Industrial waste-derived geopolymer materials with curing-controlled microstructure and strength development

Industrial waste-based geopolymer binders are promising for reducing Portland cement demand, but their mechanical performance is highly sensitive to curing conditions that govern reaction progress and pore structure evolution. This work examines how curing temperature, curing duration, and moisture environment regulate microstructure formation and strength development in geopolymer materials produced from industrial waste precursors. Geopolymer pastes and mortars are prepared with controlled mixture proportions and alkaline activation, then cured under systematically varied regimes. The evolution of solid reaction products, remaining unreacted particles, and pore network characteristics is evaluated using complementary microstructural observations and porosity assessment, while compressive strength is measured at multiple curing ages. The results demonstrate that higher curing temperatures promote rapid reaction and early densification, leading to accelerated strength gain; however, overly severe thermal curing can generate microcracks and coarsen pores, limiting later strength. Conversely, moderate curing supported by controlled moisture availability produces a more uniform binding matrix, reduced pore connectivity, and improved strength stability at later ages. The study clarifies the causal link between curing control, microstructure refinement, and mechanical performance, and provides actionable curing guidelines for converting industrial waste into reliable geopolymer construction materials.