Validation of Performance-based Method for Determining Rejuvenator Content in HMA

Abstract

This paper presents the results of a laboratory study in which the recommended values of rejuvenator contents from previous binder studies were validated through laboratory mixture performance tests. The experiments consisted of the comparison of recycled asphalt mixtures at three rejuvenator contents: 0, 2.0 (lower recommended limit) and 7.4% (upper recommended limit). In addition, a control mixture with virgin asphalt binder was also included in the experiment. The mixture performance tests included the wheel tracking at 60°C and low temperature thermal stress restrain specimen (TSRS) tests. The results from this study indicated that: (1) the properties of HMA using recycled asphalt binders with the recommended rejuvenator contents from the previous studies were comparable to the control virgin mixture; (2) it was more reliable to use the median recommended rejuvenator contents for mixtures with both satisfactory high temperature stability and low temperature fracture resistance and (3) the rejuvenator content affects significantly the properties of recycled mixtures in a similar way to that of the properties of recycled asphalt binders, by increasing low temperature grade and decreasing high temperature grade.

Keywords:

• Rejuvenator
• Recycling
• RAP
• Wheel tracking test
• TSRS test

Acknowledgements

The authors would like to thank Drs Nomura and Suzuki from the Research Institute, Taisei Rotec Co., Japan for their valuable discussions.