On the choice of a phase field model for describing fracture behavior of concrete

Numerical modeling of concrete fractures is of prime importance in the durability assessment of civil engineering structures. The phase field model has been demonstrated as a promising framework to simulate crack propagation in brittle material while using the many existing techniques. In this paper, we discuss choosing the most appropriate phase field model for describing the fracture behavior of concrete. More specifically, we present a detailed analysis of the existing models, which have been created by combining different spectral decompositions and crack density functions. The numerical simulation predictions are confronted with the experimental observation of a benchmark problem from the literature. The obtained results showed that the extensive/compressive decomposition and the quadratic crack density function are the most suitable models to study concrete cracking behavior. The investigation's size effects demonstrated heterogeneities played an important role in concrete's post-cracking behavior and softening branches, especially for the small concrete structure.