<p>Salt ion erosion, which occurs during winter maintenancer or in coastal areas and near saline lakes is a key factor affecting the long-term performance of asphalt pavement. However, the underlying molecular mechanisms of asphalt eroded by salt ions remain unclear. Thus, this study aims to investigate the erosion behavior and mechanism of asphalt and asphalt-aggregate interface exposed to NaCl, CaCl_2, Na₂SO₄, and CaSO₄ solutions. For this purpose, models of asphalt, asphalt-aggregate and salt ions were established using molecular dynamics (MD) simulation. The chemical composition and conventional binder properties of asphalt were examined by SARA fraction and physical tests. MD results showed that salt ions significantly deteriorated the performance of asphalt and asphalt-aggregate interface, as evidenced by increased cohesive energy density (CED), solubility of asphalt and diffusion capability of asphalt at the aggregate surface, reduced cohesive energy density of the van der Waals (CED_vdW), the viscosity of asphalt and the interfacial adhesion of the asphalt-aggregate interface, as well as the altered distribution of asphalt components on aggregate surface. The results of SARA fraction analysis, conventional binder properties tests and adhesion pull-off tests indicated that salt ion erosion led to decreased aromatics, saturates and resins content, penetration and ductility, the pull-off test strength, as well as increased asphaltenes content, which are consistent with the MD simulation and thermal oxidative aging results. Both MD and laboratory results demonstrated that Na⁺ and Cl⁻ exhibited the strongest erosion effects on asphalt and asphalt-aggregate interface due to their small ionic radii and great diffusivity. In contrast, Ca²⁺ and SO₄²⁻ exerted weaker effects due to their large size and strong hydration. The findings of the study provide a theoretical foundation for the development of corrosion-resistant asphalt materials under salty conditions.</p> Graphical abstract <p></p>