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Samuel Washington McCallie.

A preliminary report on the roads and road-building materials of Georgia online

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properly crowned surface. In other instances, deep side-ditches or
under-ground drains are essential to a dry roadway, particularly,
if the roadbed is formed of clay. On account of the absorbent and
retentive power of clay, it is one of the most unsatisfactory mate-
rials used in road-construction. Having once become saturated
with water, the clays readily become soft, plastic and difficult to
drain. It is practically impossible to construct, of such material,
anything like a good road, unless the drainage is perfect. For
this reason, it is always advisable to mix, with the clay, sand or
gravel, which greatly improves it for surfacing. Roadbeds, made
of such material, are usually quite satisfactory, if the side-ditches
are kept open and the ruts are filled as soon as they are made.
Some engineers advise the use of a layer of sand, two or three
inches deep, on the surface, where the clay is tough and adhesive.
A cover of this character is inexpensive and is said to pack well
under traffic during the dry season. Furthermore, it prevents
the clay from becoming sticky, in wet weather. Ashes, coal-dust,
furnace-slag, and the refuse obtained from the burning of pyrites



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ROAD CONSTRUCTION



57



in the manufacture of sulphuric acid are also used for a similar pur-
pose. The last named road-covering makes an excellent surface,
which is always compact and free from dust. Nevertheless, it has
one very serious objection, especially in cities and towns, namely,
its destructive effect upon shade-trees growing near the roadway.
It seems quite probable, however, that this objection could be re-
moved, by allowing the material to become thoroughly leached,
before putting it in place.

In repairing roads surfaced with the materials named above, it
is always best to fill the ruts and depressions with similar material.
In no case, should stones or clay be used for this purpose ; as both
have a tendency to aggravate the evil, in place of removing it.
Highway constructors sometimes resort to the burning of clays, in
order to make them porous and more suitable for road-surfacing.
This process of treatment, however, is somewhat expensive ; and
it could hardly be considered practical in the construction of com-
mon roadways.

Sand roads are often as difficult to put in good condition as clay
roads. This trouble arises mainly from the tendency of the sand
to slip and shear, when under the action of the wheel. In order
to overcome the unstable condition of the sand, it is necessary to
mix it with some foreign material, which will counteract its ten-
dency to shear, and thereby cause the particles to adhere to each
other with greater force. Common clay is one of the best and
most satisfactory materials, that can be used for this purpose. A
layer of it, from four to six inches thick, placed upon the surface
of a sandy road, will greatly improve its condition. The sand,
sooner or later, mixes with the clay, and thus forms a more or less
porous road -covering, which is free, in a great measure, from those
objectionable qualities, found in either the clay or sand road alone.
Straw, leaves, twigs, brush, refuse from sorghum-mills, and saw-
dust have all been effectively used upon sandy roads, in improving
their condition. It is claimed, that any of these materials cause
the surface of the sandy roadway to become comparatively hard
and well suited for even heavy traffic, in a short time. Mr. Potter



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58



ROAD CONSTRUCTION



strongly recommends the following method of constructing road-
ways, in alluvial districts : —

''The road is slightly raised above the original surface of the
ground, and thoroughly rolled ; then a few inches of brush or coarse
grass is put in, the first layer being laid with the ends or fibres-
pointing across the line of the road, and the second, lengthwise.
The total thickness of these two layers will depend upon the
quality of the material used, and upon the weight of the top layer
of earth, which will cover it. In all cases, these layers should not
be so thick as to prevent their compacting, with undue elasticity,,
or tendency to * ' give," under the weight of a loaded vehicle. This
method does not insure permanent excellence ; but, as long as the
grass- or brush-layer retains any of its original form or qualities,
it will greatly hasten the drying of the road after a wet season, and
will tend to greatly drain it at all times ; for no reasonable amount
of pressure can be exerted by weight upon the road-surface, that
will tend to close or obstruct the little spaces between the various
bits of straw or brush.

