Performance of Coconut Shell Alkali-Activated Concrete: Experimental Investigation and Statistical Modelling

Abstract

The increasing sustainability awareness in the concrete industry has called for a need to find ways to partially or totally replace Portland cement in concrete. The imminent need to replace Portland cement is as a result of its production process is energy-intensive and a consequential amount of carbon dioxide being emitted into the atmosphere. In a quest to improve the sustainability of concrete mixtures, this study was carried out to investigate experimentally and statistically the performance of concrete made with coconut shell ash as partial replacement of Portland cement (PC). Coconut shell ash was used to replace 10% PC in the form of supplementary cementitious material and as an alkali-activated binder. The experimental program involves evaluating the workability, compressive strength and split tensile strength of the developed mixtures. In addition, the effect of two curing media on the resulting mechanical properties was investigated. Based on the experimental study, statistical models were developed using multiple regression analysis. Experimental results showed that the compressive strength and split tensile strength increased by 7.7% and 29.4% when the concentration of the sodium hydroxide was increased from 2.5 to 10 M respectively. Results from the models developed showed good agreement with the experimental results.