Technology of jet-grouting is a method of strengthening weak or heavily watered soils by pumping high-pressure cement slurry into the well to break the structure of the soil and simultaneously stirring its particles with cement slurry. The result is a ground-cement mass which has predefined improved strength and deformation characteristics. Technology of jet-grouting has a great potential for development and application in various construction industries, such as buildings, roads, bridges and other structures under various geological conditions. The development of jet-grouting technology won't only expand its application, but can improve competitiveness in the construction services market.

Keywords: recycling, reinforced concrete, secondary crushed stone, construction waste, crushing equipment.

The article discusses the use of organic binders to modify the properties of cement soils. The scope of application of cement soils in construction practice, including the construction of highways, is considered. The influence of the use of organic binders as a complex additive that modifies the strength characteristics of cement soils has been studied. The influence of the use of complex modifiers and additives on the frost resistance and water permeability of cement soils has been determined.

Keywords: cement soil, organic binder, highway, working layer, frost resistance, modifiers

The article deals with the issues of major repairs of rooms for radiation diagnostics in medical institutions, which is becoming more and more relevant in modern conditions. Functional diagnostics plays a key role in early detection of diseases, correct diagnosis and effective treatment of patients. With the development of technology and the advent of high-tech diagnostic equipment, there is a need to upgrade medical institutions to integrate such equipment. The study, conducted on the basis of an analysis of regulatory and technical documentation and scientific papers, highlighted the main stages of major repairs of radiation diagnostics facilities, identified the main participants in these stages. Organizational charts have also been developed for each stage, which emphasize the importance of coordination between all project participants, including builders, engineers, architects and medical specialists. The implementation of such schemes helps to minimize time and financial costs, ensures the implementation of all necessary requirements and standards, and guarantees the high quality of the work performed. As a result, we receive an organized repair process that allows medical institutions to effectively use new diagnostic equipment to improve the quality of medical services and improve the diagnosis and treatment of patients.

Keywords: major repairs, healthcare facilities, radiation diagnostics facilities, medical organization, project documentation

The problem of increasing consumption of heat and energy resources in the high-rise residential sector in the conditions of dense urban development becomes more relevant every year both for its population and for management companies. In order to reduce operating costs, to reduce the dependence of engineering systems of high-rise residential building on urban infrastructure, it is proposed to introduce some energy-efficient organisational and technological solutions in the designed apartment building. In the course of the study, on the example of a high-rise 25-storey residential building in the city of Rostov-on-Don, a comparison of operating costs of thermal energy for heating with the use of energy-saving materials and structures, and costs in typical conditions of construction. The results of this work will allow, from a practical point of view, to analyse the feasibility of using such energy-efficient building envelopes and materials as foil PIR-insulation, low-emission four-chamber glazing, "green" roofing in high-rise housing construction.

Keywords: energy efficient building envelopes, heat consumption, heating costs, high-rise apartment block, economic analysis, sustainable construction

This article discusses several ways to determine the calculated lengths of steel columns in the plane of the frame. By analyzing existing techniques, the most successful method of selecting the calculated lengths for steel columns in a free multi-storey frame was determined. Taking into account the non-standard case of fastening crossbars to the considered section in the frame of the overpass, using the LIRA CAD PC, as well as the Crystal module (implemented in SCAD), the loss of stability of equally loaded elements in the most sensitive area is clearly shown.

Keywords: Euler's formula, loss of stability, coefficient of calculated length, calculated length, coefficient of stability margin, finite elements

The concept of digitalization of the construction organization project (POS) is presented, which is based on its close connection with the construction schedule. The place of the POS in the digital model of the building at the project stage (PIM) is considered. based on its digitalization, taking into account the relationship between information modeling at the project stage (PIM). The main problems that may arise when implementing the digital version of the POS in the general information model at the project stage are identified.

Keywords: BIM, TIM, POS, digital model, calendar schedule, construction organization

The article discusses the issues of stability of pedestrian paths and staircases located on sloped areas and interacting with a complex geological environment. The features of designing construction projects on sloping areas are considered. The reasons for the occurrence of various defects and destruction on the staircase, located on the embankment of Khabarovsk, were investigated. An assessment of the stability of the structure during repair work is given. Measures are proposed to increase the stability of the structure.

