Stabilization of Indian peat using alkali-activated ground granulated blast furnace slag

Abstract

Peat is an exceptionally problematic soil for construction purposes and is often stabilized by traditional stabilizers (like cement), which emits 0.95-ton carbon dioxide (CO2) per ton of cement during their production. Alkali-activated ground granulated blast furnace slag (GGBS) with its low carbon dioxide (approximately 0.07-ton CO2) emissions and higher strength gain provides a promising substitute to traditional stabilizers. Therefore, this study presents the viability of alkali-activated GGBS-stabilized Indian peat. The three types of peats (sapric, fibric, and hemic) were collected to cover a wide range of variations of fibre (6–73%) and organic content (21–79%). The sodium hydroxide (NaOH) molarities (M) of 6, 9, 12, and 15 were used to activate specimens, with GGBS percentages of 10, 20, and 30% by weight of dry peat and alkali/binder ratios of 0.5, 0.7, and 0.9. The test results show that the UCS of peat-GGBS depends on the molarity of NaOH, A/B, electrical conductivity (EC), pH, curing period, and organic content of the peat-GGBS matrix. The optimum combination for the peat-GGBS blend is 20% GGBS, NaOH molarity of 9, and A/B ratio of 0.7. Furthermore, it was found that UCS increases with the curing period and decreases with organic content (OC). The formation of aluminium silicate, sodium aluminosilicate, and potassium aluminosilicate responsible for strength gain is confirmed by XRD. The FESEM micrographs reveal that these products result in the filling of pore spaces to form a smooth and dense soil-binder matrix.