Effects of a Nonuniform Subgrade Support on the Responses of Concrete Pavement

Intelligent compaction is gaining attention for its ability to spatially map the compaction effort of a pavement support layer, and it has also been shown to be able to detect areas of nonuniform compaction, which raises the issue of what the effects of a nonuniform support condition are on the stresses and deflections in a rigid pavement. This study considered multiple nonuniform support conditions, including theoretically generated and predetermined and randomly assigned from measured field data. The slabs and nonuniform support conditions were modeled using two-dimensional and three-dimensional finite element methods with input variables being axle type, curling, and lateral and longitudinal axle movements. Overall the study found that certain nonuniform support conditions and axle positions can significantly increase the peak tensile stress in the slab over even uniform soft support. In particular, a single slab with soft longitudinal edge support and a slab with “randomly” assigned nonuniformities were critical cases that increased the peak slab tensile stresses. When the slab was modeled with preexisting through-length surface cracks, it was found that the nonuniform soft edges support conditions would result in unstable crack growth based on the significant increase in the stress intensity factor. When modeling a set of concrete slabs over a nonuniform support based on field data, the peak tensile stresses were increased relative to a uniform support based on the location of the wheel load relative to the nonuniformity and also based on the adjacent differences in nonuniform soil stiffness. The field data was also statistically reassigned by normal and beta distributions to predefined area sizes, which demonstrated that with a normal distribution, the probability of low k-values along the pavement edge increased thereby raising the probability of higher peak tensile stresses. Overall, certain nonuniform support of concrete slabs can produce much higher tensile stresses than a uniform support condition, particularly when considering different loading positions and curling conditions, soft support along the pavement edge, and preexisting cracks.

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    University of Illinois, Urbana-Champaign

    Department of Civil and Environmental Engineering
    205 North Mathews Avenue
    Urbana, IL  United States  61801-2352

    University of Brasilia

    ,   Brazil 

    Iowa State University, Ames

    2711 South Loop Drive
    Suite 4700
    Ames, IA  United States  50010-8664

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Brand, Alexander S
    • Roesler, Jeffery R
    • Chavan, Hemant L
    • Evangelista Jr, Francisco
  • Publication Date: 2013-9

Language

  • English

Media Info

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Filing Info

  • Accession Number: 01494597
  • Record Type: Publication
  • Report/Paper Numbers: ICT-13-027, UILU-ENG-2013-2028
  • Contract Numbers: DTFH61-06-H-00011 Work Plan 18
  • Files: TRIS, ATRI, USDOT
  • Created Date: Sep 25 2013 3:00PM