segregation. A material transfer vehicle is
recommended when doing runway construction. Remove
last sentence if material transfer vehicle is not
used.
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Trucks used for hauling hot-mix asphalt shall have tight, clean, and smooth
metal beds. To prevent the mixture from adhering to them, the truck beds
shall be lightly coated with a minimum amount of paraffin oil, lime
solution, or other approved material. Petroleum based products shall not
be used as a release agent. Each truck shall have a suitable cover to
protect the mixture from adverse weather. When necessary to ensure that
the mixture will be delivered to the site at the specified temperature,
truck beds shall be insulated or heated and covers (tarps) shall be
securely fastened. To deliver mix to the paver, the Contractor shall use a
material transfer vehicle which shall be operated to produce continuous
forward motion of the paver.
1.8
ASPHALT PAVERS
Asphalt pavers shall be self-propelled, with an activated screed, heated as
necessary, and shall be capable of spreading and finishing courses of
hot-mix asphalt which will meet the specified thickness, smoothness, and
grade. The paver shall have sufficient power to propel itself and the
hauling equipment without adversely affecting the finished surface.
1.8.1
Receiving Hopper
The paver shall have a receiving hopper of sufficient capacity to permit a
uniform spreading operation. The hopper shall be equipped with a
distribution system to place the mixture uniformly in front of the screed
without segregation. The screed shall effectively produce a finished
surface of the required evenness and texture without tearing, shoving, or
gouging the mixture.
1.8.2
Automatic Grade Controls
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NOTE: Delete information on automatic grade control
if not needed. Automatic grade control is needed
when the design requires elevations for the hot-mix
asphalt surface. Most specifications require an
overlay thickness and do not specify actual grades.
**************************************************************************
If an automatic grade control device is used, the paver shall be equipped
with a control system capable of automatically maintaining the specified
screed elevation. The control system shall be automatically actuated from
either a reference line and/or through a system of mechanical sensors or
sensor-directed mechanisms or devices which will maintain the paver screed
at a predetermined transverse slope and at the proper elevation to obtain
the required surface. The transverse slope controller shall be capable of
maintaining the screed at the desired slope within plus or minus 0.1
percent. A transverse slope controller shall not be used to control grade.
The controls shall be capable of working in conjunction with any of the
following attachments:
a.
Ski-type device of not less than 9.14 m 30 feet in length.
SECTION 02749
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