1.1 This test method covers the measurement of the low-strain (0-2.5 %) tensile response of geogrids by applying a force perpendicular to the initial plane of the sample. 1.2 As the geogrid deforms to a prescribed geometric shape that is essentially an arc of a sphere, formulations are provided to convert the test data to biaxial tensile stress-strain values. 1.3 In this test method, the geogrid is tested in conjunction with an impermeable membrane and the impermeable membrane is tested alone. The difference between the data from the two gives the response of the geogrid alone. 1.4 This test method requires a large-diameter sample to be tested, preferably 1 m, so that the dimension of a single aperture of the geogrid is not significant to the test. 1.5 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.6 This standard is a refinement of Test Method D5617 and equipment used for that test can be readily modified for this test. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
At present, there is no test method available to determine a common index value for the tensile performance of geogrids and geotextiles manufactured with different alignments of their constituent tensile elements, for example, geogrids with two sets of tensile elements and square apertures and geogrids with three sets of tensile elements and triangular apertures. Index values of multi-axial load at a low strain (2 %) will be used by government agencies and other specifiers in material specifications to aid free choice of material irrespective of the arrangement of its tensile elements.
Keywordsdeformation; geosynthetics; multi-axial; omni-axial; tension; low strain
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
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