Numerical modelling of pressurized fracture evolution in concrete using zero-thickness interface elements

The development of cracks due to the effect of fluid pressure is a problem that concerns many areas of engineering, ranging from structural to geotechnical or petroleum. Within the context of the Finite Element Method, the authors have recently proposed a formulation for the coupled hydro-mechanical behaviour of zero-thickness interface elements. This formulation has been verified for pre-existing discontinuities (e.g. natural joints, faults in rock). In this paper, the above formulation, complemented with an appropriate fracture mechanics-based constitutive model, is applied to developing cracks in plain concrete. The numerical results are compared with a series of wedge splitting tests available in the literature, performed on concrete specimens under the influence of fluid pressure at the notch and along the propagating crack. A good agreement is obtained in terms of wedge-splitting force vs. crack mouth opening displacement (CMOD), crack and fluid fronts vs. CMOD, and fluid pressure along the crack vs. time. The influence of splitting rate and input fluid pressure is also systematically analyzed.