Low‐Temperature Cracking Resistance of Bamboo Tar–Based Rejuvenated Asphalt Based on Viscoelastic Rheology

This study investigated the low‐temperature viscoelastic behavior and cracking resistance of bamboo tar–based rejuvenated asphalt. Original 70# asphalt, bamboo tar–based rejuvenated asphalt, and HLJ‐3 rejuvenated asphalt were tested using a bending beam rheometer at −6°C, −12°C, and −18°C. The Burgers, three‐parameter solid, and four‐parameter solid models were employed to characterize the creep response, and the low‐temperature performance was evaluated using the S/m index, performance recovery rate, and gray relational analysis. The results show that the bamboo tar–based rejuvenator reduced the creep stiffness and improved the stress relaxation capacity of aged asphalt. Across the tested temperature range, the low‐temperature performance recovery rate of bamboo tar–based rejuvenated asphalt reached 83.6%–91.0%, which was higher than that of HLJ‐3 rejuvenated asphalt. All three viscoelastic models fitted the BBR creep curves with R 2 values greater than 0.98, among which the Burgers model showed the best overall fitting performance. Gray relational analysis indicated that the instantaneous elastic modulus was closely associated with the low‐temperature cracking resistance of asphalt. These findings suggest that bamboo tar–based rejuvenator can effectively regulate the low‐temperature viscoelastic response of aged asphalt and provide a potential material option for recycled asphalt pavements in cold regions.