Conventional in mechanics of material fracture failure criteria GiC and CS based on Griffith’s energy concept about development of a fracture. These criteria postulate fact of occurrence the limiting state in the material around the tip of the crack occurs when the rate of elastic energy growth and the rate of its absorption in the bounded zone are equal. For complex composite materials such as concrete, the possibility of applying these criteria remains controversial due to the pronounced heterogeneity of this type of materials, in which the size of the individual rigid elements of the structure is commensurate with the size of the test samples. But the energy nature of destruction is fair and obvious in any materials, so for them there must be an energy criterion of destruction, which not only States the fact of destruction, but also integrally takes into account the expenditure of deformation energy not only on elastic but also on plastic processes, including thermal. The proposed effective specific energy of destruction of the material as a criterion of destruction should take into account all the features of destruction not as a fait accompli, but as a process of accumulation and dissipation of energy in the deformable volume, and not at the tip of a single crack. The article describes a method for obtaining the effective energy density of the destruction and presents results of a study of this magnitude for one of the types of concrete – autoclaved aerated concrete, given that this relatively homogeneous material is the most suitable for pioneering research is relatively new strength parameter for materials with complex structures. To determine the range of possible values of the investigated value, a factorial experiment was performed with variation of such factors as: density, loading speed and water saturation of cellular concrete. The type of dependence of energy consumption of a cubic sample in time from various factors causes the mechanism of destruction of this material – viscous or brittle and describes the process of accumulation of defects in the process of increasing elastic deformation to the moment of destruction.