Water permeability of concrete containing coal bottom ash as partial replacement of sand and cement with different grinding time

Coal Bottom Ash (CBA) is the hazardous waste that potential threats to people health and the environment. The increasing production of CBA need to find new alternative to use this material so that method exposed to landfill is prevented and could reduce the bad effect to environmental. Therefore, this paper presents an experimental investigation on the effect of CBA as sand and cements replacement on compressive strength and water permeability of concrete. For the optimum content for cement replacement, CBA was ground into three different grinding times as 20, 30, and 40 hours where the replacement levels are 10%, 20%, and 30%. Meanwhile, for the optimum content for sand replacement are 5%, 10%, 15% and 20. All the specimens were cured for 7 and 28 days. The result shows that at 20% replacement level of CBA in 30 hours grinding time has potential for cement replacement, whereas 15% replacement of CBA was the optimum for sand replacement. However, it was found that the strength of the combination of both optimum cement and optimum sand replacement with CBA shows the lowest strength. Besides that, there was an increment in water permeability test.