Study on the macroscopic performance decay and damage mechanism of emulsified asphalt under ageing environment

In order to reveal the evolution law and damage mechanism of service performance of emulsified asphalt under aging environments, this study simulated thermal-oxidative aging and employed macroscopic performance tests, rheological analysis, microscopic characterization, and molecular dynamics (MD) simulation. The results show that aging destroys the colloidal stability, causes light components to volatilize and convert to heavy components, and intensifies crosslinking reactions, resulting in gradual hardening and embrittlement. In terms of macroscopic properties, penetration and ductility decline, while softening point and viscosity increase; rheological, creep, shear, and fatigue properties also deteriorate. Grey correlation analysis indicates significant correlations between aging and macroscopic indicators; the sensitivity ranking is complex shear modulus > rutting factor > bulk modulus > 135°C viscosity > 64°C Jnr0.1 > softening point > ductility > penetration, showing rheological parameters are most sensitive. Microscopically, aging drives an evolution of component migration, structural densification, and performance embrittlement, with surface densification and microcracks observed. MD simulation further validates the mechanical degradation at the atomic scale, revealing reduced intermolecular interactions and stiffness. This study offers a theoretical basis for material selection and durability design of emulsified asphalt in aging conditions.