Keywords: staircase, slope, slope stability, stress-strain state, fortifications

The article presents an analysis of the requirements for quality control in the current regulatory documentation of the Russian Federation and the experience of developing a scheme of operational quality control (SOQC) for the installation of sheet metal waterstops, obtained on the basis of regulatory and methodological documentation and materials from manufacturers of waterproofing materials: domestic and foreign, and the practice of using polymer and metal waterstops and our own experimental studies. The content of the main information blocks of the SOQC in the practically accepted unification of requirements for quality control in construction is described. Construction defects are indicated when using polymer waterstops for waterproofing technological seams of monolithic structures of civil buildings, which can be avoided if the requirements are met and the work is performed in accordance with the developed SOQC as part of the technological map of the work production project.

Keywords: scheme of operational quality control, quality in construction, installation tolerance, requirements, sheet metal waterstop

The article discusses the measures of construction control during the construction of monolithic structures. The quality of technological processes in the construction of reinforced concrete buildings determines the existing problems of their reliability and durability. As a result, there is a need for construction control during the construction of facilities. The concept of construction control is defined. The structural and technological types of buildings are investigated. The stages of construction at which construction control is carried out are considered. The methodology for improving the efficiency of organizational and technical solutions during construction control has a significant impact on reducing construction time, and also minimizes the number of defects and deviations.

Keywords: construction control, building types, monolithic reinforced concrete construction, construction stage, quality, concrete mix

The main defects of railway structures are identified, the damage of defects is characterized by the degree of influence based on the quality indicators of building structures, a mathematical model for assessing risk and damage is created, expert surveys are conducted on the nature of the conditions for the probability of defects and bringing them to damage, an algorithm for implementing the results on the construction site is presented.

Keywords: risk assessment, probability conditions, concrete works, risk-oriented approach, risk identification

The results of experimental studies of improving additive manufacturing for construction due to the effect of an electric field (electrode heating) on the printed layers are presented. It makes possible to regulate the duration of the technological break of 3D printing in a wide time interval while ensuring high levels of layer adhesion and, accordingly, the quality of the finished construction product.

Keywords: additive manufacturing for construction, 3D concrete printing, 3DCP, extrusion, technology, technological break, cold seam, bonding, adhesion, layer, concrete, quality

This article discusses the main factors leading to a decrease in the bearing capacity of the support bases and the possible loss of stability of the offshore platform, which will entail emergency consequences. The impact of free gas in the upper sections of the soil and dynamic external loads on the safety of construction and operation of oil platforms has been assessed. Calculations for the bearing capacity of the pile foundation of the support bases of the SPBU Astra in the Caspian Sea, performed according to existing methods, were analyzed. The determination of the strength of the soil is carried out for the calculated support surface – the section of the column having the maximum area.

Keywords: geodynamic effects, bearing capacity, pile foundation, indentation depth, free gas

The results of a study of the influence of shrinkage deformations on the basic physical and mechanical properties of concrete are presented depending on various production and technological factors. The research methodology took into account the choice of the period of aging concrete in a dry, hot climate to study the influence of physical processes in concrete on its physical and mechanical properties. The influence of shrinkage deformations on the strength characteristics of concrete was studied. an increase in the intensity of mass transfer processes between concrete and the environment leads to an increase in destructive shrinkage deformations, mainly plastic shrinkage of concrete, which lead to changes in the structure and physical and mechanical properties of mature concrete. The consistency of the concrete mixture also influences the amount of strength reduction. with a greater value of plastic shrinkage of concrete, its compressive and tensile strength in bending decreases. the destructive effect of plastic shrinkage on concrete caused depends on a number of technological factors (consistency of the concrete mixture, w/c, temperature and humidity hardening conditions, etc.).

Keywords: curing period, mass transfer processes, plastic shrinkage, concrete structure, concrete strength, reconstruction, buildings and structures

The article examines the application of properties of polyethyleneimine (PEI) and polyacrylic acid (PAK) polycomplex composition for soil strengthening. During the studies, the ratio of PEI and PAA (by dry weight) was established, at which the reagents most fully enter the complexation reaction. The polycomplex composition of the optimal composition was used to strengthen the soils of some varieties. When studying the properties of hardened soils, dependencies were obtained: the ultimate strength of the hardened soil on the relative humidity and the thickness of the layer of hardened soil on the consumption of complexing reagents. The paper concluded that the use of polycomplexes for soil strengthening is promising.

Keywords: polycomplex composition, soil strengthening, polyethyleneimine, polyacrylic acid, impregnation method, dedusting, optimal humidity

The construction industry is undergoing regular changes these days, influenced by many different factors. Large and structurally complex construction projects reveal more and more imperfections in traditional construction methods, e.g. increased time or production costs, downtime, delays, etc. Lean construction and its principles have emerged in search of solutions to problems in construction. In the search for solutions to problems in construction, the term - lean construction and its principles appeared, which replaced traditional methods and aimed at finding new approaches in the implementation of construction activities. In this scientific article the definition of Lean Construction is given, and also the history of Lean Construction and its chronology are considered. The comparison of the traditional construction model and Lean model is given, and also the connection of Building Information Modeling (BIM) with Lean Construction principles is analysed and an example of this connection is given.

