SUMMARY
Infrastructural development across the world is fast growing due to the rapid growth in population. This has resulted in consequently creating an increase in the demand for construction materials, especially cement. This study presents a report of a concise investigation on the pozzolanic potentials of Pulverized Coconut Shell (PCS), Periwinkle Shell (PPS) and Palm Kernel Shell (PPKS). The chemical composition of the PCS, PPS and PPKS, physical properties of concrete constituents and mechanical properties of the pozzolans blended concrete were determined. A concrete mix ratio of 1 : 2 : 4 with a w/c of 0.6 was adopted. A total of 270 cubes and 120 cylinders were cast at an interval of 10% from 0% to 50% replacement level and cured in water for 7, 14, 21 and 28 days. Results indicate that the PCS, PPS and PPKS are good retarders as they increased the setting time of cement paste and decreased the workability of concrete as the percentage replacement increased. The addition of the PCS in the mix produced a concrete of lower density while the addition of the PPS and PPKS produced a concrete of a higher density up to a 30% replacement level, further increase resulted to a decrease in density. The compressive and tensile strengths increased with a curing age but decreased with an increasing percentage replacement level for the three pozzolans investigated. However, 10% replacement level of the PCS, PPS and PPKS in concrete is suitable for the production of pozzolans blended concrete for structural works. The models developed are in a good agreement with the experimental results.