Analytical Solution And Prediction Model For The Time-Dependent Temperature Field In Road Pavements

Due to the exposure to the natural environment which contains air temperature change and solar radiation, road pavements always suffer various temperature variations after absorbing the heat generated by the temperature change and solar radiation. As a result, the multilayered road pavements always suffer thermal stresses of different level, which are commonly believed to cause adverse effect to the reliability of the pavements. Hence, it is of great significance in practice to investigate the thermal transfer behavior of road pavements and propose an efficient model to predict the temperature field in the pavements.In this thesis, single-and multi-layer models are developed for the road pavement and the one-dimensional transient heat conduction equation is used to predict the temperature field in the road pavement. The boundary condition at the road surface is prescribed as a time-dependent temperature which includes the combined effect of air temperature and solar radiation, while that at the lower surface of the model is taken as a constant temperature. The heat conduction equation is solved analytically using the infinite integral transform in the spatial coordinate and then integrate directly in the time history. Although we only focus on the effect of air temperature and solar radiation, this model is suitable for arbitrary boundary conditions. The analytical solutions presented here are then verified by comparing to the measured results. Based on the comparisons, it is proved that the single layer model can predict well the temperature field in the road pavement, and therefore the prediction formula for temperature field of road pavement is simplified significantly. Finally, a very simple prediction formula in non-dimensional form is derived in which a simple normalized combined parameter containing the material properties and thickness of the pavement is involved.By analyzing the variation of air temperature, solar radiation and the thermal properties of the pavement material, we can establish the relationship between the outside environment factors and the inside temperature field. The prediction formula proposed here for temperature field of road pavements might as well render theoretical reference for evaluating the long-term performance of the pavements.