Research on the influence of RAP and aged asphalt on the performance of plant-mixed hot recycled asphalt mixture and blended asphalt

The overuse of resources and environmental destruction has led to the development of renewable research. Research on reclaimed asphalt pavement (RAP) has received widespread attention. In this study, reclaimed milling material from China's Changyu Highway, which has been in operation for 15 years, was used to study the influence of aged asphalt content on the rheological properties, high-temperature performance, low-temperature performance and microscopic performance of blended asphalt and the impact of RAP content on the high-temperature stability, low-temperature crack resistance, water stability and resilience performance of recycled asphalt mixtures. The results show that the impact of aged asphalt content on the performance of base asphalt shares the same trend with the influence of RAP content on the performance of recycled asphalt mixture. With the admixing of aged asphalt, the blended asphalt is harder, increases in elasticity, and decreases in viscosity. The high-temperature performance improves, but the lowtemperature performance worsens. With the addition of RAP, the water stability of the recycled asphalt mixtures improves, the high-temperature stability improves, and the lowtemperature crack resistance worsens. This result is consistent with dynamic modulus test results. Overall, based on the micro and macro properties of blended asphalt and asphalt mixtures, a reasonable RAP content of 30% for road performance is given when the gradation is ATB-25.

Automated summary

This study investigated the influence of aged asphalt content and RAP content on the properties of asphalt mixtures. The results showed that the addition of aged asphalt made the blended asphalt harder and more elastic but less viscous, improving high-temperature performance while worsening low-temperature performance. On the other hand, the inclusion of RAP improved water stability and high-temperature stability, but decreased low-temperature crack resistance.