Abstract：Important attention has been devoted over recent ten years to the behaviour of highly compacted swelling clays that are considered as a possible component of engineered barriers for high activity nuclear waste isolation. Some experimental results obtained by running suction controlled experiments on compacted bentonites are interpreted in light of microstructure features. Water retention properties as well as transfer properties and swelling responses under suction changes are related to microscopic mechanisms. Some comments on the role of adsorbed cations are also made.
