This document summarizes an experimental investigation into partially replacing cement with fly ash and sand with quarry dust in concrete. Specifically, it examines replacing cement at 15%, 20%, and 25% with fly ash and replacing 40% of sand with quarry dust. The compressive strength of the concrete mixtures was tested at 7, 14, 21, and 28 days of curing. The results showed that replacing cement with 20% fly ash produced the highest compressive strength. Replacing cement with over 20% fly ash decreased the compressive strength. Thus, a partial replacement of up to 20% cement with fly ash can increase the compressive strength of concrete.