Mechanical Performance of Hybrid Fiber Reinforced High-Strength Concrete Incorporating Steel, Coir and Palm Fibers

Abstract

The growing demand for sustainable and high-performance construction materials has encouraged the development of hybrid fiber reinforced concrete incorporating both natural and synthetic fibers. This study investigates the mechanical performance of hybrid fiber reinforced high-strength concrete (HFRHSC) incorporating steel, coir, and palm fibers. An M50 grade concrete mix containing 10% silica fume as a partial cement replacement was developed, and seven different fiber combinations were evaluated. The experimental program included workability, compressive strength, split tensile strength, and flexural strength tests conducted at 28 days.

The results indicated that the inclusion of hybrid fibers improved the mechanical properties of high-strength concrete, although workability decreased with increasing fiber content. Among all mixes, the hybrid combination containing 0.5% steel fiber, 0.25% coir fiber, and 0.25% palm fiber (M4) exhibited the best overall performance. The compressive strength increased from 58.2 MPa for the control mix to 71.1 MPa, representing an increase of approximately 22.2%. Similarly, the split tensile strength increased from 4.61 MPa to 6.42 MPa, while the flexural strength improved from 6.12 MPa to 7.91 MPa, corresponding to increases of 39.3% and 29.2%, respectively. The enhanced performance was attributed to the synergistic action of steel fibers providing crack-bridging capability and natural fibers improving energy absorption and crack resistance.

The study demonstrates that the combined use of steel, coir, and palm fibers can significantly enhance the mechanical properties of high-strength concrete and offers a sustainable solution for structural applications requiring improved strength and durability.