1.1 This test method covers performance tests applicable for determining the compatibility of geotextiles with various types of water-saturated soils under unidirectional flow conditions.
1.2 Two evaluation methods may be used to investigate soil – geotextile filtration behavior, depending on the soil type:
1.2.1 For soils with a plasticity index lower than 5, the systems compatibility shall be evaluated per this standard.
1.2.2 For soils with a plasticity index of 5 or more, it is recommended to use ASTM D5567 (‘HCR’, Hydraulic Conductivity Ratio) instead of this test method.
1.2.3 If the plasticity index of the soil is close to 5, the involved parties shall agree on the selection of the appropriate method prior to conducting the test. This task may require comparison of the permeability of the soil-geotextile system to the detection limits of the HCR and Gradient Ratio Test (GRT) test apparatus being used.
1.3 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only.
1.4 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.