The research is devoted to the analysis of available and widely used conventional measures to ensure reliable operation of the in-situ reinforced concrete structures and their compliance with legal requirements. It requires using one of the research trends of the Samara school of material sciences developed by the authors some time ago. Several stages of the work have been distinguished during the process of defining methodological foundations for effective non-destructive methods. The first stage concerned the proper mathematical apparatus of the concrete deterioration under various types of external effects. The second stage is important for determining the composition of basic physical and mechanical characteristics. Finally, the third stage is the period when the most reliable existing non-destructive methods are identified and investigation on new techniques is carried out. Thus, the combination of the A.A. Griffiths energy theory and the kinetic theory of S.N. Zhurkov has led to the formation of the mathematical apparatus that is able to simulate conditions of external effects. Testing effective methods for the concrete quality control developed by authors of this paper has been performed at the construction site. The conditions under study are characterized by a large number of ambiguous factors influencing the quantitative indicators of quality control criteria.

Abstract. This paper presents the physical phenomenon of concrete fracture process by static uniaxial compression. The analysis of strength characteristics of concrete is carried out using fracture mechanics technology, and what is more, the actual operating conditions of structures are evaluated. The expediency of using energy approach and kinetic theory is given to consider material fracture processes with a large number of defects.

The paper analyzes operating conditions of hydraulic structures, as well as the main types of external influence with temperature and humidity variations. The purpose of the research is to highlight the main parameters which will be able to assess the actual durability of concrete hydraulic structures in the process of their design. The authors use methods developed in Samara Architecture and Civil Engineering Institute to determine concrete physical and mechanical characteristics. Thus, these methods help accurately assess concrete durability, frost resistance and water resistance. These methods are based on theoretical studies of the processes of concrete destruction by means of non-destructive acoustic methods. The the energy conception developed by A.A. Griffits and S.N. Zhurkova's kinetic serve as a scientific basis for the methods. Theoretical research and its analysis of concrete destruction processes from various kinds of external influence was confirmed by results of standard measurements. The research showed that durability of concrete, that is speed of its destruction, depended on two groups of physical and mechanical characteristics. One of the groups evaluates the initial structure of concrete, while the second group characterizes the speed of the material loading . The paper proposes a forecasting method of frost resistance and water-resisting properties of concrete according to its physical-mechanical characteristics. It also introduces an indicator of their assessment which is named the length of the reduced crack. The proposed indicator has a good correlation with frost resistance and water-resisting properties . Besides, the proposed method can be used not only in laboratory conditions, but also in construction production directly on the construction site.

The study examines a methodology based on the assessment of factors which further influence properties of concrete, that is its physical and mechanical characteristics analysis. The methodology is based on the research results obtained in the Samara School of Material Engineering and previously developed by the authors themselves. Its essence is based on the study of concrete destruction processes with account of existing rules of fracture mechanics. The researchers merged the energy conception of A.A. Griffiths with the kinetic theory of S.N. Zhurkova and developed a mathematical apparatus capable of modeling the conditions of external influence on concrete. They also estimated "Rebindera effect" while applying external load from the described types of external influence. They determined three stages in the course of destruction development depending on quantity and quality of initial defects. The first stage of destruction occurs at the micro level, the destruction is negligible. At the second stage cracks begin to fuse and already influence on change of values of concrete stress-strain properties. Finally, the third stage is "direct fracture" when the main cracks are formed dividing the specimen into separate fragments not capable of carrying the external load. The work reveals parameters and divide them into two groups. These parameters have a significant influence on the nature and kinetics of the destruction processes, respectively. The authors introduce a criterion of concrete crack resistance named "the length of the reduced crack". This criterion represents the total length of all surfaces of destruction at a single width of a crack. The proposed method can be applied with the use of non-destructive acoustic methods and destructive mechanical methods. Approbation of this methodology showed sufficient reliability and authenticity of the proposed indicator as a criterion of crack resistance.

The paper presents aims to provide analysis of non-waste technology of producing piled foundations of hydraulic engineering structures. The authors introduce a complexity of additional technical and technological steps making possible to both diminish the work-load and cut the time required. The paper also describes main stages of the work and points out the main drawbacks of the traditional technology. The authors prove that on condition of proper technique training and experience it is possible to design and produce pile fields characterized by minimal materials consumption thus saving 10-15% of zero circle estimated cost and cutting the time required for construction.