Одеська державна академія будівництва та архітектури
THERMAL AND AEROMODELS OF ENERGY EQUIPMENT OF RESIDENTIAL COMPLEXES
During accidents or destruction of the infrastructure of residential complexes at low temperatures, it is necessary to restore the operation of heat supply systems in a short time. It is convenient to use gas tube boilers for this. But we need new solutions to the problems of increasing the power and energy efficiency of equipment and systems due to the reduction of resistances to the movement of liquids or gases, as well as the intensification of heat transfer. Numerous studies have shown that an increase in the heat transfer coefficient at the gas-metal wall interface by 2-5 times leads to an increase in energy consumption of boiler fans by 10 times or more. The article uses three research methods to improve the performance of boilers. Visual diagnostics of the movement of liquids and gases made it possible to identify signs of self-organization of the flow structure. Hydraulic studies in slot channels, where only the height h varied in the range h = 0.2-2.5 mm, confirmed that the distribution structure of the pulsation components of the dynamic part of the energy affects the increase or decrease in speed at a given initial pressure. The thermal experiment showed that the flow structure also affects the nature of the change in the heat transfer coefficient. For channel sizes where the pulsation components have positive values, the increase in the heat transfer coefficient is much more intense than for sizes where the pulsations have negative values. That is, visual studies of the flow structure and the correct choice of transverse channel sizes can solve the problem of increasing the flow up to 24% without additional energy costs, as well as eliminate the problem of uncertainty when solving the problem of intensifying heat transfer at the gas-metal wall boundary. Visual studies of the jet in a flooded space provide information for solving the problem of intensifying heat transfer. The use of turbulators in gas-tube boilers ensured an increase in boiler efficiency from hк.1 = 0.84 to hк.2 = 0.929. At the same time, the energy consumption for fan operation changed slightly. The use of visual diagnostics of the flow structure makes it possible to solve hydraulic and thermal problems when developing or improving energy equipment for housing complexes.
Copyright (c) 2024 MODERN CONSTRUCTION AND ARCHITECTURE https://creativecommons.org/licenses/by/4.0
DURABILITY OF RIGID PAVEMENT CONCRETE REINFORCED WITH BASALT FIBER
The purpose of the work is the development of fiber-reinforced concrete compositions for rigid pavements with properties of high strength, frost resistance and wear resistance due to the use of polycarboxylate type superplasticizer and dispersed reinforcement. The experiments were conducted according to an optimal 3-factor 15-point plan. The following composition factors were varied: the amount of Portland cement CEM I 42.5 R (from 290 to 350 kg/m3); the amount of basalt fiber BAUCON®-bazalt (from 0.9 to 1.5 kg/m3); the amount of polycarboxylate superplasticizer STACHEMENT 2570/5/G (from 0.6 to 1 % by weight of cement). The workability of all developed mixtures was S1, which corresponded to a cone slump 2...3 cm. Research results shows when increasing the amount of cement and the amount of superplasticizer to 0.9 – 1.0 %, the W/C of the mixtures decreases. The amount of basalt fiber practically does not affect the W/C of the mixture. Due to increase in the amount of Portland cement, the strength of fiber-reinforced concrete is increases, as expected. With an increase in the amount of basalt fiber to 1.3 – 1.4 kg/m3, the tensile strength in bending of concrete increases by 12 – 21 %, while the compressive strength changes insignificantly. Fiber concrete with a superplasticizer content of about 0.9 % has the highest compressive and tensile strength in bending. Moreover, due to increase in the amount of Portland cement from 290 to 350 kg/m3, the frost resistance of concrete increases to about 100 cycles. Due to the increase in strength of that composition, the wear resistance of concrete was increased. With an increase in the amount of basalt fiber from 0.9 to 1.3 – 1.4 kg/m3, the wear resistance of concrete increases by 11 – 16 %, and frost resistance increases to approximately 50 cycles. The change in the amount of superplasticizer has little effect on the wear resistance of concrete. However, with an increase in the amount of additive STACHEMENT 2570/5/G from 0.6 to 0.9 % by weight of cement, the frost resistance of fiber-reinforced concrete increases to about 50 cycles. Fiber concretes with a rational amount of dispersed reinforcement (1.3 – 1.4 kg/m3) and superplasticizer (0.9 %), depending on the amount of cement, have compressive strength from 43 to 60 MPa; tensile strength in bending from 4.9 to 6.4 MPa; wear resistance from 0.31 to 0.37 g/cm2 and frost resistance from F200 to F300. This ensures the high durability of the developed fiber-reinforced concrete for rigid pavements.
