Case Study of Seasonal Variation in the Subgrade and Subbase Layers of Highway US 20, TR-516, 2008

(2008) Case Study of Seasonal Variation in the Subgrade and Subbase Layers of Highway US 20, TR-516, 2008. Transportation, Department of


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TR-516 Tech Brief T2.pdf

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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 paper is to present the field instrumentation results and the observed changes in soil properties due to seasonal environmental effects.

Item Type: Departmental Report
Keywords: Bearing capacity, Case studies, Cone penetrometers, Frost, Groundwater, Modulus of resilience, Moisture content, Nuclear gages, Pavement design, Pavement performance, Subbase (Pavements), Subgrade (Pavements), Temperature
Subjects: Transportation
Transportation > Roads and highways
Transportation > Research
Transportation > Environment
Transportation > Environment > Weather and climate
ID Code: 19975
Deposited By: Iowa DOT Library
Deposited On: 30 Jun 2015 11:51
Last Modified: 22 Jan 2018 15:10