Toward a realistic asphalt mix ageing protocol

Abstract

The time-associated changes of the asphalt cement properties significantly impact the performance and durability of pavements. Different techniques have been introduced to simulate pavement ageing, most of which use elevated temperatures and neglect factors such as moisture and solar radiation. This research evaluated the coupling effect of solar radiation, heat, and moisture conditioning on the laboratory compacted plant mixes to achieve representative aged samples for performance testing. Rheological and chemical analysis were then performed on samples at various stages of the conditioning process and recovered asphalt cement. Temperature-Sensitivity of the rheological parameters were evaluated using time-temperature superposition shift factors. Carbonyl and sulfoxide indices and carbonyl to sulfoxide ratios were used to assess the kinetics of the age-related chemical changes. This study showed that coupling moisture and solar radiation could alter the chemistry and rheology of conditioned samples.

KEYWORDS:

• Asphalt ageing
• rheology
• age conditioning
• solar radiation
• 2S2P1D
• temperature sensitivity

Acknowledgements

The authors would like to extend their acknowledgments to the Ontario Ministry of Transportation (MTO) for funding this research through the Highway Infrastructure Innovations Funding Program (HIIFP). Special thanks to Coco Asphalt Engineering and their knowledgeable personnel for technical support with FTIR testing. Our gratitude is also extended to Steed & Evans Ltd. for their help with the collection of plant-mixed loose asphalt and virgin binder that was utilised in this research project.

Disclosure statement

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