Study of the Behavior of Air Entrained Concrete Containing Mineral Admixtures with the Addition of Coal Bottom Ash

Abstract

With the addition of different pozzolanic cementitious materials, an air entrained concrete shows different behavior in terms of durability and compressive strength. The amount of entrapped air is reduced when fly Ash is used in air entrained concrete. The resulting volume of air decreased appreciably with increasing silica-fume content in air entrained concrete. This paper has focused on the effect of replacement of coal bottom ash (CBA) as a fine aggregate in the air entrained concrete in the presence of different pozzolanic cementitious materials and it compares the different properties with the normal concrete. Experimental work shows that CBA causes a reduction in 7 days compressive strength appreciably @ 50% natural fine aggregate (NFA) replacement in comparison to that at 25%. Beyond 7 days curing CBA starts acting as a Pozzolan and there is not much strength decrement in mixes with 50% NFA replacement. Also, this replacement level mitigate the effect of reduction in air entrainment caused by fine mineral admixtures in wet state thereby increasing the air entrainment capacity of concrete. Hence it was concluded that if we increase the content of Coal Bottom Ash up to 50% then it will be beneficial for air entrained concrete production.