Concrete Microstructure Study on the Effect of Sisal Fiber Addition on Sugarcane Bagasse Ash Concrete

Abstract

Concrete made using sugarcane bagasse ash as a cement replacement is associated with a reduction in split tensile strength and therefore a need to establish the possible causes of tensile strength reduction and explore ways of mitigating that reduction. The aim of this study is to establish the possible causes of tensile strength reduction in sugarcane bagasse ash concrete and determine the effect of sisal fiber addition on its mechanical properties. Scanning Electron Microscopy was first done to analyse concrete microstructure in establishing the possible causes of tensile strength reduction in sugarcane bagasse ash concrete. Thereafter, sisal fiber addition was done by varying aspect ratios and percentages. The effect of the addition was determined on the mechanical properties of bagasse ash concrete accompanied by microstructure studies on extracted fibers and split surfaces of concrete. Concrete microstructure studies revealed that wider cracks due to drying shrinkage and poor bonding properties of sugarcane bagasse ash are the possible causes of tensile strength reduction in bagasse ash concrete. Sisal fiber addition improved the mechanical properties of bagasse ash concrete. Microstructure studies portrayed effective bridging of cracks and good adhesive properties of the fibers. Sisal fibers can be used to improve on the mechanical properties of sugarcane bagasse ash concrete with 100 aspect ratio and 1.5% addition being the optimal combination.