., and one 36,000 Ibs. They are in
constant use from about the 1st of March, when frosts
are no longer to be feared, up to August, and again
MA CAD AM- PA CEMENT. 83
from the middle of September to the end of Novem-
ber. Necessary repairs are made in the shops of the
street department. The stone used in the construc-
tion and repair of this pavement is almost exclusively
of three kinds, viz., flints, compact millstone grit,
and porphyry. Porphyry is clearly the best material
available, and but for its greater cost would be the
only stone used ; it is reserved for streets subjected
to heavy travel.
The cost of construction of a macadam pavement,
including all charges for material, labor, rolling, and
general expense, was, for the year 1893, $0.80 per
square yard where flints only were used, $1.15 where
millstone grit and flints were used, and $1.34 where
porphyry and flints were used.
The cost of maintenance for the same year was
$0.45 per square" yard as a general average of all of
the macadam pavement. In streets where the travel
is heavy the cost would be much greater, and in fact
the higher annual cost of maintaining the macadam
pavement in proportion to the amount of travel is
one principal reason given for the substitution for it
of one of the three other kinds of pavement, accord-
ing to the requirements in each case. In 1893 the
sum of about $2,260,000 was appropriated for such
change where the annual cost of maintaining the mac-
adam pavement exceeded $0.50 per square yard, and
an additional sum of $1,254,000 where the change
was made for other reasons.
84 ROADS AND PAVEMENTS IN FRANCE.
Under the system of general rechargings, as has
already been stated, such repairs as are made during
the period between successive rechargings are strictly
confined to the filling of holes and the preserving of an
even surface of the roadway. In some of this, as
well as in other operations, the roadmen work sepa-
rately, each within his section. Several times a day,
according to the weather, they scrape off the soft or
fluid mud or sweep off the dust. These scrapings
and sweepings are collected in the gutters, and are
there washed in a stream of hydrant water in such
way that the fine mud is carried into the sewers and
the coarser sand is left behind, to be removed for
The same roadmen are also required to water the
streets frequently in dry weather with hose from the
hydrants, and on streets where there is much travel
to wash them every five or six days with an abun-
dance of water and to thoroughly sweep or scrape them.
This washing is always done in the morning, as soon
as the travel becomes sufficiently active to loosen the
mud and facilitate the sweeping.
The sweeping is done, so far as circumstances ad-
mit, by sweeping-machines, each of which, drawn by
one horse, is capable of cleaning 5400 square yards an
hour, and is equivalent to the work of ten men.
One hundred machines are employed on the macadam
ASPHALT PAVEMENT. 85
III. ASPHALT PAVEMENT.
The area of asphalt pavement is about 368,000
It was adopted as a substitute for block-stone and
macadam, in order to get rid of the noise of the for-
mer and of the mud and dust of the latter. It is
noiseless and free from mud and dust, and on this
account well suited for the immediate vicinity of
dwelling-houses, public buildings, schools, hospitals,
etc. Its disadvantage, however, is that it becomes
slippery during a light rain, and must consequently
be kept perfectly clean. When the surface becomes
slimy it must be well washed with an abundance of
water and lightly sanded. The care of it demands
more labor and consequent expense than the care of
block-stone pavement. The same is, however, true
of wood pavement, the surface of which requires the
same care and nearly the same expense.
At one time there was a prejudice against asphalt,
for the reason that it softened during hot weather
and became disintegrated by severe cold. These de-
fects have been to a large extent corrected by a
proper mixture of different asphalt rocks, and also by
the adoption of the foundation of cement-concrete.
Asphalt is used not only for the roadways, but, in
a somewhat modified form, for the sidewalks; in fact
it is the material almost exclusively employed for
the latter. Thus the area of asphalt sidewalks is
86 ROADS AND PAVEMENTS IN FRANCE.
about 4,494,000 square yards out of a total area of
5,289,430 square yards, that is, 85$ of all the side-
walk pavement of Paris.
The street-pavement proper is only 402,394 sq.
yds., that is, T% of street pavements of all kinds.
Both sidewalk and street pavements are all, with
some unimportant exceptions, built and maintained
by contract. The present contract is for five years
from March 1894, and gives in detail the requirements
as to the quality and character of the materials used,
the mode of construction, etc.
The street-pavements are made of the natural
asphalt rock alone.
The sidewalks are made of a mixture of the same
asphalt rock with natural bitumen and sand.
