A study on the effect of the salt content on the solidification of sulfate saline soil solidified with an alkali-activated geopolymer

Abstract

The salt content has a significant effect on the hydration reactions of alkali-activated geopolymers, thereby influencing the curing effect. The main objective of this paper is to study the changes that occur in the mechanical properties of sulfate saline soil solidified with an alkali-activated geopolymer due to varying the sulfate salt content. Sodium silicate, lime-fly ash, and the combination of lime-fly ash and sodium silicate were selected to solidify sulfate saline soils with different salt contents. An unconfined compressive strength test was conducted to study the variation in the compressive strength of the solidified soil at different salt contents. Moreover, the consistency characteristics, phase characteristics, chemical composition and microstructure of the solidified soil were evaluated. The results showed that as the salt content increased, the unconfined compressive strength of the three curing agents first increased and then decreased. Additionally, the peak strength occurred at a salt content of approximately 1.8%. Analyses of the phase characteristics, chemical composition and microstructure of the solidified soil indicated that the influence of the salt content on curing is reflected by changes in the cement chemical composition and the pore structure.