PROPERTIES OF CONCRETE AND FIBER-REINFORCED CONCRETE FOR BASES OF ROAD CLOTHES BASED ON SECONDARY AGGREGATES WITH HETEROGENEOUS COMPOSITION
The problem of disposal of concrete scrap of dismantled building structures is relevant for most countries of the world. For Ukraine, this problem is even more acute due to the significant amount of destruction caused by hostilities and rocket attacks. In current research the properties of concrete and fibre-reinforced concrete for the bases of road clothes based on natural and secondary aggregates were compared: granite river gravel, secondary crushed stone with a heterogeneous composition, quartz sand and secondary sand from recycled reinforced concrete structures. CEM III/A slag Portland cement with a blast furnace slag content of 65% and a polycarboxylate type superplasticizer were used. Three series of samples were studied: without fibre; with glass fibre ANTI-CRAK HP 12 (length 12 mm, diameter 0.017 mm, equivalent thread diameter 0.3 mm) in the amount of 1 kg/m3; with polypropylene fibre BeneSteel 55 (length 55 mm, equivalent thread diameter 0.48 mm) in the amount of 4 kg/m3. In each series, concrete on granite gravel and quartz sand, concrete on secondary crushed stone and quartz sand, concrete on secondary crushed stone and secondary sand were studied. The workability of all mixtures was equal to S1. Due to the use of different types of aggregates and fibres, the W/C of concrete mixtures differed significantly. Concretes on secondary aggregates had a higher W/C than on natural aggregates. When using the Anti-Crak HP 12 fibre, the mobility of mixtures with equal W/C increased by 5.5 – 6.9 %. When using BeneSteel 55 fibre, W/C increased by 10.6 – 15.5 %. The type of aggregate had a significant effect on the average density of concrete. When using secondary crushed stone and quartz sand, the average density decreased by 3.8 – 4.6 %. When using secondary crushed stone simultaneously with secondary sand, the average density of concrete decreased by 5.2 – 8.5 %. When using Anti-Crak HP 12 fiber, the average density of concrete decreases by 2 %, when using BeneSteel 55 fibre – up to 4.1 %. Concretes on secondary crushed stone with heterogeneous composition and quartz sand had 4 % higher compressive strength and 2 % higher tensile strength in bending than concretes on granite gravel and similar sand (29.8 MPa and 3.18 MPa, respectively). When secondary crushed stone is used simultaneously with secondary sand, the compressive strength of concrete is only 1.1 % lower than the strength of concrete on natural aggregates, and the tensile strength in bending is 10 % lower. This confirms the possibility of effective use of these concretes for arranging of bases of road clothes. The high-quality performance of secondary aggregates in concrete explains due to their better adhesion to the cement-sand matrix. Dispersed fibre reinforcement with Anti-Crak HP 12 has a positive effect on the compressive strength of concrete on all types of aggregate and increases the tensile strength of concrete on natural aggregates. The use of BeneSteel 55 fibre was not effective due to a significant increase in the W/C of the mixture when it was introduced. In general, taking into account the economic factor, dispersion reinforcement of concrete on secondary aggregates with the types of fibres used in the research is not advisable.
STUDY OF MODIFIED BINDER FOR PRODUCTION OF AERATED CONCRETE
In the case of energy saving, the main direction in the technology of modern wall materials is to reduce the density in order to achieve better thermal performance while simultaneously increasing the strength characteristics, i.e. creation of effective wall materials. One of these materials is aerated concrete, which is successfully used all over the world. One of the ways to increase the physical and mechanical properties of the binder as the main component of aerated concrete and to expand the raw material base can be the use of waste from all kinds of production, as well as the secondary use of damaged building materials from destroyed buildings and structures as a result of hostilities (recycling). The purpose of the research is to obtain aerated concrete on a modified binder using recycling of destroyed building materials. At this stage, a modified binder is being studied. As a result of the research, the optimal ratio of the components of the modified binder (Portland cement, metakaolin, brick mortar) was determined. Mathematical models describing the dependence of the bending and compression strength of the binder on its composition were obtained. The results of X-ray phase and differential thermal analysis show that the introduction of methacoaline and brick mortar additives into the binder based on Portland cement, after 28 days of normal hardening, do not cause new phase and mineralogical formations compared to samples without additives, but only affect the quantitative mineralogical storage. More intensively expressed hydro-silicate phases and a decrease in crystallization calcium hydroxide are observed. The micrographs of the structure of the obtained binder clearly show the monolithic structure of the cement stone, the alkali-dispersed cement grains, sand and calcium hydro-silicate clusters are visible.
BEARING CAPACITY, DEFORMITY AND CRACK RESISTANCE OF DAMAGED BEAMS REINFORCED WITH FIBER CONCRETE
The results of experimental studies of the load-bearing capacity, deformability and crack resistance of damaged beams reinforced with fiber concrete in the compressed and stretched zone are presented. Test samples are made of concrete and fiber concrete. The amount of steel fiber in fiber concrete is 2% of the volume of the product. Preliminary tests were carried out on prisms and cubes. During the manufacture of beam samples, before concreting, a foam insert was installed in the area of planned damage, the shape and dimensions of which corresponded to the damage. After the concrete set to 70% grade strength, the liner was pulled out, and the resulting cavity was filled with a 2% mixture of fiber concrete. Tests of material samples showed that the introduction of steel fiber into the composition of concrete in the amount of 2% by volume increases the compressive strength limit by 15.3%. The initial modulus of elasticity of fiber concrete of the specified mixture is 38.0% higher than that of ordinary concrete of this composition. Conducted experimental studies of damaged beams showed that a beam whose cross-section is 40% damaged in the middle-compressed zone, and the shape of the damage is close to rectangular, has a load-bearing capacity of 92.0 kN, or 93.9% of the load-bearing capacity of an undamaged beam. Cracking started at the 4th loading stage, when the load value was 26.0kN, i.e. 28.3% of the bearing capacity of the damaged beam. The maximum final crack opening width was 0.6 mm. A beam whose section is 40% damaged in the mid-stretch zone has a load-bearing capacity of 92.4 kN, or 93.2% of the load-bearing capacity of an undamaged beam. Cracking started at the 5th loading stage, when the load was 32.5kN, i.e. 35.2% of the bearing capacity of the damaged beam. The maximum final crack opening width was 0.8 mm. It is claimed that the strengthening of a beam with 40% damage in the compressed or stretched zone in the manner considered in the paper is effective, as it allows achieving its load-bearing capacity, which is more than 93% of the load-bearing capacity of an undamaged beam.
