# Study on the Aging Behavior of Asphalt Binder Exposed to Different Environmental Factors  
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1 National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083, China; [EMAIL_ADDRESS]  
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4 School of Environmental, Civil, Agricultural and Mechanical Engineering, University of Georgia, Athens, GA 30602, USA 4  
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5 Gansu Provincial Highway Development Group Co., Ltd., Lanzhou 730070, China 5  
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6 State Key Laboratory of Bridge Engineering Safety and Resilience, Beijing University of Technology, Beijing 100124, China; 677 The Key Laboratory of Urban Security and Disaster Engineering, Ministry of Education, Beijing University of Technology, Beijing 100124, China 78 [PERSON]L_ADDRESS]  
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8 [PERSON] Netherlands, 8  
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6 State Key Laboratory of Bridge Engineering Safety and Resilience, Beijing University of Technology, Beijing 100124, China; 67 The Key Laboratory of Urban Security and Disaster Engineering, Ministry of Education, Beijing University of Technology, Beijing 100124, China 78 [PERSON] Netherlands, 8  
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33 [PERSON] Netherlands,  
Nevertheless, asphalt pavements inevitably confront adverse factors like sunlight, oxygen, varying temperatures, and moisture over prolonged periods, leading to aging-related challenges. This results in decreased durability and a shortened service life for asphalt pavements [1]. The primary cause of asphalt pavement deterioration lies in the aging of the asphalt binder, which binds aggregates, mineral powders, and additives together [2]. Effectively enhancing asphalt pavement durability and implementing precise pavement maintenance measures constitute urgent challenges to address. Solving these problems necessitates a more precise and profound comprehension of the principles governing asphalt binder aging. Aging typically manifests in macroscopic properties, marked by hardening, reduced penetration, decreased ductility, irreversible creep flexibility, and phase angle, as well as an increase in the softening point and zero shear viscosity. [PERSON] et al. [3] observed a decrease in the ductility with increasing aging, albeit with an elevated critical low-temperature point. SBS-modified asphalt binder displayed superior plastic deformation capability and robust resistance to aging. [PERSON] et al. [4] noted that UV aging led to higher softening point and viscosity values, accompanied by decreased ductility and penetration of asphalt binder. Layered double hydroxides enhanced asphalt binder's aging resistance. [PERSON] et al. [5] revealed an increase in complex modulus and temperature sensitivity of aged asphalt binder. Asphalt pavement exhibited signs of hardening and loosening due to aging. On the microscopic front, aging is typified by the thermal evaporation of light components, the transformation of light fractions into heavier ones, an uptick in polar functional groups, and a rise in average molecular weight. [PERSON] [6] concluded that asphalt binder aging primarily stems from light component volatilization, oxidation, structural changes, photopolymerization, and thermal condensation. [PERSON] et al. [7] observed an augmentation in the macromolecular structure and average molecular weight following aging. [PERSON] et al. [8] detected an increase in straight chain length, a higher number of large molecules, and heightened internal friction in asphalt binder molecules during motion after aging. Presently, much of the research on asphalt binder aging relies on laboratory-accelerated simulated aging [9]. The Thin Film Oven Test (TFOT) or Rolling Thin Film Oven Test (RTFOT) simulates asphalt binder aging during production, transportation, and paving. Pressure Aging Vessels (PAV) simulate aging during service life [10]. Researchers also have developed UV aging equipment. Asphalt binder UV aging tests are now increasingly becoming standardized [11; 12; 13; 14; 15]. Ozone, water, and multifactorial coupled aging are also garnering increased attention [16; 17; 18; 10].