The proposed new theory “theory of degradation”. The theory allows to define a curve of the behaviour of concrete. Conducted experimental research with the aim of charting the concrete for comparison with a new theory. The paper presents analysis of experimental data. Diagram of concrete is built according to εb.short = εb.el + εb.pl + εc.el . Experiments for each part of the equations has been treated and constructed statistical dependence. The dependences obtained were the basis for building graphs and comparing them with charts of the theory of degradation

Despite the fact that concrete and reinforced concrete are the main construction materials, to date there is no complete theory of deformation and destruction. Structural concrete is considered at the level of macrostructure, has a number of features that do not allow you to directly transfer some of the provisions obtained for homogeneous materials. Available experimental data on the resistance of the concrete crack propagation relate mainly to the laboratory samples. In the paper, a new method for obtaining the fracture mechanics parameters of concrete, which is one of the most promising areas of research of fracture of composite materials. The study investigates the characteristics of cracks at different parameters of the segment breaks off. The study was carried out on finite element models. The authors studied the influence of the tilt angles formed by the segment on the stress state at the tip of the crack. In addition, the research separately considered the changes in mechanical properties of a break-off segment. As a result, the authors built regression tables and graphs. In conclusion, the research provides recommendations for the implementation of a shape for the break-off segment.

the requirements of modern construction are the strength of building structures, as well as low cost. It is these conditions that provide new technologies that are constantly being improved. The article is devoted to the consideration of cases of a probabilistic approach to solving the problem of theoretical energy consumption for the destruction of concrete of ideal structure. The processes of concrete deformation and its destruction are studied by building mechanics. Concrete is a multicomponent material, which presents a certain difficulty in the study of crack formation. In operating conditions, the concrete/reinforced concrete structure is affected by the properties of its constituent materials; therefore, one of the most important tasks is the selection of criteria that can comprehensively characterize the basic parameters of concrete. Obtaining the strength characteristics of concrete of operated structures remains an urgent task. The article proposes to consider the ideal structure of concrete. The features of this structure are the symmetry of fracture along two principal planes. The destruction of concrete was carried out by sawing individual strips of concrete. Moreover, to describe the sawing process, the authors proposed a model of a symmetric structure of concrete in which aggregate grains are idealized. They are presented in the form of balls in the body of concrete. The features of the sawing process are revealed. The analytical dependencies of fracture sawing the ideal structure of concrete are obtained. Conclusions are drawn about the possibility of using the ideal model for obtaining the strength characteristics of concrete. The analysis of symmetrical ideal concrete compositions with various variables is performed. The significance of the work done lies in the possibility of transferring the research results to real buildings and structures and solving the main tasks that are posed in the study

The article shows the comparative analysis of two compositions of cement concrete to use in road construction. In order to compare quality characteristics of the materials the method of Y.M. Butt was used that was implemented to test Portland cement samples made at Magnitogorsk cement refractory plant and cement rock on the basis of lime slag binding agent that was developed based on blast-furnace granulated slag together with Magnitogorsk Metallurguc Plant, PJSC. Computational and full-scale experiments were conducted to forecast the time changes of qualitative parameters of road surfaces with slag. It was established that its endurance to the first and second type of corrosion is higher. It was proved that lime slag concrete can be used in the production of road fine grain concrete instead of Portland cement, the presented binding agent also proved to be more economically feasible.

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