Drying Shrinkage Response of Full-Scale Thin Concrete Overlay on Asphalt Sections

Moisture-related shrinkage is regarded as one of the phenomena that has the largest impacts on the performance of jointed plain concrete pavements. Still, most mechanistic-empirical design methods oversimplify or ignore predictions of moisture-related shrinkage and its effects on concrete pavements. This study evaluates how moisture-related shrinkage accumulates in concrete pavements and the structural response of the concrete pavement slabs to the shrinkage action. The experimental data come from six thin concrete overlay of asphalt pavements that were instrumented with sensors to measure the structural and hygrothermal response of the slabs due to temperature and moisture-related actions. After an analysis of the predictions made by current shrinkage models, a new shrinkage model was developed. This new model, which is based on the incremental-recursive application of the B4 shrinkage model, provided an excellent prediction of the moisture-related shrinkage measured in the field. In addition, the structural response of the concrete pavement slabs under the moisture-related shrinkage action was analyzed using the finite element method (FEM). The FEM analysis based on the standard practice for concrete pavement mechanistic-empirical modeling resulted in unrealistically high tensile stresses. However, much smaller stress values were found when the time-dependent (viscoelastic) behavior of concrete and asphalt was considered.

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