The contract calls for the natural asphalt rock which
occurs in certain specified localities in Switzerland,
Savoy, the Department of Card in the east of France,
and also in Sicily. It must be a homogeneous lime-
stone, of brown color and with a fine grain, having a
quite compact texture and be uniformly impregnated
with natural mineral bitumen in such way as to show
no parts either black or white. It must be entirely
free from iron pyrites and contain not more than 2% of
clay. All parts of the rock which contain less than
5$ of natural bitumen are rejected.
The rock from different localities differs in com-
ASPHALT PAVEMENT. 87
position, compactness, and in percentage of bitumen,
that generally used containing from 7$ to 13$. It
is mixed in such proportions as to give the percentage
of bitumen desired.
The contract requires that the ground asphalt rock
shall contain at least 6$ and at most 13$ of its weight
of bitumen, the exact amount to be determined in
each case. Also, that
ist. The rocks mixed shall differ only in their
percentage of bitumen, and that no part shall contain
less than 5$.
2d. The different rocks must be mixed before being
Asphalt obtained from the tearing up of old pave-
ments shall not be mixed with fresh rock or be used
at all for this work.
The asphalt rock is ground cold to a powder as
fine and homogeneous as possible with the most per-
fect rolls ; this powder must pass through a screen
with i/io-inch mesh. It is then heated in continually
revolving cylinders, and kept at a temperature of from
88 ROADS AND PA VEMENTS IN FRANCE.
248 F. to 268 F. until all moisture has been evapo-
The powdered rock, while still hot, is loaded at
once into carts, so covered as to prevent as much as
possible the escape of heat, and brought promptly to
the street where the pavement is being laid.
The 6-inch Portland cement-concrete foundation,
such as heretofore described, has already been laid.
The asphalt layer, when finished, is generally 2 inches
The powdered rock is quickly spread upon the
foundation, as soon as it arrives, levelled with rakes,
pounded with heated iron rammers at first carefully
and lightly, smoothed with a hot iron tool, pounded
again with more force, again smoothed with the hot
tool, and pounded a third time thoroughly. The com-
pression is completed by means of a roller weighing
not less than 1 100 Ibs. passed repeatedly over the
surface till the layer is quite cold.
The cost of constructing an asphalt pavement, in-
cluding the 6-inch foundation of Portland cement
concrete and a 2-inch layer of compressed asphalt,
varies from $2. 84 to $3. 10 per square yard, the concrete
foundation costing 75 to 80 cents, The expenditure
in Paris for maintenance and large repairs in 1893 was
a general average of 37 cents per square yard.
The excellence of the sidewalks of Paris is well
ASPHALT SIDEWALKS. 89
The material used for them is known as " bitumi-
nous mastic," and is composed of finely powdered
asphalt rock mixed hot with a varying proportion of
hot bitumen similar to that contained in the natural
The rock is powdered in the manner already de-
scribed. The contract requires that it be melted and
stirred during at least six hours with a quantity of
mineral bitumen sufficient to form a mastic which,
when cold, will be a homogeneous mass slightly
elastic, but not softening at a temperature of 104 F.
This mastic while still hot and in a pasty condition
is run into moulds, forming cakes that weigh about 56
Ibs. It must contain not less than 15$ nor more
than 1 8$ of bitumen.
There are two qualities of the bituminous covering
for sidewalks. The first contains by weight
Bituminous mastic 100 parts
Bitumen for fluxing 6 * '
Sand 60 "
The second contains
Bituminous mastic 100 parts
Bitumen as flux 10 ' *
Sand 60 "
And an equal quantity of bitumen from
old sidewalks, carefully freed from
sand or other adherent foreign matter 170 "
When a sidewalk is to be laid, the ground is first
90 ROADS AND PAVEMENTS IN FRANCE.
thoroughly pounded and puddled while being graded
to a slope of I in 50 from the inside toward the curb.
Upon this the foundation of hydraulic or Portland
cement-concrete, 4 inches thick including a surface
coating of 1/3 inch thick of cement, is accurately laid,
and allowed to become perfectly dry.
The bituminous covering is then prepared at the
furnaces. The mastic is broken into pieces 1/2 in. to
i in. in diameter, remelted with the 5$ or 10$ of pure
bitumen, and the 60$ of sand fine and perfectly dry
is added gradually to the mixture in the heated fur-
nace at intervals during the eight hours of heating
and stirring. During this time the mass must be kept
at a temperature of not less than 280 F. nor more
than 360 F., and be constantly stirred.
