Durability assessment of clay soils stabilised with geopolymers based on recycled glass powder in various corrosive environments

Ordinary Portland cement (OPC) is commonly used for soil stabilisation in construction; however, its significant environmental impact makes long-term reliance undesirable. This research evaluates geopolymer cement derived from recycled glass powder (RGP) as a sustainable alternative for stabilising low-plasticity silt soil (ML). Each geopolymer mixture contained a fixed RGP content of 15 %wt, activated with calcium-carbide residue (CCR) at 7, 10, and 13 %wt dosages. Control specimens were stabilised with OPC at 5 %wt and 10 %wt. After 28 days of ambient curing, specimens underwent exposure for 3 and 30 days to air-drying (AD), tap water (TW), municipal wastewater (WW), seawater (SW), gasoline (GA), and 1 M hydrochloric acid (AC) to assess their impacts on unconfined compressive strength (UCS) and microstructure. Results indicate that geopolymer formulations significantly enhance strength and durability compared to OPC-treated soils. Under AD conditions, geopolymer-stabilised samples demonstrated UCS improvements of up to 1150 % relative to untreated soil and 25 % greater than OPC-treated samples. Durability assessments revealed superior resistance in geopolymer mixtures; geopolymer specimens exposed to gasoline for 30 days exhibited an approximate 235 % strength increase, whereas OPC-treated samples experienced strength reductions. Microstructural analyses supported these findings, indicating a denser matrix with reduced pore connectivity in geopolymer-treated samples. This study demonstrates that geopolymer cement using recycled glass powder activated by CCR offers a high-performance, environmentally friendly alternative to OPC for stabilising soils under aggressive environmental conditions, significantly reducing carbon footprints associated with traditional stabilisation methods.