Cracks at mortar-stone interfaces

In split cube geometries the specific fracture energies of sandstone-mortar (14 Nm⁻¹) and limestone-mortar (6 Nm⁻¹) interfaces were determined. They are much lower than for bulk mortar (80 Nm⁻¹). A damage type law describes well the development of a process zone around the interfacial cracks. In finite element calculations the damage law descrobes the behaviour of flat interfaces, but needs improvement for curved interfaces.