This mixture when ready is run hot into heated
portable cylinders holding about I ton, and carried
at once to the point where it is to be used. It is
kept always at the same temperature by a small fur-
nace under the cylinder, and is frequently stirred dur-
ing transit and up to the moment of use.
The bituminous mixture is then spread and, while
still hot and plastic, made perfectly even and smooth
with wooden tools. A very little dry sand is sprinkled
over it, and in twenty minutes the surface becomes
quite hard, and can be walked upon.
WOOD PAVEMENT. 9 1
This bituminous covering is generally 3/5 inch
The bitumen used is always the natural mineral
product derived directly from the asphalt rock or
similar sources, and must come from certain specified
localities. It must not contain any foreign substance,
or water or clay or volatile oils ; when heated for 48
hours at a temperature of 230 F. it must not lose
more than 3$ of its weight. It must be viscous at
ordinary temperature, never becoming brittle nor
fluid ; drawn out into threads it must break only
when the thread is very slender.
The bitumen from Trinidad is also used, but owing
to the amount, sometimes as much as 33$, of fine
clay, sand, and vegetable mixed with it, it must first
be thoroughly refined.
The sand for this use must be entirely free from
earthy and foreign matters, it must be dried and freed
by successive screenings of all grains less than 1/12 or
more than 1/6 inch in diameter.
IV. WOOD PAVEMENT.
Wood pavement was adopted, like asphalt, to secure
a less noisy and more even pavement than block stone
XJNI VERSITY '
92 ROADS AND PAVEMENTS IN FRANCE,
Its area is somewhat more than 1,000,000 square
yards, which is about one tenth of the total pavement
of all kinds.
The first wood pavement was laid in 1884 under
contracts with certain companies, by the terms of which
they were to bear the first cost of it, to maintain it
satisfactorily during the eighteen years of the con-
tract, and at the end of the contract to relay it all anew.
As compensation they were to receive annually during
the eighteen years $0.40^ a square yard of pavement
laid as representing the first cost and interest thereon,
and in addition thereto as representing maintenance
$0.42 to $0.50 a square yard, according to the amount
of travel. For the purposes of this calculation the
first cost of construction, including also the cost of
removing the former pavement, was assumed to be
$3.85 per square yard.
At present and for some years past all of the new
pavements have been laid by the city directly.
The cost of substituting a wood pavement, including
the 6-inch cement-concrete foundation, for block stone
and macadam is given as follows :
Wood Pavement. Wood Pavement. Wood Pavement
Kind of Pavement. 6 in. thick. 4! in. thick. 4 in. thick.
Per sq. yd. Per sq yd. Per sq. yd.
Block-stone $3-12^ $2.63 $2.46
Macadam 3.46 2.90 2.72
The tendency to-day is to substitute, in certain
sections of the city, wood and asphalt for block stone
and macadam. In general, wood is laid in streets
WOOD PAVEMENT, 93
that are broad, open to the sun and air, and where
travel is constant. The expectation is that the pave-
ment shall wear out and not perish from decay. The
durability of the pine blocks as originally laid is from
eight to nine years upon the boulevards and main
streets, where the travel is constant and heavy. The
blocks are often worn down in such places to one half
of their original depth. The pavement of the Place
de la Concorde, for instance, was renewed in March
1895. It was laid in September 1885. Had all of the
blocks been homogeneous the pavement would have
lasted much longer. The failure of isolated blocks
made the pavement uneven before it was worn down
to the extreme limit.
The wood pavement of the Place Vendome was
renewed in May 1895, after seven years' wear.
The statement of the annual wear of the following
streets is from official sources:
Decimals of I Inch.
Boulevard des Poissonniers )
Rue de Rivoli o. 1968
Avenue de 1'Opera 0.1572
Rue de Castiglione o. 1257
" " Londres o. iioo
Avenue d'Antin o. 1060
Place de 1'Alma 0.0943
Rue de la Chausse"e d'Antin . 0.0864
Rue de Rome 0.0746
ROADS AND PAVEMENTS IN FRANCE.
The wood is used in its natural state, no treatment
by any antiseptic agent to prevent decay being made.
The blocks, it is true, are dipped in creosote, but this
is simply to protect them slightly while they are stored
in the yard awaiting use. It is of no value after they
are once laid.
All of the wooden pavements to-day in Paris are
laid upon a foundation of Portland cement-concrete 6
inches thick, the surface of which is made perfectly
smooth. The wooden blocks have in general a depth
of 6 inches and an exposed surface of 9 x 3i inches.
