Viscoelastic Computational Fracture Mechanics Approach for the Analysis of Thermal Reflective Cracking in Asphalt Overlaid Jointed Concrete Airfield Pavements

Predicting crack propagation in a composite airfield pavement is a computationally challenging task. This study presents the development of a fracture-based modeling approach to capture crack propagation in an asphalt concrete (AC) overlay on jointed Portland cement concrete (PCC) pavement structure. A four-stage numerical framework was developed to predict thermal induced joint reflective cracking. The framework leverages a combination of finite difference methods, finite element (FE) thermo-mechanical modeling, and the Generalized Finite Element Method (GFEM) coupled with the elastic-viscoelastic correspondence principle (EVCP). FE thermo-mechanical and GFEM fracture simulations were solved in 3-D. Performing the simulations in 3-D domain shows the non-uniformity of PCC joint movement through the depth and width of the concrete slabs. The results show that this non-uniformity is mainly influenced by AC stiffness and thermal expansion/contraction. Simplified design models were prepared for joint opening under different cooling cycles. GFEM s adaptive meshing and global-local analysis enable accurate calculation of stress intensity factors from the elastic solution. Application of EVCP provided the ability to address the critical challenges of incorporating 3-D viscoelastic analysis within the framework. Using EVCP viscoelastic ERR can be calculated for various AC mixtures and cooling cycles using a limited set of elastic solutions. The framework was validated using FAA outdoor test section for joint reflective cracking at the National Airport Pavement Test Facility. Thermal reflective cracking performance for different overlay scenarios was simulated in four different climatic regions, highlighting the framework s ability of capturing the effect of pavement structure and climate on overlay fatigue life.