Studying the effects of alkali treatment on the properties of kenaf fiber for reinforced concrete elements

Kenaf fibers are coming into interest to use in reinforced concrete elements in recent years due to its attractive properties such as lightweight, non-abrasive, degradable, renewable and inexpensive. However, lack of good interfacial adhesion and high moisture absorption make the use of kenaf fiber reinforced concrete elements less attractive. Alkali treatment is one of the best used chemical treatment for natural fibers. It can clean the fiber surface, chemically modify the surface and increase the surface roughness. The purpose of this study is to do a fundamental study on the effects of kenaf fiber in different pH of NaOH. In this study, various alkali pH of NaOH were used and the effects on the color of fiber, weight loss and water absorption of treated kanef fibers were evaluated. From the study, it found that the color of kenaf fiber was significantly changed due to alkali treatment and become more and more yellowish whenever the pH of NaOH increased. Treated kenaf fibers were lighter than untreated fibers. The water absorption for fiber was also higher for treated kenaf fiber and the time to reach saturation level was reduced after alkaline treatment