Laboratory aging method for simulating the extracted aged asphalt from reclaimed asphalt pavement

Abstract

This study compared the performance of extracted asphalt and laboratory aged asphalt. The five-year service asphalt mixtures were used for extraction in this study. The laboratory aged asphalt experienced the Rolling thin film oven (RTFO) aging the Pressure aging vessel (PAV) aging with variable duration (5, 10, 15, 20, and 25 hours). By comparing the softening point, viscosity, and rheological properties of both, an aging simulation protocol was established. For laboratory aged asphalt binder, the softening point increases by 3.56 %, 5.68 %, 7.43 %, 8.16 %, and 8.74 % at PAV aging times of 5 h, 10 h, 15 h, 20 h, and 25 h, respectively. The rutting index and viscosity of the aged asphalt gradually increases with the PAV duration. There is a substantial increase in creep recovery rate and a significant decrease in non-recoverable creep compliance for aged asphalt. The rheological aging index demonstrates a linear increasing trend. The sulfoxide (SO) and aromatic (CO) aging indexes of the laboratory-simulated aged asphalt progressively rise with prolonged PAV aging time. The SO and CO aging indexes of the extracted asphalt consistent with RTFO aged asphalt experienced PAV aging 20 and 25 hours. The extracted asphalt can be simulated in the laboratory under standard RTFO conditions and a 22.26 hours PAV duration at a pressure of 2.1 MPa ± 0.1 MPa. This study introduces a methodology for simulating asphalt aging in an authentic service environment by adjusting the laboratory aging test conditions.

Keywords

• Reclaimed asphalt pavement
• Thermal-oxidative aging
• Rheological properties
• Aging indexes