Thermal aspect of frost-thaw pavement dimensioning - In situ measurement and numerical modeling

The thermal behavior of pavements in winter has a major influence on their dimensioning. The Paris-based Laboratoire Central des Ponts et Chaussees and the Ministere des Transports du Quebec have models to forecast the propagation of frost, frost heave, and thaw events. They have developed a collaborative project to validate these models on an experimental pavement. This pavement was constructed in Quebec in 1998, and its thermal behavior was monitored for 3 years. Two pavements, one with a cement-treated base and one with a hot-mix asphalt pavement, were selected. Two test beds were constructed on each pavement. One test bed was thermally insulated by a layer of extruded polystyrene, and the second was not. The SSR, GEL1D, and CESAR-GELS thermal models; the site and the temperature conditions of the three winters; the pavement structures and their physical properties; the instrumentation setup; and the analysis and comparison of the results of the models among themselves and in relation to the observations conducted on the pavements were assessed. The models provided a satisfactory estimate of frost penetrations, with less than 10% deviation observed between the measured and calculated depths. The deviations between the results of the different models are explained by the differences between the modeling principles. The size and quality of the database constituted will make it possible to improve the thermal forecasting models through more in-depth studies.