The work is dedicated to the 125th anniversary of the birth of Alexey Alekseevich Gvozdev, one of the brightest representatives of Russian scientists of the XX century. The name of A.A. Gvozdev is inextricably linked with the history of the development of building structures in the USSR. He was an outstanding teacher, researcher, engineer and major organizer of building science. Fruitful scientific, engineering, pedagogical and social activities of Doctor of Technical Sciences, Professor, Academician A.A. Gvozdev was highly appreciated by the State. He was awarded a number of orders, many medals for military and civil merits, he was awarded the title of Hero of Socialist Labor, the title of Honored Worker of Science and Technology of the Russian Federation.

The paper considers the existing restrictions of the current edition of GOST 8269.0–97 «Crushed stone and gravel from dense rocks and industrial waste for construction work. Methods of physical and mechanical tests» in the evaluation of the reactivity of rocks and crushed stone of fundamental importance in terms of durability of buildings and structures made of concrete and reinforced concrete. The approaches to an estimation of reactivity of aggregates for concrete, established in normative-technical documents of the leading international and national standardization organizations, are shown. There has been analyzed the principle possibility of producing the algorithm of the complex estimation of the aggregates reactivity for concrete and choosing the strategy of reduction of the internal concrete corrosion risk depending on operating conditions, presumed service life and responsibility level of the structures.

In a series of two articles, the concept of constructing probabilistic models of the properties of concrete mixtures and concrete in the space of possible compositions on given materials is discussed. In the first part of the article, the following concepts are introduced: the mathematical space of compositions with demonstration of examples of its construction for concrete mixtures for various purposes, the length of the correlation of composition properties, and a quantitative measure of the proximity of compositions, which makes it possible to postulate the continuity of their properties. Based on the methods of Bayesian statistics and machine learning, methods are proposed for the effective use of a priori information on the properties of raw materials, accumulated statistical data on the properties of concrete mixes/concrete, expressed in the form of various empirical dependencies and physicochemical models, for constructing probabilistic models. The algorithm presented in the article makes it possible to create economical experimental plans for constructing a multidimensional response surface in the space of possible compositions. Further work with the obtained response surface can be carried out by various methods, for example, by studying slices along the coordinate axes of interest in arbitrary planes or directions.

The results of studies of the main deformation properties of heat-insulating and structural-heat-insulating lightweight concretes on granulated foam glass-ceramic with a density of 500 to 800 kg/m³, as well as structural lightweight concretes with a density of up to 1700 kg/m³ of optimal compositions are presented. Various dependencies on the evaluation of the experimental data obtained are analyzed and recommendations are given for inclusion in regulatory documents, in particular, in SP 351.1325800.2017 “Concrete and reinforced concrete structures made of light concrete. Design rules”.

The practical use of methods for determining the stress intensity factor (SIF) at normal separation was studied: eccentric compression of notched cubes and four-point bending of a notched beam. During non-equilibrium tests, the SIF value was calculated from the value of the breaking load. During  quilibrium tests, the SIF value was determined from the complete equilibrium deformation diagram, taking into account the energy indicators of destruction. The test used nanofiberconcrete, in which carbon nanotubes are used as crack propagation inhibitors at the level of the cementing agent, and various macro-sized fibers are used at the level of fine-grained concrete. As a result of the tests, it was found that the methods for determining the SIF from cubes with a notch and from deformation diagrams showed a good degree of convergence. Fiber reinforcement has an effect on the fracture toughness of a nano-cement composite, and a high-modulus fiber has a greater effect on the fracture toughness index than a low-modulus one. The stress intensity factor is a good indicator for comparing different types of fiber reinforcement in terms of their effect on fracture toughness.

The aim of the work was to study the uniformity of the structure of bored piles, to determine their actual length, to identify pile defects by methods: inter–well ultrasonic (US) monitoring (CHUM – Crosshole Ultrasonic Method), echo–pulse method (PEM – Puls Echo Method). The object of study is bored reinforced concrete piles with a diameter of ~800 mm. Based on the data obtained in the course of experimental studies, conclusions were made about the length of the pile, defects in the continuity of bored piles.

For the reinforcement of prestressed reinforced concrete structures, wire and strands, which have high mechanical properties, are widely used. Currently, a large range of high-strength wire and reinforcing strands has been developed in the world, which have a large gradation, both in geometric properties and strength. However, their use in reinforced concrete structures is hindered due to the lack of research on their work in concrete. The article presents the results of experimental studies of the coupling of a three-wire reinforcing strand and a wire with a two-sided periodic profile, as well as suggestions for calculating the base length of the anchorage required to transfer the force to concrete.

The method of calculating the strength of compressed elements according to the deformation model, taking into account the operation of compressed composite polymer reinforcement, is described. The criteria for the strength of the normal section of the compressed element are proposed when calculating according to the deformation model using piecewise-linear and curved diagrams of axial compression of concrete. The comparison of the results of calculating the strength of prototypes according to the deformation model with experimental data and with the results of calculations using the method of limiting forces is given. It is shown that the proposed method for calculating eccentrically compressed elements, taking into account the work of composite reinforcement in compression, leads to satisfactory convergence with experimental data when using both piecewise linear and a curvilinear diagrams of the axial compression of concrete. By comparing the strength calculation results of the considered sample of experimental non-centrally compressed samples made according to the deformation model using a curved diagram and the method of limiting forces, their satisfactory coincidence was established.

Anchor fastenings are one of the key elements of building structures that are directly responsible for the technical safety and structural integrity of buildings and structures. The state of the regulatory framework in the field of anchorage design is described, the relevance of the development of a new set of rules is substantiated. The content, main provisions and key requirements introduced into the regulatory document are disclosed. The expected results from the introduction of the new set of rules and ways of its further development are presented.