MODELING OF STRESS-STRAIN STATE AND STRENGTH OF DAMAGED CONCRETE BEAMS REINFORCED WITH CARBON FIBER FABRIC IN PC "LIRA-SAPR"
The study examines the problem of preserving and improving the architectural heritage in Ukraine. Many buildings and structures have a long service life or are already deteriorating due to their age and other factors. This is particularly true for reinforced concrete structures, which often have various defects and damage. Unfortunately, there are no clear methods for assessing the residual load-bearing capacity of such structures. However, the research indicates that the residual potential of damaged elements may be significantly underestimated. Therefore, it is crucial to explore and apply effective innovative solutions for strengthening these constructions. One such solution involves using composite materials (fiber-reinforced polymers, FRP) for external reinforcement of structures. Composite materials offer numerous advantages, including high strength, low weight, resistance to aggressive environments, and durability. The article presents the results of a numerical experiment aimed at investigating the influence of damage and reinforcement with carbon fiber-reinforced polymer (CFRP) on the stress-strain state and residual load-bearing capacity of concrete beams with basalt-plastic reinforcement (BFRP). For the experiment, 15 rectangular beams with dimensions of 2000×200×100 mm were prepared and nonlinearly analyzed using the "LIRA-SAPR" software, which employs the finite element method. The data obtained for each beam were compared with the results of laboratory tests, revealing that CFRP reinforcement increases the residual load-bearing capacity of the beams without significantly affecting their working deformation. Additionally, a comparative analysis was conducted on the residual load-bearing capacity and stress-strain state of the beam components: CFRP fabric, concrete, and reinforcement. The authors assert that modeling the complex stress-strain state of experimental basalt-concrete beams using nonlinear finite element calculations through the "LIRA-SAPR" software accurately reproduces experimental results, provides insight into the most likely failure mode, and reliably predicts their load-bearing capacity.
PROSPECTIVE DIRECTIONS OF URBAN CONCEPTS TRANSFORMATION IN THE CONTEXT OF THE IMMERSIVE PRESENCE ENVIRONMENTS DEVELOPMENT
The proliferation of immersive presence environments (an artificially created multimedia environment of an alternative reality) is evolving into a widespread social phenomenon that gradually influences how people live and interact. As a result, it has the potential to reshape expectations and demands regarding living spaces and their arrangement. While numerous studies have explored the impact of virtual and augmented reality technologies on urban planning, relatively little attention has been given to the possibility that the behavioral changes brought about by these technologies could prompt a reevaluation of the fundamental principles underlying urban planning. Previously, immersive environments were primarily seen as tools for a limited group of individuals to enhance their problem-solving capabilities within the existing framework of urban planning. However, with the widespread adoption of virtual presence tools, there is a potential for a significant shift in this paradigm. The exact nature and implications of these changes are still not well understood and remain uncertain. However, through the method of behavioral interpolation, we can begin to model the key aspects and potential outcomes of this paradigm shift. The object of this article is to present a theoretical framework for potential transformations in the contemporary urban planning paradigm resulting from the widespread adoption of personalized virtual reality technologies. Through analysis, five key categories within modern post-industrial urban planning are identified as likely to undergo changes: a) residential areas; b) accessibility radius; c) social cohesion; d) transportation requirements, and e) optimal density. Residential units will necessitate additional opportunities and spaces, altering living requirements and lifestyles. The significance of the accessibility radius, particularly for pedestrians, may diminish as a considerable number of desirable locations become accessible directly from individuals' homes. Reducing strain on transportation networks will enhance cities' environmental sustainability and create new opportunities for green spaces. The concept of social cohesion will experience stratified transformations, as differences related to ethnicity, religion, gender, race, age, social status, etc., become neutralized through the development of shifting virtual personas and non-deterministic identities. These interrelated changes will also diminish the weight of the optimal density category. Collectively, these transformations form a comprehensive conceptual framework that reimagines the city. This article outlines two potential directions of change in the urban paradigm that could arise from the proliferation of personalized metaverse communication technologies. The first direction pertains to the contemporary interpretation of deurbanistic concepts, incorporating elements of self-sufficiency, stability, security, and communication infrastructure characteristic of the information age. The second direction is likely to focus on various approaches to transforming the existing urban environment. This transformation will occur through the involvement of market regulatory mechanisms and the development and implementation of specialized municipal programs aimed at modernization and stimulating population growth.
MODERN ARCHITECTURAL PROCESS AND CURRENT TASKS OF ARCHITECTURAL ACTIVITY
The article is devoted to the identification of the features of the modern architectural process and the establishment of actual tasks of architectural activity. Today's society, science, and practice are experiencing phenomena that radically change the approaches and paradigms of the architectural process. The paper highlights the contradictions in the theory and practice of architecture that need to be resolved; considers aspects of the modern ideology of architecture; develops certain provisions of the theory of the environmental approach, namely, the features of "understanding" design, the communicative component of architectural activity; emphasizes the interaction of various actors in the process of architectural activity, the dialogue of the architect with stakeholders. The author emphasizes the decisive role of the architect as an organizer and coordinator of the design process, the interpretation of the architectural process as a component of the overall socio-cultural process. The biggest shifts are taking place in the field of the environmental approach to architectural activity. Environmental issues, which bring people and their lifestyles to the forefront, give impetus to the development of architectural management and marketing. These changes in priorities have led to a problematic situation in the theory of architecture and opened up a new space of work: the identification and recording of environmental experiences and images, the production of these experiences and the management of this process. The environmental approach outlines the future trajectories of architectural work, the essence of which is the inclusion of the designer in the life of the population, the materialization of their own version of life processes, the identification of a set of specialized activities that support the ideology of social progress and cultural development. Scientific research and architectural practice should be based on the achievements of the philosophy of architecture, understanding of new value orientations, taking into account the differences and pace of social change, etc. There is a need to recognize the importance of such a factor as the subject of the architectural process. Changing the basic guidelines of the consumer of an architectural object requires ensuring at the design stage the possibility of transforming an architectural object in the process of its further operation, predicting the emergence of new functions and the formation of their new material shell. The article outlines the contours of scientific innovations in the field of architecture - the theory of architectural activity in the conditions of intersubjective interaction; suggests forms of correct introduction of the concept of "design subject", which is active in the architectural environment, into design practice and theory of architectural activity.
