The article describes the peculiarities of the provisions of the new national standard GOST R 70307–2022 “Fine-grained concretes and mortars for construction. Methods for determination of strength in thin-walled and thin-layer structures”, developed in the Scientific Research Institute for Concrete and Reinforced Concrete (NIIZhB) named after A.A. Gvozdev – subdivision of JSC “SRC “CONSTRUCTION”. The tasks solved during standard’s development, opportunities and scope of application of the standard in practice are outlined. References to the primary sources of the test procedures used in the standard, peculiarities of the requirements to the test equipment, general principle aspects of the document put into effect, and proposals for prospective improvement of the supporting standards are given.

In 2022, a new GOST R standard “Concrete. Methods for determining mechanical, deformative characteristics and endurance under temperature effects” was prepared. The standard applies to laboratory tests of the variability of the properties of concrete under temperature effects, establishes methods for determining the strength and deformation characteristics when heated and in a cooled state after heating, as well as endurance characteristics when heated.

The results of the practical application of the ideas presented in the first part of the article published earlier are presented: models of strength, cone slump for 4-component concrete mixtures with plasticizing additives were constructed, also, models of strength and mobility for 5-component mixtures of fine-grained concrete, including mineral filler, were constructed. In particular, on the basis of the last example, the possibility of determining the consumption of active ash, maximizing the strength characteristics of concrete at a fixed consumption of cement, is shown.

The article contains the test results of reinforcement of grade A500C manufactured by a metallurgical plant in the Arab Republic of Egypt (ARE) according to GOST R 52544 and their analysis for compliance with the requirements of GOST 34028 for reinforcement of grades of A500СНУ and/or A500СЕУ required by the El Dabaa NPP project. The purpose of this work is to determine the possibility of the metallurgical plant to produce reinforcement that meet the requirements of the El Dabaa NPP project. A comparative analysis of the technical requirements of regulatory and technical documents (NTD) for reinforcement is given. To assess the stability of the manufactured reinforcement for the previous period, the data transmitted by the manufacturer on the technological processes of manufacturing reinforcement, the results of control of mechanical properties and chemical composition are given. The analysis of the main test results selected at the manufacturer, samples of reinforcement is presented. In particular, the actual geometric characteristics of the periodic profile, cross-sectional area and mass, the actual chemical composition and mechanical properties of reinforcement of grade A500C are given and their analysis for compliance with the requirements of grades A500СНУ and/or A500СЕУ according to GOST 34028 is carried out. The evaluation of the test results of samples of welded joints of reinforcement of grade A500C for tension, bending and shear for compliance with the technical requirements of GOST 34028 to grade A500СНУ and/or A500СЕУ is given. The analysis of the results of endurance tests of reinforcement of grade A500C and the requirements of GOST 34028 for grade A500СНУ and/or A500СЕУ is given. The article pays attention to some deviations of mechanical properties obtained from the test results of reinforcement from the requirements of GOST 34028. Conclusions are formulated about the compliance of reinforcement of grade A500C manufactured by the metallurgical plant in the ARE according to GOST R 52544 with the requirements of grades A500СНУ and A500СЕУ according to GOST 34028 for the El Dabaa NPP project. The article is informational and analytical in nature and will be useful to specialists in solving issues of assessing the compliance of reinforcement with the requirements of foreign NPP construction projects.

The opportunity to obtain building materials with high physical and mechanical characteristics attracted scientists and practitioners in the search for the use of cheap industrial waste, which would reduce material and energy consumption, having obtained materials with the specified properties. Blast-furnace and metallurgical slags are of particular interest for solving these problems, since they are characterized by a predictable chemical composition and are environmentally friendly. The current level of development of concrete technology involves the widespread use of various additives in concrete. The use of additives is rightly considered as one of the most versatile, affordable and flexible ways to control the technological parameters of building materials. As a result of the use of expansion additives, it is possible to improve the structural characteristics of concrete, reduce shrinkage deformations, accelerate the rate of strength increase, and increase durability. Ultimately, it is possible to qualitatively improve the construction and technical properties of the structure.

The article deals with the analysis of the probabilistic onset of corrosion in reinforced concrete structures subject to the penetration of chloride ions. Structural strength is an important criterion that must be evaluated in every type of structure, especially when these structures are operated in aggressive environments. When considering reinforced concrete members, the chloride diffusion process is widely used to evaluate durability. Therefore, by simulating this phenomenon, reinforcement corrosion can be better assessed and prevented. These processes begin when a threshold level of chloride concentration on the steel reinforcement bars is reached. Despite the reliability of several models proposed in the literature, deterministic approaches cannot accurately predict the time of onset of corrosion due to the randomness observed in this process. In this regard, durability can be more realistically represented using probabilistic approaches. The article presents a probabilistic analysis of the penetration of chloride ions. The penetration of chloride ions is modeled using Fick’s second law of diffusion. This law represents the diffusion process of chlorides, taking into account time-dependent effects. The failure probability is calculated using Monte Carlo simulation and first order reliability method (FORM) with a feed-forward approach. To study these phenomena, some examples are considered and a simplified method is proposed for determining the optimal values for the concrete cover.