Project status
Completed
Start date: 05/01/04
End date: 05/31/08
Researcher(s)
Principal investigators:
- David White | 515-294-1463 | djwhite@iastate.edu (project list)
Co-principal investigators:
- Charles Jahren | 515-294-3829 | cjahren@iastate.edu (project list)
- Radhey Sharma
- Vern Schaefer | 515-294-9540 | vern@iastate.edu (project list)
Student researchers:
- Matthew Cushman
- Thang Phan | 515-294-4015 | thphan@iastate.edu
About the research
Seasonal variations in ground temperature and moisture content influence the load carrying capacity of pavement subgrade layers. To improve pavement performance, pavement design guidelines require knowledge of environmental factors and subgrade stiffness relationships. As part of this study, in-ground instrumentation was installed in the pavement foundation layers of a newly constructed section along US Highway 20 near Fort Dodge, Iowa, to monitor the seasonal variations in temperature, frost depth, groundwater levels, and moisture regime. Dynamic cone penetrometer (DCP), nuclear gauge, and Clegg hammer tests were performed at 64 test points in a 6-ft x 6-ft grid pattern to characterize the subgrade stiffness properties (i.e., resilient modulus) prior to paving. The purpose of this project is to present the field instrumentation results and the observed changes in soil properties due to seasonal environmental effects.
Publications
Report: Final Report: Case Study of Seasonal Variation in the Subgrade and Subbase Layers of Highway US 20 (4.8 mb pdf) May 2008
Related publications:
- TRB 2009 Paper: Seasonal variation and spatial analysis of pavement foundation layers (off site), Oct 2011
- Tech Transfer Summary: Seasonal Variation in the Layers of Highway US 20 197 kb pdf (Tech transfer summary) May 2008
Sponsor(s)/partner(s)
Sponsor(s):
- Iowa Department of Transportation
- Iowa Highway Research Board
