The Fulton County news. [volume] (McConnellsburg, Pa.) 1899-current, 1906-08-16
Tar Improves Mncadnm.


described in bulletin issued by the
United States Department of Agri
culture.
During the spring and summer of
1905, says the Bulletin, the Office of
Public Roads co-operated with Sam
G, Lancaster, city engineer of Jack
son, Tenn, and chief engineer of the
Madison County Good Roads Com
mission, in making a series of care
full experiments to determine the val
tie of coal tar for the Improvement of
macadam streets and roads. Tests
were also made of the utility of crude
Texas oil and several grades of its
residue when applied to earth and
macadam roads
The macadam streets in the busi-
ness centre of Jackson were built
originally of the hard siliceous rock
known as novaculite. About May I,
1905, after fifteen years of wear, re-
pair of these streets became neces-
sary. The old surface was first
swept clean with horse sweeper,
so as to expose the solid pavement
beneath. This was done because tar
will not penetrate a rock surface
which is covered with dust and loose
material. Next, the surface was
loosened by means of spikes placed
in the wheels of q ten-ton steam
roller, the street reshaped, and new
material added where needed. The
road was then sprlnkled, rolled. bond
ed and finished to form a hard, COM
pact, even surface, and allowed to
dry thoroughly before either tar or
oil was applied, for these substances
can not penetrate a moist road sur
face. The best results are obtained
when the work is done in hot, dry
weather. AMI accordingly the tar was
first applied in August. II may be
well to add that the novaculite used
in the construction of the roads is
an almost non-absorbent rock.
The tar used was a by-product
from the manufacture of coke and
was practically free from moisture.
1t was brought to a temperature
which generally reached 210 degrees
Fahrenheit, but when placed on the
road Is was reduced to a tempera-
ture of from 1G0 degrees to 100 de-
grees Fahrenheit The hottest tar
produced the best results. 1t was
spread with hose.
Laborers with street cleaners
brooms of bamboo fibre, followed the
tank and swept the surplus tar ahead
They spread it as evenly and as
quickly as possible, and in layer
only thick enough to cover the sur
face. One side of the street was fin
ished at time, and barricades
placed to keep off the traffic until the
tar had had time to soak into the sur
face. The time allowed for this pro-
cess was varied from few hours TO
several days. From the results OBJ
tanned it can be stated that. under
a hot sun, with the road surface thor
oughly compact, clean and dry, and
with the tar heated almost to the
boiling point and applied as de-
scribed above, the road will absorb
practically all of it in eight or ten
hours. A light coat of clean sand,
screenings or the clean particles
swept from the surface of the road
may then be spread as evenly as pos
sible and rolled in with steam
roller.
After more than seven months, in
cluding the winter season of 1905-6,
the tarred streets and roads are still
in excellent condition. They are
hard, smooth and resemble asphant
except that they show more gritty
surface The tar forms a part of
the surface proper, and Is in perfect
bond with the maca6am. Sections
cut from the streets show that the
tar has penetrated from one to two
inches, and the fine black lines seen
in the interstices between the indi-
vidual stones show that the mechani-
cal bond has been reinforced by the
penetration of the tar. The tar is
matrix into which the stones of the
surface are set. forming conglom-
crate or concrete. A second coating
applied q year after the first would
require much more tar than the first,
as the interstices of the rock would
then be filled with tar.
A tarred street is dustless in the
same sense that an asphalt street IL
dustless, though a fine sandy powder
wears off, as in the case of asphalt
Ii can be swept or washed clean
These streets have since been swept
regularly and the city government is
in favor of treating all of the streets
with tar The cleaning that would
soon ruin an ordinary macadam road
does not injure the tarred surface
as the stones are not torn up or dis
turbed. The tar itself has antisep-
tic properties, hence its use would
be beneficial both as a germicide and
as a means OF securing cleanliness.