Bentonite grain expanding between sand grains - lms.epfl.ch/en
Sand/Bentonite mixtures are used in EBS for confinement of hazardous wastes. These mixtures offer good mechanical properties inherited by the sandy skeleton and reduced transport properties due to the presence of the bentonite. The picture shows a bentonite assemblage which is swelling - as a consequence of the first wetting of an engineered barrier - and occupying a large pore between two sand grains. Once swollen, the bentonite will reduce the initial water permeability of the mixture of about three orders of magnitude.
Swiss Federal Institute of Technology, EPFL
Laboratory for Soil Mechanics, LMS
EPFL-LMS, GC Station 18, CH 1015 Lausanne
Web page : lms.epfl.ch/en