An overview of the application of recycled textile fibers in structural concrete

Abstract Global textile production exceeds 110 million tons annually, yet less than 20% of discarded textiles are recycled, leaving enormous quantities in landfills. To address this waste challenge, the present review evaluates the potential of using recycled textile fibers (RTFs) as sustainable reinforcement in concrete, examining their effects on mechanical performance and durability. This study synthesizes experimental and theoretical research on natural, synthetic, and blended RTFs, including their recycling methods, fiber treatments, and strategies for integrating them into cementitious matrices. Results indicate that RTF inclusion generally enhances tensile and flexural strength and ductility, with an optimal fiber dosage around 0.5% by volume maximizing these gains. Beyond this optimum, higher fiber content tends to reduce compressive strength and workability due to fiber agglomeration and void formation. RTFs also improve concrete durability by mitigating shrinkage cracking and refining the pore structure, which decreases water and chloride ingress and thereby enhances freeze–thaw and chemical resistance. Microstructural observations show effective fiber–matrix interactions, as fibers bridge cracks and create a more homogeneous matrix, correlating with improved post-cracking toughness. Overall, incorporating RTFs into concrete offers a promising route toward sustainable construction by valorizing textile waste and improving material performance. Key challenges such as reduced workability and fiber dispersion issues at high fiber dosages, along with the lack of standardized design codes, must be addressed to enable broader application.