Structural Performance and Early Age Crack Resistance of High Strength Concrete Beams Reinforced with Borassus Fibers

Abstract

This study investigates the structural performance and crack resistance of high-strength concrete (HSC) reinforced with Borassus fibers as a sustainable alternative to steel fibers. Concrete’s brittleness and low tensile strength can lead to premature cracking, reducing durability and performance. While fibers can mitigate these issues, the effectiveness of different fiber types is not well established. Borassus fibers, derived from the Palmyra palm, offer environmental benefits and high tensile strength, potentially enhancing crack resistance. The research evaluates treated and untreated Borassus fibers in HSC using a four-point bending test. Beams (150 mm × 200 mm × 750 mm) were cured for 7 days, with crack measurements taken using a crack gauge detector. Results indicate that fiber-reinforced concrete significantly outperforms the control mix in load capacity, crack resistance, stiffness, and energy absorption. The ultimate load capacity increased by 38% with steel fibers (SF) and 46% with treated Borassus fibers (TBF), while untreated Borassus fibers (UBF) showed a slight decrease. First crack loads improved by 37% (SF), 46% (UBF), and 53% (TBF) over the control. TBF exhibited the most refined crack patterns, achieving a reduction in crack depth and width by 30% and 76%, respectively. increasing by 99% from 57 kN/mm (control) to 114 kN/mm, and the highest energy absorption at 1824 kN.mm.