The Calumet news. [volume] (Calumet, Mich.) 1907-1938, 1911-02-14
USE OF TAR IN
BUILDING ROADS
SAID TO MAKE HIGHWAYS CAP
ABLE OF WiTHSTANDING
HARD TRAFFIC OF
AUTOMOBILES.

AUTOMOBILES.
In view of the quite general aglta-
ton for better roads, i'm which the
copper country is more or less inter-
ested, the remarks of George McDer-
mand, roadway engineer for the Dem
yer Gas and Electric company. who
read a paper at the Good Roads con-
vention at Denver recently, are of in
terest. The subject of Mr. McDer-
mand's paper was The Use of Tar in
Road Making his suggestions being
based on practical experiments in
Denver. He said
THE rapid introduction OF the auto
mobile has been an important factor
in making good roads a necessity.
"Macadam roads will not stand au-
tomobiles traffic; this is a known
fact. 1t is clear, therefore, that we
must give the macadam the addi-
tional binder it so plainly needs. Pure
coal tar distilled to the proper constit-
uency forms this ideal binder. It's use
on public roads, either as palliative
to lay dust or as a binder i'm macadam
construction, is increasing very rap
idly.
"A tar road is noiseless, dustless
sanitary, smooth. but not slippery; IL
Is waterproof durable and economical
no %. H., 4
making is not an experiment, but is in
regular use and has been adopted In
many localities. France and England
have been using tar for more than If
ty years.
"The cost of laying a road with tan
varies with the thoroughness of tn,
work. For instance, the work or
Speer boulevard, Denver, cost Sill
per square yard, while the road laiC
on West Colfax avenue from Boule.
ward f. to Sheridan boulevard, a dist,
ance of one and one-half miles, cos
AZ cents per square yard. In the cas'
of Speer boulevard the road was lai,
in the following manner:
Makeup of Road.
"a five-inch base of crushed smelt
er Stag was laid and thoroughly rolled
at cost of 40 cents per square yard
Then three-fourths of gallon of ia
per square yard spread over il as
binder, by means of sprinkling can
| having especially constructed spouts
which kept the foundation in plac
while the surface mixture was beinI
hauled over IT. A two-inch wearing
surface was laid on top of this an
thoroughly rolled. The surface is com
posed of the following mixture:
Stag. 3S per cent: pea gravel, "a pc
cent; sand, Is per cent; Portlan
cement. per cent; (tar) bituminou
cement per cent.
| West Colfax avenue was laid dur
ing the summer of 1909. A course o
ness from one to two and one-hal
inches was spread over the road. TIL
tar was sprinkled on this course fror
a heated tank wagon; fine Basal
screenings were then spread over
and rolled. The roller in this case wa
a three ton horse roller and was yer
wide, so that the pressure per squar
inch was light. A great deal depend
on the roller in making a tar maca
dam road. A ten-ton' steam role
should be used.
| Heavy Roller Needed.
"The roller should be heavy enoug
to press the fine stones down into tn
voids and bring the surplus tar to tn
surface so that IL may be thorough
absorbed with fine material; otherwis
the tar will run under the pressure G
traffic.
1.-The West Colfax road is in yer
good condition, Notwithstanding tn
crude method of rolling. and this roa
will last for many years.
"A saturated tar macadam road
laid i'm two courses, the base and tn
wearing course. The base is compose
of rocks or broken Stag with the lars
est pieces not exceeding three inche
in their longest dimensions; this
then well rolled and from one-fourt
to one-half gallon of tar per squar
yard spread over It.
1.-THE top course Is composed
smaller rock with the percentage {
sand to fill all voids, and should be 6
least two inches in thickness aftt
rolling. From one and one-fourth
one and one-half gallons of tar pc
square yard is then applied. After a
lowing about six hours for tar to sat
urate. fine screenings are spread owe
II and thoroughly rolled; all surplr
tar that is pressed up to the surfaC
: is covered with more screenings an
rolled smooth.
"The cost of a completed road la
under the above specifications range
from SIS cents to rs cents per squai
!, yard"
!, Nearly $50, 100000 of Britishr capit
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