738.1 738.2(b)
738.1POLYMER REQUIREM ENTS—
Geogrids m ust be manufactured from either polymeric coated polyester (PET), high density polyethylene
recycled material is allowed in polymer resins used in the manufacturing of geogrid products. Requirements for the polymers are indicated in Table A.
Table A1 Requirements for Geogrid Polymers (All values are minimums unless indicated otherwise) Property Units Test Method PET HDPE PP Carboxyl End Group (CEG) Content of PET Yarns mmol/ kg ASTM D7409 < 30.0 N/A N/A Number Average Molecular Weight (Mn) of PET Yarns - ASTM D4603 25,000 N/A N/A Polymeric Coating Except for manufacturing selvedge edges, the polymeric coating for PET geogrids must be continuous with no more than 10% of the surface area having uncoated, unbound fiber bundles as determined according to ASTM D610 , 5.1 -5.3 and
5.5Procedure .4 N/A N/A
Carbon Black Content2 % ASTM D5596, ASTM D1603 or ASTM D4218 N/A 1.0 to 3. 5 1.0 to 3.5 Melt Flow Index g/10 min ASTM D1238 using Condition 190/2.16 for HDPE and Condition 230/2.16 for PP N/A 0.50 0.25 Density g/cm3 ASTM D792 or ASTM D1505 N/A 0.940 0.905 Resistance to UV Degradation3 % ASTM D4355 and ASTM D6637 (Method A or B) N/A 95 95 Notes:
maximum average roll value and Carbon Black Content which is a minimum and maximum average roll value range. The maximum average roll values are determined mathema tically similar to a MARV, except the values are the average plus two standard deviations.
tested to determine the Ultimate Tensile Strength (T U) in the machine direction (MD) for uniaxial geogrids and both the machine and cross machine directions (MD and XD) for biaxial geogrids. The value is calculated by dividing T U of the UV exposed material by the T U of the virgin material and multiplying by 100. T U of all samples are determined according to ASTM D6637, Method B. For biaxial geogrids the minimum required value must be met in both the MD and XD.
or unbound surface area.
738.2CLASS 1 UNIAXIAL GEOGRIDS—
stabilized earth (MSE) walls.