Assessment of the Strength Properties of Biu Soil Concrete Incorporating Rice Husk Ash and Soybean Hull Ash

This study assessed the strength properties of Biu soil concrete incorporating rice husk ash (RHA), and soybean hull ash (SBHA) as partial replacement of cement. The aim was to evaluate the potential of these locally available materials in improving the performance of the soil and to produce a sustainable concrete suitable for structural applications in Biu Borno State. The study adopted a 1:2:4 mix ratio and 0.5 water-cement ratio, with RHA and SBHA combined at a constant 20% replacement levels across various mix compositions. Experimental tests conducted included chemical composition analysis, compressive and flexural strength tests at 3, 7, and 28 days of curing. Results showed that RHA and SBHA met the ASTM C595 pozzolanic standard with over 80% combined oxide content. Strength performance improved significantly in mixes BSC-03 and BSC-04, with BSC-04 achieving 21.74 N/mm² (compressive) and 4.53 N/mm² (flexural) at 28 days. The study concludes that up to 20% replacement is optimal and does not compromise structural integrity. It recommends further research on durability and large-scale implementation to support sustainable construction in Biu – Borno State, Nigeria.