Performance Assessment and Carbon-Saving Potential of Rice Husk Ash and Cassava Peel Ash Blended Concrete in Obajana, Nigeria

Abstract

The increasing demand for environmentally friendly building materials has led to the investigation of pozzolanic admixtures as partial substitutes for conventional Portland cement. This study investigates the performance assessment of rice husk ash (RHA) and cassava peel ash (CPA) blended concrete. The experimental methodology involved the production of concrete specimens using 100 cm3 cubical moulds and 150*300 mm cylindrical moulds. A consistent mix proportion of 1:1:2 and a water-cement ratio of 0.55 were maintained. Chemical, physical, and mechanical evaluations were conducted to determine the suitability of the ashes as pozzolans, with the compressive strength, and split tensile strength assessments at varying replacement levels (3.5–14%). The results show that both RHA and CPA possess high silica and alumina contents, and satisfactory pozzolanic indices. The optimum compressive strength was attained at a 7% replacement level, yielding 35.45 N/mm² for RHA and 34.77 N/mm² for CPA. Concurrently, the corresponding split tensile strengths after a 28-day curing period were recorded as 4.02 N/mm² and 3.97 N/mm². These findings suggest that RHA and CPA can substantially enhance performance of concrete in demanding environments, thereby offering a sustainable alternative for the construction sector and facilitating progress towards a more ecologically sound built infrastructure.