Micro-fabric transformation of Taleqan white clay under constant volume swelling condition

Abstract

Expansiveness has been widely discussed for a long time. The stress deformation response of swelling soils is intimately associated with several factors including clay mineralogy, soil fabric, and geochemistry of the pore fluid. What presently is lacking is research on the changes of micro-fabric due to the swelling volume changes. As a basis for tackling the swelling problem, we need a better understanding of the swelling mechanism at the micro-scale, and we need to engage with the micro-fabric transformation which is a gap in the knowledge. To explore the swelling-induced changes in particles' geometric arrangement, a series of constant volume (CV) swelling tests (ASTM D-4546) were performed on clay specimens of wide range of plasticity. Pre- and post-swelled specimens were scanned and snapshot at low magnifications (250×, 500×) in ‘General’ fabric level and medium magnifications (1000×, 2000×) in ‘intermediate’ fabric level.