Introduction. This article analyzes the design features of volumetric blocks made of fibroblast concrete using a formwork made of moisture-resistant drywall. The basic principles that describe the characteristics of the design with the shaping of these volumetric blocks implemented using shotcrete technology are also outlined. This is especially true for low- and medium-rise buildings.

Materials and methods. To form the construction of fiber-reinforced concrete volumetric blocks with formwork based on moisture-resistant drywall (hereinafter referred to as GCLV), it is suggested that a system of basic principles is used that increases energy efficiency, reduces costs, and promotes the disposal of safe industrial waste. The application of the basic principles underlying the development of a volumetric block made of lightweight fibrotorcrete with non-removable formwork enabled a systematic approach to a constructive solution to be implemented.

Results. The introduction of an effective innovative method made it possible to develop a reinforced concrete volumetric block created using shotcrete technology. This approach has made it possible to reduce labor costs, increase strength characteristics, and enable the production of bulk blocks both in the factory and directly on the construction site.

Discussion and Conclusion. The multilayer structure of new-generation bulk blocks made of fibrotorcrete created by the authors is based on the key principles that emphasize the effectiveness of their use in the construction of buildings with small and medium storeys.

Introduction. The article is dedicated to the history of the development and implementation of the project for the construction of the ceiling of the nave of the church of St. Tikhon, Patriarch of Moscow and All Russia, at 17 Commune Street, St. Petersburg. The church was built and is under construction on an order of a local religious organization with donations from whoever cares to do this and church visitors. The original project envisaged the construction of an arched cylindrical vault above a masonry nave, which called for complex engineering solutions and considerable labor and financial costs. By October 2024, it became clear that construction in the traditional way would not enable the church to be consecrated, having completed this project in a short time and with limited funds. The aim of the study was to develop an alternative solution to the construction of arched brickwork with puffs on the short side of the nave of the temple.

Materials and Methods. Having considered the options available, we decided to make use of arched beams as stiffeners, which were supposed to take on some of the load, including from the strut. It was assumed that it was possible to replace the prestressed reinforcement of the upper row with a combined one making it possible to optimize the arch design. In order to identify the required parameters, loads were collected and the stress strain of the arch was calculated, including in the SCAD program provided it was at the operational stage. The reduction of stress zones is achieved by additional reinforcement with rods and clamps.

Results. The research enabled us to reduce costs while maintaining the structural rigidity of the arch. In accordance with the calculations, the formwork drawings have been developed. The process of transferring parameters from drawings to actual dimensions and concreting was meticulously organized by means of modern quality control tools at each stage. The installation of ready-made reinforced concrete structures turned out to be more technologically advanced and faster than a monolithic system.

Discussion and Conclusion. The brick vault project was successfully completed with minimal deviations involved. The support area of the structures and the height of the arch rise fully corresponded to the calculated values. The solution was found to have made it possible to considerably cut down the load on the base, increase the overall structural rigidity, while freeing the space under the dome from tightening, reduce construction times making it possible to meet the deadlines as well as to reduce the costs. The scientific novelty of using arches with a mixed reinforcement system is the simplicity of the design, the absence of the need to increase the cross-section of the truss elements and the possibility of using combined reinforcement.

Introduction. Current trends in the paint and varnish materials industry are embracing environmental friendliness and versatility lending wooden products good aesthetic and protective properties. The structure of wood, as a natural material, is constantly undergoing intensive and progressive processes of oxidative degradation under environmental conditions affecting the strength of wood and causes significant structural changes. Therefore the interest in improving the durability of paint coatings under the influence of environmental factors on their performance justifies the intensification of research in the development of new effective solutions. One of the effective ways to prevent the destruction of the wood structure is to apply a protective layer of paint and varnish material by chemically modifying the surface and, above all, by introducing siccatives. The introduction of siccatives makes it possible to ensure a uniform drying rate throughout the entire volume and additionally disperse the pigment, which improves the physical and mechanical properties of the paintwork and increases its durability.

The purpose of the research work is to establish the effect of the addition of a metallic catalyst in the form of highly dispersed precipitation waste from an electric arc furnace on the physical and mechanical properties of paint and varnish materials.

