Sustainable Utilization of Recycled Construction Sand in Structural Concrete: A Mechanical Performance Study

With the natural river sand rapidly becoming depleted, and being used in construction industry construction and demolition waste, a swift shift towards sustainable alternatives in the production phase of concrete needs to occur. The potential alternative to virgin fine aggregates will be recycled construction sand (RCS) which is available at Pimpri Chinchwad Municipal Corporation (PCMC) plant at crushing and sieving plant C&D waste. The aim of the research is to experimentally examine the mechanical properties of concrete with the partial substitution of recycled construction sand (RCS) for conventional river sand, focusing on compressive strength, split tensile strength, and flexural strength as the major outcome measures. Natural sand was substituted with RCS (recycled concrete sand) in different proportions to form mixtures of concrete. These samples were left to dry after 28 days under normal conditions and they were examined. The results indicated that an increase in the mixture's composition led to a reduction in the split tensile, flexural, and compressive strengths of the cubes. This decline can be attributed to the angular shape and high absorption qualities of recycled concrete sand (RCS), which weaken aggregate bonding. These findings suggest that using RCS to replace 20–30% of natural sand in structural concrete does not have a detrimental effect on the material's compressive strength. The increasing emphasis on sustainable development, which supports the concepts of recovery and reuse of building waste materials supplied by modern civilization, is the rationale for the introduction of recycled construction sand as a partial replacement of natural fine aggregate in concrete mixes.