EXPERIMENTAL STUDY

This study investigated the effect of partially replacing Ordinary Portland Cement (OPC) with eggshell powder (ESP) in concrete production as a sustainable approach to reduce cement consumption and utilize agricultural waste. The aim of the study was to evaluate the performance of concrete containing eggshell powder as a partial replacement for cement. The specific objectives were to determine the workability of concrete containing varying proportions of ESP, evaluate its compressive strength, assess its water absorption capacity as an indicator of durability, and identify the optimal ESP replacement level that yields the best concrete performance. The experimental study was conducted by preparing concrete mixes with 0%, 5%, 10%, 15%, and 20% replacement of cement with eggshell powder. Waste eggshells were collected, cleaned, dried, ground into fine powder, and sieved before use. Concrete cubes were cast and cured in water, after which several laboratory tests were performed. Workability of the fresh concrete was determined using the slump test, compressive strength was measured at 7, 14, and 28 days using a compression testing machine, and water absorption tests were carried out at 28 days to evaluate the durability-related properties of the hardened concrete.The results showed that workability slightly increased at 5% ESP replacement, indicating improved particle packing within the mix, but gradually decreased at higher replacement levels due to increased water demand of the fine ESP particles. The compressive strength of the concrete improved at moderate replacement levels, with the optimum strength obtained at 15% ESP replacement after 28 days of curing, while further increase in ESP content led to a reduction in strength. The water absorption values for all concrete mixes were below 10%, indicating that the inclusion of ESP did not adversely affect the durability of the concrete. Based on the findings, the study concluded that eggshell powder can effectively replace cement up to 15% without significantly compromising the essential properties of concrete. It is therefore recommended that ESP be considered as a sustainable partial cement replacement material in concrete production, particularly for applications such as pavements, floor screeds, and foundations, where environmentally friendly and cost-effective construction materials are desirable