Whatever material is used in the improvement of an earth
road, it is of prime importance, that its surface should be
rounded, hard, and as compact as possible. Traffic alone will
accomplish this desired result in time, if the road is* properly
drained. The main objection to this method of hardening the
road is the tendency of the wheels to form ruts. To overcome
this difficulty and to obtain satisfactory results, the roadway
demands constant attention, until the loose earth is thoroughly^
compacted. The same object is more speedily and effectively
accomplished by the use of the roller, and its general adoption is
strongly advocated by all the leading highway constructors. It
is true, that the roller adds slightly to the first cost of a roadway •,.
but, in the long run, its use is undoubtedly economy, as it in«
creases the effectiveness of the roadway, and, at the same time^
makes it much more durable."



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CHAPTER IV



MAINTENANCE AND REPAIR OF ROADS

A roadway having been properly constructed and thrown open
to traffic, the next duty of the roadmaster is to see, that it is sea-
sonably repaired, and kept as near as possible in its original con-
dition. Many unthinking persons are of the opinion, that a road,
when constructed of broken stones or other durable material, will
remain in good condition for an indefinite time, with but little or
no attention. Such, however, is a most grievous error, as is well
attested by the practical experience of all road-builders. It
would, indeed, be a difficult matter to select any of the varied
products of man's handiwork, that demands more constant and
watchful attention than our common roadways. The forces,
active in their destruction, are varied and continuous ; and, if
they are not retarded in their incipiency, dissolution will speedily
follow. In no instance, is the old adage, '* A stitch in time saves
nine," more forcibly illustrated, than in this.

Two different methods of road-maintenance are in general use,
namely, the *' periodical method " and the "continuous method. ''^
The former consists in going over the road two or three times
each year, with a squad of hands, and making such repairs as are
necessary to keep the road in a passable condition. This method
is usually unsatisfactory, and is rarely ever productive of first-
class roadways. This is due to the road's often becoming well-
nigh impassable, in places, before the necessary repairs are made.
The natural consequence of such a system is fairly good roads for
only short periods, two or three times each year ; and, during the
remainder of the time, they are necessarily bad. "The contin-
uous method " is far more satisfactory ; it is generally adopted in

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6o MAINTENANCE AND REPAIR OF ROADS

all sections of the country, where first-class roads are maintained.
Under this system, repairs are always made at the opportune time
by laborers constantly employed for that purpose ; and no break
or defect in the road is allowed to advance beyond an incipient
state. The practicability of this method of maintaining common
country-roads is well illustrated by the following statement of
Mr. J. O. Sanford, of the Vermont Board of Agriculture : — ^

"The main road through our town, six miles long, not only takes
the travel of the other roads, but is the thoroughfare, by which
the inhabitants of other towns reach the city with their produce,
lumber, wood and a great deal of heavy trucking. The best
farmers live along the road, and have enough business of their
own, without caring for a section of road. Because of this, and
for various other reasons, I conceived the idea of employing one
man to keep this road, and therefore engaged a faithful man,
with his horse, the town furnishing a cart.

'*He was employed from spring to fall, and his instructions
were to begin at one end and work one mile each day, covering
the entire route each week and fixing the worst mud-holes, using
the best road material at hand ; and, at the close of each day, to
pass over the mile worked, gathering the loose stones, and putting
them, where they would give no more trouble, *****
There was much ridicule and prejudice against this system of
management for a time. The man employed was instructed not
to participate in any discussions on the subject ; not to answer
questions relative to the road or his work upon it ; and to refrain
from talking about the matter generally, on penalty of being dis-
charged. Other people talked and ridiculed ; but the work went
on ; and after a few months the condition of the road improved,
and people noticed the fact. They also discovered, that the ex-
pense was not large ; that all the work done was remedying
defects and at the same time preventing greater ones. And so the
work went on and prejudice died out. At the next annual town-
meeting, the people without opposition continued the system;

circular No. 24, U. S. Dept. of Agri., Office of Road Inquiry.



