Performance of Concrete with Coconut Shell Ash and Retarder, Plasticiser and Super-Plasticiser for Sustainable Concrete Development
1 *Oriola, Q. O., 2Adeniran-Bakare S.M., and 3Adebayo, A. O..
1,2Department of Civil Engineering, Yaba College of Technology, Yaba, Lagos, Nigeria.
3Department of Civil Engineering, Ladoke Akintola University of Science and Technology, Ogbomoso, Oyo, Nigeria.
DOI: 10.36108/laujoces/6202.61.0211
Abstract
The increasing demand for sustainable construction materials necessitates the evaluation of alternative cementitious materials to improve concrete performance and environmental efficiency. This study investigated the utilization of coconut shell ash as partial cement replacement combined with chemical admixtures such as retarder, plasticiser and super-plasticiser dosage at 0.2%, 0.8% and 0.8% respectively by weight of cement to enhance concrete properties. Concrete materials including sand, granite, cement, and coconut shell ash at 10%,20% and 30% by weight of cement were characterized for moisture content, bulk density, and chemical composition. Mix proportioning of 1:2:4 was adopted, and 36 cubes were cast per mix using varying replacement levels. Fresh concrete properties were assessed through slump, compaction, and setting time tests, while hardened properties were evaluated through density, compressive strength, and soundness at 7, 14, and 28 days curing using standard laboratory equipment. Slump values ranged from 51–143 mm, compaction masses varied between 16.9–18.8 g, and setting times ranged from 220–390 min. Density values ranged from 2.32–2.52 kg/m³, compressive strength varied from 6.60–36.70 N/mm², and soundness ranged between 0.2–0.9 mm across all mixes and curing ages. Coconut shell ash up to 10% replacement improved overall performance, while higher percentages reduced strength. Chemical admixtures enhanced workability and stability, indicating CSA suitability for sustainable concrete development.
Keywords: Coconut shell ash, concrete properties, compressive strength, workability, chemical admixtures, pozzolanic material, sustainability