Keywords: lean manufacturing, lean construction, construction, lean construction principles, lean technology, lean model, lean philosophy, life cycle of an object, information modelling technologies, engineering

An important condition for the high-quality development of the construction industry is the further increase in energy efficiency and environmental friendliness of design solutions in the field of roof enclosing structures. Therefore, solving the problem of correctly choosing the most effective roof instalation to increase the life cycle of the entire building becomes more relevant. The widespread use of a wide variety of both traditional and more durable and reliable roofing coverings in modern construction practice makes it difficult to choose the most effective option. The article develops a methodology for choosing an effective roof instalation option based on the use of economic and mathematical tools, based on the analysis of organizational and technological calculations and technical and economic comparison of various options

Keywords: additive optimality criterion, roofing, roofing covering, operation, methodology, organizational and technological calculations, rational technology, roof tiles, operating costs, efficiency, economic and mathematical modeling

The overview of the existing horizontal and vertical nodal joints for 3D modular building blocks and plane elements has shown that tongue and groove is the most commonly used connection today. Other types of module attachments are also discussed. Special attention is paid to a modular integrating system encompassing a design description. It is emphasized that the efficiency of modular construction depends, among others, on nodal joints used therein.

Keywords: modular construction systems, operational reliability, horizontal and vertical attachments, coupling bolts, tongue and groove connection

This article analyzes trends and examples of the use of digital technology in order to increase the efficiency and improve the quality of construction projects. BIM technologies already at the design stage make it possible to provide as much as possible all the signs that affect the construction object at the beginning of construction and its further operation. The number of these signs increases, due to the fact that the complexity of the construction process of construction objects increases, as the scale of construction increases, the volume of construction products and building materials increases. In this connection, the requirements for the general designer, contractor, customer, etc. are increasing. At the same time, the customer expects to find, in addition to the project, a solution to reduce costs and increase the functionality of the construction object with the highest parameters. The need for high-performance special technologies and methods of organizing the management of construction works is becoming more acute. BIM technologies are the physical and functional characteristics of a construction object presented in digital form. Digital technologies are an integrated special resource of competencies in order to obtain information about a construction object. It provides the basis for the possibility to accept special decisions of a construction object from construction to the moment of its demolition. This model provides an opportunity to delegate a virtual digital model from the creators of the project to the subcontractor, general contractor, owner, as well as the manager of the construction object. The technical tasks of using information modeling technologies are the starting point for planning an investment project both from the customer's position, since they define the scope of using a BIM model at all phases of the operation of a construction object according to the criteria for evaluating information, and from the position of the contractor, since it acts as the basis for generating a plan when a BIM project will be implemented. The list of characteristic technical tasks of BIM modeling application at different stages of the construction object life cycle is determined. The BIM project algorithm is proposed.

Keywords: information modeling of the construction of objects, labor productivity, physical wear, defects, reliability, diagnostic tasks

The construction industry plays an important role in the national economy, and the products of construction industry enterprises are essential for economic growth and development of the state. At the same time, the current state of affairs in the construction industry is characterized by the presence of economic uncertainties and other restrictions. One of the main directions of development of the construction sector, as well as other sectors of the national economy of the country, is expanded reproduction in the conditions of import substitution, which determines the search for the most promising territories for the location of new construction industry facilities.

Keywords: construction, construction industry, construction complex, strategic management, import substitution

The functional and spatial aspects of the formation of the architectural environment of medical rehabilitation and rehabilitation centers for injured athletes are investigated. The theoretical basis on the problems of functioning of similar facilities - rehabilitation centers for the disabled is considered, the characteristic components of the environment are identified, as well as the technological stages of the rehabilitation process. The generalization of the best Russian experience and existing architectural and planning solutions of medical institutions with rehabilitation functions is carried out. A comparative analysis of analog facilities was carried out in three conditional groups: a) large medical centers with rehabilitation functions for the disabled; b) multidisciplinary rehabilitation centers; c) specialized rehabilitation centers for athletes. A number of promising approaches and trends are identified that can be applied to the formation of conceptual models and adaptive architectural and environmental solutions for sports medicine and rehabilitation centers.

