Dynamic mechanical properties of pavement crack sealant under the combined effects of ultraviolet aging and freeze–thaw cycles

As a commonly used material for pavement rehabilitation, pavement crack sealant faces significant challenges in maintaining long-term performance under extreme environmental conditions, such as low winter temperatures and intense ultraviolet (UV) radiation in summer. Ensuring its structural integrity and functional stability under these conditions is essential. This study aims to investigate the effects of UV aging and freeze–thaw (F–T) cycles on the dynamic mechanical properties of crack sealants, and to identify the patterns of performance variation under harsh service conditions. Indoor simulation tests were conducted to comprehensively evaluate the viscoelastic properties, low-temperature performance, deformation recovery ability, fatigue behavior, and self-healing capacity of crack sealants under UV aging, F–T cycles, and their combined effects. The results indicate that UV aging increases the material modulus while diminishing creep recovery and self-healing capabilities, with these effects becoming progressively irreversible. F–T cycles lower the glass transition temperature and stiffness but have a limited impact on self-healing behavior. When combined, UV aging and F–T cycles exhibit a compensatory interaction in terms of low-temperature and viscoelastic properties, while jointly accelerating the deterioration of deformation recovery and healing performance. This study elucidates the coupled mechanisms of environmental stressors on crack sealant behavior and provides a theoretical foundation for the development of high-performance crack sealants tailored to harsh service environments. • UV aging and freeze–thaw cycles jointly degrade the dynamic properties of crack sealants. • Aging causes crack sealant softening, embrittlement, and reduced self-healing ability. • A multi-index evaluation clarifies crack sealant performance under extreme environments.