a high temperature increase of two grades is
recommended. Each grade adjustment is 6 degrees C.
Polymer Modified Asphalt, PMA, has shown to perform
very well in these areas. The low temperature grade
should remain the same. The Engineer may lower the
low temperature grade to comply with the
recommendations of the FHWA's software program
"LTPPBind", if it is believed to be appropriate.
**************************************************************************
Asphalt cement binder shall conform to AASHTO M 320 Performance Grade (PG)
[_____]. [As an alternate, ASTM D 3381 Table 2, Viscosity Grade [_____] or
ASTM D 946 Penetration Grade [_____] may be used]. Test data indicating
grade certification shall be provided by the supplier at the time of
delivery of each load to the mix plant. Copies of these certifications
shall be submitted to the Contracting OfficerEngineer. The supplier is
defined as the last source of any modification to the binder. The
Contracting OfficerEngineer may sample and test the binder at the mix plant
at any time before or during mix production. Samples for this verification
testing shall be obtained by the Contractor in accordance with ASTM D 140
and in the presence of the Contracting OfficerEngineer. These samples
shall be furnished to the Contracting OfficerEngineer for the verification
testing, which shall be at no cost to the Contractor. Samples of the
asphalt cement specified shall be submitted for approval not less than 14
days before start of the test section.
2.3
MIX DESIGN
The Contractor shall develop the mix design. The asphalt mix shall be
composed of a mixture of well-graded aggregate, mineral filler if required,
and asphalt material. The aggregate fractions shall be sized, handled in
separate size groups, and combined in such proportions that the resulting
mixture meets the grading requirements of the job mix formula (JMF). No
hot-mix asphalt for payment shall be produced until a JMF has been
approved. The hot-mix asphalt shall be designed using hand-held hammer
procedures contained in AI MS-02 and the criteria shown in Table 3.
Laboratory compaction temperatures for Polymer Modified Asphalts shall be
as recommended by the asphalt cement manufacturer. If the Tensile Strength
Ratio (TSR) of the composite mixture, as determined by ASTM D 4867/D 4867M
is less than 75, the aggregates shall be rejected or the asphalt mixture
treated with an anti-stripping agent. The amount of anti-stripping agent
added shall be sufficient to produce a TSR of not less than 75. If an
antistrip agent is required, it shall be provided by the Contractor at no
additional cost. Sufficient materials to produce 90 kg 200 pound of
blended mixture shall be provided to the Contracting OfficerEngineer for
verification of mix design at least 14 days prior to construction of test
section.
2.3.1
JMF Requirements
**************************************************************************
NOTE: In Table 3, use a 75 Blow (compactive effort)
Marshall Mix for all pavements designed for tire
pressures of 690 kPa (100 psi) or higher. For
pavements designed for tire pressures less than 690
kPa (100 psi), use a 50 Blow Mix. Also, use a 50
Blow Mix for shoulder pavements.
In Table 3, delete the column which does not apply,
SECTION 02749
Page 15
Previous Page
