The effect of long-term aging on fatigue cracking resistance of asphalt mixtures

ABSTRACT

Asphalt aging is recognised as one of the important factors causing cracking related failures in asphalt pavements. Asphalt aging occurs during production, construction, and service life of the asphalt surfaced pavements. Since constituents of asphalt mixtures are continuously increasing (increased recycled asphalt pavement (RAP), rejuvenators, compaction aids, warm-mix additives, fibres, etc.) and interactions between these constituents are complicating the mixture design process, relying solely on the volumetric mixture design is usually not resulting in asphalt mixtures with the highest possible performance. Thus, asphalt mixture test methods for rutting and cracking should be improved and incorporated into current mixture design methods to be able to develop more durable asphalt mixtures that last for their intended service lives. In this study, the most effective asphalt mixture long-term aging protocol was determined to achieve reliable semi-circular bend (SCB) test parameters that are correlated with in-situ cracking performance. The selected aging protocol will be integrated into the balanced mix design procedures that are currently being developed. Developed asphalt mixture design methods are expected to improve the longevity of asphalt materials, reduce life-cycle costs for agencies, and improve long-term road users’ comfort.

KEYWORDS:

• Aging protocol
• cracking
• asphalt mixtures
• long-term aging
• semi-circular bend test
• flexibility index
• dynamic shear rheometer

Acknowledgements

This paper describes research activities that were requested and sponsored by the Oregon Department of Transportation (ODOT). The contents of this paper reflect the views of the authors and do not reflect the official views or policies of the State of Oregon or Federal Highway Administration. Federal and State sponsorship and interest are gratefully acknowledged. The authors thank the members of the ODOT Project Technical Advisory Committee and ODOT research for their advice and assistance in the preparation of this report. The authors would like to thank Ihsan Ali Obaid for his help with laboratory testing.

Disclosure statement

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

Notes

1 FE is the total energy necessary for fracture inducement, and it shows the fracture tolerance of the mixture, therefore, represents the cracking performance of the mixture (Roque et al. 2011).

Additional information

Funding

This paper describes research activities that were requested and sponsored by the Oregon Department of Transportation (ODOT).