DETERMINATION OF REMAINING FLEXIBLE PAVEMENT LIFE. VOLUME IV. ANALYSIS OF IN-SITU GRANULAR LAYER MODULUS FROM DYNAMIC ROAD RATER DEFLECTIONS

The objective of the study was to investigate the ability of elastic layered theory coupled with non-linear dynamic modulus tests to predict comparable pavement deflections to that measured from dynamic Road Rater deflections. It was found, for over 180 test dates, pavement sections, sensor combinations, that the theoretically predicted deflection over-estimated the measured Road Rater deflections by a factor of about 2 to 4 (2.8 average). In order to obtain equal predicted and measured deflection values, the granular layer non-linear modulus was adjusted by a factor K1. A linear log-log relationship was found when the K1 factor was regressed to the measured surface deflections. It was concluded that the current laboratory method of modulus characterization to incorporate non-linear behavior underestimates the modulus of that granular material. An investigation was undertaken to determine whether the effect of shear strain was responsible for the decrease in granular layer modulus. It was found that the modulus does decrease with increasing shear strain and shear strain is proportional to surface deflection. These results indicated that relationships between surface deflection, shear strain, and granular layer modulus can be applied to predict in-situ modulus from deflection measurements.

  • Supplemental Notes:
    • See also Volume 3, PB-296564. Prepared for Maryland State Highway Administration, Brooklandville. Also available in set of 4 reports, PB-296561-SET.
  • Corporate Authors:

    University of Maryland, College Park

    Department of Civil and Environmental Engineering
    College Park, MD  United States  20742

    Maryland Department of Transportation

    State Highway Administration, 2323 West Joppa Road
    Brooklandville, MD  United States  21022

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Witczak, M W
    • D'Amato, P A
  • Publication Date: 1978-10

Media Info

  • Pagination: 265 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00197624
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: FHWA/MD/R-79/4 Final Rpt.
  • Files: NTIS, TRIS, USDOT, STATEDOT
  • Created Date: Aug 28 1979 12:00AM