Frostburg mining journal. [volume] (Frostburg, Md.) 1871-1913, 1900-11-03
TAR MACADAM PAVEMENT.
Cheap and Durable Even When
Used For Heavy Traffic.

Used For Heavy Traffic.
United States Consul f. NJ. Shepard
ut Hamilton, Ont, says:
after years of experiment this city
Is laying Il pavement that for excel
lence durability and cheapness is COM
mcndcd for examination to those in
charge of similar work in the United
States. The possibility of making good
roads at reasonable cost has been DEM
lnStratcd. and tests extending over
number of years on business streets
prove that tarred macadam makes not
only a smooth and solid roadway, but
one that can be kept in perfect repair
at nominal expense. The first cost in
this city. where limestone is abundant
and near at hand, is from 20 to Sc cents
per square yard. and the engineer csti-
mates the cost of repairing on heavy
traffic streets at less than ] cent per
ward year, while asphalt costs over
8 cents. The addition of tar renders
the roadway impcrviOuS to water,
frostproof in winter and prevents mud
and dust in summer. 1t is easily re-
paired and does not require scraping,
tIlIS iNOlulllS VITAL VI lhC
face.
"Onc block of tar macadam laid
more than year ago on n business
street where there is heavy teaming
shows no pcrccptible wear today. In
residential streets these pavements
have been in use eight years without
any repairs and are still in good cOndi-
Tho of this mpthDI of
roadmaking depends on care in its eX-
ecutiOn. as in the case of all composite
work of this character, and | submit
for the information of those interested
the substance OF an interview with
the engineer of public works, E. G..
Barrow, covering details of the proc
esSeS in use here. Either stone or &C.
ment curbng should be placed before
beginning the roadway. Cement costs
here 30 cents per lineal foot and is 6
inches thick, 20 inches in depth and
laid on broken stone or gravel Corners
are rounded and an iron plate imbed
ded for protection. On business streets
stone is preferable.
AN essential in rOadmaking is a hard
and compact foundation. which can be
secured only by the liberal use of heavy
rollers % to 16 tons) while the base is
being prepared. The grade and Gambler
should be so designed as to carry wa
ter off the surface quickly, and all
earth above the sNbgradc should be re-
moved so as to conform to its level-12
inches below the natural surface
which Suhgrade should be thoroughly
rolled and soft spots filed with stone.
The foundation must be compost, q sol
id bed of stone not less than six inches
in thickness. If the soil is of spongy
nature, large, fiat stones are preferred.
All interStces should be filled with
small stone and gravel we'll rolled in.
Over this a coating of gravel should be
rolled hard and then n layer of tar Satu-
rated stone, not exceeding two inches in
diameter. These stones before being
mixed with boiling tar Us to II impe-
rial gallons to the cubic yarD must be
thoroughly dried, either in the summer
sun or by exposure on heated plates,
until all moisture is expelled.
after thorough rolling another stra-
tum of tarred stone of the same dmen-
siOns and thickness is added, rolled
and covered with layer of gravel and
quarry chips, also mixed with tar, one
inch in thickness, to be rolled down
from thrce-fourths to one-half an inch.
a top dressing of screenings is then
added, and if light color is desired it
may be obtained by adding cement.
Most of the stone used here is machine
crushed"