STRUCTURAL FEATURES OF RESIDENTIAL BUILDINGS IN MODERN UKRAINIAN CITIES, BASED ON THE EXAMPLE OF ODESA CITY
The article is devoted to Ukrainian cities that are very different in their history, size, functions and architecture. In the period of crisis and almost complete halt of new housing construction and critical resource limitation, the most promising approaches for the development of residential areas are those that use existing housing structures and available resources. One of the most advanced areas is the use of existing housing structures. Instead of building a new housing stock with new networks and infrastructure, it is possible to develop and compact the existing housing stock (both historical and Soviet), thus reducing the amount of old housing stock and increasing the number of available square metres of housing for city residents. Each city has its own specific history and background, as well as housing structures that were formed at different times. The history of the formation and structural features of the residential development of Odesa city have been studied, so it is important to understand it in the general typology of Ukrainian urban settlements. The main criteria for dividing urban settlements into the types are the following factors: city size, number of residents, historical background, planning structure and functional content. The structural features of the residential development of modern Ukrainian cities are studied, the characteristic features and their impact on the development of residential development are identified. The development strategy for Odesa residential areas has been proposed to create a high-quality high-density living environment in historic cities. The purpose of this paper is to study the structural features of the residential development in modern Ukrainian cities, to determine their characteristic features and influence on the development of the residential development on the example of Odesa. The materials for this study are the structural features of residential development in modern cities. In particular, the impact and consequences of the crisis period on the housing infrastructure and the city structure are considered in order to understand better the crisis contribution to the formation of the modern city. The combination of the research results of the available material base and theoretical foundations of the structural features of residential development in modern cities became the main methodological basis of this work.
residential development of modern Ukrainian cities
ARCHITECTURAL AND URBAN PLANNING ASPECTS OF CITY RENEWAL IN UKRAINE
Cities that are at the epicenter of military conflicts find themselves in an extremely difficult situation. In addition to the most terrible ‒ human losses, the infrastructure of cities, housing stock and industry are destroyed. An extremely difficult task for such territories is their post-war reconstruction. This process can be successful only when there is an understanding of the main approaches and mechanisms for restoration work in such cities. The necessary solution is the development of effective strategies and programs for the reconstruction of cities. This determines a number of priority tasks, namely: analysis of the experience of recovery of the countries of the world after similar destructions and study of the peculiarities of housing reconstruction, as the most acute problem. The article examines the main directions of post-war reconstruction of cities, since post-war reconstruction is an extremely difficult task for any city and country. And for this, it is necessary to determine the priority directions of the restoration and development of cities, depending on the characteristics and nature of their destruction. The restoration of cities should not be limited to reconstruction, but should be decided on a case-by-case basis, taking into account the degree of destruction, the economic component and social reintegration. The experience of countries that have gone through the stages of war and reconstruction is of considerable importance in creating programs for the reconstruction of cities. The set of measures that will contribute to the implementation of programs of reconstruction and provision of housing for the population accretes the world experience. Therefore, the article examines the world experience of the restoration of war-ravaged cities. For partially destroyed cities with a preserved urban environment, it is possible to develop an actual design solution that will take into account the type of reproduction ‒ restoration, reconstruction, or new construction. For territories that have suffered severe destruction, possible options for the implementation of the reconstruction program and provision of housing for the population are: new construction, housing rental, temporary construction of modular or container facilities, formation of a replacement housing fund, compensation for housing. An approach to architectural and town-planning solutions has been developed, which consists in mastering the underground space, the spatial composition of the courtyard space, and the architectural solutions of the buildings.
CURRENT STATE AND PROBLEMS OF FORMING INCLUSIVE SPACES IN THE WORLD AND NATIONAL ARCHITECTURE
The article analyses the current state and problems of forming inclusive spaces in the world and national architecture. The International and Ukrainian regulatory documents that regulate the inclusiveness and barrier-free accessibility for all the population groups are analysed. The concedcpts of "inclusion", "disabled person", "disability", "people with limited mobility", "barrier-free space" are defined. The main organising elements of a quality inclusive environment in all the social spheres are identified. An urgent task is to provide the availability of residential and public buildings for all the citizens, regardless of their physical capabilities. Inclusive spaces of modern architectural development are not only about creating the appropriate infrastructure, but also about transforming the existing one. The purpose of this research is to identify the main elements of the organisation of a high-quality inclusive environment in all social spheres. The necessary analysis of the current trends in the architectural development of inclusive spaces in large cities, as well as the peculiarities of accessibility for people with disabilities and people with limited mobility, has been carried out. Main research methods are comparative and historical analysis; visual and analytical method; monitoring method; analysis of statistical data and qualitative indicators; collection, analysis, presentation, and interpretation of the information on theoretical and practical issues of organising an inclusive environment, which is reflected in the works of foreign and Ukrainian researchers. The findings of the study showed that the developments aimed at solving the problems of creating inclusive spaces are relevant and timely. An important aspect of a barrier-free environment is the development of inclusive spaces in modern cities. The different types of barrier-free environment, including physical barrier-free, digital, educational and economic, social and civic, as well as the information barrier-free, are very important for the development of inclusive spaces in the world and national architecture. Persons with disabilities and people with limited mobility have extremely limited opportunities to realise their rights.
THE IMPACT OF SUSTAINABLE DEVELOPMENT ON NEW CONCEPT OF MODERNISATION OF RESIDENTIAL BUILDINGS
Modernization of multi-apartment buildings is one of the steps towards achieving the goals of Sustainable Development of cities and communities. It is not only energy efficient, but also inclusive and spatial solutions. New concept has been introduced such as "Sustainable modernization" is a harmonious and balanced process that combines coordinated changes in today's and future needs, and "Sustainable modernization of residential buildings" is a complete set of actions for the regeneration of buildings and residential areas, including the regeneration of communal communications and nodes. Because only energy efficiency of buildings is not enough for the achievement of the goals of sustainable cities and communities, considering the fulfillment of all the tasks set. The goal is to make cities and human settlements inclusive, safe, resilient and sustainable. Regeneration today is the modernization of multi-apartment buildings to achieve energy efficiency to conserve and reduce the use of energy resources, which helps reduce utility costs and carbon emissions. But it does not satisfy the task of inclusive and planning decisions as Sustainable Urban Development. Panel mass housing construction heritage makes up a significant part of the country's housing stock in post-Soviet countries. These buildings were built according to standards that do not meet modern requirements and energy inefficient. New concept of regeneration on the basis of sustainable development is proposed as the modernization of residential buildings considering the wishes and needs of co-owners, inclusive and sustainable planning. That is, the architectural and planning decision includes the need for the house and the surrounding area for inclusive and reconstruction taking into account the social needs of the residential quarter.
