Mechanical properties of kenaf fiber reinforced concrete with different fiber content and fiber length

Abstract

The purpose of this paper is to discuss the findings of an experimental research conducted on the effects of fiber content and fiber length on the mechanical properties of kenaf fiber reinforced concrete (KFRC). The experimental results can be set as the foundation for the future research related to the development of KFRC as a sustainable and green construction material. In this study, compressive strength, splitting tensile strength, and flexural strength of KFRC are determined experimentally and the properties of plain concrete are used as a reference. The treated bast kenaf fibers with the alkaline solution of pH 13 is used as the reinforcement in concrete. The influence of five fiber contents (0.5%, 0.75%, 1.0%, 1.5%, and 2.0%) by volume of concrete and two fiber lengths (25 mm and 50 mm) to the KFRC are investigated. Concrete of Grade 30 strength is used and designed by using DOE method. This research is conducted according to British Standard (BS) and American Society for Testing and Materials (ASTM). The results indicate that the workability of KFRC is reduced compared to plain concrete. In terms of mechanical properties of KFRC, the results showed that the compressive strength decreased with increase in fiber content. However, the study also found that, by adding appropriate fiber content and fiber length in concrete, the flexural strength and indirect tensile strength of concrete can increase and, at the same time, the KFRC can have similar compressive strength to the plain concrete. Further, KFRC generally exhibits more resistance to cracking and toughness than the plain concrete.