Simulation and Mechanical Response Analysis of Functional Gradient Pavement Slabs Under Impact Loading

The modulus of asphalt-based, cement-based, and inorganic binder materials in the layers of airport pavements or bridge deck pavements varies significantly, leading to complex stress distributions and cause cracking. Based on this, the concept of functionally gradient materials offers a novel solution for optimizing the stress distribution. This study employed the Fortran-based subroutine for secondarily developing the Abaqus finite element software, creating the model of the impact load from B737-800 landing gear, and three types structures with gradient modulus. For comparison, two conventional airport pavement structures were also analyzed. By comparing the wheel load position when the impact load reaches its maximum value, it was found that in both conventional airport pavement structures, the maximum tensile stress at the bottom of each layer occurs directly beneath the wheel imprint. Furthermore, the most critical load position was where the wheel spanned the transverse joint while adjacent to the longitudinal joint. The results indicate that all three gradient pavement structures improve the mechanical response. Among them, the Fully paved gradient layered pavement closely approximates the continuous gradient pavement. The gradient pavement design approach proposed in this study provides valuable insights for the structural design of airport pavements and bridge deck pavements.