Volume 1, Issue 2 (February 2004)
A Simple Compatibility Testing Protocol for Bentonite-Based Barrier Systems
This paper investigates macroscopically observable properties of bentonite. Bentonite slurries were prepared with varying pore water chemistry, using salt solutions for which compatibility problems have been shown. Using these samples, a rapid testing protocol was developed for evaluation of compatibility. Fann viscometer and filter press testing are well-established methods to examine bentonite quality and expected permeability of bentonite based barrier systems. This paper presents new research into the use of these simple tools to examine potential alteration or compatibility problems. Bentonite slurries made using the permeant of interest can be quickly evaluated for comparison with water-hydrated slurries. These results were confirmed with permeameter tests using GCLs. The permeability from the GCLs can be compared with the relative values inferred from the filter press and viscometer testing related to the double layer thickness. The authors believe that this work suggests that a few quick and simple tests can be done to evaluate potential compatibility issues with bentonite in natural form or in prefabricated geosynthetics. For industry, this will have the advantage of a very quick and cheap test that may be carried out to evaluate compatibility issues.