The role of structure in the chemically induced deformations of FEBEX bentonite

Abstract The paper presents the experimental results of an investigation aimed at understanding the role played by the soil structure in the evolution of chemo-mechanical-coupled processes in bentonite. The objective was pursued by subjecting samples with different structures to similar salinisation–desalinisation cycles. Samples were prepared at approximately the same void ratio by means of either static compaction at hygroscopic humidity or starting from slurries consolidated under mechanical loads. The investigation was carried out both from a macroscopic point of view (measuring the induced deformations) and from a microscopic point of view (ESEM analysis, mercury intrusion porosimetry). It is evidenced how the behaviour of the compacted samples differs from the one in the consolidated samples, especially as far as the evolution in time of the deformations is considered. An attempt to explain the differences by means of structural considerations is then provided.