EXPERIMENTAL EVALUATION OF STRENGTH DEVELOPMENT IN HIGH PLASTICITY CLAY STABILIZED WITH GGBS-BASED ALKALI-ACTIVATED BINDER UNDER VARYING NaOH MOLARITIES

Abstract

The clayey soil experiences swelling and shrinking properties because of the change in moisture content, which affects the soil’s load-bearing capacity and the stability of the foundations. This article aims to evaluate the geopolymer stabilisation method of clayey soil, which utilises Ground Granulated Blast Furnace Slag (GGBS) activated with sodium hydroxide (NaOH) as an alternative to conventional binders. The soil specimens were subjected to 6%, 12%, and 18% GGBS, based on the dry weight of the soil, and activated with 8 M and 12 M NaOH solutions at an alkali-to-binder ratio of 0.5. Three specimens were prepared for each mixture, and the average unconfined compressive strength (UCS) was obtained at curing ages of 0, 7, and 28 days. The UCS of untreated soil was 160.5 kPa. Stabilised soil samples indicated that there was an improvement in terms of strength compared to natural soil. For 6% GGBS soil samples cured for 28 days, there was an increase of 21.5%, and for 12% GGBS samples cured for 28 days, there was a 429% increase. For 18% GGBS samples cured for 28 days, it indicated the highest UCS of 2543 kPa with a 1484% improvement compared to untreated soil samples cured with 12 M NaOH solution. From the above-mentioned results, it is concluded that GGBS-based geopolymer stabilisation is used to improve the strength of clayey soil and is considered a green technology for soil stabilisation using industrial wastes.