4.1 Clay mineral is a major functional component of GCL systems that reduces the hydraulic conductivity of industrial, waste, or ground water through the liner.

4.2 Clay mineral quality can vary significantly and affect the hydraulic conductivity of the GCL composite. This test method evaluates a significant property of clay mineral that relates to performance.

1.1 This test method covers an index method that enables the evaluation of swelling properties of a clay mineral in reagent water for estimation of its usefulness in geosynthetic clay liners (GCLs). This test method is not applicable for clays with polymers.

1.2 It is adapted from United States Pharmacopeia (USP-NF-XVII) test method for bentonite.

1.3 Powdered clay mineral is tested after drying to constant weight at 105 ± 5 °C; granular clay mineral should be ground to 100 % passing a 150-µm (No. 100) U.S. Standard Sieve with a minimum of 65 % passing a 75-µm (No. 200) U.S. Standard Sieve. The bentonite passing the 150-µm U.S. Standard Sieve is used for testing after drying to constant weight at 105 ± 5 °C.

1.4 The values stated in SI units are to be regarded as standard.

1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.