Materials and Methods. The initial components for obtaining oil paint compositions (paintwork material) were used in the experiments as: binder-natural olifa, pigment-ochre, fine aggregate-chalk. To the intensification of the drying process, the addition of metal catalyser, which is a highly dispersed waste of deposition from electric arc furnace, was introduced. The granulometric composition of chalk was evaluated using scanning electron microscopy, and dust using a microsizer 201c laser analyzer.

Results. According to the results of the optimisation, regression equations represented as a polynomial of the second degree and the optimal material composition of the paint material were obtained. In order to solve the problem of drying, a metal catalyser was added to the optimal composition in the amount of 0.05 % of the binder weight. A comparison of the obtained results of regulatory tests of the physical and mechanical properties of the two formulations, the control (without additives) and the modified with the addition of a metal catalyst in the form of dust, indicate the prospects of its use as a siccative.

Discussion and Conclusion. The introduction of a siccative into the oil-based paint and varnish material in the form of a by-product of highly dispersed precipitation waste from an electric furnace accelerated the polymerization process and improved the physical and mechanical properties of the modified composition in comparison with the control one. Improving the physical and mechanical characteristics of oil paint will increase the resistance of coatings to environmental factors and thus increase its durability.

Introduction. Advances in the construction industry are causing new composite materials to emerge. This is preceded by experimental studies, particularly analytical techniques for predicting the properties of new materials. Polymer composite materials (PCMs) which have proved to be efficient in other industries are commonly utilized in construction as well. PCMs have a number of features that should be taken into consideration while developing analytical techniques. PCM is considered under the condition of isotropy of the final material and compliance with the mixture rule during its manufacture. The objective of the study is to analytically determine the predicted strength limits of multicomponent composite materials with mineral fillers.

Materials and Methods. There are diverse methods for identifying the characteristics of polymer composites. An integral method for determining the modulus of elasticity and the Poisson's ratio of a binary polymer composite material is set forth, based on the assumption that there is a relationship between the elastic potentials of the composite components. The transition of analytical forecasting of characteristics from binary to multicomponent polymer composite material is also shown.

Results. The major characteristic of building polymer composites is their strength. A formula has been obtained for the analytical determination of the predicted tensile strength of a binary polymer composite material, and the predicted tensile strength for some multicomponent polymer composite materials has been obtained based on these formulas as well.

Discussion and Conclusion. The results enable us to conclude that while forming the composition of a multicomponent polymer composite material, it is recommended that fillers with similar characteristics, in particular, elasticity modules are combined.

Introduction. The influence of the chemical and mineralogical composition of Portland cements and the chemical base of superplasticizers on the magnitude and kinetics of autogenic (contractional) shrinkage of concretes from highly mobile and self-compacting concrete mixtures has been revealed. The relevance of the issue is due to the commonly overlooked role of autogenic shrinkage in the formation of the field of temperature-shrinkage stresses in the early hardening period of massive monolithic structures. In order to calculate intrinsic stresses, data on the magnitude and kinetics of autogenic shrinkage are required, and the insufficiency and some inconsistency of data on the effect of superplasticizing additives on the magnitude and kinetics of autogenic shrinkage, depending on the material composition of cement and the chemical and mineralogical composition of clinker, are critical to the expediency of obtaining new data on the issue. The objective of the work is to develop scientific ideas about the influence of prescription factors and material properties on the quantitative and qualitative parameters of autogenic shrinkage using the example of materials commonly used in the production of monolithic reinforced concrete structures in the Rostov region.

Materials and methods. Experimental studies were conducted using six Portland cements from four manufacturers that are fast-hardening according to GOST 31108-2020 classification. Superplasticizing additives based on polycarboxylate esters and naphthalene formaldehydes in a dosage of 0.5% of the commercial product were employed. The properties of cements are identified according to GOST 30744-2001 and GOST 310.5-88. Deformations of the hardening cement paste (stone) were determined by means of the Le Chatelier method. The amount of autogenic shrinkage of concrete was determined by the calculation method based on the amount of autogenic shrinkage of cement, taking into account the true value of the I/C of concrete and the concentration of aggregate in concrete.

