Behaviour of the Interface Bonding Between Asphalt Overlays and Rigid Pavements

The application of an asphalt mix overlay over old rigid pavement is a way to extend the service life of a pavement construction up to 10 years. The effectiveness of this maintenance measure strongly depends on the bonding conditions between the asphalt and the concrete layer and the effective transfer of the stresses and strains from the upper to the lower layer under traffic loads. The bond characteristics were investigated using laboratory tests and numerical simulations. Static testing equipment was used for the determination of the shear and tensile adhesion strength of cores from six sections of one highway. All six sections include three different pre-treatment methods and two types of asphalt mixtures. To evaluate resulting stresses and strains in the pavement construction under traffic load, finite elements simulations were carried out. Thereby, a simulation of the laboratory shear test setup provides information about the bond conditions as defined in the finite element model, which is used as input to simulate stresses and strains under different loading conditions. This approach is not only used to identify significant resulting stresses and strains due to traffic load but also to derive threshold values for future laboratory shear adhesion tests.