Influence of Cement and Sand Replacement on Strength Properties of High-Volume Fly Ash Concrete

Fly ash, a waste product from coal combustion in thermal power plants, can be effectively reused in concrete to reduce disposal issues and construction costs. This study investigates the partial replacement of cement (40%, 50%, 60%) and sand (50%–90%) in a 1:1.5:3 concrete mix. Results show a decrease in compressive strength with higher fly ash content, making it suitable for low-load structural applications. Economic analysis was also conducted for the fly ash concrete mixes