Mutual Interaction between Cyclic Swelling-Shrinkage and Structure of Clays: Fid-Bau Portal

Mutual Interaction between Cyclic Swelling-Shrinkage and Structure of Clays

Oztoprak, Sadik / Sargin, Sinan / Ozkan, Mert

Swelling potential and swelling pressure of clays may either increase or decrease after multiple full-wetting and partial- or full-drying cycles. Therefore, it seems to be misleading to obtain the swelling potential and swelling pressure with one cycle of wetting. Previous research demonstrated that this change in the swelling behavior is generally accompanied with the structural changes caused from particle re-alignment. In this work, full drying-full wetting cyclic swell-shrink tests were carried out on 14 undisturbed and reconstituted samples of Istanbul Gurpinar clay. To understand the effect of initial structures and structural changes of the clay samples, SEM analyses were carried out at the end of the tests, and snapshots were taken after the each wetting and drying cycle. The swelling potentials either decreased or increased, and swelling pressures decreased for the same clay depending on the initial micro-structure. On the other hand, observed cracking and shrinking patterns of samples after drying cycles seem to be a useful indicator for defining the micro-structure. The results reveal that there is a mutual relationship between cyclic swelling-shrinkage and the structure of clays.