Three dimensional elasto-visco-plastic finite element model for combined physical-mechanical moisture induced damage in asphaltic mixes

In order to understand and quantify the physical processes leading to moisture induced damage in asphalt and in order to combine them with the mechanical ones, an extensive, experimental and analytical, investigation is undertaken at Delft University of Technology in the Netherlands. In this investigation new tools were developed that enable the simulation of moisture infiltration due to pressure driven (i.e. hydraulic suction and water flow) and moisture gradient driven (i.e. molecular diffusion) processes. In addition, the tools for the simulation of the various physical damage inducing processes, associated with these moisture infiltration processes, have been developed. The modeling of moisture induced damage in asphalt mixes, however, cannot be done correctly without a generic constitutive theory for the dry response of the asphalt components. This contribution presents a three dimensional visco-elasto-plastic constitutive model for the mastic and shows the coupling with the moisture infiltration model. The same formulation can be used for simulation of the response of the other components. A methodology for the determination of the model parameters is also presented. At the end of this paper a micro-scale simulation is given to illustrate the damage generated in the mastic-aggregate interface due to both plastic strain and moisture induced damage.