Performance of Concrete Under Elevated Temperatures for Varying Composition of Fly Ash

Fly ash, a by-product generated by the combustion of coal has been broadly used in concrete applications over the last half century. Fly ash is typically used as either an addition or as a cement replacement. In this study the effect of variation in percentage of fly ash over the compressive strength and also the change in compressive strength for the same mixes of different grade of concrete (M20, M30, and M35) when exposed to different elevated temperatures was studied. Various percentages of fly ash are 20%, 30%, and 40% and the different intensities of temperature are taken as 600°C, 800°C, and 1000°C at which concrete cubes are tested for compressive strength. From the study it is concluded that the compressive strength of concrete reduces with the increase in fly ash content and as the exposure temperature of fire is increased the compressive strength of concrete decreases. However, the dip is comparatively less steep with fly ash content 20%-30% and the results of 20% are slightly better at 800°C.