Beyond oxidation: a new framework for understanding and effective simulation of asphalt aging in the era of climate-adaptive pavements

Asphalt aging has become a climate-sensitive infrastructure problem, shaped by combined thermal, UV, moisture, and oxidative stressors. This review draws on more than 80 years of laboratory aging research and critically examines legacy protocols and newer multi-stressor simulations, focusing on the aging pathways they trigger and the aging states they produce. An aging triad is proposed as a guiding structure that links environmental stressors, material composition, and dominant physico-chemical mechanisms. It explains why outcomes from different methods are often not equivalent across climates or binder classes. Aging issues are also summarized for non-standard materials, including polymer-modified binders, cold mixes and emulsions, and recycled-content systems, where classical protocols can introduce bias or fail to represent field processes. FA2MS is then presented as a literature-derived framework that accounts for climate, material type, objectives, and laboratory constraints when selecting protocols. Priority research needs are identified to improve comparability, standardization, and field representativeness.