The record-union., 1893-09-22
HOW TO BUILD ROADS.
A Practical Paper by "a Modern
Builder.
Tho Principal Upon Which the Mod
ern Road Building Engi-
neer Proceeds.


most economic roads. was written for the
late Road Convention by w. E. McClin-
took, c.. E., of the Massachusetts High
way Commission. 1t was read before
the convention, but it is desirable that it
shall have greatly wider bearing. The
RECoRD-UNIoN therefore prints it as the
first comprehensive paper Of instruction
On road building published in this State
since the good road agitation began:
It would be of little use for one who
has gained his experience in the study
and manipulation of the roads Of Massa-
chusetts to attempt even an outline OF
the necessary policy to be pursued IN the
management Of California roads. There
are, however, some few general pr1ncl-
pies that must be borne in mind and
which will apply equally well to any
location.
THE WEATHER.
It must be remembered at the outset
that the weather is a very important
factor among the numerous agencies
which are constantly at work tending TO
destroy a road. By far the greatest wear
of an ordinary country road is from the
falling rains, the strong, dry winds, or
the expanding and contracting influence
Of frost.
The effect of the rain is two-fold:
passes to the foundation.
THE WASH FACTOR.
The surface wash is of three kinds,
viz: First, by the water accommodating in
the side cutters. These are made so deep
and wide as to encroach on the roadway,
when they become dangerous. Second,
by flowing from the center of the road
way to the cutters, channels are formed
which gradually become source of an
~ xGyaxy nm
safe. Third, by following small wheel
ruts on a falling grade the center of the
roadway is slowly but surely made the
gutter, and is thus destroyed.
The rain water reaches the foundation
OF roadway either by passing directly
through the surface, if it be loose and por-
GUS, or by soaking in from the sides.
In making a study of the effects of
water on a roadway it is we'll to bear the
above facts in mind, and then determine
what action is necessary to prevent waste
and destruction.
FEATURES OF A PERFECT ROAD.
In this connection we find that the two
essential features of perfect road are
porous foundation and non-porous sur
face.
With a porous foundation all water
will quickly pass downward; none will
stand to soften the ground, and the frost
can do but little harm to the roadway if
it be free of water. Underground water
which flows toward the road will be
powerless to harm it, il it's foundation is
porous, so as to permit the same to pass
downward, or if it intercepted by drain
or drains and thus carried to some con-
venient water course. If the road
traverses sandy or gravelly location no
precaution need be taken to secure drain
age of the foundation, as nature has al
ready furnished it. On such a soil we
shall need no heavy stone, no extra
depth of any kind of stone, and no drains.
If the natural soil over which the road is
laid out be clayey or loamy and i'm
pervious to water, then we must take
those precautions which will furnish an
artificial porous foundation. II the road
be on side hill drain constructed on
the uphill side will prevent any water
from passing underneath it.
DRAINAGE.
If the road traverses level ground, one
drain on each side must be built; or in
stead of these, one in the center, with
slope Of the impervious material toward
the center from both sides, the proper
crown being made by the top covering
The drains may be built of rough stone,
laid in the bottom of a trench from two
and half to three feet deep, or of common
tile or vitrified pipe with open joints.
Small stone or fairly good sized gravel
stone should be filled in over the drain to
lead to water-course or to the surface of
the ground at a point where it can readily
flow away; otherwise the water will pass
to the lowest point of the road and there
stand until 1t so sottens the foundation as
to render it unable to bear up the traffic.
Open side bitches will accomplish the
same results as the drains, and if the
road be through farming country, or,
in fact, any section where the open ditch
will not be an objection, 1t can be built
for far less money, and may, on the
ground of economy, be adopted. If the
natural soil be heavy clay it may be
necessary to put IN center drain, or to
place coarse stone carefully under the
whole width of it, so as to permit the
water to easily pass to the side bitches or
center ditch, whichever may be used.
Our motto at this point should be- keep
all water from the road foundation.
EFFECTS OF RAIN ON ROADS.
We will now pass to the effects of rain
falling on the surface. Ii the wash of the
cutters be great, the only remedy will be
to pave them with any kind of rough
stone which may be most conveniently
obtained. Such pavement is compare
lively inexpensive, and will save enough
to more than pay for it. At times the
water may be removed in the grass gut
ters, with no expense for pavement. If
possible, the growth of grass should be
encouraged at the sides of road and the
gutter made rather broad and flat, as by
such an arrangement the water will be
spread out more and its velocity be
greatly reduced, thus preventing wash
outs.
We have already discussed the ques-
ton of how to keep the water out of a
foundation when it flows toward it from
the sides. We will now treat of that part
of the rain which falls directly on to the
road.
WATER ON THE SURFACE.
1t is well to bear in mind that too much
water passing over the surface washes
away the finer material which bonds the
coarser and holds it firmly in place. By
passing through the surface il reaches the
foundation and softens it, so as to render
it unable to bear up the load. We must
consider the roadway itself as a roof
which is to keep the water away from the
foundation, exactly as the shingles on
roof prevent the ruin Of the interior of the
building. If the top surface be water
tight, we shall have perfect road as far
as its ability to bear up load is concerned.
If we at the same time get durable and
a smooth surface, we have got the most
economical road we can build. Ii we are
seeking road which will be good during
all seasons OF the year, we must reject all
material that is hbrous, or which absorbs
water or does not let it flow off quickly.
All loans and clays come under this
class. They are good iii the traffic be
light when they are but just moistened.
During a long dry period they are all
dust, and when it is wet there is nothing
but mud. The fibrous nature of the ma
terial holds the water, and it evaporates
instead Of draining OF. This is a slow
process. and during the rainy season one
evaporation Is not completed before an
other wetting takes place, and we have