This study seeks to determine the suitability and potential use of quarry dust in concrete as a partial replacement of river sand and come up with an optimum mix. Concrete mixes bearing varying proportions of quarry dust and river sand will be cast and tested, and that which bears the proportion yielding the maximum compressive and tensile strength shall be selected as the ratio for the optimum mix. This is with the aim of making use of an abundant waste material to replace river sand, so as to reduce the cost of concrete production and control environmental pollution brought about by sand quarrying.