Potential Use of Recycled Foundry Sand as Fine Aggregate in Self-Compacting Concrete: Sustainable Engineering Research

This research aims to identify an eco-friendly and low-mass substitute for fine aggregate (FA) in self-compacting concrete (SCC). The study specifically examines the potential of waste foundry sand (WFS) as an FA replacement. The primary objective is to explore the impact of processed WFS in SCC, addressing both the WFS disposal issues and enhancing the environmental performance of SCC. After collecting the WFS, it was sieved, segregated, washed thoroughly with water, and then oven dried to remove all clay, carbon, and hazardous content. Treated foundry sand (TFS) is utilized as a substitute for FA in SCC. This study examines the effects of TFS on SCC’s strength, flowability, durability, and microstructural characteristics. Various proportions of TFS are investigated, including replacing 0, 10, 20, 30, 40, and 50% of FA by weight with TFS in the concrete mixture. This research demonstrates that TFS can effectively replace FA in improving the flowability and passing ability of SCC. Furthermore, the findings on SCC’s strength and durability after incorporating TFS suggest that using 30–40% TFS is optimal, as it does not negatively impact the structural performance of SCC. Alternatively, the use of TFS in SCC results in a dense microstructure, improved gel formation, and better bonding of the constituents of ingredients used in SCC. Overall, the results of this study reveal that the use of TFS in SCC can help reduce the amount of waste and improve its sustainability. This also shows that the process can reduce the density of the mix.