Enhancing Mechanical and Durability Properties of Concrete Using Recycled HDPE Fibers: Experimental Evaluation

Abstract

This experimental study examines the effects of introducing High-Density Polyethylene (HDPE) fibers at volume fractions of 0%, 1.0%, 1.5%, and 2.0% on key properties of concrete. Among the traits evaluated are impact resistance, flexural strength, compressive strength, and ultrasonic pulse velocity (UPV). The results demonstrate that the UPV values, which varied from 4.38 to 4.42 km/s, remained essentially constant, suggesting no alteration in the composite's density and homogeneity. The 28-day compressive strength improved gradually with the addition of fibers, reaching a high of 36.42 MPa at 2.0% fibers, a 9.8% improvement over the plain concrete. However, flexural strength and impact resistance peaked at 4.18 MPa and 4 blows, respectively, at 1.5% fiber content, indicating the best improvement in toughness-related characteristics. A decrease in performance was observed beyond this ideal dosage, which was probably caused by impaired fiber dispersion and workability. The results support previous research on how synthetic fibers can improve post-cracking behavior by efficiently bridging cracks.