SEASONAL VARIATION OF MOISTURE AND SUBSURFACE LAYER MODULI

In 1995 the Montana Department of Transportation initiated a study on the seasonal variation of pavement strength, with an emphasis on spring thawing. Ten sites representing a cross section of Montana subgrade soil and pavement structure were selected and instrumented with moisture and temperature sensors. Field measurements of surface deflections, moistures, and temperatures were initiated in autumn 1996 and continued through the spring of 1997. The moisture and deflection data were used to determine the thaw-weakening characteristics of the sites and to develop subgrade modulus values for use in the future design of pavement structures using AASHTO mechanistic design methodology. Results indicated that in several areas not only the subgrade but also the base course layers were prone to thaw weakening. The length of thaw weakening varied from 4 days to a 3-week period. In addition, it was found that in almost all cases the subsurface moisture content began to increase rapidly when the subsurface temperature rose to around -2 deg C during the spring. In some cases it was found that when the subsurface temperature finally warmed to 0 deg C, the moisture content had reached its prefreeze value. This research provides a general description of the test sites and measurements; it quantifies the effects of thaw weakening on typical roads in Montana based on deflection and surface and subsurface moisture and temperature.

• Record URL:
  https://doi.org/10.3141/1709-12
• Summary URL:
  http://scholar.google.com/scholar_lookup?title=SEASONAL+VARIATION+OF+MOISTURE+AND+SUBSURFACE+LAYER+MODULI&author=V.+Janoo&author=K.+Shepherd&publication_year=2000
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309066883
• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1709, Geotechnical Aspects of Pavements 2000.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Janoo, V
  • Shepherd, K
• Publication Date: 2000

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 98-107
• Serial:
  • Transportation Research Record
  • Issue Number: 1709
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Base course (Pavements); Deflection; Field studies; Modulus of resilience; Moisture content; Pavement performance; Seasonally frozen ground; Subgrade (Pavements); Temperature sensors; Thaw
• Uncontrolled Terms: Spring thaw; Thaw weakening
• Geographic Terms: Montana
• Subject Areas: Design; Geotechnology; Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces;

Filing Info

• Accession Number: 00799050
• Record Type: Publication
• ISBN: 0309066883
• Files: TRIS, TRB
• Created Date: Sep 28 2000 12:00AM