Characterization of Asphalt Aging by Analytical Techniques: A Review on Progress and Perspectives

This review describes the chemical composition of asphalt, which is relevant for the development of materials with higher quality and durability. Asphalt aging can occur in the short term (during machining and storage periods) and the long-term (during the time the pavement is exposed to the environment). To understand the effect of aging on the chemical and physical properties of asphalt, we reviewed the short-term (rolling-thin film oven test (RTFOT) and its variations) and long-term (pressure aging vessel (PAV) and its variations) aging methods and the effects of the sun's ultraviolet radiation (Suntest and its variations). We also explored the main chemical reactions that occur in the aging processes, such as oxidation, polymerization, and aromatization. For a more accurate assessment of the classes of compounds that undergo aging reactions, fractionation techniques have been developed over the years, such as separation of asphalt into saturates, naphthenic-aromatics, resins, asphaltenes, organic sulfides, nitrogenates, and oxygenates, among others. Despite several studies on the theme of asphalt aging, it is still necessary to understand the phenomena that occur in those processes.