Performance Evaluation and Life Cycle Assessment of Eco-Concrete Incorporation of MSR

With the rapid advancement of urbanization and growth in the construction industry, concrete has become one of the most widely demanded construction materials globally. However, the excessive exploitation of river sand has led to severe ecological degradation and environmental challenges. To address these issues, the replacement of sand with manufactured sand recycled (MSR) has been proposed. Five concrete mixes were prepared with MSR substitution rates of 0%, 25%, 50%, 75%, and 100%, and their workability, physical and mechanical properties, durability, and life-cycle carbon emissions were evaluated. The results indicate that the density of MSR concrete is comparable to that of conventional river sand concrete, with only a slight and manageable increase in water absorption. Compressive strength decreases as the MSR content rises, with a reduction of approximately 11.5% observed at full (100%) replacement. Durability tests reveal that both the capillary water absorption coefficient and chloride-ion migration coefficient increase noticeably with higher MSR levels; notably, the chloride diffusion coefficient increases by 54.1% at full replacement. When considering all performance aspects alongside environmental benefits, a 50% MSR replacement emerges as the optimal balance, maintaining strength and durability within acceptable limits while significantly lowering CO2 emissions and energy consumption compared to the reference mix. These findings demonstrate that MSR can effectively reduce environmental impacts associated with river sand extraction and serve as a viable alternative for sustainable construction. Future work should aim to optimize mix proportions near the 50% replacement mark, investigate the role of mineral admixtures or chemical additives in enhancing performance, and strengthen long-term durability monitoring. Practical application of 50% MSR concrete is recommended initially for projects with moderate strength requirements, with potential for higher replacement ratios as the technology advances.