Skip to main content

Full text of "Roads and pavements in France"

See other formats

" " rwt^i n n^_n n n rt_fi__n_ - n_-ft n fv 



^Received yl/ldAJ' > 

Accessions No. lf>5D J J . c/js.v M). 

r u u J 






formerly Professor of Mining at the 

Sheffield Scientific School and at the Massachusetts 

Institute of Tecknvlogy, 



f * OF THE ^ >V 


V. OF ^f 








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. 


BOSTON, October 1895. 




Historical i 

A perfect wagon-road 4 

Grade 8 

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 

Street-sweeping 101 

Watering of streets 103 

Width and convexity of Paris streets 104 

Classification of French roads 106 



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 


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. 



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 
or country. 

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 


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. 


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? 




ing a new road upon a new line, or in improving one 
already built, may be conveniently grouped under the 
following heads, viz. : 

1. Grade. 

2. Material. 

3. Mode of Construction. 

4. Maintenance. 

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 
for discussion. 

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 


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 


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 


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- 
porary remedy. 

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, 

Broken Stone. 

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. 


* 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 : 



ib. Yds. 

Coat of Stone per 
Cub. Yd. 



$0 6 to $i 8 

$O 96 


II 12 

i ^ 6^ ^ 

o 83 to i 48 

Millstone Grit . . 


) . ( 

I Q1 to 2 7^ 



f 3,892] 

2 ii to 3 54 




The average travel was 227.8 units in the 24 hours. 


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 ; 


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 
solid roadway. 


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- 


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 


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. 

Stone Roads. 

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- 


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, 



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 


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- 
ciently solid. 

Telford's System. 

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 


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. 



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. 


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- 


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. 


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. 


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. 


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 ' 

Less than 

2 inches (o' n 05) 

6 Q j. 16 80 

Between 2 

in. (o in .o5) and 

4 in. (o tn .ioi 

26.13 38.29 



" (o'Mo) and 

6 " (o'M5) 

27.58 26.05 



" (o m .i5) and 

8 " (o' n .2o) 

20.19 n-43 



" (o'".2o) and i 

2 " (o m .3o) 

15.12 6. ii 


More than 

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 


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 
years before. 

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. 

Binding Material. 

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 


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 contains. 

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 


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. 



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 

u t< 

" " " 

" " 


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 
ivliole ividtJi. 

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. 

K&SUM&. 33 


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 


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 





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. 



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 
stone layer. 

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 


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 


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 
3X8 feet. 

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 


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 
checker-board arrangement. 

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 


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. 


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 


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 
of material. 

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. 


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 


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 


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. 



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. 

Binding Material. 

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 




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- 


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. 


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 
a day. 

Cost per 
cubic yard. 

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. 


Modified Recharging. 

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. 


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. 


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- 

FIG. 5. 

being amply sufficient. The convexity is 1/50, or i|- 
inches to the yard. 

FIG. 6. 

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 



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. 


\ ne 



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. 

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 


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. 



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 


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 


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 



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 : 



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." 



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. 

No. of 

Cost per 

Total Cost. 


de grande communication. . 
d'interet commun . . . 


5 08 1 

2 ^OQ I 6 

II 7^2 8^2 


vicinaux ordinaires 

17 dl6 

2 0^6.64. 

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 


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 


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. 



Routes Nationales. 

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. 


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 

carriage 1/2 

3. Each horse, cow, or ox unharnessed, and each 

saddle-horse 1/5 

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 


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. 


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. 


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. 

321,803 31,551,860 

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 

yards 49. 

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:" 

Materials $58.75 

Labor 3O.7i-$89.46 

The Average Cost of Stone. 
The average cost in the several Departments that 


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 

... 15.45 

... " 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. 


O.OO ' 

0.61 " 

< < < ( < 

0.67 " 

tt < < < < 

0.73 " " 

< < < < < < 

1.96 " 

n < i n 

2.20 " 

< < < < < < 

2.27 " 

< < < < < < 

2.38 " 

< < < < < < 

2.40 " 

< i < < < 

2.78 " " 

tt ( < ( 



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. 


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.) ; 


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- 


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. 


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 
inches thick. 

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 



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 


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. 


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. 


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 

Foreman 30 

Pavior of the first class 29 

" " second " 28 

Helpers (five classes) $25 to 28 



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 







i - 





: : ;5: 








'^,' ' ' 

5 : - ;: ; 




; J Vv 


: ^V. 

1 '-' ';-.-' 

'-.'" ' 

^- 1 


||; .^ 







!- v^ 









FIG. n. 

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 
longer utilizable. 

It is considered necessary that not less than 1/35 of 


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 
all seasons. 

The Vosges granite and the hardest of the quartz- 


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 


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 


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. 


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 


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 

? *- 


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. 


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 
other uses. 

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 
pavements alone. 



The area of asphalt pavement is about 368,000 
square yards. 

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 


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. 

Asphalt Rock. 

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- 


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. 

Street Pavement 

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- 

FlG. 12. 

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 


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 


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 " 

170 parts 

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 


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- 



FIG. 13. 

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. 


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. 


Wood pavement was adopted, like asphalt, to secure 
a less noisy and more even pavement than block stone 
and macadam. 




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 


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 ) 

I 0.2908 

"Italians ) 

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 



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 

FIG. 14. 

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 


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 

9 6 


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- 


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 


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 
6 inches. 

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 

c S 


u . 


u ^s 

*ES| . 

Total Width of Street. 

*o ^^O 

*j jjjrjfe * 

o S 



|f| 1 



32 8 ( 10 met ) 

21 64 





c c8 

3 b 

30 36 (12 met ) 

23 61 


7 87 

49 2(15 met ) 

29 52 



I /^O 


65 6 (20 met ) 

TQ 'if) 


1/6 1 


Boulevards and Avenues 

i 45-92 
1 52.48 



j 59-04 



Exceptional Streets 

1 .036 




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 


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 
as manure. 

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 

Potash 0.42 

Lime 2.57 

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 


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 
or boat. 

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 


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. 

Street Sweeping. 

The sweeping of the streets is done by hand or by 

The force engaged comprises 

Yearly Pay. 

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 


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 
women sweepers. 

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 
spreading sand. 

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 


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 


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. 



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. 

1 06 


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 
government engineers. 

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 >. 

OF ^X 



LD 21-ioOw-7,