Simulation of compressive failure in quasi-brittle materials involving contact on crack interfaces

This paper proposes a method for simulating compressive failure in quasi-brittle materials involving microor meso-scale contact on crack interfaces. The macroscopic compressive failure is assumed to be caused by tensile and shear fractures at micro-scale, both of whose traction-crack-opening behavior is represented by the cohesive crack model. The penalty method is employed to realize the frictional contact on cracked interfaces under compressive loading. First, the discrete micro-crack behavior is introduced to a finite ele- ment framework in consideration of material inhomogeneity of cement-based materials and by using penalty springs. Then, after verifying the basic performance for simulating fracture behavior involving tensile or shear cracks, we examine the role of the micro-scale frictional contact behavior on the compressive fracture behavior. Finally, a numerical example is presented to demonstrate the validity of the proposed method in comparison with the experimental result, reported in the literature, for the compressive fracture behavior in mortar and cement paste.