The document experimentally investigates partially replacing sand with marble dust in concrete mixes. Five concrete mixes were prepared with 0%, 5%, 10%, 15%, and 20% sand replaced by marble dust by weight. Cubes were tested to determine the compressive strength at 7 and 28 days. The 10% replacement mix achieved the highest compressive strength at 28 days, while the 15% replacement mix achieved the highest bond strength. In general, strengths increased up to 15% replacement, then decreased with further replacement. The study aims to utilize an industrial waste product, marble dust, to potentially reduce costs while maintaining strength in concrete.