Partial Replacement of Cement by Coffee Husk Ash for C-25 Concrete Production

Concrete is a mixture of aggregates and binders. From concrete ingredients, the binder and the costliest and environmental-unfriendly element is cement, which is an ecological unsociable process due to the discharge of CO2 gas into the atmosphere and ecological degradation. Coffee husk (CH) has been considered as a category of agriculture by-product; as its quantity rises, the disposal of it is becoming an environmental problem. Hence, this study investigated the suitability of coffee husk ash (CHA) as a partial replacement for ordinary Portland cement (OPC) in conventional concrete production. Initially, CH samples were collected from different coffee treatment centres. The CHA was then ground and its chemical and physical properties were investigated using Atomic Absorption Spectrophotometer method. After that, the pastes containing OPC and CHA at different levels of replacement were investigated. For this purpose, six different concrete mixes with CHA replacement 0, 2, 3, 5, 10, and 15% of the OPC were prepared for 25MPa conventional concrete with water to cement ratio of 0.5 and 360 kg/m3 cement content. The results of the study show that, up to 10% replacement of OPC by CHA achieved advanced compressive strength at all test ages, i.e. 7, 14, and 28 days of age using compressive test machine.