Fatigue life and endurance limit prediction of asphalt mixtures using energy-based failure criterion

Abstract

Fatigue cracking is one of the major types of distress in asphalt mixtures and is caused by the accumulation of damage in pavement sections under repeated load applications. The fatigue endurance limit (EL) concept assumes a specific strain level, below which the damage in hot mix asphalt (HMA) is not cumulative. In other words, if the asphalt layer depth is controlled in a way that keeps the critical HMA flexural strain level below the EL, the fatigue life of the mixture can be extended significantly. This paper uses two common failure criteria, the traditional beam fatigue criterion and the simplified viscoelastic continuum damage model energy-based failure criterion (the so-called G^R method), to evaluate the effect of different parameters, such as reclaimed asphalt pavement (RAP) content, binder content, binder modification and warm mix asphalt (WMA) additives, on the EL value. In addition, both failure criteria are employed to investigate the impacts of these parameters in terms of the fatigue life of the study mixtures. According to the findings, unlike an increase in RAP content, which has a negative effect on the mixtures’ fatigue resistance, a higher binder content and/or binder modification can significantly increase the EL value and extend the fatigue life as was proved before by other researchers, whereas WMA additives do not significantly affect the mixtures’ fatigue behaviour. A comparison of the model simulation results with the field observations indicates that the G^R method predicts the field performance more accurately than the traditional method.

Keywords:

• Asphalt pavement
• endurance limit
• fatigue life
• fatigue failure criterion
• field observations

Acknowledgements

The authors would like to acknowledge the financial support from the FHWA DTFH61-08-H-00005 project, Hot Mix Asphalt Performance-Related Specification Based on Viscoelasticity Continuum Damage (VEPCD) Models and the TPF 5(230) study, Evaluation of Plant-Produced High-Percentage RAP Mixtures in the Northeast.

Disclosure statement

No potential conflict of interest was reported by the authors.