Utilization of quartz quarry dust as a sustainable partial sand replacement in cement mortar

The construction industry’s reliance on natural sand has caused environmental degradation and resource depletion. This study investigates quartz quarry dust (QQD) an abundant by-product of quartz mining, as a partial replacement for fine aggregates in cement mortar. Mortar mixes with 0–20% QQD replacement were evaluated for workability, bulk density, water absorption, and compressive strength. Results show that 10% QQD replacement optimizes performance increasing 28-day compressive strength from 10.8 MPa to 18.5 MPa and reducing water absorption from 6.4% to 5.7%. Higher replacement levels reduced strength and workability due to increased particle angularity and void formation. SEM and XRD analyses confirmed the high silica content and crystalline quartz structure of QQD, supporting its physical and chemical stability in the cement matrix. The findings demonstrate that QQD is a sustainable, mechanically compatible, and environmentally beneficial partial sand substitute. Incorporating QQD can reduce natural sand consumption, valorize quarry waste, and support greener construction practices, with 10% replacement providing an optimal balance of strength, water absorption, bulk density and workability of cement mortar.