Effects of Aging on the Properties of Asphalt Binders and on the Dosage of Rejuvenating Agents

The aging of asphalt materials in the plant and during their service life modifies their chemical composition and properties due to mechanisms such as oxidation, volatilization, polymerization, and photo-oxidation. Since the extraction and recovery of binder from the asphalt mixture is challenging due to process uncertainties, many studies utilize laboratory aging, which can underestimate the results of the different mechanisms. Therefore, this article evaluates the rheological and performance properties of binders aged in the laboratory and recovered from RAP (Reclaimed Asphalt Pavement). Specifically, it seeks to compare the mechanisms and degree of aging on properties measured at high and intermediate temperatures, and their potential impact on the dosage of rejuvenating agents, identifying the parameters most sensitive to oxidation. The data showed that laboratory aging of binders can underestimate the effects on material properties, especially when compared to field mechanisms, which can result in incorrect dosage of the rejuvenating agent. Thus, the most assertive parameters for differentiating materials in relation to aging included RAIPD, RAIFAT, RAITOT, ωc, GRP, Tδ = 45°, true IPG, and the Nf obtained in the LAS test. These parameters provide the appropriate indices for the dosage of rejuvenating agents, in addition to highlighting the importance of the 2s2p1d model for measuring and obtaining rheological parameters.