An evaluation of the effects of Corncob Ash on the Properties of Concrete
1,*Ibrahim, A. G., 1Mako, M., 1Gambo, S., 2Mu’azu, U. and 1Usman, J.
1,Department of Building, Faculty of Environmental Design, Ahmadu Bello University, Zaria-Nigeria
2,Department of Building, Federal Polytechnic, Kauran Namoda, Zamfara State, Nigeria
DOI: 10.36108/laujoces/5202.41.0101
Abstract
Cement is the most energy-intensive and expensive material in concrete production. However, energy efficient and cost-effective concrete could be achieved using Supplementary Cementitious Materials (SCMs), which require less heating and emit less CO2. The research evaluated the effects of corncob ash (CCA) as a partial replacement of cement on the properties of concrete. A grade 20 N/mm2 concrete was produced using the Department of Environment (DoE) method of concrete mix design which served as control and another concrete was produced by partially replacing the cement content in the concrete with 5, 10 and 15% corncob ash. The concrete properties were evaluated for workability at the fresh stage while the compressive strength was assessed at 3-, 7-, 14- and 28-days curing periods. The specimens were characterized using scanning electron microscopy (SEM-EDX) and Fourier Transform Infrared Spectroscopy (FTIR). Result shows decrease in slump value and increase in compressive strength with increase in the percentage of corncob ash. Samples with 5% corncob exhibited similar compressive strength (20.57 N/mm2) compare to the control (20.87 N/mm2) at 28 days of curing, as confirmed by SEM-EDX images and FTIR result. The addition of CCA leads to increase in water absorption. Therefore, corncob ash can be used to replace up to 15% cement in concrete production, and where higher compressive strength is required, 5 % replacement is recommended.
Keywords: Concrete, Corncob ash, C-S-H, SEM-EDX, FTIR