Laboratory Study of Aging Characteristics of Binder Warm Mix Asphalt Chemical Additive: Rutting, Fatigue Resistance, and Chemical Composition

This paper studied Warm Mix Chemical Additives (WMCA) aging behaviors. The three asphalt binders [base asphalt (neat), binder WMCA ZycoTherm (ZYC), and binder WMCA Evotherm M1 (EVM)] were treated with a short-term aging (STA) and long-term aging (LTA). The rheological rutting resistance factor (G*/sin δ) and linear amplitude sweep (LAS) by Dynamic Shear Rheometer (DSR) tests were conducted on all samples to test the indexes of rheological properties, in addition to chemical compositional changes were monitored by the Flame Ionization Detector (TLC-FID) to identify saturates, aromatics, resins, and asphaltenes (SARA). The results show that the value of the complex modulus rutting factor (G*/sin δ) and fatigue behavior of all asphalt binders increases with aging severity. Additionally, after LTA, the values of the Traffic volume indicator (N_f) at 15% share strain of base asphalt gradually decrease, while those of ZYC 0.07 and EVM 0.75 increase. After LTA, the rutting resistance of the ZYC improves while EVM deteriorates. EVM's rutting factor index degrades with aging, but its fatigue aging index improves. In addition, aging has greater effects than that of neat. The SARA change is due to adding WMCA to the binder. Saturates increases after aging. Aging affects the relationship between SARA fractions. The slope in the SARA chemical structure changes because of aging based on coefficient determination (R²). Aging influences the stability of Neat and binder WMCA. Moreover, after LTA some binder WCMA changes become stable. Based on the aging performance, binder WMCA demonstrated significant improvements has excellent resistance to temperature, and ideal choice for long-term applications.