Investigation of the Rheological Properties and Aging Behavior of Aged Asphalt Binder in a Dynamic Pore Water Pressure Environment

Asphalt pavements in rainy regions are prone to aging and moisture damage, which can significantly impair the performance of asphalt binders. This study examines the rheological properties and aging behavior of asphalt binders under dynamic pore water conditions. Short-term and long-term aged asphalt binders were subjected to different dynamic water environments to assess their moisture sensitivity at high, medium, and low temperatures. Rheological evaluations were conducted using a dynamic shear rheometer (DSR) and a bending beam rheometer (BBR), while Fourier transform infrared spectroscopy (FTIR) was employed for quantitative analysis of aging behavior. The results at high temperatures showed that prolonged hydrodynamic exposure improved the performance of short-term aged binders but had detrimental effects on long-term aged binders. At medium temperatures, increased hydrodynamic exposure led to a reduction in the fatigue life of the aged binders. Low-temperature performance, as indicated by the S/m index, was found to deteriorate progressively with longer hydrodynamic exposure. FTIR analysis revealed that extended dynamic water exposure resulted in increased concentrations of hydroxyl, carbonyl, and sulfoxide functional groups in both short-term and long-term aged binders. As the dynamic water exposure time increases, there is a strong correlation between the rutting factor, fatigue resistance, low-temperature performance and sulfonation index (SI) of the aged asphalt binder.