EFFECT OF COCONUT SHELL ASH AS A PARTIAL REPLACEMENT FOR PORTLAND CEMENT IN COMPRESSIVE STRENGTH AND WORKABILITY OF CONCRETE

Abstract

The cost of cement used in concrete works is on the increase and unaffordable, yet the need for housing and other constructions requiring this material keeps growing with increasing population. The environmental impact of Portland cement is significant because its production emits large amounts of COâ‚‚. Utilization of industrial waste or secondary materials has been encouraged in construction field for the production of cement and concrete because it contributes for reducing the consumption of natural raw materials as resources. The volume of wastes generated in the world has increased over the years due to increase in population, socioeconomic activities and social development. One of the most attractive options of managing such waste is to look into the possibility of waste minimization and reuse. Agricultural waste material, in this case, coconut shells, which is an environmental pollutant, are collected and burnt in the open air (uncontrolled combustion), which in turn was used as pozzolana in partial replacement levels of 0, 5, 10, and 15 % of Ordinary Portland Cement with coconut shell ash. A total of 32 cubes were produced and cured by immersing them in water for 7, 14, 21 and 28 days respectively. Properties such as compressive strength and workability were determined. From the tests conducted and the tests results recorded, the data analysisshowed improvement in both compressive strength and workability of concrete with addition of coconut shell ash after 28 days. Addition of ash contributes to strength increase but only up to a certain amount of ash content.