A comparative study between discrete and continuum models to simulate concrete fracture

We present a comparative study between models that follow the two main trends to study fracture of quasi-brittle materials like concrete. On the one hand, we focus on a discrete model that represents the fracture process by cohesive elements that are inserted in the original mesh only when the opening condition is met. Such elements also implement contact and friction algorithms. Besides, mesh size is selected so as to represent the inter-locking effect between the crack surfaces. Everything considered, this approach leads to an explicit and multiscale modeling of fracture. On the other hand, we analyze a continuum model based on the strong discontinuity approach. It localizes damage in bands that are narrowed to the limit of having null width and thus, simulate the fracture surface. The initiation and propagation processes are modeled by a bifurcation analysis that searches for the surfaces where damage can be localized at every step. Finally, we use both approaches to do 3D simulations of fracture tests in concrete that allow an evaluation of their relative performance.