Introduction. Corrosion of steel reinforcement is one of the main factors of destruction of reinforced concrete structures exposed to aggressive environment. The use of steel reinforcement with protective coatings applied to its surface in factory conditions is one of the important directions in the creation of durable reinforced concrete structures.

Aim. To show possible prospects for the use of various reinforcement protective coatings in Russia to increase the durability of reinforced concrete structures under the influence of aggressive environment. To develop proposals on the need to carry out research work to create a regulatory base and introduce into practice the construction of reinforcement with a protective coating.

Materials and methods. The determination of the prospects for the use of protective coatings of reinforcement in reinforced concrete structures was carried out by analyzing scientific and technical literature, articles, regulatory and technical documents and information from open sources on the problem under study.

Results. The experience of using steel reinforcement with protective coatings in Russia and abroad is given. The most widely used technologies for applying protective coatings to reinforcement in factory conditions are highlighted. The main advantages and disadvantages of reinforcement with a protective coating are shown on the example of studies, both in terms of the durability of the coating itself and in terms of working together with concrete. The state of the domestic and foreign regulatory base differs significantly from each other. In contrast to Russia, an extensive regulatory base has been created abroad that allows the design of reinforced concrete structures with reinforcement with protective coatings. Using the example of foreign experience, the most economically feasible types of protective coatings have been identified. With a certain increase in the cost of reinforcement with protective coatings compared to black reinforcement, economic efficiency is generally achieved by increasing the service life of the reinforced concrete structure.

Conclusions. Modern design and construction practice shows that for a number of reinforced concrete structures operating under the influence of aggressive environment, it is necessary to use reinforcement with protective coatings. There are great prospects for the use of reinforcement with protective coatings in Russia, but it is necessary to develop а regulatory and technical base in this direction. Based on the results of the analysis of the issue, proposals are given on the need to carry out research and a list of necessary regulatory and technical documents for the introduction of reinforcement with a protective coating into the practice of construction.

Introduction. Over the past 20–30 years, a wide range of effective porous aggregates with a high content of glass phase of various types and low-heat-conducting lightweight concretes of various structures based on them has been developed.

In recent years, JSC Research Center of Construction has developed a new highly efficient single-stage technology for the production of porous granular foam glass ceramics (UCS). It is based on the production of raw granules by mixing and granulating a highly porous powder of opal-cristobalite rock with a sodium-containing solution. This ensures the maximum area of the interfacial boundary, the most uniform distribution of all components at the micro level and, as a result, ensures glass formation at a temperature that does not exceed the foaming interval of the finished glass phase.

The aim of the publication is to study the problems of the features of the strength characteristics of lightweight concrete on granular foam glass ceramics.

Materials and methods. The strength of cubes made of light concrete on the UCS under compression (R) was determined on samples with a size of 10 × 10 × 10 cm and 7 × 7 × 7 cm according to State Standard 10180-2012 with an assessment of strength according to State Standard 18105-2018.

The prismatic strength coefficient (K_pp) was determined by the results of compression tests of samples-prisms with dimensions of 10 × 10 × 40 cm and 7 × 7 × 28 cm and samples made from the same batch-cubes with dimensions of 10 × 10 × 10 cm and 7 × 7 × 7 cm.

Bending tensile strength (R_tb) (Figure 2) and splitting strength (R_tt) were determined, respectively, on 10 × 10 × 40 cm prism samples and 10 × 10 × 10 cm cube samples according to State Standard 10180-2012 with an assessment of strength values according to State Standard 18105-2018.

Axial tensile strength (R_tb) and splitting strength (R_tt) were determined, respectively, on prism samples measuring 7 × 7 × 28 cm according to State Standard 10180-2012.
The strength of the prisms (prismatic strength, R_b) was determined on samples of prisms 10 × 10 × 40 cm according to State Standard 24452-80.

Results. The article presents the results of experimental and theoretical studies of the basic strength properties of thermal insulation and structural-thermal insulation lightweight concrete on granulated foam ceramic (UCS) with a density of 500 to 800 kg/m³, as well as structural lightweight concrete with a density of up to 1700 kg/m³ of optimal compositions (prismatic compressive strength, prismatic strength coefficient, axial tensile strength, tensile strength during bending and splitting).

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".

Conclusions. Experimental data have been obtained on a higher prismatic strength coefficient for lightweight concrete at the UCS, which in the future may be the basis for increasing the standard design strength resistance under axial compression for this type of lightweight concrete.

The values and formulas for determining the prismatic strength and the prismatic strength coefficient of light concrete of the tested compositions at the UCS can be used in the calculation and design of large-format wall panels of a new type.

Experimental and calculated data on the tensile strength of the tested compositions of lightweight concrete of a porous structure at the UCS have been obtained, which can be taken into account when adjusting regulatory documents.

When using lightweight concrete of a porous structure on the UCS to increase the shrinkage crack resistance of such concrete for enclosing structures, it is advisable to use dispersed reinforcement with polymer fiber, which also increases the heat-protective properties of such structures. The article presents the results of studies of the main strength properties of thermal insulation and structural-thermal insulation lightweight concretes on the UCS 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.

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".

Introduction. State Standard 32803 was developed more than 8 years ago and took into account the level of development of production and the approach to the problem in this period. At the same time, over the past period, the scope of application of straining concretes has expanded, new technologies for the production of such concretes have been developed both at precast concrete plants and on the construction sites. The use of modern technologies for the production of straining concretes and the development of new types of such concretes, in particular self-compacting and heat-resistant, significantly expands the scope of use of straining concretes in structures that are subject to requirements for surface quality and durability, strength, water resistance, frost resistance, absence of defects.

At the same time, such concretes can be effectively used for underground construction and in special structures, such as capacitive and hydraulic structures, with obtaining high grades of water permeability resistance, frost resistance and abrasion resistance in the concretes used for their construction.

Aim. The revision of State Standard 32803 was carried out in order to clarify and adjust the types of straining concrete and expanding additives for the production of such concretes.

Materials and methods. The new edition of the standard takes into account the possibility of using both waste products and new materials.

Results. An updated version of the standard is presented, compiled taking into account new and updated editions of previously developed regulatory documents.

Conclusions. The use of expanding additives in the composition of prestressing concrete, including additives, makes it possible to solve the urgent problem of protecting the environment, since large-tonnage waste from various industrial productions is used for the manufacture of such additives.

The construction of sports facilities using cast-in-place reinforced concrete has recently acquired a steady trend towards its development. This was largely facilitated by the development of the regulatory framework for design, as well as modern construction technologies. At the same time, the practice of implementing monolithic structures shows that there is often a low-quality production of construction works. The main defects and deviations made in reinforced concrete structures are shown on the example of the Climbing Center building under construction.

One of the main defects was the recorded damage to the corbels of the main pylons of the structure, on which the large-span trusses rest. The survey showed that the result was an unacceptable technical condition of these elements. In order to bring the structures to the standard level of technical condition, a design for strengthening the support nodes of the trusses was developed and implemented, which is presented in the text of the article.

The article provides answers to questions on the instructions of SP 63.13330.2018 on the design of concrete and reinforced concrete structures, most often received by the developers of the set of rules from its users. The range of issues related to the instructions of the set of rules for calculating the strength of normal and inclined sections of reinforced concrete structures and for calculating their crack resistance is considered. Answers to the questions of users of the set of rules are presented, explanations of its individual instructions are given, and for some instructions, recommendations are given for their implementation.