Effect of temperature and salt concentration of pore fluid on the behaviour of an expansive soil during drying and wetting cycles

Abstract

ABSTRACT A study was conducted on the effects of temperature and salt concentration of pore fluid on the properties of an expansive soil during drying and wetting cycles. The experimental tests were performed on modified and conventional odometers at constant and variable temperatures under 10 kPa surcharge pressure. Distilled water and solutions of sodium chloride and calcium chloride with concentration of 250 g/litre were used for making samples and distilled water was used for inundating samples during the wetting stage. The results showed that the swelling potential is decreased with increasing the number of cycles for both constant and variable temperature conditions. It was revealed that the potential of swelling is a function of salt concentration of pore fluid of the sample and the effect of temperature on the potential of shrinkage and swelling is negligible. The variation of void ratio with water content is dependent on the salt concentration of pore fluid and the position of void ratio-water content curve is a function of temperature. The results of scanning electron microscopy (SEM) tests showed that the structure of soil is changed during drying and wetting cycles which results in the reduction of potential of shrinkage and swelling.