Performance Evaluation of Mortar Incorporating Olivine Sand as a Partial Cement Replacement: Mechanical, Microstructural, and Durability Aspects

The construction industry’s environmental footprint, driven by Portland cement production’s high CO2 emissions, necessitates sustainable alternatives. This study explores olivine sand, a magnesium-iron silicate mineral, as a partial cement replacement in mortar cubes. Mortar mixtures with 5–30% olivine sand substitution were prepared, maintaining consistent workability. Olivine was characterized using XRF, XRD, SEM, and particle size analysis. Fresh properties (workability, setting time, density) and hardened properties (compressive/flexural strength, density, water absorption) were assessed at various curing ages. Microstructural analysis via SEM-EDS and XRD examined hydration products and interfacial transition zones. Results indicate olivine’s potential as a filler, with possible slow pozzolanic activity, influencing strength and durability. Statistical validation confirmed significant effects of replacement levels. Findings suggest optimal olivine incorporation ranges, contributing to sustainable cementitious materials and reduced clinker reliance.