Stabilisation of expansive clay bed using calcium chloride solution

Abstract

moisture fluctuation because of their intrinsic mineralogical behaviour. As these volumetric changes threaten the stability of almost all lightly loaded structures, various remedial techniques have been developed to reduce the damage they cause. Among these measures, chemical stabilisation using multivalent cations is aimed at altering the chemical environment around the clay particles upon which the behaviour of clay depends to a great extent. In the present work, an attempt is made to study the efficacy of calcium chloride (CaCl2), a strong electrolyte, on the plasticity and swell characteristics of an expansive clay bed. One per cent CaCl2 solution was applied to the expansive clay bed by ponding and also through boreholes. The relative influences of lime and calcium chloride on the properties of the clay bed are brought out by using data from a previous study of lime piles on an adjacent site. The plasticity index of the clay bed is decreased by 7– 15% and 40–60% with lime and calcium chloride treatments respectively. Similarly, the swell pressure of the clay is decreased by 20–25% and 50–65% respectively. From this study, it is revealed that the modification of clay properties with calcium chloride is several times greater than that for the conventionally used lime