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MAINTENANCE AND REPAIR OF ROADS 6 1

and at the last town-meeting, they elected the Road Commis-
sioners for three years, with the same system of road-manage-
ment. The general results are, that much better roads are
secured at less expense ; and the tax-rate for highways has been
reduced each year as the roads grew better."

The merits of this system of road-maintenance is highly com-
mendable, and if it were more generally adopted throughout the
country, the result would be a speedy improvement in highways.
The system is applicable, not only to broken-stone roads, but also
to earth roads. If the best results are to be obtained from this
method of repairing roadways, it is essential, that the men em-
ployed should be faithful in the performance of their duties, and
have a practical knowledge of road-construction. Furthermore,
they should be able to so classify and plan their work, that the
various improvements and repairs could be carried on, at all sea-
sons of the year. When the method, thus outlined, is thoroughly
systematized and put in working condition, it is practically the
same plan, that is adopted by "section-bosses," in maintaining
railroads.

There are two systems of maintaining highways by the continu-
ous method of repair now in common use ; (i) by contract with pri-
vate parties; (2) by laborers regularly employed for that purpose by
the road authorities. The contract system, as a general rule,
proves to be unsatisfactory, on account of the diflSculty of forcing
the contractors to fulfil their obligations ; while the hired-labor
system, on the other hand, meets with universal approval and is
always fruitful of satisfactory results. The latter system is in
vogue, both in this country and in Europe, wherever good high-
ways are kept up. The expense of maintaining a roadway in good
condition depends largely upon the perfection of its construction,
the nature of the traffic, and the character of the material used in
surfacing. If the road is not properly constructed, the wear and
tear of the destructive forces becomes much more effective ; and,
in a comparatively short time, it becomes impassable. The hard-
est roads to maintain are those defective in drainage. In repairing



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62 MAINTENANCE AND REPAIR OF ROADS

roadways, this defect should be especially gfuarded against, by
keeping the side-ditches and the under-drains always open. The
amount of traflSc, which passes over a road also affects, in a con-
siderable degree, the cost of maintenance. This is due, not so
much to the actual wear of the material, as to the breaking up of
the hardened surface by the wheels of heavily loaded vehicles. A
road under light traffic, if well constructed, may last for several
years with little or no repairs ; whereas, the same road under
heavy traffic would likely go to pieces in a short time. Further-
more, the nature of the material used in forming the hardened sur-
face of a road affects the cost of repairs in a marked degree. Some
surfacing materials, owing to their toughness and a tendency to
bind together in a perfect bond, are quite durable ; while others
are soft, and possess very inferior wearing qualities. Trap rock,
tor instance, under a similar system of repairs, will last many
times longer for surfacing than inferior limestone or shale.

A good roadway is one, that has a smooth, hard surface, free
from dust and mud. In order to secure these essential conditions,
the surface of the road must be kept clean, .well drained and prop-
erly repaired. The first of these conditions, namely, cleanliness,
is of very great importance. Especially is this true of broken-
stone roads. If the material, which originates from the wear of
stones, is not removed from the roadway, it soon becomes quite
thick, and finally interferes, more or less, with travel. In wet
weather, the waste from the broken stones forms mud; while in
the dry season it exists as dust, which is scarcely less objectiona-
ble. Moreover, when this material accumulates upon the sur-
face, even to the depth of only a fraction of an inch, it causes the
wheel to leave a track, along which, sooner or later, a rut is
formed by running water, so that in a short time the continuity of
the hardened surface is broken by the deepening of the rut, and
the roadway becomes rough and uneven. Besides the formation
of ruts, the waste from the broken stone also obstructs surface-
drainage, and thereby gives rise to numerous mud-holes. These
in turn soften the hardened way and allow the wheels of vehi-



