A micromechanical model based on the Mori-Tanaka homogenization scheme is presented to investigate the effective non-linear behaviour of a three-phase brittle composite materials. The matrix phase is assumed to be linearly elastic coupled with damage, the inclusion phase is elastoplastic and the third phase represents cavities. We use the Ju's energy-based damage model to describe the anisotropic damage of brittle material behavior and the classical J2P theory for the elastoplastic one. To handle our micromechanical modeling we have developed a robust numerical algorithms for an incremental tangent formulation which enables us to simulate and predict, within reasonable CPU time and memory, the response of such composite materials. As an application, we have simulated the mechanical response of Fiber-Reinforced-Concrete. Our predictions are compared with experimental data obtained by experimental tests performed on several specimens of Fiber-Reinforced-Concrete. We have also validated our micro-macro predictions against 3D and 2D Finite Element simulations.