They are placed in rows, with a space of 7/16 inch
between two successive rows, and the blocks arranged
so as to break joints. Experiments have been tried
of making the spacing between the rows 1/4 inch, and
WOOD PAVEMENT. 95
even 1/8 inch only, in order to secure greater solidity,
but the results are not stated.
The actual laying is very simple and rapid. The
blocks are placed on their edges within easy reach of
the pavior, who with a hatchet quickly lays each block
in its proper place in the row, spacing the rows as he
goes on by strips of wood of the required thickness
and itj- to 2 inches broad and 5 or more feet long.
These he lays in obliquely with their ends projecting
above the surface, so that they may be readily with-
drawn when some half-dozen rows have been laid, and
used again as the work proceeds.
As soon as they are withdrawn hot coal-tar is poured
into the spaces between the rows so as to fill about i
inch of the 6 inches of depth. This is done in order
to hold the blocks more firmly in place during the sub-
sequent operations, and not as a preservative of the
The 5 inches remaining of the 6 inches of depth are
at once filled carefully with a fluid mixture of cement
and sand in the proportion of 750 to 850 Ibs. of Port-
land cement to each cubic yard of sand.
The surface of the pavement is then covered with a
thin layer of coarse gravel, the hardest and sharpest
preferred, in order that, under ordinary travel, the
hard particles may be ground into the fibres of the
wood and make the surface harder and less slippery.
They penetrate the wood to the depth of one fourth of
an inch or more, and materially increase the durability
ROADS AND PAVEMENTS IN FRANCE.
of the pavement as well as its impermeability to water.
When the pavement is first laid and when first wet
the wood swells, and the expansion manifests itself in
a lateral pressure, which is provided for near the curb-
stone on each side of the street by leaving a free space
of 2 inches between the pavement and the curb, which
space is later filled with sand as required.
SAND 2 Sil
FIG. 15. Plan.
Kinds of Wood.
The wood first used was Norway spruce or fir.
Later the more or less resinous pine from the Landes,
South of France, has been much used, and with better
results. The pitch-pine from Florida is considered
more durable than the latter, and is used to a limited
extent. Within the last three or four years experi-
WOOD PAVEMENT. 97
ments have been made with the " Jarrah " and
" Karri " woods from Australia, the " Teak" from
Java, the so-called " Bois de fer " from Borneo, and
the " Liem," from Annam all of them much harder
and more compact than the woods heretofore used.
It is too soon to expect conclusive results, but it is
believed from the observations already made that one
or other of these woods, or one equally hard and
homogeneous, will prove more economical on streets
where the wear is greatest than any of the woods here-
tofore used. Great care is taken that, whatever be the
wood, the blocks laid in any one street shall be as
nearly homogeneous as a strict selection can insure.
Could they all be absolutely homogeneous, the wear
would be uniform and the formation of holes due to
the decay or giving way of isolated blocks be pre-
vented. It would greatly lengthen the life of a pave-
As has been already stated, the standard depth of
the blocks, that is, the thickness of the pavement, is 6
inches ; but on several streets it has been reduced to
4f inches, and even to 4 inches. A thickness of 4j
inches is apparently quite sufficient in streets where
the travel is moderate and where repairs become neces-
sary, not from wear, but because of the holes due to
the decay of isolated blocks.
When a pavement must be entirely renewed, in con-
sequence of wear rather than of decay, a certain num-
ber of the blocks taken up may still be perfectly sound
98 ROADS AND PAVEMENTS IN FRANCE.
and comparatively little worn. In order to utilize
what value these may still have, they are carted to the
yard of the street department and cleaned. Then by
means of a circular saw the worn part of each block is
cut off evenly, reducing the height of the block to 4},
4, or even 3 inches. The several sizes are piled, to
be used again on streets where the travel is light.
If the trials of the imported hard woods prove as
successful as anticipated, the use of them will doubtless
be increased, even at the relatively high cost. To
bring the cost within satisfactory limits the thickness
of the pavement may be made, say, 4 inches instead of
Cost of Construction and Maintenance.
p Construction Cost Annual Maintenance
per square yard. per square yard.
Block-stone $2.81 to $3.85 $0.14
Macadam 0.80 1.34 O-44
Asphalt 2.84" 3.10 0.37
Wood 3.00 0.46
The above figures are for the year 1893, as appears
by official report. ~ x ~
Width and Convexity.
