# Mechanism of Rejuvenation in Aged SBS-Modified Asphalt by Density Functional Theory
## 5 Conclusions  
1. In SBS-modified asphalt, SBS molecules are the least stable and prone to fracture. The energy difference between SBS and aromatic components is the largest, and that between SBS and asphaltenes is the smallest. This indicates that SBS has the best compatibility with aromatic components and the poorest compatibility with asphaltenes. The value of energy is related to the structure and size of molecules.
2. The interaction between aromatic components in rejuvenator with asphaltenes in aged asphalt is not stable. And it could be affected by the asphalt aging level. The interaction between heavy components molecules in aged asphalt with saturate components molecules in rejuvenator are closer than those with aromatic component molecules, which could be related to the molecular structure.
3. The interaction between light components in rejuvenator with SBS exhibits great interaction potential and closeness of molecular force. After rejuvenator is added into  
Figure 11: \(Q_{\text{transfer}}\) between light components in rejuvenator and heavy components in aged SBS-modified asphalt.  
the aged SBS-modified asphalt, a certain amount of rejuvenator reacts first with the SBS molecules, leading to a certain degree of reduction of rejuvenation. (4) \(E_{\text{binding}}\) between saturate components in rejuvenator with asphaltenes in aged SBS-modified shows good consistency with \(G^{\star}\) of aged SBS-modified asphalt before and after rejuvenator is added. Therefore, the results of \(E_{\text{binding}}\) can be used as a qualitative evaluation indicator for rejuvenation of aged SBS-modified asphalt.  
The types of aged asphalt prepared in this study are limited. It is necessary to supplement with a variety of aged asphalts in subsequent experiments to validate and improve the correlation between rheological test results and quantum simulation results. Only one rejuvenator was investigated in this study. In the future, it is necessary to supplement with different rejuvenators to validate the applicability of the conclusions. Furthermore, this study lacks discussion on the practical implications and potential applications of these findings in real-world scenarios. Exploring the practical benefits and limitations would be the next job in the future.  
Conceptualization, P.L.; Methodology, Z.L.; Software, Z.L.; Validation, S.C.; Formal analysis, Z.L. All authors have read and agreed to the published version of the manuscript.  
The authors gratefully acknowledge the financial support from the Science and Technology Project of Housing and Urban-Rural Construction Department of Gansu Province (Grant No. JK2023-17) and the China Municipal Engineering Northwest Design and Research Institute Science and Technology Project (Grant No. XBSZKY2338) and the help of [PERSON].  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
Author [PERSON] was employed by the company Gansu New Development Investment Group Co., Ltd. The remaining authors declare that the re-search was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.