Meso-scale finite element modeling of non-homogeneous three-phase concrete

Assumptionof material homogeneity is not realistic in study of the mechanical behavior of concrete. When a concrete specimen under loading condition starts to crack, it changes from a continuous state into a discrete one. Under such circumstances, application of classical finite element methods is no longer valid. In this study, the authors used the meso-scale modeling in which concrete is assumed as a non-homogeneous three-phase material consisting of three phases; aggregate, cement paste, and internal transition zone (ITZ). Many mechanical properties of concrete depend on the size, geometry, and arrangement of its aggregates. In this paper, aggregates of different sizes are generated with circular, elliptical, and irregular shapes, and then randomly distributed within the specimen. The lattice beam finite element method was used in which a regular or irregular meshing compromised of beam elements is constructed. This method is used to trace crack paths when concrete specimen is under loading condition. Three loading tests including three-point flexural, compression, and tensional tests were done. In order to validate the model, we expect the crack development of this concrete specimen model to be similar to previously established models.