**4. Conclusions**

The influence of water on the interface of the crumb rubber–asphalt mixture was studied using the multiscale method. At the macroscale, the performance of the crumb rubber–asphalt mixture before and after water immersion under the two failure modes of medium-temperature fatigue failure and low-temperature fracture failure were analyzed. At the microscale, the adhesion work and water stability index between crumb rubber asphalt and basalt and limestone under dry and wet conditions were analyzed. A molecular dynamics simulation was carried out on the molecular model of crumb rubber asphalt and a representative molecular model of basalt and limestone at the molecular scale. The interaction energy and interaction energy density between the asphalt model and the mineral model were calculated and analyzed. The research conclusions are as follows:


**Author Contributions:** L.W.: resources, writing—review and editing, supervision. Y.L.: writing—original draft, conceptualization, methodology, software, validation. L.Z.: formal analysis, writing—review and editing, visualization. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was supported by a gran<sup>t</sup> (No. 2019GG031) from the Key Science-Technology Project of Inner Mongolia, China.

**Data Availability Statement:** The data presented in this research are available on request from the corresponding author. The data are not publicly available due to privacy.

**Conflicts of Interest:** The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
