The Washington herald., 1908-08-20
METHODS TO PREVENT DUST
Specially Constructed Roadway the
Only True Way.
Oils and sticky Substances Prove
30 Be Temporary ENpedfentE
Which Wear out.

The thousands of experiments for the
suppression Of dust on macadam roads
which have been made during the last
ave years have developed much data on
the subject which IS summarized in
Municipal Engineering as follows
All kinds o1 promising compounds which
make the dust sticky or heavy have been
tired Sometimes they have been OF a
character that would permit OF being dis
solved in water and used from an ordi-
nary sprinkliug cart. giving 20 the water
q soaQy or sticky character. 10 delay
evaporation
Several Of these liquids have demon
strated their ability 20 keep the road
dusJIess 1or q short period None Of
them aims 10. OF has succeeded IN. pre-
venting dust formation
Sea water has also been used in sea
coast cities 10 some advantage. resulting
in a considerable saving in sprinkIing ex-
pehse-
Considerable areas have been treated
with oils OF various grades and g-avities
produced from petroleum OF asphalt Their
effect upon the road has lasted c01sid-
erahly longer and a good treatment with
oil viii keep the road GUstIess for weeks.
inssmuch as it VIII not evaporate. but
viii disappear only by absorption into
the roadway. The serious detriment in
TIE use Of oil. however. has been the fact
that 1t Is obnoxious 70 pedestrians. Skirts
and shoes are stained by it, and the au-
tomobiiists and carriage owners often
complain OF damage 70 their vehicles
Moreover. the oily dust which does
arise sometimes from an 0I-treated road
IS especially dusty and obnoxious. and
property owners on oil treated roads have
made much complaint against the treat
menr
Il has been generally recognized dur
ing the last year or two that all these
methods are mere .paIItatives and co not
strike al the source Of the trouble. name
". the weakness Of the natural macadau
binder Under old style traffic q
nacadan road wore out very slowly. but
automobiles viii destroy the finest surfac-
Ing in a year. stripping the top dressing
down 10 The No > stone. The water
then finds easy access and does great
damage
Many counties. facing the problem Of
automobile wear. preferred 70 give VI
all attempt al maintaining a TOP DRESSING
OF fiEe, screened stone. AID have admit
ted JIatilc directly upon the coarser
stone. which constitutes the second LAYER
Il was recognized that If this mosaic OF
No. 2 stone could only be made wafer
proof, It would give tremendous durabfl-
ity, inasmuch as the abrasion on this sur
face, as compared with a surface Of the
mosaic, IN fact, on al old road. IS prac-
ucally non-dust-prOducing but is very
susceptible 10 disturbance by water and
disruption by frost
It has been found that tar would be
tar compound IS applied TO the road IN a
liquid condition and hardsns among the
fine f1tersJices Of the roadway. somewhat
Ike cement in concrete II is absolutely
waterproof. and a road 50 treated WIN
shed water like the proverbiaI ducks
back In fact. if the road happens 10 he
imperfectly drained. so as to leave pud-
dies after a rain. the water in the puddles
will not be absorbed by the road and viii
only disappear by evaporation.
4 single treatment will give good -
suits for year. and will frequently sboyy
good effects much longer SprinklinR Is
unnecessary, and a good occasional
cleaning is the only care REQUIRED
A treatment for such roads costs about
800 per mile, and calls for no apparatus
except an ordinary sprinkling cart with a
special adjustable nozzle
It is pretty well esta abiished that t,s
traviated surface preserves the road so
well as TO more than save its cost in the
renewal OF the stone Automobile traffic
instead Of breaking ii up. actually makes
il smoother