Stiffness-Based Evaluation of Base and Subgrade Quality Using Three Portable Devices

The quality of base and subgrade construction has conventionally been evaluated using measurements of density and moisture content. These measurements are not without problems. First, they require the use of nuclear gauges that pose potential safety hazards to the operator, who usually requires expensive certification and monitoring. Second, measured properties do not relate to pavement design input parameters or performance. Fundamental material properties such as resilient moduli that are key inputs in a mechanistic-empirical–based design cannot be obtained from measurements of density and moisture content. Third, they may not be suitable for evaluating new materials. The objective of this study was to investigate the suitability of three portable devices to evaluate base and subgrade quality using stiffness-based measurements: the lightweight deflectometer (LWD), GeoGauge, and dynamic cone penetrometer (DCP). Seven pavement sections in Virginia were evaluated. A high spatial variability in stiffness moduli was found for all project sites. No significant correlations among the devices were found. The 85th percentile stiffness moduli for the devices compared well for all projects. The effect of dry density was not evident, but the moisture content had a significant influence on the measured stiffness with all three devices, especially the LWD. A limited laboratory investigation indicated that high LWD moduli may occur at low saturation levels because of soil suction and at high saturation levels because of the development of pore water pressure in association with the transient nature of the LWD loading. Unlike the LWD, the GeoGauge and DCP did not indicate dramatic changes in moduli because of changes in degree of saturation.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 19p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01155572
  • Record Type: Publication
  • Report/Paper Numbers: 10-1721
  • Files: BTRIS, TRIS, TRB
  • Created Date: Jan 25 2010 10:46AM