Abstract:
Silicate cement exhibits prolonged setting time and low early strength, with significant strength gain occurring in later stages. While sulfoaluminate cement demonstrates rapid hardening and early strength advantages, its post-hardening strength growth remains limited. Optimizing silicoaluminate cement mix ratios enables complementary advantages of these materials. However, industrial solid wastes like blast furnace slag and fly ash, often discarded, pose environmental challenges. Blast furnace slag (classified as slow-cooling slag or sand-like water-quenched slag) serves as raw material for cement production and concrete aggregates. This study developed coal-based cement grouting materials using blast furnace slag as primary component and fly ash as supplementary material, employing silicate and sulfoaluminate cements as binders. The research evaluates mechanical and flow properties of different silicate-sulfoaluminate cement mix proportions. SEM analysis revealed C—A—S—H gel formation as the primary hydration product. Optimal reinforcement occurred when silicate-to-sulfoaluminate cement ratios are 2∶3, combined with blast furnace slag powder aggregates, fly ash, and C—S—H gel. Test specimens achieved 28-day compressive strength 18.63 MPa, flexural strength 4.77 MPa, slump 36.12cm, and setting time of 102 min, demonstrating superior performance. This research provides theoretical foundations for developing and applying coal-based cement grouting materials.