Aging effects on rheological properties of high viscosity modified asphalt

Abstract

This work investigated the aging effects on the rheological properties of high viscosity modified asphalt (HVMA). First, the high- and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer, respectively. The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope. Besides, a study was performed to compare the aging effects on the rheological properties of HVMA, crumb rubber modified asphalt (CRMA), and neat asphalt (SK-90). The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging. The complex shear modulus of the HVMA was improved by the aging in the whole frequency range. The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging. Thus, the aging improved the high-temperature viscoelastic performance of HVMA. With a decrease in temperature from −12 °C to −24 °C, the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase. Both of the short- and long-term aging of HVMA were caused by an oxidation reaction, while modifier swelling also happened after long-term aging. Compared to CRMA and SK-90, aging had a limited influence on the high- and low-temperature rheological properties of HVMA.

Keywords

• High viscosity modified asphalt
• Rheological properties
• High-temperature
• Low-temperature
• Aging mechanism