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MAINTENANCE AND REPAIR OF ROADS 63

cles to cut rapidly through the layers of broken stone. In order
to reduce to a minimum these evils, resulting from an accumula-
tion of waste upon the surface of a stone road, it is essential, that
all foreign materials should be removed from the surface as fast as
they accumulate. This is best accomplished by sweeping, when
the waste is dry and in the form of dust. Both hand- and machine-
brooms are used for this purpose. The former, which is the most
suitable for country-roads, is usually made of birch or willow
twigs. The sweeping of a road may appear at first thought to be
a very expensive undertaking. It is however not so costly as it
seems. The accumulated dust on roadways usually collects at cer-
tain favored places, and is not evenly distributed over the entire
surface. Consequently, in removing the dust from the road, only
a comparatively small part of the entire superficial area has to be
gone over with the broom. The dust, when it is removed from
the surface, should be so disposed of, that it will neither interfere
with the drainage of the side-ditches, nor be again distributed over
the road by the action of the wind. Too much sweeping should
also be guarded against. Otherwise the fine material forming the
bond between the individual stones is weakened ; and they become
easily loosened and removed from their position. A road kept
too clean is apt to "ravel" and go to pieces rapidly under traffic.

When the surface accumulations are in the form of mud, it is
necessary to remove them* by means of hoes and scrapers. Care
should always be taken, in the use of these implements, to see
that the stones are not loosened and removed from their bedding.
To avoid this danger as much as possible, it is advisable to use
wooden hoes and scrapers. If the road-surface is not hard and
well bonded, it is usually best to make no attempt whatever to
remove the surface accumulations, as the injury to the surface is
likely to be greater than the benefit derived from the removal of
the dust.

The amount of actual wear upon the surface of any well-con-
structed road is comparatively small. The destruction of the
Toadway generally arises from the formation of ruts produced by



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64 MAINTENANCE AND REPAIR OF ROADS

the vehicles following each others' tracks. To prevent the occur-
rence of these ruts, and also to repair them, when once formed,
is one of the many duties devolving upon the person in charge of
the roadway. As previously stated, the best way to prevent the
occurrence of ruts is to keep the surface of the road as clean as
possible, so that the wheels of the vehicles will leave no track.
Any depression or rut, however small, rapidly increases in size ;
and they should always be repaired at the earliest opportunity.
Potter says, that, when these breaks in the surface occur, all water
and mud should be removed from them, and the surrounding sur-
face should be loosened to the depth of about one inch, by means
of a pick. A layer of broken stones, in the case of a macadam-
ized road, should then be spread over the loosened spot, care being
taken to bring the large stones to the center or deepest part of
the depression, and the smaller ones to the edges. The stones
should be beaten, as they are put into place, until they become
thoroughly united with the broken stone of the original surface.
In order to secure a quick and a complete bond between the new
and the old material, it is always well to sprinkle the broken
stone before ramming. Even when every precaution in such re-
pairs is taken, it is often well to make frequent examinations, in
order to see, that the material is properly consolidated, and that it
forms an even surface with the rest of the roadway. If the
mended places are higher than the corresponding surface, they
will soon give rise to depressions on the opposite side of the track-
way ; while, if the opposite conditions prevail, the former depres-
sion or rut will again appear in an exaggerated form. It is also
essential, in repairing ruts and depressions, to use material simi-
lar to that made use of, in the original surfacing. Otherwise, it
will wear unevenly, and give rise to a rough surface.

When the stone-covering of a roadway becomes reduced in
thickness, by continuous wear, so that it is no longer able to sup-
port the traffic, which is to pass over it, two different methods of
repair are adopted. One of these methods, called the patch-work
method, consists in increasing the thickness of the stone-covering



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MAINTENANCE AND REPAIR OF ROADS



65



over a small area of the road at one time. This plan of repair
seems to be best suited to roads of light traffic, where the rate of
wear is naturally low. No broken-stone surface wears equally
rapid at all points along its course. Consequently, if the weak-
ened places are, from time to time, renewed to their original con-
dition, the roadway may continue in a fair condition for an indef-
inite period. The other method of road-repair consists of a com-
plete removal of the entire road-covering at one time. In accom-*
plishing this work, the old material is first loosened up and then
rolled, after which the new material is placed on and consolidated^
The object in removing the old material is to insure bond between
it and the new. This latter method is usually adopted, in repair-
ing roads much used.

