Numerical study on the effect of mixture morphology on long-term asphalt mixture ageing

Abstract

Asphalt mixtures with similar percentages of air voids can have different morphologies and can age differently. Prediction of ageing behaviour without considering the influence of mixture morphology may thus lead to erroneous conclusions and non-optimal mix design. This article investigates the long-term field ageing of asphalt mixtures by incorporating mixture morphology. For this, a computational analysis on diffusion–reaction process has been conducted by implementing fundamental mechanism of ageing and conducting a parametric sweep of the morphology. To investigate the ageing gradient along the depth of asphalt mixture, diffusion controlled oxidative ageing on one dense and one open-graded field core was investigated. The proposed model based on the mixture morphology information was able to predict the aged viscosity better than the existing model. As mixture morphology is controllable, having insight into how the morphology parameter influences the mixture's ageing susceptibility can be of great value to its design.

Keywords::

• ageing
• asphalt mixture
• mixture morphology
• diffusion

Acknowledgements

The assistance of Alvaro Guarin and Ibrahim Onifade in the scanning of the asphalt mixture cores is kindly acknowledged.

Notes

^1. Email: [email protected]

^2. Email: [email protected]

Additional information

Funding

The authors would like to extend their sincere gratitude to the Swedish Transport Administration (Trafikverket) for providing the financial support for the project.