Strength and durability assessment of high-strength concrete with weathered crystalline rock waste as a sustainable partial replacement for fine aggregate

Sand mining from riverbeds has been a vital component of the construction industry for decades, providing a fundamental ingredient for concrete production. However, the indiscriminate extraction of sand from riverbeds led to serious environmental issues, like erosion of riverbeds, destruction of aquatic habitats and increased susceptibility to flooding which emphasizes the necessity of finding alternate materials. Recent studies on Weathered Crystalline Rock, a soft upper layer in quarries – often discarded as waste – have shown that WCR-sand could be a viable alternative to fine-aggregates in concrete thereby alleviating the environmental impacts caused by the extraction of natural resources. Five mixes of M65 grade concrete with sand replacement of 5%, 10%, 15% and 20% with WCR-sand were prepared, cured for maximum 90 days and tested for mechanical and durability properties. Results obtained led to the conclusion that WCR-sand can be a partial replacement up to 5% – theoretically and even up to 10% practically – of sand in concrete without affecting the mechanical and durability properties. This could potentially reduce sand-mining and rock-quarrying up-to 5 to 10% which not only helps curb the depletion of natural resources, a major environmental concern today, but aids in managing waste materials from quarrying.

Keywords:
Weathered crystalline rock sand; Mechanical properties; Durability properties; Waste material; Sand-mining and environment