FEATURES OF THE COMBINATION OF SOCIAL OPPORTUNITIES AND CIVIL ENGINEERING IN URBAN PLANNING
A term "engineering" has his root in the Latin word "ingenium", that means an "intellect" or "talent". It originates from a word "ingeniare", that is translated how to "found" or "invent". Exactly in this Latin expression there is an initial idea about work and ability to decide difficult tasks. There is the nearest to the man, her comfort residence and work. An engineering concept, as disciplines, is constrained with the use of scientific knowledge and technologies for planning, town-planning, architecture, creation and support of the different engineering systems and constructions. In the modern value, engineering embraces the wide spectrum of industries, such as mechanical, electric, computer, chemical, civil, aerospace et al, and has an important value for development of technologies and infrastructures of settlements, that are necessary for modern society. Self-society needs development of different types of engineering, that influence on his normal functioning and steady development. In this context the "civil engineering" is the nearest to the man, her comfort residence and work. A management social process is totality of actions and strategies, sent to influence and organization of the social phenomena, processes and co-operations in society. It includes a management behavior, by activity, relations and other aspects of human life, that take place in public terms. Thus a management social processes ("social engineering") is based on research, analysis and understanding of sociological, psychological, economic, political and cultural aspects of society. Him a primary purpose consists in the achievement of certain social goals and decision of problems, including technical, that stand before society. The basic aspects of management social processes it an analysis and prognostication: careful research and analysis of social processes help to understand their reasons, consequences and tendencies.
ADHESION WHEN USING PARTIAL SHOTCRETE WITH MOBILE EQUIPMENT
The current methods have been analyzed and materials that are used for the repair and renovation of concrete and reinforced concrete elements of the construction of the future. One of these is the considered method of shotcrete, the use of wet shotcrete, its advantages and disadvantages. Defects that occur during the manufacture, storage, transportation, installation and operation of concrete and reinforced concrete structures are given. The formation of different types of cracks that occur before the operation process and the appearance of cracks during the operation of structures under central tension and along one surface during eccentric tension are considered. The work presents regulation of the technical properties of repair mixtures achieved by the use of special types of cement, additives and aggregates, special laying methods and hardening conditions, as well as appropriate preparation of the surface of old concrete. The study is aimed at determining the adhesion of repair mixtures applied by the shotcreting method. Partial application of the repair mixture was used, using a mobile installation in laboratory conditions, in order to determine the optimal technological parameters of spraying. The methodology of experimental studies for determining the adhesion of fine-grained shotcreting using standardized forms with modernized partitions has been developed. Prepared beam halves with a surface angle of 20°, like old concrete, were used to increase the contact area and reduce swirl during shotcrete. A two-factor, nine-point plan of the experiment was developed, in which the thickness of the layer of fine-grained shotcrete (1 cm, 2 cm, 3 cm) of partial application and the speed of spraying of the shotcrete fiber concrete mixture (0 m/s, 35 m/s, 70 m/s) were varied. An experimental study was conducted and the results of the studies were presented.
Technology and organization of construction production
ANALYSIS OF FACTORS INFLUENCING THE INTEGRITY OF INSULATED FACADES OF HOUSES AND SEARCH FOR METHODS OF THEIR REPAIR
In modern construction, after the insulation of facades over time, the next stage is necessary – their repair. Repair of insulated facades preserves and increases the operational efficiency of thermal insulation systems of facades, ensures durability and improves the appearance of the building. Research results indicate the importance of correct installation and maintenance of insulated facades at the initial stages of construction. It was found that at this stage, various defects can occur, which negatively affect their thermal insulation efficiency and overall reliability during operation. Defects in the installation of insulating materials and other factors can reduce the effectiveness of insulation. The work examines various aspects of the repair, such as replacement of thermal insulation layers, replacement of damaged components and restoration of the appearance of the facade. One of the key tasks is the restoration of the thermal insulation layer, which may be damaged as a result of mechanical or other influences. It is important to inspect in detail, determine the degree of damage and, if necessary, replace insulating materials that may lose their thermal insulation properties in the future. In addition, the restoration of the outer finish layer is the part of the process of repairing insulated facades to ensure an attractive appearance of the building and to protect the internal structural layers, especially the thermal insulation material, from climatic and other factors. It was established that over time, different materials of the thermal insulation layer have different indicators of destruction. Particular attention should be paid to the selection of system materials that have similar vapor permeability properties. This approach will help ensure the necessary properties of the thermal insulation system and keep the appearance of the building in perfect condition for a long period of operation. It has been established that after the restoration of isolated facades, it is important to take care of their maintenance. Properly performing regular inspection and maintenance will help detect possible problems in a timely manner and prevent serious damage in the future. Climate and local building standards must also be taken into account when selecting repair materials to ensure optimal facade performance. In the process of research, it was found that repair methods are chosen, first of all, based on the technical condition of the building and the degree of damage obtained as a result of the survey. This allows you to choose the appropriate repair methods and assess the associated risks. It should be noted that a specialist who carefully examines and determines the state of facade insulation must have certain competencies in the arrangement and repair of facades. Therefore, the research results emphasize the importance of quality repair and maintenance of insulated facades to ensure their reliability, efficiency and durability. It was found that in order to ensure the quality and safety of construction objects, it is important to carry out systematic repair and maintenance of insulated facades, which can be damaged due to various influences. This allows you to preserve the building's energy efficiency and maintain its aesthetic appearance over a long period of operation.