Results. The ratio of "autogenic shrinkage/total contraction" of the investigated cements with additives at the age of 5 days was 0.37–0.74, the quantitative values of the total contraction of the studied cements in combination with additives at the age of 5 days ranged from 2.93 to 3.43 ml/100 g of cement, which does not contradict the available data. Change in the amount of autogenic shrinkage in the presence of additives at the age of 5 days was from 0.64 to 1.65 relative to the nonadditive standard. The effect of additives on the kinetics of autogenic shrinkage was manifested both in acceleration or deceleration, and in the absence of any effect. The calculated value of autogenic shrinkage of concretes of classes B25–B35 from highly mobile and self-sealing mixtures at the age of 5 days ranged from 0.36 to 1.18 mm/m.

Discussion and Conclusion. Scientific ideas about the kinetics of autogenic shrinkage have been developed depending on the type of cements and additives. In order to describe the change in autogenic shrinkage over time, a formula similar to the formula EN 1992-1-1 for the change in concrete strength over time is set forth. The classification of concretes according to the kinetics of autogenic shrinkage is suggested. The patterns of changes in the amount of autogenic shrinkage of concretes from highly mobile and self-compacting 

Introduction. Currently, there is very little information in the Russian literature on the development and practical application of numerical methods for studying the stress-strain state of concrete and reinforced concrete structures, taking into account the creep of concrete. As a rule, when analyzing the long-term deformation of such structures, calculators apply an empirical approach based on the use of the reduced modulus of deformation in combination with the coefficient of creep. The purpose of this study is to verify and validate the developed finite element algorithm and the corresponding software based on the results of experimental studies of the stress-strain state, prestressed reinforced concrete beam structures, taking into account the creep of concrete, available in the literature.

Materials and Methods. As a mathematical tool for modeling the process of long-term deformation of reinforced concrete girder structures, the finite element method was used in combination with a simple procedure for numerical integration along the time coordinate of the operator-matrix resulting equation. The program code is implemented on the basis of the Microsoft Visual Studio computing platform and the Intel Parallel Studio XE compiler with the built-in Intel Visual Fortran Composer XE text editor. The processes of storing and processing working arrays are implemented in terms of sparse matrices. The descriptive graphics of the Matlab computer system were used to visualize the calculation results. All of the computational experiments were performed using the authorized Polygon complex. The objectives of the study include evaluating the accuracy of the proposed methodology for analyzing the long-term deformation of reinforced concrete structures with various methods of external force action, including the effect of prestressing.

Results. A program for calculating reinforced concrete beam structures in a three-dimensional formulation has been developed and debugged using a discrete reinforcement scheme, according to which the reinforcing frame is modeled by rod (beam), and the concrete array by volumetric finite elements. To determine the restoring force caused by the tension of the cable reinforcement on concrete, a two-dimensional finite element model consisting of truss and spring finite elements is used. The simulation of long-term deformation was performed within the framework of the theory of linear viscoelasticity in combination with the principle of superimposition of influences.

Discussion and Conclusion. A comparative analysis of the results of field and computational experiments on the stressstrain state of reinforced concrete beams of rectangular cross-section with post- and prestress is performed. The proposed method makes it possible to calculate prestressed reinforced concrete girder structures with variable quasi-static loading, taking into account the linear creep of concrete.

Introduction. The heating system is an integral part of the construction site. In the article, the author explores the life cycle of a heating system, a complex system of engineering and technical support for buildings and structures, the elements of which must function stably, efficiently and fully throughout the heating period during the entire service life. The productive operation of the heating system is laid at the stage of its design, installation, adjusted and maintained at the stages of operation and modernization. Therefore, studying the life cycle of a heating system is an important scientific and practical task, and managing the stages of the life cycle becomes important, as it allows for efficiency, adaptability, cost-effectiveness and reliability.

Materials and methods. The authors have developed the structure of the life cycle of a building heating system using methods of analogy, comparative analysis and synthesis based on scientific and practical research results. The study focuses on the water heating system of residential and public buildings. The purpose of the work is to create a model of the life cycle for effective management of its stages and stages.

