Assessment of Embodied Energy and Carbon IV Oxide Emission of Concrete Containing Corncob Ash

Abstract

The purpose of this study is to assess the Embodied Energy (EE) and Carbon IV Oxide (CO₂) emissions saving potentials of Corn Cob Ash (CCA) as partial replacement of Ordinary Portland Cement (OPC) in concrete. Cement manufacture is energy intensive and contributes considerable amount of CO₂ emissions into the atmosphere. Globally, Concrete is the most consumed man-made material and about 95% of CO₂ emissions from a cubic meter of concrete are from cement manufacturing. In this study, the experimental plan was designed to carry out compressive strength, flexural strength, density and water absorption tests on the concrete using 0, 5, 10, 15 and 20% CCA contents to replace OPC. Inventory method of analysis was used to determine the EE and CO₂ emission for all the concrete mixes. The results indicated that the water absorption, density, compressive and flexural strength decreased with increase in CCA content and increased with curing period. The optimum blend was obtained at 10% CCA and 90% OPC contents. The EE and CO₂ emission decreased with increase in CCA contents. At 20% CCA content the EE was 2382 MJ/m³ which is 12.04% less than that of control samples. Also, 16.37% embodied CO₂ emission saving was obtained for samples containing 20% CCA. The regression equations generated gave standard deviation, S, < 1.0, P-value < 0.05, T-statistics > T24, 0.05 and F-statistics > F1, 23, 0.05. All these indicated that there is good relationship between the predictors and the responses.