Keywords: rehabilitation center for athletes, functional-spatial, architectural-planning, environmental solutions, models, approaches

Performance of construction and installation works in the conditions of existing health care facilities requires participants of the construction industry to take into account technical equipment of facilities, their specifics, influence of various factors and external conditions on the organisation of construction production, architectural and design solutions of facilities, preservatThe performance of construction and installation works in the conditions of existing healthcare institutions requires from the participants of construction production to take into account the technical equipment of facilities, their specifics, the impact on the organisation of construction production of various factors and external conditions, architectural and planning solutions of facilities, preservation of the functionality of medical institutions and the possibility of their current operation. This article raises the question of searching for new or existing techniques in organisational and technological design, which help to increase the validity of organisational and technological solutions. The practice of reconstruction of medical institutions in modern construction production does not take into account enough factors influencing the development of architectural and planning solutions. However, it is these factors that are determined at the stage of formation of medical and technological task. Such insufficient attention to the factors can significantly affect the organisation of the construction process. The article considers the experience and peculiarities of the organisation of construction production in the reconstruction of healthcare facilities, reflected in the works of domestic and foreign scientists and researchers.

Keywords: reconstruction, healthcare facilities, organizational and technological solutions, documentation, workspace, time, labor costs, transactional model, productivity

The article discusses proposals for improving the use of discharge-pulse technology in the construction of boron-injection piles and camouflage widenings of bored piles with diameters of more than 300 mm. The application of voltages on the electrode system of a pulse current generator from 10 to 50 kV and an electric capacity of about 300 UF is considered. It has been found that in the case of using a relatively low voltage on the electrodes and an increase in the electrical capacity of the capacitor bank, the duration of the shock wave pressure on the ground increases several times. This contributes to a more intensive penetration of the liquid hardening material into the intergranular space of the near-well soil massif. It is proposed to use solutions using slag-alkali binders as a hardening material in the formation of boron-injection piles. Such solutions have greater fluidity compared to cement solutions and, when hardened, form a stone with greater strength and density. The article presents data from experimental studies confirming the increased strength (R = 130 MPa) and frost resistance of a solution prepared on slag-alkali binders, as well as data on determining their corrosion resistance to various aggressive media contained in groundwater. The possibility of stable breakdown of the interelectrode gap in aqueous solutions of slag-alkali media of various consistencies has been established, optimal energy parameters of the discharge have been determined for maximum effect of fixing the soils of the foundations.

Keywords: foundations, drilling piles, discharge-pulse technology, slag-alkali binders

One of the tasks of the state is to create decent living conditions for the population, including providing people with high-quality and comfortable housing. However, over time, housing wears out, becomes outdated, and becomes unsuitable for use. In order to slow down and prevent rapid deterioration of capital construction projects, capital repair measures are being implemented. They are aimed at restoring and replacing structural elements of residential buildings that have fallen into disrepair. Overhaul of housing is a complex of organizational, technological and economic measures aimed at reducing and eliminating the physical deterioration of buildings. Thus, the creation of decent living conditions for the population and the safety of the housing stock, as well as increasing its energy efficiency, depend on the effectiveness of the organization of the capital repair system and its organizational and technological support.

Keywords: major renovation, apartment building, repair and construction work, energy saving, energy efficiency

In order to negate the loss of strength, that can lead to collapse of constructions, we should take measures to prevent cracking. Every crack emersion in reinforced concrete indicates that the accumulated stress has been released in this area of the structure. The cause of cracks are internal tensile stresses that can occur due to internal processes in the element and from external loads on the structure. It is possible to eliminate cracks that have already appeared with the help of repair compounds that fill the volume of cracks in various ways. Injection, as one of the solutions, will help to maintain the strength and durability of the structure.

Keywords: cracking, concrete, reinforced concrete slab, crack, defect, deformation, strength, soil, repair compound, foundation, foundation slab, injection

The article is devoted to the assessment of signs that can lead to the destruction of building structures that undergo physical wear over time. The destruction of the elements can lead to adverse consequences. A mathematical basis is used to diagnose structural failure. With its help, it is possible to determine the influence of signs contributing to the destruction of the structure on the degree of destruction. This article discusses the main provisions of the general kinetic theory, as well as methods of its application in order to determine the emergency condition of structures. The technical condition of the structures is considered from the standpoint of the determinational theory. The concept is based on the principle of reliability of the structure before the first failure. The object's trouble-free operation model embodies the science of the speeds of processes in the field of structuring and decomposition of complex system structures throughout the life cycle and shows the adaptive response of structures to factors that shorten the service life of the object. This concept makes it possible to more accurately assess the risks of structural failure from the effects of certain adverse factors.

Keywords: construction and technical expertise, defects, reliability, diagnostic tasks, diagnostic methods, efficiency