College of Engineering

This paper details the development of a new 1‑D combined finite difference and finite element procedure for calculating in-depth pavement temperatures, which has been implemented in the CalME design method.  The model is driven by a database of known surface temperatures rather than raw climatic inputs and an energy balance at the surface, since it was noted that the pavement structure had little impact on the surface temperature (if the surface properties remain constant).  The model runs quickly, enabling direct simulation of in-depth temperatures while performing Monte Carlo based simulation of pavement reliability.  The disadvantages to this approach are that it requires the surface temperatures to be developed independently and that it does not have a coupled moisture model for the prediction of freeze/thaw conditions.  The paper also details some anomalies in the output of the Enhance Integrated Climatic Model (used in the new AASHTO mechanistic-empirical design method), that were found during development.  Finally, the paper collects various published values for thermal properties of pavement materials, to aid in the implementation of thermal models.