Investigation into the Effect of Replacing Natural Sand by Normalized Crushed Sand on Concrete Performance

In the context of sustainable development and environmental protection, the current study aims to give scientific evidence of the feasibility of replacing natural siliceous sand with crushed limestone sand in concrete. It assesses the effect of this replacement by comparing concretes without natural sand to a reference mix incorporating natural sand. For fixed water-to-cement ratio, cement content, and coarse aggregates proportions, and for different dosages of admixture to reach the same slump, the results proved that the concrete containing natural sand required more admixture to reach the same slump value as the crushed limestone sand concrete. For the same workability, the compressive and flexural strengths were not affected by the total replacement of natural sand with crushed sand. The three types of concrete fell within the same range of durability even though scanning electron microscope (SEM) analysis seemed to reveal a better paste-fine aggregate interface for crushed sand concrete. The concrete properties could be maintained when using crushed limestone sand conforming to the standard grading requirements, as the only fine aggregate in concrete.