This document summarizes research on utilizing industrial by-products like pond ash as a partial replacement for sand in concrete. Pond ash is a by-product generated in large quantities by thermal power plants, and disposing of it poses challenges. The research involved casting concrete cubes with 0-50% sand replaced by pond ash. Compressive strengths were tested at 7 and 28 days. 10-20% replacements increased strength while higher replacements reduced it. Microstructural analysis using SEM imaging showed improved calcium silicate hydrate gel formation and reduced voids for 10-20% replacements, explaining the strength improvements. The research demonstrated the feasibility of using pond ash to partially replace sand in concrete production.