a TABLE OF CONTENTS - UNDP

y
The temperature of the D.B.M. just prior to the dumping of the material from the
hauling vehicle shall be at least 120oC (240oF) but not exceed 163oC (325oF).
When Bituminous Prime Coat is specified prior to the placement of D.B.M. the
bituminous prime coat shall be applied in accordance with the requirements of the
specifications. No D.B.M. shall be placed until the prime coat has penetrated the
base or subgrade and has cured sufficiently.
When a bituminous tack coat is specified prior to placement of any course of
D.B.M. the bituminous tack coat or coats shall be applied in accordance with the
requirements of the specifications. Tack coat may not be required where the
delay between course laying is less than 48 hours and when the surface is fresh
and clean at the discretion of the Engineer.
18.6.16.2 Loading Material Into the paving Machine
The mixed material shall be dumped from the hauling vehicles directly into the
paving machine .
When dumping directly into the paving machine from trucks, care shall be taken
to avoid jarring the machine or moving it out of alignment. Trucks shall be
securely attached to the paving machine while dumping.
18.6.16.3 Placing and Finishing by Means of a Propelled Paving machine
The bituminous mixture shall be spread and finished true to crown and grade by
an automatically controlled bituminous paver. Bituminous mixtures may be
spread and finished by hand methods only where machine methods are impractical
as determined by the Engineer.
The automatically controlled paver shall spread the bituminous mixture without
tearing the surface and shall strike a finish that is smooth true to cross section
uniform in density and texture and free from hollows transverse corrugations and
other irregularities.
The paver shall be operated at a speed which will give the best results for the type
of paver being used and which co-ordinates satisfactorily with the rate of delivery
of the mixture to the paver so as to provide a uniform rate of placement without
intermittent operation of the paver.
All mixed material shall be delivered to the paver in time to permit completion of
spreading finishing and compaction of the mixture during daylight hours.
All bituminous mixtures shall be delivered to the paver at a temperature between
120oC - 163oC. Mixtures delivered to the paver at lower temperatures shall be
discarded.
The longitudinal joints in successive layers shall be offset not less than fifteen
(15) centimeters nor more than thirty (30) centimeters. The width of surface or top
course placements shall conform to traffic lane edges as shown on the plans.
257