Aging Evolution and Performance Correlations of Base and Rubberized Asphalt Binders Based on 2S2P1D Viscoelastic Parameters

Aging has a significant influence on the rheological behavior and service performance of asphalt binders. In this study, base asphalt binder (BAB) and rubberized asphalt binder (RAB) with different aging levels were investigated to clarify their aging evolution and performance correlations. Rheological tests were conducted to evaluate high-temperature rutting resistance, intermediate-temperature fatigue performance, and low-temperature cracking resistance. The 2S2P1D viscoelastic model was used to analyze the evolution of viscoelastic parameters, while gel permeation chromatography (GPC) was adopted to characterize molecular weight changes during aging. The results showed that aging increased the rutting resistance of both binders, but reduced fatigue performance and low-temperature cracking resistance. Among the 2S2P1D viscoelastic model parameters, G∞, δ, and β were more sensitive to aging than the other parameters and exhibited relatively clear variation trends. Selected viscoelastic parameters also showed significant correlations with rheological performance indices. GPC results indicated that both binder systems progressively evolved toward higher molecular weight during aging, with the molecular weight distribution curves shifting toward the high-molecular-weight region. For RAB, Mw was more sensitive to aging than Mn and showed some fluctuation at intermediate aging stages, reflecting a more complex molecular evolution. Overall, the results indicate that selected 2S2P1D viscoelastic parameters can serve as sensitive indicators of aging evolution and provide a useful basis for interpreting the performance correlations and rheological changes of asphalt binders from a viscoelastic perspective.