Investigation of the oxidation ageing of RAP asphalt blend binders and mixtures

ABSTRACT

This study evaluates the oxidation ageing properties of asphalt blends and mixtures combined with various percentages of RAP and SBS-modified binder, rejuvenator and neat binder. Four ageing methods were conducted in the laboratory on the asphalt blends and mixtures. The results showed that the G-R parameter, the ICO and the flexibility index increased, while the ΔT_cr decreased with the RAP content and the ageing level. The SBS-modified binder and rejuvenator improved the cracking resistance of the RAP binder and mixture. After PAV 20 h ageing, the asphalt blends containing a low amount of RAP were equivalent to their virgin binder after PAV 40 h ageing. The asphalt blends containing a low amount of RAP after PAV 40 h ageing were equivalent to their virgin binder after PAV 60 h ageing. It was found that binders subjected to RTFO, PAV 20 h ageing, PAV 40 h ageing, and PAV 60 h ageing had rheological and chemical properties equivalent to those of loose mixtures subjected to the STOA protocol for 4 h at 135°C, the LTOA protocol for 8 h at 135°C, the LTOA protocol for 12 h at 135°C, and the LTOA protocol for 24 h at 135°C, respectively.

KEYWORDS:

• Reclaimed asphalt pavement
• oxidation ageing
• rheology
• cracking resistance
• chemical property

Acknowledgements

The statements made herein are solely the responsibility of the authors.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Natural Science Foundation of Jiangsu Province [grant number BK20151413] and National Natural Science Foundation of China [grant number 51878162]. The authors appreciate the funding supports.