Performance Enhancement of Asphalt Mixtures Using Recycled Wind Turbine Blade Fiber

To facilitate the sustainable recycling of retired wind turbine blades (RWTBs) and promote the green development of the wind energy sector in China, this study investigates the reuse of crushed RWTBs as composite fiber additives in asphalt mixtures. A systematic optimization of the incorporation process was conducted, and the effects of RWTB fibers on pavement performance were comprehensively evaluated. Using the entropy weight method, the optimal fiber content and particle size were identified as 0.15 wt% and 0.3–1.18 mm, respectively. The experimental results demonstrated that, under optimal conditions, the dynamic stability, low-temperature flexural tensile strain, Marshall stability after water immersion, and freeze-thaw splitting strength of the base asphalt mixture increased by 27.1%, 23.8%, 9.9%, and 8.1%, respectively. Microstructural analyses using SEM and EDS revealed that the reinforcing mechanism of RWTB fibers involves adsorption, bridging, and network formation, which collectively enhance the toughness and elasticity of the asphalt matrix. In addition, a comparative evaluation was performed using the Analytic Hierarchy Process (AHP), incorporating both performance and cost considerations. The comprehensive performance ranking of fiber-modified asphalt mixtures was consistent for both base and SBS-modified asphalt: BF AC-13 > RWTB AC-13 > GF AC-13 > PF AC-13 > unmodified AC-13. Overall, this study confirms the feasibility of high-value reuse of RWTB waste in road engineering and provides practical insights for advancing resource recycling and promoting sustainability within the wind power industry.