Determination of the Strength and Orientation of Destruction Concrete's Surfaces for Different Types of Bulk Stress State

Criteria of concrete strength and their dependence on the character of deterioration at the volume tense state types: 3-axial compression, cases of the compression-extension and 3-axial extensions are described. The compression tensions are taken as negative. In the case of 3-axial compression the criterion of the strength is presented as the functions from the main tensions σ1, σ3 and from the Lode-Nadai μσ parameter, which allows to take into account the influence of the middle tension σ2 on the concrete strength. It was shown that the analogy is possible between the offered criterion of concrete strength at 3-axial compression and the Coulomb-Mohr strength criterion, if you take that every Lode-Nadai μσ parameter corresponded its threshold value envelope of Mohr cycles, and the family of the envelopes has unlinear character. Criteria of the strength at the availability of the tensile stresses are represented as unlinear functions from the main tensions σ1, σ2, σ3. The deterioration character in these cases is tied with the formation of cracks at the main tensile stresses surfaces (areas). Criteria of the strength coincides on the borders of the tensile states and forms general criterion of the concrete strength at the volume tensile state in common.