The Clarksburg telegram. [volume] (Clarksburg, W. Va.) 1874-1926, 1912-07-25

49, - p = y II -.
produced By She front wheels and that
practically the entire disturbance OF
the road % produced by the rear or
driving wheels. II the eject were pro-
duced by suction or vacuum the action
Of both front and rear wheels should
be somewhat similar at least. 1t seems
apparent to the writer, therefore, that
the road best adapted to motor trafic
Is the road which will best resist this
powerful traetive shear. It has already
been demonstrated that no plain mac
adam road is capable Of resisting this
force.
The efforts OF progressive highway
engineers are thus directed prtmari.
~ toward the preservation of our stone
surfaced roads and the construction of
dustless roads by the use of a binder
more powerful than stone dust and.
secondly. to minimizing or mitigating
the aust nuisance.
For the purpose Of discussing inteIli-
gently the experiments thus far CON
Quoted with special binders the term
dust preyenhves" has been applied
to all OF the various binders having for
their main object either suppression or
the prevention of dust. These may be
divided into two classes, temporary
and permanent The temporary binders
serve merely as palliatives and require
frequent renewal. The permanent bind.
ers. so called. enter into the structure
or the road as a Constituent element
and are either Incorporated with the
other materials at the time of the con.
struction or applied later by a surface
treatment.
In the class OF temporary binders
may be included water. salt solutions.
Hight oils ana tars and oil and tar
emulsions. waste sulphife liquors. etc.
while the permanent binders include
the heavy petroleums and tars. pitches
and numerous oil. tar and asphalt prep.
aradons. The value of salt solutions.
which have been used to some extent.
ues In the hygroscopic character of the
dissolved salt which. having consider
able affinity for water. keeps the road
surface in moist condition long after
surface treated with water ulone
would have become dry through evapo.
ration.
The light oils and tars as well as the
oil and tar emulsions depend for their
eject upon a comparatively small
amount of true binding base left upon
the road surface after the volatile
products have evaporated. These ma.
terials prove effective only SO long as
they retain their binding power. When
the binding. power is destroyed 1t is
necessary TO apply more material.
The heavy DIS aud tars differ from
the lighter products In that they con.
tain a much greater amount of true
binding base. The results are. there.
fore. OF u more lasting character and
hence the name permanent bInders.p
The semisolid and solid preparations
usually contain a still greater amount
Of binder With some few executions
all Of the true Ginders are bitumens.
The usual method Of applying these
materials 10 the road surface is BY
sprlnkling. The temporary binders can
usually be applied cold. but the perma.
nent binders because of their much
Greuter yiscosity must be heated until
sufficiently tluid. In England and
France the use of coal tar- is practiced
to large extent. and their methods of
application have been highly developed.
Machines nre in general use which are
self propelllng md In which the tar Is
heated and applied to the road surface
MS a spray under high pressure. These
so chilled tar sllrayers" are not only
very economical In the use of tar. but
insure II more even distribution and
letter penetration OF the road surface
than II Is possible to obtain in almost
amy other way
In the construction of dustless roads
the crucial question Is that OF cost. The
effort must be to develop form of
construction which will withstand fast
automobile traffic aud ut the same time
be within the tinanciul resources of the
community. This is largely being done
at present by tho use of bltuminous
binder instead of rock dust The two
methods generally employed are known
as the penetration and the mixing
methods. In the former the hot liquid
binder is sprinkled or sprayed over the
stone and allowed to penetrate through