Laboratory-simulated aging fails to fully replicate the complex aging behavior of asphalt binder under actual environmental conditions. This study aims to preliminarily investigate and analyze the differences between natural aging and PAV aging of asphalt binder. To achieve this objective, the asphalt binder was aged using three distinct methods: PAV aging, natural thermal-oxidative aging, and all-weather aging. The divergence in asphalt binder aging behavior was systematically investigated through encompassing low-temperature performance, chemical structure, elemental composition, molecular weight, and macroscopic and microscopic performance correlation analyses. Key findings include: the harsh environment in the cold and arid regions resulted in inferior low-temperature performance of asphalt binder after 12 months of natural thermal-oxidative and all-weather aging compared to PAV-aged asphalt binder, with the stiffness modulus at −12 °C increasing by 114.8% and 105.3%, respectively. Natural aging induced more significant asphalt binder’s chemical structural changes than PAV aging but exhibited less prominent oxidative reactions and macromolecular structure formation. Whether from a macroscopic or microscopic perspective, thermal-oxidative conditions were identified as the primary driver behind both the natural aging behavior and the aging pathway of asphalt binder. The influence of other factors on the aging behavior of asphalt binder was not significant. The poor correlation (R² < 0.62) between oxygen content, molecular weight, and low-temperature performance across different aging modes underscores a fundamental divergence in aging pathways between PAV and natural aging. This study preliminarily identifies the key differences between laboratory-accelerated aging and natural aging of asphalt binder and paves the way for optimizing the parameters of laboratory-accelerated aging protocols.

Laboratory-simulated aging fails to fully replicate the complex aging behavior of asphalt binder under actual environmental conditions. This study aims to analyze the differences between natural aging and PAV aging of asphalt binder. In order to achieve the goal, in-door and natural environments were used to age the asphalt binder. The divergence in asphalt binder aging behavior was systematically investigated through encompassing low-temperature performance, chemical structure, elemental composition, molecular weight, and macroscopic and microscopic performance correlation analyses. Key findings include: The harsh environmental conditions in cold-arid region resulted in inferior low-temperature performance of naturally aged asphalt binder (12 months) compared to PAV-aged counterparts. Natural aging induced more significant asphalt binder’s chemi-cal structural changes than PAV aging, but exhibited less prominent oxidative reactions and macromolecular structure formation. Whether macroscopic or microscopic perfor-mance, hot oxygen was the main reason for the natural aging behavior of asphalt binder. The influence of other factors on the aging behavior of asphalt binder was not significant. The forced aging of PAV aging affected the cross-scale behaviors between oxygen content, molecular weight, and low-temperature performance in asphalt binder. This diminished the influence of oxygen content and molecular weight on the degradation of low-temperature performance, resulting in discrepancies compared to natural aging.

Laboratory simulation of aging cannot restore the complex aging behavior of bitumen well. The objective of study is to reveal the role of various field aging factors on the aging process of virgin bitumen and SBS(Styrene–Butadiene–Styrene)-modified bitumen. The influence of different field aging factors on aging behavior of virgin bitumen and SBS-modified bitumen were discussed. To achieve this goal, three different field aging styles were used to carry out field aging of virgin bitumen and SBS-modified bitumen. The aging behavior of the two types of bitumen were characterized based on rheological performance, and the influence degree of various aging factors on the rheological performance of bitumen was quantitatively analyzed through the contribution rates. The findings indicated that field aging had an obvious influence on the rheological performance of the two types of bitumen, which showed that the complex modulus, G-R parameter and stiffness modulus increased, and creep rate decreased. The contribution rates significantly indicated the degree of influence of hot oxygen, light and other factors (wind, water, dust, etc.) on the two types of bitumen. Among them, hot oxygen was the main factor leading to the aging of two types of bitumen. The virgin bitumen was not sensitive to aging caused by light, and the aging of SBS-modified bitumen was greatly affected by light. Other field aging factors (wind, water, dust, etc.) led to the aging of virgin bitumen to a certain extent, but inhibited the aging of SBS-modified bitumen.