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

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.