Laboratory evaluation of performances and thermo-oxidative aging characteristics of high-viscosity modified asphalt

High construction temperatures and complex application conditions make the high-viscosity modified asphalt (HVMA) susceptible to aging. This work presents a comprehensive investigation of the performances and thermooxidative aging characteristics of HVMA. Fistly, an instant high-viscosity modifier (HVM) was synthesized and then optimized by entropy weight method. The modification mechanism and high- and low-temperature performances of HVMAs were investigated by the Fourier transform infrared spectroscopy (FTIR), temperature sweep, and low temperature creep tests. Besides, thermo-oxidative aging characteristics were evaluated by the frequency sweep, multiple stress creep recovery (MSCR) and fluorescence microscopy (FM) tests. Results shows that the recommended formulation of instant HVMA (HVMA-I) was 12 % instant HVM and 0.2 % stabilizer. Grafting and cross-linking reactions involved in HVMA-I, thus ensuring the excellent high- and low-temperature performances. The thermo-oxidative aging of HVMA consisted of the modifier degradation and the binder oxidation. Short-term aging produced a marginal effect as a fluctuating change direction for complex modulus. Long-term aging had pronounced effects on the performances of HVMA. At the macroscopic level, the complex modulus was increased and the nonrecoverable creep compliance was decreased; at the microscopic level, the fluorescence area was reduced and phase network was degraded.