Sustainable concrete production using toxic foundry sand and its subsequent effect on water contamination

Amid growing concerns about diminishing river sand resources and escalating environmental apprehensions related to toxic landfill waste, this study explores the potential of Toxic Foundry Sand (TFS) as a substitute for Standard Fine Aggregate (SFA) in concrete production. The investigation into various TFS replacement ratios in M20 concrete focuses on their impact on workability and compressive strength. Although TFS exhibits properties similar to fine aggregate, making it a promising candidate for partial replacement, differences in bulk density and fineness modulus compared to river sand suggest that TFS should be utilized as a partial replacement only. The study proposes an optimal replacement ratio of 30 % TFS and 70 % SFA to achieve satisfactory compressive strength in M20 concrete. The workability of fresh concrete remains unaffected in both nominal and 70:30 mixes, ensuring ease of mixing on the job site. As an innovative aspect, the study includes testing the water exposed to TFS-infused concrete for portability. Prolonged exposure to water on TFS-infused concrete (70:30 mix) raises concerns, as certain parameters such as chloride and hardness exceed acceptable limits. Therefore, careful control and treatment of Toxic Foundry Sand Contact Water (TFSCW) are deemed crucial on job sites to address potential water quality issues and ensure overall environmental safety.