Asphalt concrete crack propagation parameters from XFEM modelling of the Texas Overlay Test

ABSTRACT

Paris’ power law is commonly used to describe transverse thermal cracking propagation in asphalt concrete (AC) pavements. In its most common format, it relates the rate of change in the crack length per cycle to changes in either the stress intensity factor K or the energy release. The parameters defining this relationship for ACs can be obtained using the Texas cyclic Overlay Test (OT_R). This paper describes two numerical approaches for simulating the OT_R using the extended finite element method (XFEM). The first uses the direct low-cyclic fatigue (LCF) approach and the second uses the virtual crack closure technique (VCCT). Comparisons of the model predictions to laboratory OT_R measurements for six mixtures suggest that the XFEM model coupled with VCCT is better suited for simulating the OT_R. The model output includes the crack length and the energy release rate ERR (i.e. $\mathrm{\Delta }{J}_R$) as cracks propagate. This data was used to fit the modified Paris’ law parameters $A^{\mathrm{\prime }}$ and $n^{\mathrm{\prime }}$ as a function $\mathrm{\Delta }{J}_R$. Subsequently, the traditional A and n Paris’ power law parameters were fitted by estimating the corresponding ΔK. Using this model, it was possible to efficiently estimate the AC cracking parameters using as input only the tensile modulus and the critical ERR.

KEYWORDS:

• Cracking
• fracture parameters
• energy release rate
• XFEM
• overlay tester

Acknowledgements

The authors would like to thank Dr. Imad Abdallah from the University of Texas, El Paso, and Dr. Lubinda Walubita from the Texas Transportation Institute for providing some of the laboratory data used in this study.

Disclosure statement

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

Data availability statement

Details on the laboratory data and simulation input/output data can be made available upon request.

Additional information

Funding

This work was supported by the Texas Department of Transportation.