METHODS OF RENOVATION OF MULTI-STORY RESIDENTIAL BUILDINGS IN MODERN UKRAINE
The current situation in Ukraine shows that the restoration of multi-story residential buildings is one of the most important problems of society. Existing research is mostly focused on assessing the technical condition of buildings to extend their service life or repair damage caused by uneven settlement of foundations and other operational factors. Since high-rise reinforced concrete buildings for residential and public purposes were usually designed and built without taking into account possible loads from military conflicts, as well as due to the lack of practical experience in their restoration and strengthening, the issue of ensuring their operational suitability and restoration is very relevant. To the stages of the building operation process, as a single technological process, in the event of damage with: inspections, monitoring, planned, unplanned and major repairs and liquidation. The article analyzed the current state of damaged multi-story buildings, studied the accumulated experience of their inspection, and considered constructive and technological measures for their restoration and reconstruction. The structural features of panel houses make it impossible to replace destroyed or severely damaged structures with new factory elements due to the lack of technical access for installation. The most optimal solution is the construction of new structures on the site of destroyed ones using rolled profiles, reinforcement, monolithic concrete, bricks and aerated concrete blocks. Taking this into account, the perspective for further research is a more detailed study of the problem and the development of structural and technological solutions for the restoration of residential buildings with economic justification of the feasibility of their implementation. In addition, there is a need to supplement the current regulatory documents regarding the reconstruction of buildings damaged as a result of military conflicts.
ANTI-LANDSLIDE MEASURES OF THE SECTION OF THE SLOPE OF THE ODESSA COAST
Calculations of the stability of the section of the landslide slope of the Odesa coast were performed in the work. The site is located in the Kyiv district of Odessa and is adjacent to the children's health and sports camp "Viktoria". The territory covers the coastal part of the plateau, the terraced slope and the beach area. Artificially created terraces and berms stand out in the relief of the slope, at the foot of the slope in some places a preserved natural beach. The specifics of this area are complex engineering-geological (block structure of the slope, loess subsidence soils) and hydrogeological (several aquifers, high level of groundwater) conditions. Previously, before the implementation of a complex of anti-slide measures, large-scale deep sliding and squeezing landslides took place in this area. The partially implemented engineering protection measures, which consisted in the planning of the slope surface and the arrangement of shore fortifications, did not lead to a complete stabilization of the landslide processes. At the present time, undamped, slow-flowing deformations occur on the landslide slope. These deformations are related to the blocky structure of the slope, hydrogeological conditions, as well as rheological properties of meotic clays. Stabilization of landslide processes is possible only with a comprehensive approach in the appointment of anti-slide measures. The assessment of the stability of the slope and the appointment of anti-slide measures were carried out taking into account the features of the engineering and geological structure, hydrogeological conditions, as well as the results of the field survey of the slope. Calculations of the stability of the slope were carried out according to flat schemes by the methods of Bishop and Janbu. Calculations were also carried out in a three-dimensional setting using the finite element method in the Midas GTS NX geotechnical software complex. The Mohr-Coulomb elastic-plastic model described the behavior of the soil in the calculation scheme. The proposed set of anti-slide measures, which includes: installation of absorption wells on the plateau, to lower the groundwater level; arrangement of the lower and upper tiers of key piles with vertical drainage above them; organized removal of stormwater from the surface of the slope; planning and fastening of the slope surface.
EFFECTIVENESS OF DECENTRALIZED HEAT SUPPLY BASED ON TRADITIONAL HEAT GENERATORS WITH VAPOR COMPRESSION ENERGY TRANSFORMATION OF LOW-TEMPERATURE SOURCES
The research is devoted to solving the urgent problem of increasing the efficiency of decentralized heat supply of public buildings and industrial enterprises with typical municipal and industrial heat generators on the basis of heat pump energy conversion of pre-cooling of heat flows of the return energy carrier from the heat network, initial cold water and flue gases. The aim of this work was to analyze and identify conditions that would increase the energy efficiency of the improved system while expanding the total volume of generated heat for decentralized heat supply. Additionally, the work aimed to ensure the environmental friendliness of primary fuel energy use. The proposed approach aims to improve the energy and environmental performance of heat sources by regulating the temperature of the waste energy carrier to its design value, following a standardized temperature schedule. The most important result of the study of the improved system of decentralized heat supply is the established generalized dependence of determining the actual conversion coefficient in the heat pump operation. It allows qualitative analysis of the dependence of energy efficiency of the heat supply system on the temperature change of the analyzed low-temperature sources, the ratio of the above-mentioned water flow rates and the influence of cold water distribution for municipal and industrial-technological purposes. The results of the analytical study of the improved heat supply system create a basis for adjusting the temperature schedule of heat supply, taking into account the characteristic conditions of decentralized heat supply and heat consumption modes of municipal and industrial systems.
STUDY OF STRENGTH AND STRAINS OF COMPOSITE MATERIALS BASED ON FILLED POLYMERS
The article aims to study compressive and bending strength of polymer materials and their strains with various amounts of filler to determine the optimal value. The polymer composite material consists of polymethyl methacrylate as a binder and quartz sand as a filler with the fractions at 0.14 mm, 0.315 mm, 0.63 mm. The filler amounts were changed from 100 to 500 weight parts. The strength of polymer filled material was determined by testing cube samples under compressive and beam samples under bending. The strains were determined by testing prism samples under tensile. The study results show the significant impact of the fraction type on the strength and deformation characteristics of composite materials based on polymethyl methacrylate. The samples with the finest fraction of filler 0.14 mm and 150 weight part demonstrate the biggest strength ‒ 90 MPa under compressive and 40 MPa under bending. The increase both particles size and their amount led to the decrease the strength of filled composite. The analysis of the dependencies between stresses and strains shows than deformations drop as far as the amount of mineral filler declines. In proportion as the quantity of filler goes up, the creep deformations occur under less amount of tensile stress. It is linked the less interaction on the border "filler-polymer" and, as consequences, the bigger possibilities of polymer to plastic deformations. Based on obtained dependencies, the patterns of defect development under loading have been proposed that involves taking into account interphase interaction on the borders "filler-polymer" and "filler-filler". The less the particles size, the bigger their specific surface and structure-forming effect. The increase of sand particles size and their amount leads to growth of porosity, goes down the strength of composite material and drops the capability of elastic recoverable strains. The practical importance of this study is the possibility the usage of the filled polymer composites for recovering and renovation works where traditional cost cement fillers are replaced with cheap and ecofriendly fine sand.
