Simplified Solution for Periodic Thermal Discontinuities in Asphalt Overlays Bonded to Rigid Pavements

Abstract

This work investigates the elastic fields which develop in an overlay bonded to a rigid substrate when the system is subjected to thermally induced stress. A two-dimensional solution of the displacement field is derived for periodic discontinuities distributed in a hot mix asphalt overlay bonded to a rigid pavement, where the length of the pavement before cracking develops is much larger than its layer thickness. A series form solution is obtained, requiring calibration due to the limitation of the basis functions used. The formulation allows thermal cracks of variable depth to be considered, and its accuracy is verified through comparisons with numerical solutions obtained with ABAQUS. Energy release rates are calculated from the model for top-down plane strain cracking and three-dimensional channeling. By comparing the energy release rates with the fracture toughness of the overlay, conditions for crack initiation and an estimation of crack depth for a given temperature change can be estimated. Although several simplifying assumptions are made in the current approach, it is shown to be more general and therefore more widely applicable as compared to existing closed-form solutions. The solutions are valuable to the pavement analyst who seeks to understand the general mechanisms of thermally induced pavement deterioration and for the researcher wishing to perform early stage verification of more complex pavement models.