e construction of the surface.
The bituminous material may be applied by means of hand spreading cans
not unlike an ordinary garden watering pot, except that a slotted
nozzle is substituted for the ordinary perforated one. If hand methods
are employed for spreading, the bituminous material is heated in open
kettles and then spread on the surface, the quantity required usually
being about one-half gallon per square yard of surface. The
temperature of the binder should be great enough to insure fluidity
and the road should be dry at the time of the application. As soon as
the material has been spread, the surface is finished with a dressing
of chips.
=Finishing the Surface.=--For surface dressing the best material is
stone chips ranging in size from about 1 inch down to one-fourth inch.
But the chips must be of durable material, or they will quickly grind
into dust. They must be free from dust when applied, as the presence
of any considerable amount of dust interferes with the proper
finishing of the surface. The stone chips are rolled into the surface,
a sufficient quantity being used to just cover the surface.
=Patching.=--It almost always happens that some small areas will not
be properly cleaned or that for some unknown reason the coating peels
off the surface. Such places must be promptly patched to prevent them
enlarging under the action of traffic. This work is usually done by
patrolmen, who inspect the road at frequent intervals and make the
necessary repairs. The patrolman is equipped with a small heating
kettle, a spreading can and the necessary brushes, tampers and
miscellaneous tools needed for the repair work. The place to be
patched is carefully cleaned, coated with bituminous binder and stone
chips and tamped until dense and solid. Repairs made in this way are
exceedingly important in that they arrest deterioration in its early
stages and maintain a high degree of serviceability.
II. Penetration Macadam
A considerable mileage of macadam has been constructed in which an
attempt was made to eliminate the difficulties of maintenance by a
method of construction that involves applying a bituminous binder in
such a manner as to permit it to penetrate two inches or more into the
surface. It is expected that the binder will coat the stones to such
an extent as to increase materially the stability of the bituminous
macadam over the surface treated one. It is also expected that less
difficulty will be en
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