38 
PARK AND CEMETERY. 
, wis. 
TARVIATED PARK ROAD IN MADISON 
still greater depressions. Still an- 
other objection exists in case the sup- 
ply of water is inadequate. The de- 
mand upon the waterworks system 
is usually already great at that sea- 
son of the year when the sprinkling 
of the streets is most urgent and in 
many cases the heavy demand of the 
sprinklers seriously interferes with the 
pressure throughout the system. 
The application of tar or asphaltic 
oil on the surface of the road is gen- 
erally spoken of as surface treatment. 
The writer’s experience with the use 
of tar in the surface treatment of ma- 
cadam streets dates back to the year 
1908 when the first trial was made. 
The material used was a prepared tar 
known as Tarvia A made by the Bar- 
rett Manufacturing Co. 
The street in question was one built 
of crushed limestone in 1897. The 
surface was in ideal condition with 
very few depressions or irregularities. 
The preliminary treatment of the 
road surface before applying the tar 
consisted in thoroughly sweeping the 
street surface to remove as much of 
the dust as possible. The consist- 
ency of the tar was such as to make 
it necessary to heat it before it could 
be applied. Application was by means 
of sprinkling cans with broadened 
nozzles. Approximately one-half gal- 
lon of tar was applied per square yard 
of surface- The surface of the tar 
was covered with a thin layer of 
coarse limestone screenings approx- 
imately one-quarter inch in diameter 
from which practically all the dust 
had been removed. The street was 
rolled with a fifteen ton roller and 
was thrown open to traffic as soon as 
possible thereafter. After a short time 
and after the excess of screenings had 
been worn away, the street resembled 
in many respects a sheet asphalt pave- 
ment. After the lapse of two years 
a second treatment was given similar 
in all respects to the first, except that 
the quantity of tar per square yard 
was about one-third of a gallon. This 
second treatment was given primarily 
to cover the individual stones which 
projected above the general surface 
of the pavement and were thus not 
thoroughly covered by the first treat- 
ment. Several excavations made in 
the street since the last treatment 
show that the tar penetrated the sur- 
face of the road from three-quarters 
of an inch to one inch and thoroughly 
bound the surface. How soon it will 
be necessary to again apply the tar it 
is impossible to tell; however, it is 
safe to say it will not be necessary to 
apply another treatment for at least 
three years and possibly not for five 
or six. The above mentioned treat- 
ment has practically eliminated the 
formation of dust caused by the 
breaking down of the stone under 
traffic. The street is, however, not 
dustless as more or less dust is 
brought upon it from traffic and other 
outside sources and it has been found 
advisable to give the street more or 
less sprinkling with water to keep 
down the small amount of dust which 
does accumu’ate on the street from 
the sources mentioned above. The 
street surface is so well bound that 
any ordinary rain will free the sur- 
face from dust as though it were an 
asphalt pavement. One objection to 
the above, mentioned treatment is that 
it leaves the street slippery at those 
times when due to weather condi- 
tions, other pavements like asphalt 
are also slippery. 
The cost of the first treatment was 
7c per square yard. In this cost is 
concluded all the items which should 
enter, namely, the cost of cleaning the 
street, the cost of the tar, of heating 
and applying it, the cost of the 
screenings and applying them, and the 
cost of rolling. The second treat- 
ment cost 4c per square yard as the 
quantity of tar applied per square 
yard was less. 
In addition to applying the heavy 
tar mentioned above a lighter tar 
(Tarvia B) requiring no heating be- 
fore applying, has been used with 
considerable success. This tar is suf- 
ficiently fluid under ordinary temper- 
ature to run freely from the tank cars 
in which it is shipped. Before apply- 
ing the tar the road surface must be 
cleaned of all dirt so as to expose the 
stone surface. The cleaner the sur- 
face of the street the better will the 
result be in the end. If any cakes of 
dirt or screenings are allowed to re- 
main on the surface then the tar will 
not penetrate into the macadam but 
will instead be absorbed by the layer 
of dirt or screenings. The first heavy 
rain will simply loosen the dirt layer 
and the street will in consequence be- 
come muddy. The street may be swept 
either with a rotary street sweeper 
or with push brooms. The former 
method is the more economical but 
is somewhat objectionable on the part 
of the public on account of the rais- 
ing of dust while the sweeping is be- 
ing done. The raising of a dust while 
sweeping may be lessened somewhat 
by sprinkling lightly with water pre- 
vious to sweeping. 
The tar is hauled from the tank 
cars to the street in wagons equipped 
with a sprinkling attachment attached 
to the rear of the wagon. Several 
such attachments are on the market, 
the general principle of all being the 
same. Suitable regulating valves are 
provided on the attachment which 
makes it possible to gauge the quan- 
tity of tar to be applied. In practice 
about one-third of a gallon of tar is 
applied per square yard. 
The tar, especially during warm 
weather, penetrates into the surface 
of the macadam sufficiently at the 
end of from six to twelve hours to 
enable the street to be thrown open 
to traffic. The efficiency of the tar 
as a dust preventative lies in the fact 
that it penetrates the surface of the 
street from one-fourth to one-half 
inch and firmly binds the stone. 
The cost of the cold tar application 
described above is about l-9/10c per 
square yard. In order to get the best 
results a second application of tar 
should follow the next season after 
the first application. These two ap- 
plications will then be sufficient for 
the two or three following seasons. 