COMPARISON OF THE EFFECTIVENESS OF SUPERPLASTICIZERS IN CONCRETES FOR RIGID PAVEMENT
More and more roads with hard cement concrete pavements are built in developed countries, including Ukraine. The production of almost all types of concrete involves the use of plasticisers. Today, polycarboxylate additives are the most effective plasticisers. However, the effect of water-reducing modifiers depends on the formulation and technological characteristics of a concrete. In the construction of hard pavements, concrete mixes with relatively low mobility are used, in which it is necessary to determine the effectiveness of various plasticisers, taking into account the type of cement. Accordingly, the purpose of the study is to establish how the strength of concrete pavements is determined by different types of plasticisers. The strength of concretes with four different plasticisers was compared. The plasticisers considered were: Polyplast SP-1 (based on a mixture of sodium salts and polyethylene of phthalate sulphuric acids); Coral ExpertSuid-5 (based on carboxylic acid polymers and esters), Coral MasterSilk (based on lignosulphonates), and Sika® Plastiment®-1230 (produced on the basis of lignosulphonates). These were added in two dosages ‒ 0.8 and 1.2% by weight of cement. The cement used was PC II/A-Sh-500 R-H in the amount of 350 kg/m3, the crushed stone was as fine as 5–20 mm, and the washed quartz sand had the fineness modulus 2.4. The mobility of all concrete mixes was S1 and depended on the composition of the concrete. It has been found that the use of Coral ExpertSuid-5 can reduce the water/cement ratio most significantly. The use of Coral MasterSilk reduces the water/cement ratio to a slightly lesser extent. SP-1 and Sika® Plastiment®-1230 have approximately the same, and the lowest, effectiveness in reducing the water demand of the mixture. At the design age, the highest strength (55.9-57.5 MPa) was observed in concrete pavements modified with Coral ExpertSuid-5 and Sika® Plastiment®-1230 plasticisers. At the age of 3 days, concretes with the Coral ExpertSuid-5 additive have the highest strength. An increase in the dosage of these two plasticisers from 0.8% to 1.2% increases the early strength of concrete, but does not change the strength at the design age. The strength of the concrete modified with the Polyplast SP-1 and Coral MasterSilk additives was lower at the early and design ages. That is, taking into account the use of mixtures of low mobility and cement PC II/A-S-500 R-H, the effectiveness of the additive based on carboxylic acid polymers in increasing the strength of concrete at the design age is approximately equal to that of the lignosulphonate-based additive.
OPTIMIZATION OF ACCELERATED CARBONIZATION HARDENING EFFECTS OF EXPANDED CLAY CONCRETE
The paper examines the data obtained during the study of accelerated carbonization hardening of expanded clay concrete. The mechanisms and methods of carbonization hardening, the influence of recipe and technological factors on strength characteristics are considered. The most significant of them were the consumption of the binder, the relative amount and granulometry of the filler (ground limestone) and aggregate (keramzite), the concentration of the plasticizing additive (SYM) and the technological parameters of carbonization ‒ the maximum pressure and time of carbonization. The nature of the influence of the relevant properties on the strength characteristics is considered. The results of the planned and implemented experiment were studied using the methodology of response surfaces. Experimental-statistical models of compressive strength were built for 1 hour, 28 days and 180 days from the end of the carbonation procedure. The degrees of influence of various factors are determined. Constructed dependencies were displayed using a series of diagrams of isolines of strength at the limit values of three factors of weak influence. The proposed hypothesis is that in experimental-statistical models of the properties of materials closely related to their structure, a tendency to simplification is created when the corresponding materials pass through the stage of structure formation. Insignificant components of the experimental-statistical model, mainly related to the interaction of factors determining the structure of the material, are reduced. Corresponding transformations arise, in particular, for constructed strength models. Two tasks of optimizing the long-term strength of expanded clay concrete are formulated. The first task is related to the elimination of hard additional constraints during optimization, while the long-term strength reaches its maximum. The second engineering-based task contains additional requirements for the economical use of binder and the convenience of the carbonization process. The distributions of the parameters of the desirability function were determined for both tasks. As a result of the optimization, two main sets of recipe-technological factors and corresponding properties of composite materials were obtained.
optimality according to the combined criterion
MECHANOCHEMICAL ACTIVATION OF PORTLAND CEMENT AND ITS INFLUENCE ON THE THERMOMECHANICAL CHARACTERISTICS OF CEMENT-WATER COMPOSITIONS AND SOLUTIONS BASED ON THEM
Issues discussed in the article related to determining the influence of mechanical activation in a rotary high-speed mixer of cement-water compositions and solutions based on them. Relevant for this study is the activation of cement in combination with the consumption of ground quartz sand (S = 250 m2/kg), the amount of which was adjusted in the range from 0 to 40 % of the cement mass. The use of this technology, along with reducing cement consumption, ensures acceleration of the processes of cement hydration and intensification of exothermic heating of the hardening composition. Mechanical activation is also reflected in the acceleration of the loss of mobility of cement-water compositions filled with ground sand. The presented experimental data made it possible to evaluate the influence of the activation times (90 and 180 sec) of the binder on the diameter of the spread of the aqueous cement-containing composition. It has been established that the main contribution (up to 90 % of the total value) to the decrease in the water-binder ratio (provided that equal-viscosity compositions are obtained) is achieved when the cement-containing composition is activated for 90 seconds. Subsequent activation of the binder (up to 180 sec) has a slight effect on the growth of the diameter of the composition spread and does not exceed 5-10 %. The exothermia of the hardening cement-water composition determined by the thermos method indicates a significant influence of mechanical activation both on the kinetics and on the achievement of the maximum temperature of its heating. The introduction of ground sand does not change the overall picture of the effect of mechanical activation on exothermic heating, changing only the decrease in intensity and the decrease in maximum heating of the cement-water composition. The influence of mechanical-chemical activation of Portland cement with the addition of quartz sand on the strength of a 1:1 mortar at 3 and 7 days of age was revealed. Experimental studies indicate a positive effect of binder activation on the compressive strength of the mortar. The increase in strength of samples using mechanically activated cement reached 15-25 % compared to the control.
