Sustainable production of self-compacting concrete through valorization of industrial by-products: Mix design optimization, performance enhancement, and cost efficiency

The increasing demand for sustainable self-compacting concrete (SCC) requires innovative approaches to reduce cement consumption and natural aggregate depletion while maintaining superior fresh and mechanical properties. Although ground granulated blast furnace slag (GGBFS), limestone powder (LSP), and quarry dust (QD) each has been extensively investigated as concrete constituents, limited research has systematically evaluated the combined influence of GGBFS as a supplementary cementitious material, LSP, and QD as partial fine aggregate replacement materials in SCC. This study investigates the incorporation of GGBFS as a partial cement replacement together with LSP or QD as partial fine aggregate replacements to develop sustainable SCC with enhanced performance and reduced environmental impact. Ten SCC mixtures were prepared with 20% GGBFS replacing OPC and 10-20% LSP/QD replacing natural fine aggregates at a constant water-to-binder ratio of 0.45. The mixtures were evaluated through fresh property tests, hydration kinetics, compressive strength measurements, SEM-based microstructural analysis, and life cycle assessment (LCA). The results demonstrated that SCC mixtures incorporating a binary binder system and partial fine aggregate replacement with LSP or QD achieved improved fresh-state and mechanical performance due to enhanced particle packing. The incorporation of 20% GGBFS reduced superplasticizer demand by ∼18%, while optimized LSP/QD combinations improved flowability and passing ability. Although GGBFS reduced early-age strength because of delayed hydration, the ultra-fine LSP and QD compensated through filler and nucleation effects. Consequently, the optimized mixtures achieved 10-20% higher 90-day compressive strength than the control SCC. SEM analysis confirmed a denser microstructure with reduced calcium hydroxide and enhanced C-S-H gel formation. Additionally, the optimized SCC achieved approximately 14% reduction in material cost, 20% energy-related savings, and CO₂ reduction of about 133 kg/m³. Overall, the proposed SCC incorporating GGBFS, LSP, and QD provides a viable pathway for low-carbon, cost-effective, and sustainable construction.