INVESTIGATING THE MECHANICAL PROPERTIES OF COMBINED OIL PALM AND COCONUT FIBERS IN FIBER REINFORCED CONCRETE

The study investigated the effect of combined coconut and oil palm fibers on the mechanical properties of reinforced concrete. The mix design for both plain concrete and fiber-reinforced concrete was based on a 1:2:4 ratio of cement, sand, and coarse aggregate, with a water/cement ratio of 0.6. The fibers were added as reinforcement at 0.5% and 1% by weight to control crack propagation. Concrete composites were cured for 7, 14, 21, and 28 days, with plain concrete used as the control. Key mechanical properties, including compressive strength, flexural strength, split tensile strength, and water absorption, were evaluated. The compressive strength increased steadily with curing age for all concrete mixes. At 28 days, the compressive strength of the control specimen was 29.5 N/mm², while the concrete with 0.5% and 1% fiber content exhibited higher strengths of 36.5 N/mm² and 32.8 N/mm², respectively. The addition of fibers significantly enhanced the flexural strength of concrete. The bond strength between the fibers and concrete ingredients improved with each fiber percentage. Both the 0.5% and 1% fiber-reinforced concrete showed superior performance compared to the control.The fiber-reinforced concrete exhibited increased tensile strength, with the 1% fiber content providing the highest split tensile strength among all samples tested. The tensile strength increased by up to 7% and 2% for 0.5% and 1% fiber content, respectively, compared to the control mix. Water absorption tests showed variations across the samples at different curing ages (7, 14, 21, and 28 days). Fiber addition slightly affected water absorption, with differences observed between the control and fiber-reinforced samples. In conclusion, the inclusion of combined coconut and oil palm fibers, particularly at 1%, significantly improved the compressive, flexural, and tensile properties of concrete. These fibers offer a promising reinforcement option for enhancing the mechanical performance and durability of concrete in structural applications.