This cumulative habilitation thesis describes important aspects of the highly non-linear and time-dependent material behaviour of cohesive friction materials in several peer-reviewed journal articles. The focus is on the constitutive modelling of these materials with special attention to material failure in numerical simulations, as well as experimental methods for obtaining material parameters for the calibration of such models.
Accordingly, the work is divided into two parts: First, classical and generalised continuum models for cohesive friction materials are presented, investigated and applied in 2D and 3D finite element simulations. Special focus is put on the objective modelling of different failure mechanisms depending on various loading scenarios. In addition to quasi-brittle crack formation under tensile loading, shear band formation under compression and shear loading, crushing under strong multi-axial compression, and time-dependent failure due to creep are dealt with. Subsequently, a comprehensive test programme for characterising the complex material behaviour of hydrating shotcrete is presented, as well as an improved method of the wedge splitting test for determining the specific mode I fracture energy. Finally, several suggestions for future research activities are discussed on the basis of the results presented.