A multi-scale continuum model for particle composite materials with microcracks is proposed. Constitutive equations, based on the kinematics of the material at the microscopic level, are derived using an integral procedure of equivalence. These equations account for the geometry and the texture of the material internal phases. Differently from the classical continuous models obtained using standard homogenisation techniques, the multi-scale continuum includes internal scale parameters which allow taking into account size effects. The study of a one-dimensional problem points out the influence of the microstructure on the macroscopic behaviour of the composite material.