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The possibility of assessing the impact of the concrete fracture relief and its interphase boundaries on the concrete strength characteristics is considered. Using the fractal theory, the fractal dimension of the concrete fracture relief in 3D space and the phase boundaries in 2D space is determined. The relationship between the above-mentioned fractal dimensions and the breaking load during compression of concrete samples is established. An increase in the indicators of the breaking load by 24% with an increase in the values of the fractal dimension of the fracture relief from 2.202 to 2.268 and the interphase boundaries from 1.699 to 1.782 was recorded. This trend of changes in the values of the breaking load and the fractal dimension of the relief and interfacial boundaries is explained from the standpoint of the mechanics of concrete destruction. A smoother surface of the fracture relief corresponds to higher indicators of its fractal dimension and the strength of concrete. The fractal dimension describes the compactness of filling the space with the object of study, which is higher for a smoother fracture surface. An increase in the fractal dimension of the interfacial boundaries indicates an increase in the energy spent on the work of destruction, and an increase in the strength of concrete accordingly. The obtained fractal models allow us to predict the values of the breaking load of concrete based on the analysis of the surface of the destroyed samples. [ABSTRACT FROM AUTHOR]

A series of experiments were performed by using following geometric primitives and its combinations: sharp and blunt edges, wedge, half-length with "flamholder" or "bump" elements, cylinder, EXOMARS and others. Shock-wave structures are presented in the paper. Numerical calculations are carried out by using the author's codes for the study of aerothermodynamic processes on the model surfaces. [ABSTRACT FROM AUTHOR]