Contribution to the study of an eco-sand concrete containing recycled sands from waste granite and recycled clinker

Abstract

The reuse of waste materials, particularly granite and undercooked or overcooked clinker, in sand concrete formulation is the focus of this study aimed at conserving natural resources and protecting the environment within the framework of sustainable development. To achieve this objective, we replaced ordinary sand with recycled sands in the sand concrete volume. Specifically, we incorporated granite waste (GS) and recycled clinker (CS) at rates of 20 and 40%. Subsequently, we conducted a series of evaluations on the different formulations. These evaluations included fresh state properties such as density, workability, and air content, as well as mechanical properties like compressive strength, flexural strength, rebound hammer, ultrasonic pulse velocity, modulus of elasticity, and X-ray diffraction (XRD). Additionally, we analyzed durability parameters such as water absorption, dimensional variation, freeze-thaw resistance, acid attacks, and chloride penetration on hardened concrete. We compared these results with reference samples and considered potential correlations among the different parameters. The results obtained showed improvements in workability, hardness, and homogeneity with enhancements in microstructure, with the best results obtained from SCC compared to the control concrete and SCG. The results of mechanical properties demonstrated that concretes containing recycled clinker sand are more resistant in compression and flexural strength compared to SC0 and SCG, with maximum strengths observed in concrete containing 40% recycled clinker at ages 7, 28, and 90 days. Durability parameters were acceptable with slight reductions in ultrasonic pulse velocity and modulus of elasticity after freeze-thaw cycles. A good correlation was observed among the various parameters.