An Experimental Study on Fly Ash Pellets in Concrete Replacing Coarse Aggregate

The quantity of fly ash produced from thermal power plants in India is approximately 80 million tons each year and its percentage utilization is less than 10%. During the last few years, some cement companies have started using fly ash in manufacturing cement, known as Pozzalanic Portland cement. It mainly concentrated on replacement of cement with fly ash but production of artificial aggregate with fly ash helps in utilizing large volume of fly ash in concrete. The world is much interested in this part recently due to this large scale utilization which also reduces environmental pollution and dwindling of natural resources. In this present investigation an attempt is made by partial replacing of coarse aggregate with fly ash pellets. For preparing fly ash pellets a ratio of 15:85 (cement: fly ash) is considered throughout investigation. The main objectives of the present work is focused on preparing light weight aggregates and to find optimum replacement of fly ash pellets and to identify the chemical compounds formed in different replacements (of fly ash pellets in coarse aggregate) by assessing the spatial variations in the chemical compositions which was done by using XRD studies. Based on the above mix ratio, fly ash aggregate are prepared and same aggregates were used for casting the cement concrete cubes, cylinders and same were tested for compressive strength at 3,7,28,60 and 90 days curing period and compared with Controlled concrete. Split tensile strength, Acid attack test also done and compared with the Controlled concrete. The results revealed that the compressive strength properties of concrete is increased significantly up to 20% replacement of fly ash aggregate and later on strength decreased for 30%, 40% replacements of fly ash aggregate.