Assessment of the Aging Process of Finished Product-Modified Asphalt Binder and Its Aging Mechanism

Styrene-butadiene-styrene-modified asphalt binder (SBSMA), crumb rubber-modified asphalt binder (CRMA), and high-viscosity-modified asphalt binder (HVMA) have been widely used in porous asphalt concrete. However, the aging of the modified asphalt binder significantly affects the performance of the porous asphalt concrete. The main aim of this research is to quantitatively assess the aging degree of finished product-modified asphalt binders of SBSMA, CRMA, and HVMA at high, medium, and low temperatures, and to explore the aging mechanism at the microscopic level. This study used rolling thin-film oven and pressurized aging vessel to simulate the aging of asphalt binders. Dynamic shear rheometer, bending beam rheometer, Fourier transform infrared spectrometry, thin-layer chromatography with flame ionization detection, and scanning electron microscopy were employed to investigate how aging affects the rheological and microscopic properties of finished product-modified asphalt binder. The results showed that at high temperatures, short-term aging significantly impacted HVMA [change rate of the rutting factor (CRRF)=18.9%], while long-term aging had an enormous influence on CRMA (CRRF=179.5%). Short-term aging had the greatest effect on the fatigue property at medium temperature of CRMA [change rate of Nf (CRNf)=59.9%], followed by SBSMA (CRNf=46.1%) and HVMA (CRNf=26.2%). However, the effect of long-term aging on the fatigue properties of HVMA (CRNf=99.2%) is the largest, followed by that of CRMA (CRNf=95.8%) and SBSMA (CRNf=56.6%). At low temperature, compared with CRMA and HVMA, aging had the greatest influence on the low-temperature rheological properties of SBSMA. In addition, the three finished product-modified asphalt binders exhibited similar changes in microscopic level after aging.