Performance of Binary Cementitious Matrix Concrete Containing Coconut Shell Ash as Partial Replacement of Cement Under Aggressive Environment
1*Sanusi, A.M., 2Agboola, S.A.,3Musa, A. K., 4AbdulRaheem, A.A., 5Hanafi, A. A., 6Abdulsalam, R.A.
1Department of Building, University of Abuja, FCT, Nigeria
DOI: 10.36108/laujoces/6202.61.0151
Abstract
Magnesium sulphate attack is one of the major causes of durability deterioration in concrete structures due to the ingress of sulphate ions through interconnected pore networks. Leading to the formation of expansive compounds and progressive internal damage. This study investigates the performance of binary cementitious matrix concrete incorporating Coconut Shell Ash (CSA) as partial replacement of Ordinary Portland Cement (OPC) under aggressive sulphate exposure. CSA was used at 10% and 15% replacement levels after preliminary trial mixes. Concrete specimens were cured in 2.5% MgSO₄ solution to simulate a sulphate-rich environment, and compressive strength was evaluated up to 180 days. Sorptivity and water absorption tests were also conducted to assess durability characteristics. Results indicated that although CSA-blended concrete exhibited lower early-age compressive strength compared to the control, significant strength improvement was observed at later curing ages due to pozzolanic activity. At 180 days, the control sample recorded a strength loss of 17.7% under sulphate exposure, whereas 10% and 15% CSA replacements showed lower strength losses of 3.8% and 4.75%, respectively. Additionally, CSA incorporation reduced sorptivity and water absorption, indicating improved pore refinement and resistance to ingress of harmful agents. Among the mixtures tested, 10% CSA replacement demonstrated the best overall performance under prolonged sulphate exposure. The study concludes that CSA can effectively enhance sulphate resistance and durability of concrete, with 10% replacement recommended for structural applications in aggressive environments.
Keywords: Aggressive Environment, Coconut Shell Ash, Durability, Magnesium Sulphate, Sorptivity.