Experience has shown that the different conditions
to be satisfied are nearly realized by giving the road-
* Notes al'appui du Compte des Depenses de 1'Exercise 1893.
Monsieur L. Boreux, 1'Ingenieur en chef de la Voie publique.
way such a convexity that the cross profile of the
surface is parabolic. v
From the following table will be seen the propor-
portion of roadway and sidewalk in streets of certain
standard widths, as well as the convexity usually
" , '
i J3 O
Total Width of Street.
*j jjjrjfe *
32 8 ( 10 met )
30 36 (12 met )
49 2(15 met )
65 6 (20 met )
T Q TO
Boulevards and Avenues
Cleaning and Watering.
Cleaning comprises three general divisions:
1 . The removal of mud and household refuse, which
is done by contract.
2. Sweeping and watering, which is done exclusively
by the street department, except that sand is furnished
by contract as well as the use of some of the sweeping-
3. The removal of snow and ice.
The surface (streets and sidewalks) cleaned is about
18,894,000 square yards. The total expense for the
100 KOADS AND PAVEMENTS IN FRANCE.
year 1893 was $1,850,611, which is a general average
of nearly 10 cents a square yard.
The removal of mud and of household refuse is
made between 6.30 and 8.30 A.M. from April I to
October I, and between 7 and 9 A.M. from October I
to April i. Each house-owner is required by law to
furnish from 9 P.M. for the several tenants one or more
receptacles for refuse which are to be brought out each
morning onto the street in front of the house one
hour at least before the carts come by ; as soon as
emptied they are taken into the house.
The contractors furnish their own carts for the
removal of this refuse, and become the owners of it.
They generally sell it to farmers or kitchen gardeners
This refuse is said to be a good fertilizer, nearly
equal to farm-yard manure, as appears by the follow-
ing analysis :
Nitrogen o. 38
Phosphoric acid . . , . 0.41
The city nevertheless has difficulty in disposing of
this refuse, due mainly to the objections on the part
of adjacent villages to the use of it within their ter-
ritories or to the carting of it through them. Arrange-
ments have consequently been made with all the
STREET CLEANING. IO1
principal railways radiating from the city for transport-
ing it at a reduced tariff to more or less remote points.
The total amount of refuse removed in the year 1893
was 1,050,000 " tonnes;" of which 680,000 tonnes
were utilized in the immediate vicinity, 100,000 tonnes
transported on the river to distances from 6 to 37
miles, and 270,000 tonnes transported by railway.
The market value of the fresh refuse varied in 1893
from I2J- to 25 cents a cubic yard, taken on the cart
The total expense of the removal of all kinds of
refuse, including the street sweepings that are not
washed into the sewers, was, in 1893, $377,186.
Each of the twenty wards is made the subject of a
separate contract for a period of five years, and no one
contractor is awarded more than four of these con-
tracts. The contractor furnishes the cart, horse, and
driver. The city furnishes a street-sweeper to assist
in loading, a woman to sweep up whatever may have
fallen when the refuse barrels are emptied into the
cart, and a rag-picker, who remains in the cart and
The expenses attending this method of disposing of
the refuse at more or less remote points and these ex-
penses under the new contracts are 23 per cent greater
than under the former contracts have led the engi-
neers to study more carefully the methods pursued
elsewhere, notably in England. Within the last two
years a furnace has been built by the city for burning
102 ROADS AND PAVEMENTS IN FRANCE.
a certain amount of the refuse, and although the results
are understood to be satisfactory, the question is not
considered settled, as experiments are still going on.
The sweeping of the streets is done by hand or by
The force engaged comprises
37 inspectors $360 to 396
1 3 1 foremen 336 ' ' 348
6 12 roadmen 324
1383 laborers 300 " 324
95 I women sweepers 192 "216
408 rag-pickers, paid 24 cents a day for about
three hours' labor.
The women sweepers are required to work only
seven hours a day. The rag-pickers are occupied only
while the carts are collecting and removing the house-
hold refuse. They keep whatever of value they find,
which is estimated to be about twenty cents a day.
The others are required to work ten hours a day.
The prescribed routine of service is as follows:
4 to 6.30 A.M. Sweeping and washing of the
sidewalks and the streets; sprinkling of sand where
required ; general cleaning of the urinals.
