Environmental conditions in pavement performance have emerged as an issue of interest. Subgrade behavior under climatic changes is directly related to soil moisture content, which influences the resilient modulus of the material. Consequently, pavement performance is directly related to weather and material properties which depend on the design and location of the road.
The Federal Highway Administration (FHWA) developed the Seasonal Monitoring Program (SMP) as part of the Long-Term Pavement Performance (LTPP) instrumentation program to monitor moisture and temperature seasonal variations. Data have been collected and analyzed for years, including at the Ohio/SHRP Test Road (U.S. 23, Delaware County, Ohio).
The Enhanced Integrated Climatic Model (EICM) was developed by the University of Illinois, the United States Army Cold Regions Research and Engineering Laboratory (CRREL) and the Texas A&M University. EICM is a one dimensional model that predicts heat and moisture flow during a period of time, for different climatic conditions. The EICM has been incorporated as part of the ME-PDG (Mechanistic Empirical Pavement Design Guide).
Designing pavements confidently using the ME-PDG requires knowing the accuracy of the EICM compared to field data. Moisture and temperature data from the Ohio SHRP Test Road have been compared with results from EICM for nine different sections (4 PCC sections and 5 AC sections). Good agreement was obtained for temperature, while moisture variation data was spread, showing poor and irregular correlations.
The Mechanistic Empirical Pavement Design Guide (ME-PDG) was used to predict the date of failure or first appearance of different distresses, which was compared to the behavior observed in field for five different sections (2 PCC sections and 3 AC sections).The ME-PDG seems to calculate distresses and failure dates accurately in some of the cases.