Identification of a cohesive zone model for cement paste-aggregate interface in a shear test

The development of tools, using a micromechanical approach, predicting the macroscopic behaviour of heterogeneous materials such as concrete, requires the knowledge of their microstructures (geometrical properties of phases), the behaviour of phases and the interaction laws between phases. This study is focused on a numerical modelling of a local shear test on a cement paste-aggregate composite using a cohesive zone model with the objective to identify the behaviour of the cement paste-aggregate interface. The computations use a 3D finite element modelling of the composite, using a cohesive law at the interface between the two phases. The cohesive model mimics the behaviour of the well-known interfacial transition zone. This work presents a methodology for the identification of cohesive law parameters at different stages of hydration and for different confining stresses using experimental results.