Comprehensive analysis of crack resistance and failure modes in cement concrete reinforced with recycled water bottle fibers: Influence of fiber diameter, length, and content under compression

Abstract

The rapid increase in Polyethylene Terephthalate (PET) product consumption has spurred a global waste crisis, with improper disposal causing severe environmental damage. Waste from PET water bottles, in particular, has greatly contributed to landfill accumulation. To address this, various recycling methods have been developed, including the use of recycled rPET in construction materials like concrete. This study examines the effects of recycled PET fiber content, diameter, and length on the compressive strength and crack resistance of concrete, first to optimize fiber-reinforced concrete for sustainable applications. Using multivariable regression analysis, the study identifies optimal fiber configurations that maximize first crack and failure strength. Results indicate that a fiber content of 1.5%, shorter fiber lengths (5 cm), and a blend favoring thicker fibers (70/30 ratio) significantly improve compressive performance. Sample 11 achieved the highest stress threshold of 35 MPa, suggesting an ideal mix for enhanced structural integrity under compression. This research addresses a gap in sustainable concrete solutions by emphasizing the importance of specific fiber parameters in enhancing concrete durability and crack resistance. Unlike previous studies that often generalize the benefits of fiber-reinforced concrete, this work provides a systematic approach to pinpoint optimal PET fiber configurations, thereby supporting eco-friendly, high-performance alternatives for construction. The dual focus on environmental sustainability and performance optimization highlights the study’s unique contribution to advancing sustainable materials in construction. The findings of our study open up new paths for future research, including long-term durability studies, exploration of other textile fiber waste materials for concrete reinforcement.