Reflection Crack Analysis of Asphalt Overlay on Cement Concrete Pavement Based on XFEM

Based on the improved Paris formula, the reflection cracking characteristics of asphalt overlay on the cement concrete pavement are carefully scrutinized. The fatigue life is also predicted through the indoor simulation tests and establishing the two- and three-dimensional extended finite-element method (XFEM) models. Four fracture factors of the Paris formula in the asphalt mixture are appropriately calculated by fitting the N-a curve of the indoor test, and their predicted values are then exploited in the numerical simulations. The obtained results show that the numerical model can successfully predict the results of the indoor simulation test. It indicates that the XFEM has apparent advantages in examining the reflection cracking of the asphalt overlay on the cement concrete pavement.

Development of a multi-modal overlay tester for the evaluation of asphalt overlay cracking behaviors

Reflection cracking is a critical issue in asphalt overlay pavement. Temperature variation and traffic loading are the main fracture modes acting on the material. In this paper, a multi-modal overlay tester is proposed for the evaluation of the reflection cracking resistance of an asphalt mixture, an approach that simulates three loading modes on asphalt specimens. A fine dense-grade hot mix asphalt is used as the test specimen and subjected to different loading conditions such as single Mode I, II, and III loading simulations and combined I+II and I+II+III loading simulations. Results show coefficients of variation (CVs) of 2.5%, 10.3%, and 7.4% for the Mode I, II, and III loading simulations, respectively. Furthermore, the β coefficient, with a CV of 7%, is used to represent the crack resistance of the asphalt mixture. Finally, the crack propagation occurs rapidly when subjected to tension and lateral displacement prior to repeated traffic loading simulations.