The contribution employs meso-level discrete numerical model to approximate mechanics of concrete failure. The model represents the material by assembly of rigid-like particles interconnected by nonlinear bonds with strain softening. Spatial material randomness is introduced by varying the local meso-level strengths and fracture energies of inter-particle bonds. The variations are modeled using realizations of stationary autocorrelated random field and studied for two different correlation lengths. The study is focused on maximal load and energy dissipation during the progressive failure. It is found that material fluctuations in notched beams do not influence the mean values of maximal load and dissipated energy, but they influence their variance. In the case of unnotched beams, the mean of maximal load decreases with decreasing correlation length of material properties; however, the coefficient of variation of the peak load increases.