Chemo-mechanical effects in kaolinite. Part 1: prepared samples

The results of laboratory tests on chemo-mechanical interactions in kaolinite samples prepared with inorganic, salt, acid and base solutions are presented. In particular, the effects of the different solutions on the liquid limit, one-dimensional compressibility, permeability and residual shear strength are considered. Kaolinite proves relatively insensitive to salt solutions, whereas variations in pore fluid pH cause large strength changes, associated with non-negligible changes in one-dimensional compressibility. The partly inconsistent effects induced by acids and bases on the residual shear strength and on the one-dimensional compressibility do not permit any easy interpretation of the experimental evidence. Mineral dissolution and the associated formation of new compounds are probably involved in the behaviour observed. These aspects will be investigated in part 2 of this paper.