The Princeton union., 1907-07-11
Keeping Down the Dust.

SVs
Owing to the increase Of motor We.
hicles many of our roads are now sub
jected to a wear for which they are
unsuited. Owing to the dirt raising
power of the automobile the dust prob
lem has reached an acute stage in
many places. The matter has resolved
Itself into a local study, since it has
been closely demonstrated that pre-
ventives which work on one soil are
either useless or harmful on another.
This phase Of the problem was recently
discussed by road expert, Mr.. J. W.
Howard, before the American Road
Makers association. Said this author
ity:
Each locality Is a; separate problem as
to what available materials to use for
constructing roads and what methods to
adopt for reducing dust. My experience
testing pavement and road materials in
my laboratory and constructing pave
ments and road surfaces for many years
In many places. convinces me that not
cheap first cost, but economic mainte-
nance, is true economy. This applies also
to suppressing dust. Water alone, or
mixed with salts or with alkau and oil,
has very limited application. Certain
adhesive asphaltic oils for soft road ma
ter1als and specially prepared coal tar
products for hard macadam and similar
roads seem to be the present solutions Of
dust problems for thousands of miles Of
highways.
The condition Of many Of the main
roads in the country after a few days
Of fine weather is such as to justify
almost every expression that may be
ased to designate it. The surface con-
sists either of thick layer of dust or
Of a variable mixture Of sand and loose,
sharp stones, according to the locality
Every fast vehicle that passes, and
often merely a puff Of wind, raises the
dust in clouds, binding and choking
the users of the road, penetrating way
side houses and christening the people
like one of the plaques of Egypt. The
more frequented highways are often
shrouded throughout the day in a dense
white pail Of dust stirred up by the
time to settle. 1t is not surprising that
the public grumbles and demands re-
lief in one direction or another.
The English public is confronted with
the same problem, and there the ques-
ton of the hour is the choice of meth
DDS in the use Of tar. An article in the
T,on6op Enr;poor;,,r cove +1,o+ +or ~,
some tar compound is the most satis-
factory and adds:
Tarring has it's defects and it's linnita-
ttons, but on the whole it appears at pres
ent the most promising solution. How it
can be best applied is the next considera-
ton. It seems obvious that the proper
time is during the reconstruction Of the
road. when the surface material can be
mixed with tar before being laid, so that
every Individual stone is covered. An al
ternatlve method advocated by some is to
coat the road thoroughly before the: sur
face material is laid and then roll the
latter until the tar is forced up into the
interstices. If it be true that tar always
finds it's way upward to the top of the
road, there is something to be said for
this method of using it. Usually, howev-
er, tar has to be applied to an existing
surface, and then the treatment is neces-
sarily less thorough. The ordinary proce-
dure is to sweep the road clear Of dust
and then to apply the tar, brushing the
latter into the interstices by hand labor.
Sand is then laid to prevent the tar being
picked up by the wheels Of vehicles. : A
second coating is given after six. weeks,
but single dressing only is required in
subsequent years. -
The tarredc surface eliminates the ex-
pense Of the water cart and adds to the
life of the road. By the use of a tar
ring machine the annual cost Of main
tanning the tarred surface after it has
been laid is cut in two.