Characterization and Modeling of the Ultraviolet Aging Behavior of Asphalt Exposed to Laboratory and Outdoor Aging

Ultraviolet (UV) radiation is an important factor that causes the aging of asphalt binders, leading to significant changes in their high- and low-temperature performances and making asphalt pavements more susceptible to cracking. To better understand the behavior of UV aging and optimize the maintenance strategies for asphalt pavements in high-UV areas, this study conducted a one-year outdoor aging experiment in Chongqing, China. Two types of asphalt samples, 90# matrix asphalt and styrene-butadiene-styrene (SBS)-modified asphalt, were prepared for the laboratory UV-accelerated aging experiments. Using comprehensive macro- and microtesting methods, a series of aging indicators were obtained, and their sensitivity and correlation were studied, particularly focusing on the complex shear modulus (G*). The results revealed distinct differences between UV-induced aging and thermal oxygen aging, with significant shifts observed in the four main components of the binder. Using these indicators, this study established and validated a nonlinear regression model, thereby proving its effectiveness and reliability for laboratory and outdoor sample analyses. Notably, the study confirmed that approximately 6–7 days of laboratory-accelerated aging corresponds to one year of outdoor exposure in Chongqing. Correlation analyses further indicated that G* is closely related to other aging indicators, emphasizing its utility in predictive models for asphalt aging that require adjustments based on environmental temperatures. These findings provide valuable insights for optimizing maintenance strategies for asphalt pavements, particularly in regions with high UV exposure, enhancing pavement performance, and extending their lifespan.