6.30 to 8.30 A.M. Removal of the household refuse
STREET CLEANING. ... 1 03
and the street sweepings ; continuation of the above
8.30 to ii A.M. Picking up horse-droppings; wash-
ing of the gutters ; watering of the streets by watering
carts and hydrant hose ; thorough cleaning and disin-
fecting of the urinals. End of the day for the
ii A.M. to i P.M., dinner. If circumstances require
it, a part of the force continue work and dine later.
i to 4 P.M. (end of the day). Sweeping by the
machines; watering; picking up horse-droppings;
sweeping of sidewalks ; thorough cleaning and disin-
fecting of the urinals ; washing of benches, etc.
4 to 7 P.M. Extra service with extra pay, when
necessary for sweeping, watering, washing gutters, or
7 to 9 P.M. During five months of winter spreading
sand on the asphalt and wood pavements.
When the streets are swept during a dry season
they are first watered to avoid dust. When the sur-
face is muddy, it is well watered in order to loosen
the mud. During a rainy time the sweeping-machines
are passed several times in succession over the surface
to clean it and remove the puddles of water. When
the asphalt or wood pavement is not muddy, it is
dried by the rubber scraper. The dry sweeping^
are removed in carts. The semi-fluid ones are washed
in the gutter in a stream of hydrant water and the
fine particles carried into the sewer. The coarse
104 ROADS AND PAVEMENTS IN FRANCE.
sand is reserved to be used elsewhere, or carted
A conspicuous feature is the great abundance of
water used to keep the streets clean. The water of
the Seine is pumped into reservoirs and is used for
this and all other purposes except drinking.
During hot or dry weather the streets are thor-
oughly washed clean
Block-stone and macadam pavements every three
Asphalt pavements every two days ;
Wood pavements every day.
In general this washing is done between 4 and 8
o'clock in the morning. The gutters are washed
twice a day, and the pavements are sanded as often as
necessary to prevent their becoming slippery.
The city owns 394 sweeping-machines, 100 of
which are assigned to the care of the macadam pave-
ments, 234 to general -cleaning, and 60 kept in reserve
for special service.
The cleaning of the sidewalks is done entirely by
The watering of streets is done wholly by the road-
men engaged in cleaning and by those in charge of
the macadam pavements, and either by means of
watering-carts or hydrant hose. Formerly it was done
by watering carts only, but at present the latter method
STREET CLEANING. IO$
is adopted wherever practicable as being the cheaper ;
the cost is stated to be about one half of that by
The watering begins, in ordinary seasons, on the
1 5th March on the macadam pavements and ends
on the 1 5th October; and on other pavements it begins
April ist and ends September 3Oth.
There are two watering periods daily, the first be-
ginning at 5 A.M. and ending at 10 A.M. ; the second
is from I to 5 P.M. In very warm weather the first
is continued until n A.M., and the second extends
from noon to 6 or 7 o'clock.
The area watered by the hydrant hose is, however,
as yet only 43^- per cent, while that watered by carts
is 56^ per cent of the whole.
CLASSIFICATION OF ROADS IN FRANCE.*
The roads are divided into six classes, viz. :
ist. Routes Nationales, which belong to the state
and are constructed and maintained by the national
2d. Routes Depart ementales, which belong to the
several departments and are constructed and main-
tained by them.
3d. Chernins Vicinaux de Grande Communication.
These roads connect and may pass through two or
more communes, and are maintained by the communes
interested and served, with additional aid from the
funds of the department. This aid is authorized by
law, and is always depended on. The roads of this
class are intended to serve almost identically the same
purposes as the departmental roads, but are under
quite different control and management an anoma-
lous condition which will doubtless disappear in time.
* Dictionnaire Administratif des Travaux Publics. A. Debauve,
Ingenieur en chef des Fonts et Chaussees. Paris, 1892.
4th. Chemins Vicinaux de Moyenne Communication,
or d' Inter et Comnmn. These roads connect two or
more communes, but do not have the importance of the
roads of the third class. They are maintained largely
at the cost of the communes interested, but are con-
trolled and directed by the administration of the de-
5th. Chemins de Petite Communication, or Vicinaux
Ordinaires, are of still less importance than the roads
of the fourth class. They are maintained by the
several communes separately, under the supervision of
6th. Chemins Ruraux. These are roads of the
least importance. They are wholly controlled and
maintained by each commune, without any interference
on the part of the national or departmental government.
Classes numbers 3d, 4th, and 5th constitute the
CJicmins Vicinaux, which may be described as " parish"
roads. They correspond to the via Vicinalis of the
Romans, and connect market towns with each other,
and hamlets with their centres.
OF THE >.