Consideration of the Hygrothermal Actions in Concrete Pavement Design Procedures: Do we Follow the Right Approach?

Concrete moisture-related and thermal (hygrothermal) actions are known to have a large impact on the performance of concrete pavements. Despite that, current mechanistic-empirical design procedures oversimplify the prediction of these actions and their effects on the structure of the pavement. This paper evaluates the most common simplifications adopted by current mechanistic-empirical design procedures. The evaluation is based on the experimental data collected from fifteen thin bonded concrete overlay of asphalt pavements that were instrumented with sensors to measure the structural and hygrothermal response. The experimental data included the response of the slabs under the ambient environment, measured during fifteen months, and the response measured under the wheel of the Heavy Vehicle Simulator. The analysis of the experimental data shows that some simplifications adopted by current mechanistic-empirical design procedures lead to a considerable underestimation of the effects of thermal and moisture-related actions. The study emphasizes the need for a better understanding of a number of phenomena before a fully realistic modeling of the hygrothermal actions in concrete pavements can be achieved. Among those phenomena are concrete tensile creep, slab- base interaction, and concrete moisture content effect on the coefficient of thermal expansion.