Mechanical and durability performance of eco-friendly geopolymer-stabilized soil

This work compared the mechanical performance and the durability of clayey soil stabilized using mechanochemically activated geopolymer (MAG) with conventionally activated geopolymer (CAG). The effect of ground-granulated blast-furnace slag (GGBS) content on the long-term durability of geopolymer-stabilized soil has also been studied. The samples of geopolymer stabilized soils were immersed in 1% magnesium sulphate (MgSO4) solution for 60 and 120 days. The appearance, ultrasonic pulse velocity, unconfined compressive strength (UCS), and FTIR spectroscopy of those samples were considered to evaluate their sulphate erosion resistance. Before the exposure to the MgSO4 solution, the UCS of MAG samples was higher (12%–45%) than that of CAG-stabilized soil. Furthermore, the strength of the geopolymer-stabilized soil improved by 114%, 247%, and 361%, at 50%, 75%, and 100% GGBS content, respectively. After exposure to the MgSO4 solution, the results showed that the mechanochemically activated geopolymer-stabilized soil has better resistance to sulphate erosion than the conventionally activated geopolymer-stabilized soil. The residual UCS for MAG and CAG samples were 93% and 89% when exposed to 1% magnesium sulphate solution for 60 days, whereas they declined to 70% and 58%, respectively, after 120 days of immersion.