American Falls press. [volume] (American Falls, Idaho) 1907-1937, 1915-12-02
TEXTBOOK AND ROAD BUILDING.

] TEXTBOOK AND ROAD BUILDING.
There is at Washington, a textbook
in Concrete, Brick and Stone-the road
20 Chevy Chase, built by the plans and
under the direction of the Office of
Public Roads of the United States and
for the sole purpose of informing the
public and the members Of congress
interested in the improvement OF the
public highways upon the methods and
cost of construction, types of roads,
a%daptability of material and economy
Of maintenance. Thousands of people
travel over this. road, which is built
cry day, and hundreds of practical road
builders from all parts of the country
have inspected it from time to time
and have marvelled at the excellence
of the work. Manufacturers who have
supplied bituminous materials for the
treatment of the road have detached
their special experts for this service
and the traffic over the road has DEM
o%nstrated under carefully observed
conditions the relative value Of the
several types of road making up this
great highway.
The Chevy Chase road Is experiment
tai. 1t consists of different types Oh
Observation-Disclosures macadam laid
by the penetration method, surface
treatments of waterbound macadam,
asphaltic surfaces on concrete foun
d~ations, bituminous surfaced concrete,
plain and oil cement concrete and Wit
] rified brick, all of which are under
daily observation by expert road build
ers to ascertain which of the types is
best suited to the traffic and which
is condemned by practical test under
the same conditions of climate, soil,
rainfall, heat and cold and like traffic
requirements. 1t wourd be just the
same to the Office of Public Roads
which has written this open book In
concrete, brick and stone, whether
any parts of 1t or all parts Of 1t should
fail, failure in material used, in IN
struction, in durability, in cost, in
INTERCHANGEABLE test is the thing.
Roadbuilding Is a science now and
efficiency is the only test OF quality.
In the stones used In the construction
of the Chevy Chase road, their specif-
ic gravity, their weight per cubic foot,
their water absorption, their percent
age of wear. their hardness and theii
toughness are all determined by the
most careful scientific tests. Patrol
: men are constantly employed on this
road to keep account OF whatever de-
fects in materials and construction
may develop and exact data as to. the
cost Of maintenance. In o of the
experiments covering 1881 square
yards the cost per square yard for
/, 2M inch bituminous wearing surface
was 46.18 cents This experiment was
made in 1911. For the maintenance OF
, surface there vas 10 expense In the
two following years; but IN 1914 this
expense was S79.70. On another sec
ton OF the road the cost per square
surface was GAP cents and for supple.
: mentary construction 1920. This *
pertinent covered an area OF 705 square
yards and In the three years from 1871:
to 1914 inclusive, there was no ex
perse for maintenance. All surfaces
9 on this road were built of a uniform
thickness of eight inches ana OF a 10
tai width of nineteen feet The has,
. course was Of stone ranging in siz
from one TO three inches spread 10
depth OF five inches, the voids 5sini
filled with screenings. The wearln.
9 course consisted of stone ranging rro1
q" one to two inches, generary, and upo
=" this course the bitumen was apple
in two applications Of approximatef
d" IL to " gallons respectively. TIL
cost of the stone used in the founda
J. ton and wearing courses varied ac
cording to the expense OF quaryin
{ and delivery, as II would vary at a.
70 other points; and of all the material
d tenance exact account has been KEEP
The Chevy Chase road vas fortu
. nately placed for the reason that a
! of It's sections or types have been sui
u jected to precisely the same sort {
"a traffic year In and year out and tn
/" section or type that has not stood tn
H. strain has been as important an oil
"a iect lesson to road builders as the sex
= ton or type that has maintained itse
under like strain. The road as
C. whole is a great experiment conducte
r by the most competent engineers I
III demonstrate the most practicabl
u thighs.