An experimental evaluation of the performance of concrete reinforced with recycled fibers made from waste plastic bottles

This study addressed the issue of recycling waste plastic bottles as recycled plastic fiber (RPF) into sustainable waste plastic fiber-reinforced concrete (WPFRC). Thus, the effects of different RPF lengths (30, 50, and 70 mm), widths (2, 4, and 6 mm), and contents (0.3, 0.45, and 0.6 vol%) on the performance of WPFRC were systematically evaluated through the laboratory test series of workability, fresh unit weight, compressive and flexural strengths, drying shrinkage, water absorption, and ultrasonic pulse velocity. Results indicated that the addition of RPF had a negligible effect on the fresh properties of the WPFRC mixtures, while significantly enhancing the load-bearing capacity and reducing drying shrinkage in the WPFRC specimens, particularly at early ages. Additionally, all WPFRC specimens exhibited low water absorption rates and high ultrasonic pulse velocities, indicating good quality and durability. Overall, the study found that an RPF content of 0.45% by volume, an RPF length of 70 mm, and an RPF width of 2 mm yielded the best performance for WPFRC. As a result, incorporating RPF into concrete fosters the development of strong, durable, and sustainable materials for green construction. •The impacts of WPF with different dimensions and contents on the performance of WPFRC were investigated.•Increasing fiber content and length improves strength while reducing drying shrinkage and water absorption of WPFRC.•Longer and narrower fibers provide a better interlocking effect and a higher reduction in the drying shrinkage of WPFRC.•Increasing fiber width decreases flexural strength and has an insignificant effect on the water absorption of WPFRC.•Optimizing the WPFRC performance requires considering the effect of fiber content, length, and width on UPV values.