Road Performance and Multi-Objective Optimization Study of rWTB—Salt-Retaining Asphalt Mixture

With the intensification of global climate change, the issue of snow and ice accumulation on roads during winter has become increasingly severe, prompting the widespread application of salt-storage asphalt mixtures in highway construction of alpine regions due to their ability to sustainably release salts for snowmelt. The incorporation of salt-storage fillers significantly compromises the road performance of asphalt mixtures, particularly exacerbating deterioration in low-temperature crack resistance and moisture stability while accelerating pavement distress. Although fiber reinforcement technology has been validated for enhancing asphalt mixture performance, conventional fibers suffer from high production costs and inadequate environmental sustainability. The rapid expansion of the wind energy sector in recent years has generated substantial quantities of retired wind turbine blades (rWTB), posing a global challenge for recycling. This study proposes utilizing rWTB in salt-storage asphalt mixtures and investigates their road performance and underlying mechanisms through experimental analysis. The results demonstrate that rWTB fiber addition markedly improves the mechanical properties of salt-storage asphalt mixtures, yet excessive fiber dosages (>0.3%) induce localized fiber agglomeration, thereby slowing or reversing optimization trends. Given the multi-objective optimization challenge of rWTB fiber incorporation, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) algorithm was employed as an optimization tool. In-depth analysis yielded four distinct optimal fiber dosage schemes with performance-oriented priorities: 0.2848%, 0.2903%, 0.2881%, and 0.2882%. These findings provide novel insights for rWTB resource recycling and scientific evidence for enhancing the performance of salt-storage asphalt mixtures.