Properties of Concrete Incorporating Coal Fly Ash and Coal Bottom Ash

Abstract

Million loads of coal wastes are being generated everywhere across the globe in the form of fly ash and bottom ash. Utilization of such waste materials in concrete is an eco-friendly choice. Therefore, the objective of the current experimental investigation is to explore the effects of fly ash and bottom ash on the properties of concrete by replacing them partially with natural fine aggregate and cement, respectively, on an individual basis as well as on combined basis. Concrete specimens are prepared by replacing 0%, 20%, 30%, 40% and 50% of sand by coal bottom ash and 0%, 20%, 30%, 40% and 50% cement by coal fly ash. Thereafter, the concrete specimens are prepared by replacing optimum percentages of both cement and sand by coal fly ash and coal bottom ash, respectively. The compressive strength, split tensile strength, flexural strength and density of the above mixes are obtained from the experimental investigation. From these results, it is found that for concrete mix with 20% coal fly ash and 30% coal bottom ash, the compressive, split tensile and flexural strength reduce by 10.5%, 10.7% and 9.6%, respectively, with reference to those of the control mix. Moreover, for the above concrete mix, the dry density also reduces by 10.3% from the control mix. These properties of the concrete mix with 20% coal fly ash and 30% coal bottom ash are further improved by adding a suitable dose of superplasticizer.