The weekly Iberian. (New Iberia, La.) 1894-1946, 1921-12-31

be expended next year, over and a.
bove amounts previously authorized
it can be readily seen that the Am
erican people are in earnest about
this matter of good roads and are
taking to heart the fact that eighty
five per cent of our highways are yet
to be surfaced and made practicable
for modern motor traffic.
That our cities are making trem-
endous strides in street paving is IN
Dictated in reports from city engl-
neers to The Asphalt Association,
New York, which indicate that over
thirty million square yards equlval-
ent to 1850 miles of asphaltic pave
ment, thirty feet wide, were laid on
city streets this year Reports from
State Highway Departments indicate
that twenty-three million square
wards were laid on the state high
ways while the area laid in counties
and other districts brought the total
to 6S,O00,000 square yards equivalent
to 5000 miles of asphalt pavements
IS feet wide. This is more than suf-
| ficient to build one asphalt road
eighteen feet wide from Augusta,
Me-, to San Francisco, Cal, and an
other from Augusta, Me, to New
| Orleans.
I The great change which has come
over the system of road and street
building recently is the realization
that the material Of good road
should not be capable of absorbing
water, but water roofed. Not only
does rain percolate through and des-
troy a road but when frost comes it
heaves the pavement and foundation.
Prolonged drought is also very harm
| full to plain macadam surfaces which
| become dusty and ravel.
Impact is a new and destructive
enemy of pavements. When a loaded
! motor truck weighing with its load
22,500 pounds and moving at rate
of fifteen miles an hour encounters
an obstacle on the highway sufficient
to give the rear wheel a drop of one
inch the effect upon the road is prac
tically the same as though the total
weight were multiplied by six. In a
sense the truck becomes projectile
and batters the pavement by sue
cession of mighty impacts.
Two methods of resisting impact
have been developed among highway
engineers, one being to design
rigid structure which will withstand
the impact as armor plate is expect
ed to withstand the projectile. This
method is an effort to match the
strength of the destructive agent
with an equal or superior strength
on the part of the defensive agent.
It calls for constantly increasing
thickness of slab and more reinforce
ment, just as more powerful guns
and increasingly effective armor pier
cling projectiles call for thicker ar
NOR.
This method has found consider
able favor in the Eastern states, but
out on the Pacific coast highway en-
ginners have for the past quarter Of
century been practicing another
method of construction, to which they
point as the infallible solution of the
impact problem
In California and Oregon the en-
gineers do not attempt to stop the
mighty impact of the motor truck in
its tracks, so to speak, but they cush
ion the shock. They construct an ell
astic slab which clings close to the
earth subgrade beneath and it alb
serbs the shock of impact by slight
ly yielding.
The Western engineers argue that
if you put shock absorbers in the
vehicle why not put them in the
road? They point to repeated tests,
which have shown that an elastic or
resilient slab made of asphalt and
stone shows more than double the
resistance to SCATTERING by heavy
blows than has been shown by a rig
id slab of similar thickness and de- |
sign.
At Visalia, California, is such a
pavement composed of seven inches of
stone and asphalt laid in 1894 and
in good condition today with no out
lay for maintenance during 81 years.
More than 100000 yards of the
SO called "black base" type of pave
ment have been laid on the Pacific
coast and over four-fifths of this |
large yardage is not over inches
in total thickness.
TO THE PUBLIC.