Unlocking the multi-mechanical properties of high-strength high-ductility engineered geopolymer composites incorporating waste glass powder as precursor

This study developed high-strength, high-ductility engineered geopolymer composites (EGC) using waste glass powder (WGP) as a green precursor, achieving high-value utilization of glass waste while expanding the low-carbon EGC system. WGP exhibited irregular particle morphology and contained abundant amorphous components, demonstrating both geopolymerization reactivity and filler effects. When WGP partially replaced moderate dosage of ground granulated blast-furnace slag (GGBS) and fly ash simultaneously, the resulting EGC developed a dense microstructure with enhanced micro-hardness, and elevating silicate modulus and alkali dosage further improved the micro-properties of WGP-EGC. The high-volume replacement of GGBS with WGP negatively impacted the EGC strength, while WGP substitution for fly ash exerted a positive effect. Combined replacement of both GGBS and fly ash with WGP produced WGP-EGC with comparable or better mechanical strengths than the reference EGC. Under a direct tensile loading, the uniaxial tensile performance initially improved and then declined as the WGP replacement ratio for either GGBS or fly ash increased, and the positive effect observed when WGP replaced fly ash was more significant than that when it replaced GGBS. When WGP replaced appropriate proportions of GGBS and fly ash simultaneously, the resulting WGP-EGC exhibited superior uniaxial tensile performance compared to the reference EGC. Increasing the silicate modulus and alkali dosage enhanced the WGP-EGC’s tensile stress and strain capacity, and concurrently increased the average crack width and number. The WGP-EGC prepared with 1.3 modulus and 9.0 % alkali dosage exhibited the best tensile performance, achieving a tensile stress of 12.9 MPa and a tensile strain of 8.5 %.