Surface Modification of Recycled Polyester Fiber and Performance Evaluation of Its Asphalt Mastic and Mixture

The use of recycled polyester fiber (Re-PET) partially addresses the scarcity of non-renewable polyester (PET), but its thermal resistance in asphalt mixtures is relatively low. To enhance the reutilization and thermal resistance of Re-PET, it was modified through in situ growth grafting with tetrahedral nanoSiO2. A novel nanoSiO2 hybrid material (SiO2/Re-PET) was successfully prepared, and the effects of the surface modification on the morphology and thermal resistance of the Re-PET were investigated with the examination of its mechanism of modification. The results demonstrated an increase in the surface roughness and specific surface area of SiO2/Re-PET, as well as a higher melting point and structural stability compared to Re-PET. Subsequently, Re-PET and SiO2/Re-PET asphalt mastics under a filler–asphalt ratio of 1.0 were prepared, and their classical and rheological properties were investigated and compared. The results indicated an increase in the softening point and shear strength of SiO2/Re-PET asphalt mastic, as well as a significant improvement in its high-temperature performance. Furthermore, subsequent pavement performance tests revealed a significant improvement in the performance of SiO2/Re-PET asphalt mixtures compared to Re-PET asphalt mixtures. Consequently, the findings of this research promote the recycling of Re-PET, ultimately advocating for the sustainability of pavement construction.