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Self-compacting concrete (SCC) is an innovative concrete that has helped in overcoming challenges associated with vibrated concrete such as congested reinforcements, noise from vibrators, and cost of hiring vibrators. This research examined the bond strength between partially replaced Self Compacting Palm Kernel Shell (SCPKS) concrete and high yield reinforcing bars wherein the granite content of the concrete was replaced by 50% of palm kernel shell (total replacement disintegrated on removal of mould). SCPKS concrete specimens of mix ratios 1:2:4, 1:1.5:3 and 1:1:2 were produced and cured for 7 days, 21 days and 28 days at water to cement ratio (w/c) of 0.5 and 0.6 respectively. Flow, bond strength, and flexural tests were conducted on the samples. The highest bond strength was recorded for mix ratio 1:1:2 at w/c of 0.5 when tested at 28 days with a value of 5.56 N/mm2. This value is 0.072% higher than the 28th day strength of 5.52 N/mm2 for SCC without replacement of the granite content. Also, the highest flexural strength was recorded for mix ratio 1:1:2 at w/c of 0.5 when tested at 28 days with a value of 6.88 N/mm2. It was concluded that palm kernel shell can be safely used for partial replacement in SCC.

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Consideration on High Performance Concrete (HPC) has risen drastically because of the requirement for application of concrete volume with high strengths for construction work. In this study, the mechanical properties of HPC with Guinea Corn Husk Ash (GCHA) as supplement of cement was investigated. The proportioning of Ordinary Portland Cement (OPC) with GCHA is from 0 - 20%. Design of the concrete mix was done to achieve a characteristic strength of 50 N/mm². The chemical composition of the GCHA was determined using X-ray Fluorescence (XRF)  Slump and compacting factor of fresh HPC were determined. Concrete cubes (for compressive strength), beams (for flexural strength) and cylinder (for split tensile strength) samples were cast and cured in water for 7 - 56 days. Density, compressive, flexural, and split tensile strengths were determined on the hardened HPC and were further examined using SEM analysis. Compressive strength at 56 days showed that control and inclusion of 5% GCHA gave strength 56.85 N/mm2 and 57.76 N/mm2, respectively above the designed target strength of 56.56 N/mm2 while inclusion of 10% GCHA met characteristics strength of 50 N/mm2. However, 5% GCHA-concrete had the highest flexural and split tensile strengths at 56 days of curing. Integration of 10% GCHA as replacement of OPC would produce concrete of higher strengths compared to conventional HPC at longer curing age. Based on the SEM results, uniform distribution of filler was obtained at 10% GCHA inclusion. At higher percentage of GCHA, resulting composite presents multiple and distinct grains with possible weak interfaces.