Influence of Hybrid‐Treated Coconut Fibers on the Mechanical and Fracture Parameters of High‐Strength Concrete

ABSTRACT This study investigates the influence of hybrid‐treated coconut fiber (HTCF) content on the mechanical and fracture properties of high‐strength concrete (HSC) with a target strength of 60 MPa. The fibers were treated by boiling for 1 h, followed by immersion in a 1% NaOH solution, enhancing their surface morphology and composition, as confirmed by SEM and XRD analyses. The dry density of HSC increased at 0.25% fiber content (FC) but decreased at higher levels. Pulse velocity peaked at 1% FC, surpassing the control mix by 2.27%. At 0.5% FC, compressive strength and elastic modulus increased by 5.22% and 2.85%, respectively, while tensile strength improved by 33.31% at 1% FC. At 0.75% FC, and increased by 5.12% and 12.40%. and peaked at 0.25% FC, improving by 42.19% and 73.62%. decreased with fiber addition. These results underscore the significance to optimize HTCF content for enhanced HSC performance.