Flexural behaviour of reinforced concrete beam incorporating coal waste

Abstract

This research deals with the study of coal waste in concrete. In this study, the coarse and fine aggregates are completely replaced by coal bottom ash in blended cement concrete. The physical properties of concrete are investigated by using coal waste (fly ash and bottom ash). 30% of cement are replaced by fly ash as partial replacement of cement, 100% of the fine and coarse aggregates are replaced by the bottom ash. Before using the bottom ash as a replacement material of natural aggregates, the sieve analysis test is done on the bottom ash to determine the gradient curve of the aggregates. A number of tests are carried out to investigate the hardened and fresh state properties of concrete including slump, compressive strength and flexural behaviour of concrete beam tests. Test specimens with dimensions of 100x 100 x 100 mm are subjected to compressive strength test. In order to demonstrate the structural application of coal wastes, two reinforced concrete beams with dimensions of 2200 x 200 x 150 mm containing coal waste were casted and tested in flexure. The ultimate load, deflection upon loading, cracking history and mode of failure of the beams were investigated. From the sieve analysis result, it shows that the particles distribution of coal bottom ash used in this research did follow the overall limit of standard and can be used as aggregates replacement. The results showed that the fresh and hardened properties of the conventional and coal waste concrete beams are almost similar. For example, the difference in moment capacity between bottom ash concrete and conventional concrete is 0.017%.In addition, the results of the flexural performance of the reinforced concrete beams containing coal wastes indicated better stiffness with comparable ultimate load and mode of failure to the control beam. The overall results revealed that coal wastes can be used as cement and aggregates replacement materials in concrete for construction application.