Ascertaining the Potential of Locally Sourced Coconut Shell Ash as a Partial Replacement for Portland Composite Cement in Concrete Production

This current study evaluated the potential of coconut shell ash, sourced from coconut vendors in Sekondi-Takoradi in Ghana, as a supplementary cementitious material in concrete production. Concrete specimens were prepared with Portland limestone cement (PLC) partially replaced with coconut shell ash (CSA) in proportions of 0%, 5%, 10%, 15%, and 20%. Performance of CSA concretes was evaluated using tests, including slump, flexural strength, and compressive strength tests. X-ray fluorescence (XRF) spectrometry analyses revealed the presence of essential elements in cements such as Ca, Si, and Fe in CSA, thus a potential supplementary cementitious material (SCM). Workability was low for CSA concretes (18mm-34mm slump). Compressive and flexural strengths rose progressively up to 10% partial replacement levels at ages 7, 28, and 70 days, beyond which the loss of clinker effect sets in. Density and water absorption declined as the proportion of CSA addition increased. Empirically, the elemental composition of locally sourced CSA in Ghana was established, as well as characterizing CSA concrete, thereby broadening the frontiers of existing literature on CSA as an SCM. Practically, polynomial regression models were developed to aid construction practitioners in determining the optimal level of partially replacing PLC with CSA in concrete mix at ages 7, 28, and 70 days. Finding an alternative use of CSA in CSA concrete will reduce carbon dioxide (CO2) emissions into the environment, thereby contributing to combating climate change, which has a direct relation with Sustainable Development Goal (SDG) 13: climate action.