Enhancing Mechanical Properties of Concrete Using Polymer-Modified Recycled Carpet Fiber Composites

Recycled carpet fibers (CFs) offer a sustainable solution to reduce the carbon footprint of concrete production, but their application often compromises compressive strength despite improvements in tensile and flexural properties. This study addresses the challenges by investigating the effects of incorporating polymer alongside CFs in concrete to enhance its mechanical behavior. Various proportions of CFs and polymer were tested to identify optimal dosages, followed by an evaluation of the combined effects of polymer and CFs on the mechanical properties of concrete. Results indicated that 1.5% CFs reduced compressive strength by approximately 25% while increasing tensile strength by 30% and flexural strength by 110%. However, incorporating 1% polymer increased compressive strength by 42% and further improved tensile and flexural strength by 130% and 175%, respectively. When combining 1% polymer with 1% CFs, the modified concrete demonstrated a 21% increase in compressive strength, a 200% increase in tensile strength, and a 55% increase in flexural strength compared to control concrete. These findings suggest that the hybrid use of polymer and CFs not only mitigates the compressive strength reduction typically associated with CFs but also enhances workability and overall mechanical performance. The results emphasize the potential of polymer-modified CFs-concrete as a sustainable, environmentally friendly alternative to conventional concrete, with optimized proportions of 0.5% CFs, 1% polymer, and 1% hybrid polymer-CFs offering the best balance of properties for practical applications.