Treatment of Collapsible Soils by Additions of Granulated Slag and Natural Pozzolan

The study of collapsible soils, due to flooding, is a major problem in soil mechanics. The majority of researches carried out regarding this type of soil have been devoted to their identification, collapse mechanisms and treatments using salts, hydraulic binders and glass fibers. However, little research has been reported on their improvements using industrial waste (e.g., slag) or natural materials (e.g., pozzolan) in order to meet environmental and socio-economic challenges. In this work, a series of tests were conducted to examine the effect of adding granulated slag and natural pozzolan, at different contents, on the suction and the collapse potential (Cp) of a soil reconstituted in the laboratory, and having a behavior similar to natural and undisturbed soils. The obtained results showed clearly that treated collapsible soils with granulated slag and natural pozzolan, lead to a significant reduction in the collapse potential (Cp) followed by a decrease of suction. Furthermore, SEM/EDAX analysis conducted on the same samples revealed that the soil pores were filled with these two materials particles and as a result a significant improvement of the physical and mechanical characteristics of the soil was noted.