Evaluation of mechanical properties, durability, and sustainability of concrete reinforced with recycled GFRP fibers: Experiments and optimization

Waste wind turbine blades (WTB) pose significant environmental and disposal challenges due to their increasing volume and complex composition. This study proposes integrating mechanically recycled fibers from WTB into glass fiber reinforced concrete (GRC). A comprehensive evaluation of fresh properties, mechanical performance, durability, and life-cycle sustainability was conducted to identify optimal hybrid reinforcement strategies. Compared to AR glass fibers, recycled GFRP fibers increased flowability by 71.4%, compressive strength by 24.4%, and impact resistance by 36.6% at optimal dosage. A hybrid reinforcement system containing 7% recycled GFRP fiber, 3% AR glass fiber, and one layers of fiberglass mesh induced pronounced strain-hardening behavior, with toughness indices I₅, I₁₀, and I₂₀ reaching 4.3, 8.6, and 17.4, respectively. Accelerated aging and wet–dry cycling tests further validated the long-term durability of the optimized composite, projecting a service life of approximately 50.4 years. Life-cycle assessment demonstrated additional economic and environmental advantages, showing a 8.7% cost reduction and limiting carbon emissions to 625 kg CO₂-equivalent per m³ of GRC. These findings underscore the viability and sustainability of this high-value reuse strategy for waste WTB in GRC industry.