Sustainable Concrete Production Using Quarry Dust and Ceramic Waste as Sand Replacements

Natural river sand constraints motivate the use of sustainable alternative fine aggregates in concrete production. This study investigates partially replacing natural sand with quarry dust (QD), ceramic waste (CW), and their combination at 0% to 50% levels. Fresh and hardened properties were evaluated through slump, 7-day and 28-day compressive strength, water absorption, and steady-state thermal conductivity across all modification streams. Ceramic-only mixes achieved the highest compressive strengths, reaching 55.13 MPa at 50% replacement due to intensive angular particle interlocking visible at 7 days, though water absorption increased significantly. QD mixes provided the best durability performance, reducing water absorption to 2.01–2.39% while maintaining near-control strength at 40% replacement. Hybrid mixes showed no consistent synergistic benefits. Comprehensive thermal conductivity profiling revealed significant heat transfer reductions; the QD series achieved optimum insulation at 20% replacement (27.3% lower than control), while ceramic-only mixes displayed a progressive decline down to 0.5256 W/m·K at 40% substitution. Overall, QD at 40% offered the best structural–durability balance, while ceramic waste configurations proved highly effective for specialized applications requiring high mechanical strength combined with enhanced thermal isolation.