Synthesis of Bentonite Clay-Based Geopolymer and Its Application in the Treatment of Expansive Soil

Geopolymer technology is gaining a lot of interests in research and development because they act as a ‘versatile admixture’ for different purposes. The focus of the present work was: (1) To investigate the suitability of Bentonite soil for the synthesis of Geopolymer (2) To investigate the effect of Bentonite soil-based Geopolymer for potential improvement in swelling–shrinkage behaviour of expansive soil. The source material for Geopolymer synthesis was commercially available Bentonite cohesive soil. The presence of montmorillonite mineral causes high water absorption response and swelling–shrinkage behaviour, which makes it extremely difficult to use for civil engineering construction purposes. The critical soil parameters of Bentonite soil such as Liquid Limit (LL), Plastic Limit (PL), Differential Free Swell Index (DFSI), Plasticity index (PI) and Flow index (I<inf>f</inf>) were found to be very high (LL = 609%, PL = 51%, DFSI = 662%, PI = 558% and I<inf>f</inf> = 0.55) due to the presence of Montmorillonite mineral. Remarkable improvement in the properties was observed after treating Bentonite soil with 4% of synthesized Geopolymer. The sample was prepared on weight basis and were cured for a period of seven days, after the end of curing period the test was conducted. A drastic reduction in the studied parameter was observed, after the seventh day, the LL, PL, DFSI, PI and I<inf>f</inf> values were observed to be decreased; 509%, 40%, 329%, 469% and 0.28, respectively. Thus, the study revealed that Geopolymer can be effectively used for treating expansive soil.