Evolution of SBS-modified asphalt performance under aging and rejuvenation cycle conditions

Improving the poor long-term service performance of rejuvenated SBS-modified asphalt (REF -LT) is highly challenging. In this study, a blend of aged and virgin binders was used to rejuvenate REF -LT and the evolution of the asphalt performance was observed during regeneration and reaging processes. An SBS-modified asphalt (SBM) and base asphalt (BA) were mixed with REF -LT in specified ratios to prepare SBMand BA -rejuvenated asphalts. The rejuvenated asphalts were subjected to short- and long-term aging. The high/low-temperature rheological properties, fatigue resistance, rejuvenation mechanism, and changes in the functional groups of the rejuvenated and reaged asphalts were characterized using a dynamic shear rheometer (DSR) and Fourier transform infrared spectroscopy (FTIR). The antiaging performance of the rejuvenated asphalt was evaluated. Temperature sweep results showed that both SBM and BA mitigated hardening in REF -LT. BA had a stronger softening effect on REF -LT than SBM. However, the BA -rejuvenated asphalt was more temperature sensitive than the SBM-rejuvenated asphalt. The BA -rejuvenated asphalt had poor resistance to reaging, whereas the SBMrejuvenated asphalt demonstrated outstanding resistance to long-term aging. The Glover-Rowe (G -R) parameters indicated that after short-term aging, the rejuvenated asphalts remained in the no cracking zone, demonstrating outstanding resistance to thermal cracking. A total of 20 h of long-term aging of the rejuvenated asphalts decreased the crossover frequency and increased the rheological index, suggesting an increased risk of cracking. Relaxation tests showed that the BA -rejuvenated asphalt had a lower peak stress than that of the SBMrejuvenated asphalt; however, the durability of the BA -rejuvenated asphalt was compromised because of the peak stress rapidly increased after reaging. Although the BA -rejuvenated asphalt exhibited good short-term crack resistance, its poor durability resulted in inferior thermal crack resistance to that of the SBM-rejuvenated asphalt after long-term aging. Linear amplitude sweep (LAS) tests indicated that the SBM-rejuvenated asphalt had a lower damage rate than the BA -rejuvenated asphalt, suggesting that the polymer network structure provided excellent damage resistance. The fatigue life of the BA -rejuvenated asphalt decreased considerably after reaging, indicating insufficient long-term fatigue resistance. The FTIR results indicated that the REF -LT rejuvenation process involved physical blending and the SBM-rejuvenated asphalt exhibited superior antiaging capability to the BA -rejuvenated asphalt. Increasing the BA content did not improve the long-term antiaging performance of the BA -rejuvenated asphalt. The higher antiaging performance of the SBM-rejuvenated asphalt resulted from the polymer network structure.