AN EVALUATION OF IN-SITU ELASTIC MODULI FROM SURFACE-DEFLECTION BASINS OF MULTILAYER FLEXIBLE PAVEMENTS

Determination of in-situ modulus is an essential step in the nondestructive structural evaluation of flexible pavements. The research herein was undertaken to develop a method for evaluating the in-situ modulus of each pavement constituent layer by using surface deflection basins. The elastic layer theory and the Gaussian method of elimination were used to formulate surface deflection in terms of elastic modulus, load intensity, and layer thickness. The resulting equations were very complex, so that it was impossible to compute layer modulus directly from surface deflection basins. These equations, however, were used to analyze the effect of changing layer modulus on the surface deflection. On the basis of this analysis, a computer program for calculating in-situ modulus values from Road Rater deflection basins was developed, essentially by incorporating iteration procedures into the BISAR computer program. Using the developed computer program, the in-situ modulus of each pavement consistent layer of some of the experimental pavements at the Pennsylvania Transportation Research Facility was computed. The effect of various influencing factors on the in-situ moduli was investigated. Among the findings were (1) in-situ moduli decreased with cumulated traffic loading more significantly for surface and base course materials than for subbase and subgrade materials, (2) for a constant surface plus 5-day ambient temperature, the modulus of the base course increased with an increase in the base course thickness, and (3) increasing the thickness of surface plus base course increased the subbase modulus. (FHWA)

  • Corporate Authors:

    Pennsylvania State University, University Park

    Pennsylvania Transportation Institute, Transportation Research Building
    University Park, PA  United States  16802

    Pennsylvania Department of Transportation

    P.O. Box 2926
    Harrisburg, PA  United States  17120

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Anani, B A
    • WANG, M C
  • Publication Date: 1979-11

Media Info

  • Pagination: 152 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00334278
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-PA-80-009 Final Rpt., FCP 45C3-254
  • Contract Numbers: 75-2
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Aug 15 1981 12:00AM