Effect of lye alkaline solution treatment on engineering properties of oil palm empty fruit bunches (EFB) fiber strengthen foamed concrete

Abstract

Natural fibers have become attention-grabbing and interesting these days to be employed as an industrial material and structural material for rehabilitating of structures. Nevertheless, the natural fibers to matrix interface interactions with cement matrix remain a key issue in getting the desired mechanical properties. Treatment of natural fibers is crucial in improving matrix to filler adhesion, thus improving its mechanical properties. In this study, oil palm empty fruit bunches (EFB) fiber was studied for use as reinforcement materials for cementitious composites in foamed concrete. The effect of fiber treatment on mechanical properties of EFB fiber reinforced foamed concrete was investigated comprehensively. For lye-treated EFB fibers, these fibers were washed three times with tap water to eliminate unwanted debris, dusts and impurities and dried at room temperature for 48 hours. Lye chemical solution of 2%, 4%, 6%, 8% and 10% wt. concentration were prepared using distilled water and lye chemical pellets. For the 2% wt. concentration, 2 grams of lye chemical was dissolved in 100ml of distilled water which is equivalent to 100 grams. For the 4, 6, 8 and 10% wt. concentrations, 4 grams, 6 grams, 8 grams and 10 grams of lye were dissolved in 100ml of distilled water respectively. The EFB fibers were soaked in the prepared solutions for a period of 24-hours after which they were removed and thoroughly rinsed until a neutral pH of the rinsing solution was attained. A pH meter was used to determine the pH value of the solution after rinsing. Finally, the dried fibers were sealed in a plastic bag before the composite manufacturing to avoid atmospheric moisture contamination. From the results obtained through experimental works, it can be concluded that the lye treatment of the EFB fibers modifies the fibers adequately causing a variation in the axial compression and flexural properties of the foamed concrete. Above all, 6% lye concentration gave better mechanical properties and therefore is considered a better treatment concentration value in the range of 2% to 10% wt. for improving the mechanical properties of EFB reinforced foamed concrete.