Experimental investigation on the stabilization of soft clay using granulated blast furnace slag

Abstract

Soft clay is associated with a soft consistency and poor shear strength. High percentage fines lead to higher liquid limit and lower plasticity index. Low bearing capacity and excessive settlement lead to uneconomic engineering structure constructed over it. There is a serious need to mitigate this problem and hence soil stabilization is the need of the hour. In the present study, Granulated Blast Furnace Slag (GBFS) which is an industrial waste/by-product of steel industry is used as a stabilizer to improve the geotechnical property of the soft clay. Soft clay is replaced by granulated blast furnace slag in various percentages by weight (10%, 20%, 30%, 40% and 50%) and examined for its plasticity, compaction and strength properties of the mix. From the experimental investigation, it is shown that the plasticity index decreases and unconfined compressive strength (UCS) increases upon addition of slag to the soil. With the curing age, UCS value increased indicating the chemical reaction between free lime and soil. 40% slag replacing the soft clay is recommended as stabilizer as it gave the maximum increase in UCS value compared to the rest mix. Based on the laboratory work, it can be concluded that granulated blast furnace slag can be used as a potential stabilizer for soft clay and also largely solves the problem of disposal of slag.