In repairing earth roads, the chief part of the work, which
consists in renewing the former crown of the surface, opening up
the side-drains, and filling the ruts and depressions, can usually be
accomplished quite well by means of a road-machine. "There is
hardly a month in the year," says Potter,* "when the road-machine
cannot be used to an advantage on the road ; but the spring is the
best time to do efficient work, because the soil is loose and the
roots of grass and weeds do not interfere. Every spring, before
the ground becomes too hard, the road should be gone over thor-
oughly with the road-machine ; the ditches cleaned out, so that
water may have a free outlet ; ruts and holes filled ; elevations in
the road and the shoulders on the side of the road, planed off;
the grade, improved ; and the road, put in a good condition gen-
erally. In repairing a road, which is in fair condition, commence
at the ditch and work towards the center, scraping lightly with
the entire length of the blade, till the last rounds the middle of
the road." Where the machine is not used, these various repairs
must be accomplished by means of manual labor, which adds
greatly to the cost of maintenance.

Country Roads, page 31.



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CHAPTER V



ROAD MATERIALS

The three essentials of a road-surfacing material are hardness,
toughness and the ability to unite into a compact bond. It rarely
happens, that all these qualities are met with, in a high degree, in
any one variety of stone. Massive quartz, for instance, is remark-
ably hard ; but it is at the same time quite brittle, and its pow-
dered dust possesses little or no cementing qualities., The hard-
ness and toughness of a rock depends, not so much upon its min-
eral composition, as upon the physical structure and the condition
of the individual minerals, of which it is composed. Rocks hav-
ing the same mineral composition may differ widely in their
■structure, and also in their usefulness as road materials. These
differences of structure have generally been brought about by a
re-arrangement of the mineral constituents, so that an originally
massive rock may assume a schistose or laminated structure. The
minerals in such rocks are orientated, that is, their longer axes all
have the same direction.' This arrangement of the minerals causes
the rocks to break with greater ease along certain lines than along
others, which unfits them, in a large measure, for road purposes.
A rock, to be well suited for macadamizing material, should pos-
sess a massive structure, and should have no weak lines, along
which it can be easily broken. These conditions are generally
met with, in rocks of igneous origin. The minerals in these rocks
occur in the form of grains, as in most of the granites ; or they
may occur in the form of crystals, giving rise to a felt-like struc-
ture, as is seen in many of the so-called trap rocks. The latter
structure is usually characteristic of great toughness ; and it en-



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ROAD MATERIALS



67



ables the rock to undergo long and continued wear without going
to pieces. The binding quality of a stone used for road-surfacing
is scarcely of less importance, than its hardness and toughness.
Prof. Shaler, in speaking of this quality, says;' *'This process
of cementation, which gives solidity to the macadam road is
mainly due to, and to be measured by, the energy of cementation
of the dust on the broken stones, either that made in crushing the
material, before it is applied to the way, or that produced by the
rubbing of the bits together, which is brought about by the action
of the roller or the wagon-wheels ; furthermore, that the binding
action is, as to its value, determined not only by the intensity,
with which the particles hold together when first set, but by the
extent, to which this dust may re-cement, when broken up by the
wheels, after it has been watered either artificially or by occasional
rains." The binding quality of the various stones used for road
purposes is quite variable. It reaches its greatest degree of devel-
opment in the diabase variety of trap, limestones and chert; while
it is almost entirely wanting in quartz and sandstone. Roads sur-
faced with the last two varieties of stone should in all instances
have some foreign material used as a binder. Otherwise, the
broken fragments will be diflScult to compact into a hardened sur-


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Online LibrarySamuel Washington McCallieA preliminary report on the roads and road-building materials of Georgia → online text (page 5 of 22)