Research on low-temperature and fatigue properties of recycled asphalt based on the stability of the micelle structure

The research is focused on the asphalt colloid system and provides a detailed analysis of why the effective recovery of low-temperature performance and fatigue performance is challenging during the regeneration of aged asphalt. This study initially examined the alterations in the stability of colloidal structures and micelle structures while rejuvenating aged asphalt. These were performed through four-component analytical tests and asphalteneresin (A-R) adsorption experiments, respectively. Subsequently, the impact of the regeneration process on the low-temperature performance and fatigue performance of aged asphalt was assessed using bending beam rheometer (BBR) tests and linear amplitude sweep (LAS) tests, respectively. In addition, linear regression analysis was employed to determine the relationship between the stability of colloidal and micelle structures and the performance of recycled asphalt in terms of low-temperature and fatigue resistance. The results show that regeneration of aged asphalt results in 100% recovery of colloidal structural stability, while the maximum recovery of micelle structural stability is only 68.2%. The stability of the micelle structure in recycled asphalt is primarily influenced by the proportion of aged asphalt to virgin asphalt. When the mass ratio of aged asphalt to virgin asphalt is 2:8, the stability of the micelle structure can be restored to 58.1%. However, when the mass ratio is reversed to 8:2, the stability of the micelle structure can only be restored to 21.6%. The impact of the regeneration agent on the recovery of micelle structure stability is minimal. Out of all the samples that underwent regeneration, the highest level of enhancement in the stability of the micelle structure achieved by the rejuvenators was approximately 15%. Linear regression analysis showed that the low-temperature performance of recycled asphalt was significantly affected by the stability of the colloid and micelle structure. The fatigue performance of recycled asphalt was only significantly affected by the stability of the micelle structure. Therefore, enhancing the stability of the micelle structure in recycled asphalt can effectively improve its low temperature and fatigue performance. This study provides valuable insights into the underlying factors contributing to the subpar low-temperature and fatigue performance of recycled asphalt. Moreover, it contributes to the development of more effective rejuvenators for aged asphalt recycling.