Effect of Chemical Treatment of Kenaf Fibers on the Structural Performance of Reinforced Concrete Beam

This paper seeks to evaluate the impact of various chemical pretreatments applied to kenaf fibers on both the mechanical characteristics of concrete and the structural behavior of a reinforced concrete beam. The presence of microcracks limits reinforced concrete constructions. Hence, kenaf fibers are used as a substitute. Multiple investigations have demonstrated that inadequate treatment of kenaf fibers fails to resolve the problem of interfacial adhesion between the kenaf fibers and concrete. The study examines the use of chemical treatments to improve the bonding between kenaf fibers and the concrete matrix. Several chemical agents, including Sodium hydroxide (NaOH), Potassium permanganate (KMnO4), Potassium dichromate (K2Cr2O7), and Hydrogen peroxide (H2O2), are employed to alter the surface properties of kenaf fibers. The goal is to enhance the overall mechanical properties of the composite material by improving the compatibility between the hydrophilic nature of kenaf fibers and the hydrophobic nature of concrete. Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR) are used to examine the microstructural and mechanical alterations caused by the chemical treatments. Following the application of analytical procedures to fibers treated with various chemical agents, multiple samples of cubes, cylinders, and small beams are subjected to testing for compressive strength, splitting tensile strength, and flexural strength at intervals of 0%, 0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.5%, 1.75%, and 2%. Ultimately, a set of reinforced concrete beams are constructed, utilizing both untreated fibers and treated fibers, with the precise proportion of fibers determined from previous investigations on the mechanical characteristics of fiber-reinforced concretes. An analysis is conducted on the bending and microfractures of the beams following the bending tests. The findings demonstrated that kenaf fibers, when subjected to an alkaline solution followed by potassium dichromate treatment, had excellent structural properties when used to reinforce concrete beams.