A three-dimensional generalised finite element analysis for the near-surface cracking problem in flexible pavements

Near-surface cracking is one of the major distress types which results in reducing pavement service life. Heavy traffic loads, construction deficiencies, and surface mixture characteristics are among the predominant factors contributing to near-surface cracking. In addition, non-uniform tire-pavement contact stresses have a potential to generate extremely complex stress states near the surface. Prediction of crack initiation under these conditions requires high accuracy in the computation of state variables in pavement structure such as stresses, strains and displacements in the pavement. The generalised finite element method (GFEM) provides a computational framework in which arbitrary orientation of cracks in a finite element mesh is possible when using an enrichment strategy. The enrichment strategy in the GFEM can also increase the accuracy of the solution using higher-order polynomial approximations. A 3D analysis of near-surface cracking is performed using the GFEM. A 3D large-scale model of a long-lasting pavement is built, and cracks at various locations near the surface are introduced. Numerical experiments of a long-lasting pavement structure with defects at the aggregate scale illustrate the complex fracture conditions on and near the surface in the vicinity of a dual tire configuration.