Reconstruction of crosslinked network in terminal blend rubber powder modified asphalt with BR to enhance thermal storage stability and rheological properties

This research aims to enhance the low-temperature performance and thermal storage stability of crumb rubber (CR) modified asphalt by introducing cis-1,4-butadiene rubber (BR) into desulfurized rubber powder-modified asphalt using terminal blending technology. The study employed rheological tests, differential scanning calorimetry (DSC), fluorescence microscopy (FM), and Fourier-transform infrared spectroscopy (FTIR) to evaluate the characteristics of the modified asphalt and its modification mechanism. The results reveal that the introduction of BR significantly improves the cold resistance and tensile properties of the asphalt, with a glass transition temperature decrease of over 15 degrees C and ductility at 5 degrees C increasing by nearly 30 cm. Furthermore, thermal storage stability is enhanced, evidenced by a segregation value reduction from 4.2 degrees C to 0.2 degrees C after 48 hours, and a softening point decrease from 5.6 degrees C to 0.6 degrees C. The Performance Grade (PG) rating improves from PG64-16 to PG76-28. Fluorescence microscopy indicates that BR transforms the two-phase structure of the CRmodified asphalt into a continuous two-phase structure. FTIR analysis suggests that BR initiates a vulcanization crosslinking reaction, forming a crosslinked-filled structure where BR acts as the main framework, while desulfurized rubber hydrocarbons and fillers serve as the filler material. This study demonstrates the potential of BR in improving the properties of desulfurized CR-modified asphalt.