Evaluation of a Simulation of Subpavement Conditions as They Affect the Implementation and Removal of Seasonal Load Restrictions

The structural stability of highway pavements is significantly impacted by freeze–thaw processes, especially during the thaw period when a layer of water gets trapped between the pavement and the remaining frozen layer below. This reduces the structural stability of the sub-pavement materials and the subsurface structure remains in this weakened state until the freeze layer is completely thawed. The pavement degradation caused by heavy vehicles that traverse weakened pavements during this thaw may appear as rutting, depressions, cracking, frost heaving, pot holes, and corrugation. One current practice to minimize damage to the pavement is the application of load limits called seasonal weight restrictions (SWR). The decisions on when to employ SWR depend upon knowledge of when structural weakening begins and ends. Phase 3 of the Clarus Initiative included a demonstration of a Seasonal Weight Restriction Decision Support Tool to develop a data analysis, meteorological, and pavement modeling decision support tool to assist transportation agency control strategies during critical freeze–thaw periods. The Enhanced Integrated Climatic Model (EICM) was used to integrate Clarus-enhanced observations and forecasts into the EICM and display the EICM results in a web-based presentation. This paper discusses the structure of the EICM, its configuration requirements, and how the output relates to the sub-pavement conditions that impact structural stability of the base and subgrade layers. It provides presentations of past and current conditions based upon observed data and forecast guidance, and the findings from the 2-year demonstration test and findings from the 2-year demonstration project.