Results. The study of the heating system helped to identify five stages of its operation (pre-design, design, operation, modernization and disposal) and to create a life cycle structure. In the future, this will make it possible to create an energyefficient, reliable and economical system that meets modern operational requirements, improve the quality of its maintenance, and simplify the management process.

Discussion and conclusion. The life cycle of a heating system includes all stages from design to modernization. Proper management of these stages ensures efficient operation of the system, increasing comfort and reducing costs. An integrated management approach makes it possible to maximize the heating potential. A systematic study of each stage helps to choose the optimal system that meets the criteria of efficiency, safety and cost-effectiveness. The structure of the life cycle allows one to create a single digital model for intelligent management of an object at all stages.

Introduction. Construction plays a major role in the economy of the Russian Federation contributing to sustainable development and improving the living conditions of the population. Modern construction facilities include residential and commercial buildings, municipal and infrastructural structures such as roads and bridges, as well as industrial and energy facilities, including wind power facilities. Wind energy is becoming an important part of the construction industry, contributing to innovation and technological progress. As objects of the construction industry, wind power facilities go through their life cycle which includesthe main stages: design, construction, operation and disposal (renovation). Each stage requires effective management to ensure reliable operation and safety of the facility. Thus, in order to ensure the future generation of environmentally safe energy by a wind power plant, it becomes necessary to analyze the planned construction site and, as a result, manage solutions at the design and construction stages. During such an analysis, it becomes possible to identify potential problems during the operation phase of a wind power facility. These include, first of all, wear, corrosion of structural elements and frostbite of the blades. These problems are the reason for the decrease in performance and service life of the object. The aim of the work wasthus to search for the possibility of extending the service life in the life cycle of wind power facilities by solving the problem of blade icing at the design and construction stages.

Materials and methods. The research is based on the method of analyzing the life cycle of construction facilities, including the systematization and optimization of their management processes. The model of the life cycle of wind power facilities, developed by the author earlier, helped to identify the problems of the facility's operation phase. The most significant problem that significantly affects the duration of the operation phase is the problem of blade icing. An analysis of the life cycle of a wind power facility has shown that it is advisable to ensure a successful solution to this problem at the design and construction stages of the facility. The data of the conducted analysis of the problem are based on the research results of domestic and foreign authors.

As a result, a generalization and systematization of existing anti-icing methods was carried out, on the basis of which a new method of implementation was set forth and an appropriate work methodology was developed. Such a solution, envisaged at the design stage of the construction facility, will enable one to successfully manage its life cycle, and, in particular, the operation stage.

Results. Throughout the course of the research, the author has been able to increase the duration of the operation stage in the life cycle of wind power facilities. To this end, an analysis of the life cycle of construction facilities was carried out, during which the causes affecting the life of the facility were identified. The most significant reason leading to a sharp reduction in the service life of the construction site is the problem of icing of the blades during the cold season. Based on the analysis of operating conditions, the causes of icing of the blades of wind power structures have been determined, the basic principles of anti-icing protection have been established, and a new method for solving this problem using UAVs (unmanned aerial vehicles) has been set forth, as well as a technique for applying hydrophobic coatings to prevent the icing process. The implementation of the research results will ensure the required performance, which, in turn, will increase the service life of the wind power plant.

Discussion and conclusion. Successful lifecycle management of such construction facilities as wind power plants requires attention not only at the stage of operation of the facility, but also at the stages of design and construction. The key task of the operation stage of a wind power facility is to ensure the necessary productivity and increase the service life of the facility. This can be solved by carefully analyzing the life cycle and preventing future operational problems at the design and construction stages. The method set forth in the study to combat blade icing can be implemented not only for existing wind power plants that do not have special anti-icing systems, but also for projected facilities. Moreover, the suggested solutions for combating icing of the blades can be included in the design documentation as mandatory types of work carried out during the construction phase, as well as subsequently during the operation phase with a certain frequency.

Solving the problem at the design stage of the facility will ensure an increase in productivity and an increase in the service life of a wind power plant operating in cold and humid climates. Thus, the results of the study provide a theoretical basis for managing the life cycle of wind power facilities, as one of the promising construction projects.