The Combined Effect of Calcium Chloride and Cement on Expansive Soil Materials

In this study, the chemical stabilization of moderately to highly plastic expansive soil using calcium chloride with added cement is introduced as an effective alternative to the conventional approaches using a single additive such as lime, cement, or a by-product of industrial processes. Using only calcium chloride may lead to its leaching or dissolution over time, leaving a collapsing skeleton with weak bonds. The chemical effect produced by additives is dependent on the constituents of the stabilized soil and the curing period considered. Herein, calcium chloride concentrations of 2%, 4%, and 8% with the addition of 2% cement by dry weight of the soil were considered. The main objective of this study is to investigate the addition of a low amount of cement as a binder to improve the strength and durability of a chemically treated expansive soil. The engineering properties were investigated at 3 curing times: 3 days, 7 days, and 28 days. A laboratory investigation was carried out to investigate the effect of the addition of calcium chloride with cement on the swell potential, swell pressure, compression index, suction, and unconfined compressive strength. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) testing was conducted. The X-ray diffraction patterns were recorded to observe the mineralogy of the material. The results confirmed that calcium chloride with cement is very effective for stabilizing the expansive soil. A reduction in the swell potential by 8% and 25% and a reduction in swelling pressure by 28% and 37.4% were observed for 4% and 8% calcium chloride with cement addition. The compression index decreased with the increase in the calcium chloride content.