To meet the ever increasing demand of electricity, Thermal Power Plants (TPPs) are being set up all over the world, thereby resulting into more consumption of the coal in these plants. The disposal of ash derived from combustion has become a major issue now-a-days. The study of Fly Ash, as it is called, has found that it can be used in various civil engineering applications such as bricks and concrete making. This paper reviews the utilisation of Fly Ash as the admixture in partial replacement of ordinary Portland cement to upto 35%, and even more upto 50% in High- Volume Fly Ash (HVFA) concrete which reduces the water demand, improves the workability, minimizes cracking due to thermal and drying shrinkage, and enhances durability to reinforcement corrosion, sulphate attack, and alkali-silica expansion. This admixing proves to be a best filler material which also reduce overall cost of construction and act as an eco-friendly material.