The subgrade of road bed soils is generally constructed near the optimum moisture content-dry density combination standard Proctor tests. However, environmental and seasonal variations alter the design moisture contents and the resilient properties of subgrade soils. These changes influence structural performance of pavements. Recent pavement design guides, which use the resilient modulus for characterizing pavement materials, require additional information on seasonal moisture content variations and their influence on resilient properties. This report presents results from an experimental study which investigated the influence of moisture content variations on the resilient modulus of soils. Two soil types, sand and silty clay compacted at above, and below optimum moisture content levels, were tested using the AASHTO T-294 procedure. Two in-cell displacement measurement systems measured displacements with respect to the ends of the specimen and the middle one-third of the specimen. Results indicated that the influence of moisture content on moduli appears to be more evident in clays than in sands. The effect of moisture content on the resilient modulus computed from both measurement systems is discussed. The measurement coefficients used to convert end system moduli to middle system moduli are provided for various moisture content levels in both soils. The influence of conditioning confining stresses and moisture contents on accumulated plastic deformations is also evaluated. The regression model results for the tests conducted in the investigation are also included.


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 87-102
  • Monograph Title: Modeling and model verification; testing pavement layers and materials; and low-cost drainage structures
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00715546
  • Record Type: Publication
  • ISBN: 0309061725
  • Files: TRIS, TRB
  • Created Date: Jan 2 1996 12:00AM