SYMPOSIA PAPER Published: 01 January 2004

Quality Requirements for Bentonite in Geosynthetic Clay Liners and the Validity of Test Methods


GCLs are primarily used to seal against water, because its very low permeability property. This very good sealing performance is caused by bentonite as sealing material, which is interspersed between two geotextiles as an approximately 10 mm thin layer of powder or granulate. The objective of performance tests of new bentonites in GCLs, is primarily to investigate how low the water permeability of the bentonite is, after its processing into a pulverised or granulate form, as it is required for their use in GCLs. The production of a test GCL for the purpose of performance testing, is very costly. Mainly due to economical reasons, producers of bentonites and GCLs are anxious to be able to predict the permeability by use of simpler test methods. The laboratory tests for bentonites commonly applied are methylene blue test, the fluid loss test ASTM D 5891, and the swelling volume after ASTM D 5890. However, they are only to a limited extend suitable for this purpose. But even highly sophisticated mineralogical and chemical investigations like x-ray diffraction and ion distribution are not helpful to forecast the water permeability value in the produced GCL.

Author Information

von Maubeuge, K
Egloffstein, T
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Developed by Committee: D35
Pages: 11–28
DOI: 10.1520/STP12195S
ISBN-EB: 978-0-8031-5500-8
ISBN-13: 978-0-8031-3484-3