Finite Element Fracture Analysis of Airport Overlay System Using J-Contour Integral Approach

The flexible overlay system often fails before reaching its design life due to the occurrence of reflective cracking caused by stress concentrations in the vicinity of joints and cracks in the underlying pavement. Reflective cracking can lead to roughness, spalling, and moisture infiltration at joints and cracks, which can greatly reduce the life expectancy of the overlay. In this paper, a two-dimensional (2-D) finite element fracture model of rehabilitated airfield overlay system subjected to mixed-mode loadings was developed in this study to obtain accurate and reliable critical fracture responses in asphalt overlays placed over rigid airfield pavements. Stress intensity factor (SIF) and J-contour integral approach based on fracture mechanics theory were selected and implemented to analyze the mechanism of airfield pavement cracking. The finite element fracture model with the path-independent J-integral concept can obtain reliable and accurate stress predictions at the vicinity of the crack tip of rehabilitated pavements. The predicted stress intensity factors (SIFs) of 2-D finite element pavement models using singular elements were verified by comparison with reference solutions based on displacement correlation technique (DCT). The J-contour integral can be determined from the stress intensity factors using interaction integral method. The verified fracture model was applied to investigate a number of complicated environmental effects and critical aircraft gear loading conditions in an airfield overlay system. As a critical gear loading, the gear configuration and tire pressure of Boeing 777 aircraft were selected and compared with fourteen different loading positions. The 2-D gear loading magnitude in plane strain condition was adjusted with the horizontal stress responses of 2-D axi-symmetric condition. The fracture models with existing different crack length were analyzed and compared to investigate the stress concentration change at the crack tip. Other geometric and environmental factors such as model thickness, temperature gradient, subgrade support, load transfer efficiency, interlayer friction were analyzed with stress intensity factors in mode I and mode II.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01044165
  • Record Type: Publication
  • Report/Paper Numbers: 07-3450
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 8:08PM