The Waxahachie daily light. [volume] (Waxahachie, Tex.) 1894-current, 1916-08-09
MlClDln R1l0s TOO EXPENSIVE
FOR CITY STREETS Or DTHlTs|

day. is particularly adapted 20 main
Highways connecting centors Of pop
uIation. bot Is not satisfactory for
city streets and Il too expensive Tor
rsra roads other than main high
Ways or pixies The department
has been Investigating
From II to Is feet Is recon
meaded as a suitable width. provid-
cd the road s. fIankcd on each side
with firm shoulders from TO 5 feet
vide. TO prevent shearing OF the
sides by wheels.
The Macadam method OF road con-
struction was first introduced about
the beginning OF the nineteenth cen
fury in England by a Scotchman
named John Louden MacAdam.
The chief features Of this con-
structlon, which has since become
one OF the foremost methods OF road
building In every country of the
world, are: a raised. thoroughly
drained. and crowned earth founda-
ton; a snb-surface OF broken stone
fragments. not larger than az
inches and diameter and of uniform
size: a surface binding OF stone dust
and screenings.
During the last forty years this
method has been modified and the
stone fragments are graduated in
size with the coarser stones at the
bottom.
Recently various bituminous prep
arations have been added to the sur
face OF binders. Heavy, petroleum
oils, asphalts, bituminous cements
and tar mixtures are now used large
~ for this purpose. The addition
OF some such binding material rem
ders the road impervious 10 the
damaging action Of water and forms
hard. smooth. resilient surface
Although 1t formerly was thought
necessary To surface the load with a
layer of macadam from to IL
inches in depth. Uncle Sans road
experts declared the surface should
be as thin as Is consistent with du-
rability- not over 6 inches deep in
any case and often only three. This
saving of surfacing material greatly
Towers the cost of the road, without
detracting from ito wearing quail
ties in the least, they contend.
The road-bed should be OF porous
material, well drained. and should
be free from clay or loan.
Grades exceeding 6 feet to every
leo feet are considered excessive for
heavy traffic. Curves with less than
200 feet radius should be avoided.
Build around the slope of a hill
not over 1t. Build as straight as
possible, always considering grading
first. A special recommendation Is
made by the office OF public roads
that the surface crossing of railroad
tracks be eliminated through cul-
verts or overhead bridges.
Trap rock is considered by the
government experts as the best
for road building purposes, al
though some GRANTEES and the hard
or limestoncs give good results. The
United States of public roads tests
samples OF rock submitted to it
without charge. and furnishes adj
vice Is to the fitness of any sam
Pile for road building.
The cost is entirely dependent on
local conditions and the availability
of materials. However, an estimate
OF the cost of the maeadam surface.
foundation and drainage costs
eliminated, places the average ex-
penditure, where imported trap rock
is used, at approximately $4,000 to
SIS 900 per mile for l5-inch road
with an average depth of 5 inches.
Where a local stone Is Immediately
available tte cost OF the surface may
be as low as $500 to $4,000 per
mile.
In Massachusetts,, the actual cost
of imported trap rock, in place and
rolled. was $40 per ton, covering
3.13 square yards OF surface at 5
inches fn depth. Local stone was Sc
cured in this instance at s1.22 ton.
Construction Of niacadam roads
as of any other kind. in the opin-
lon OF the United States road bureau
should always be under the direc-
tion OF an experienced road engi-
neer, II best results are to be OBJ
tanned
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