of polyester geosynthetics is determined from GSI
GRI GG6, "Determination of the Number Average
Molecular Weight of Polyethylene Terephthalate (PET)
yarns Based on a Relative Viscosity Value", and ASTM
D 4603, "Determining Inherent Viscosity of
Poly(Ethylene Terephthalate) (PET) by Glass
Capillary Viscometer." The carboxyl end group
number is determined from GSI GRI GG7, "Carboxyl End
Group Content of Polyethylene Terephthalate (PET)
Yarns."
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2.2.1
Geogrid Reinforcement
Geogrid shall be a geosynthetic manufactured for reinforcement
applications. The geogrid shall be a regular network of integrally
connected polymer tensile elements with aperture geometry sufficient to
permit significant mechanical interlock with the surrounding soil,
aggregate, or other fill materials. The geogrid structure shall be
dimensionally stable and able to retain its geometry under manufacture,
transport and installation. The geogrid shall be manufactured with 100
percent virgin resin consisting of polyethylene, polypropylene, or
polyester, and with a maximum of 5 percent in-plant regrind material.
Polyester resin shall have a minimum molecular weight of 25,000 and a
carboxyl end group number less than 30. Polyethylene and polypropylene
shall be stabilized with long term antioxidants.
2.2.2
Geotextile Reinforcement
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NOTE: Survivability - The AASHTO M 288 requirements
are minimum requirements and will not normally
control in the product selection. The AASHTO
reference can be avoided by listing the grab, tear,
burst, and puncture strengths. These properties are
listed in AASHTO M 288. The puncture strength (ASTM
D 4833), the trapezoidal tear strength (ASTM D4533)
and the mullen burst strength (ASTM D3786) are
recognized as important geotextile properties. For
the intended application, the commonly specified
values for puncture, burst and tear seldom control
the product selection.
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Geotextile shall be a pervious sheet of polymeric material and shall
consist of long-chain synthetic polymers composed of at least 95 percent by
weight polyethylene, polypropylene, or polyesters. The geotextile shall be
manufactured with 100 percent virgin resin, and with a maximum of 5 percent
in-plant regrind material. Geotextile shall be formed into a network such
that the filaments or yarns retain dimensional stability relative to each
other, including the selvages. Polyester resin shall have a minimum
molecular weight of 20,000 and a carboxyl end group number less than 50.
Polyethylene and polypropylene shall be stabilized with long term
antioxidants.
For survivability during installation, and in addition to installation
damage used in calculating the long term design strength, the geotextile
shall meet the minimum requirements in AASHTO M 288 Class 1, and shall have
a minimum mass per unit area of 270 g/m2 8 oz/sy.
SECTION 02832
Page 17
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