A number of factors affect the redistribution and value of axial forces in the cores of structural slabs, such as the location and quantity of supports, the presence or absence of prestress in the structure, the shape of the base crystal of the slab, which is the forming element, and the height (thickness) of the slab, which can be varied within certain permissible limits. A change in one of these features with the rest of the parameters remaining unchanged significantly changes the stress-strain state of the structure. The paper describes the description of finite element models of a structural grid slab with a plan dimension of 12.0×24.0 m. Four models of the slab are adopted, differing only in one parameter ‒ the thickness of the structure. The following values of the structure height were adopted: 1.5 m (model No. 1), 1.3 m (model No. 2), 1.1 m (model No. 3), 0.9 m (model No. 4). The analysis and design of all models were performed, which were accepted. New profiles of the structural groups of rods were selected so that they met the check conditions for the first and second groups of limit states and the percentage of rod cross-section utilisation was as high as possible. The maximum deflections of the models after the analysis were compared. The lowest weight as an optimality criterion is the most common criterion for structures, in particular metal structures, as this criterion is quite easy to formalise. The weight of each slab model was calculated and it was found that the optimal design solution is model No. 1 with a height of 1.5 m, since only for this model the deformability is within the permissible limits. The model characterised by the lowest weight is model No. 3, but the maximum vertical deflection of this structure is greater than the maximum limit. In conclusion, the analysis of the displacements of the slab model nodes revealed that only the maximum deflection of the slab in model No. 1 does not exceed the maximum permissible deflection of 4.8 cm. The maximum deflections in models No. 2, 3, 4 exceed the maximum permissible value of the absolute deflection. Consequently, the check condition for the second group of limit states is not met in models 2, 3, and No. 4, and model No. 3, which has the lowest weight, cannot be recognised as the most effective among the others. Considering the condition of sufficient stiffness, the optimal design solution is model No. 1. The difference in weight between model No. 1 (8.9 tonnes) and model No. 3 (8.33 tonnes) with the lowest weight is 6.8 %.
THE MULTI-STOREY BUILDINDS STEEL FRAMES PROGRESSIVE COLLAPSE MECHANISMS IN FIRE
An overview of previous studies, dedicated to the vitality of the multi-story building with a steel frame was carried out. Currently, measures are available to increase the multi-story buildings' steel frame vitality in fire, which affects the potential progressive collapse mechanism. The quantitative vitality indicators have been determined earlier. The model used to study a multi-story building steel frame is described. The way of modeling the fire action on steel structures is presented. The criterion for the steel frame elements destruction is determined. The measures of increasing vitality for the multi-story building steel frame model are presented. The sequence of multi-story buildings' steel frames different elements destruction for a various measures of increasing vitality is determined. The collapse duration of each of the considered progressive collapse mechanisms is analyzed. It is established that the initial destruction in the unheated frame element leads to a less projected and more unfavorable progressive collapse mechanism in the event of an accident evacuation. It is determined that to avoid the initial destruction in the unheated frame element, you need to use an attachment of the outriggers to the columns joint with the admission of vertical displacements. It is established that in the case of beam destruction earlier than the column, the progressive collapse mechanism will be longer than in the column's initial destruction case. Earlier internal column destruction leads to a longer progressive collapse mechanism than earlier external column destruction. It is established that the progressive collapse mechanism of the type "beam - the internal column - the external column – progressive collapse" is the longest and the most predictable. The gradation of the progressive collapse mechanisms of steel frames in the role of a qualitative vitality indicator is determined. The gradation presented can be used for the research of frames with a variety of spans and floors.
RESEARCH OF CHARACTERISTICS OF INTERIOR COMFORT OF MULTI-APARTMENT RESIDENTIAL BUILDINGS FOR DIFFERENT PERSONALITY TYPES
During the period of quarantine restrictions, and later the full-scale invasion of russia into the territory of Ukraine, issues related to the change of residence intensified, accordingly changes in the level of social communications, problems of comfort, and realization of all vital functions in the living space of apartment buildings. The main purpose of the article is to study the relationship between the architectural characteristics of comfort in the interior of a residential apartment and the personality types of residents. The subject of our research is the architectural and spatial characteristics of the comfort of a residential apartment. The analysis of scientific research in the field of psycho-design and socio-design indicates the stratification of human personality types into 4 types, which realize all their vital functions in the "field of life". Another area of research focuses on finding the most integrated characteristics of the interior of the living space. These characteristics include size, shape, color, and details. The main research method is the construction of a two-component matrix, with the help of which it is possible to determine the relationships between the components of the interior of the dwelling and the level of comfort for its residents. As a result of the analysis and evaluation of the concept of interaction of socio-psychological features of character and the corresponding architectural and spatial characteristics of comfort depending on the type of personality, practical recommendations have been formulated that can be applied in the process of pre-project analysis and at the stage of creating architectural and planning decisions of apartments and creating interior design. Experimental verification of the results obtained in the process of creating the interior design of several residential apartments in Ivano-Frankivsk shows that the level of comfort of residential apartments where the algorithms of this study were applied is significantly higher than in architectural and planning decisions where this methodology was not used.
LOADS ON SUBMERGED WALLS OF PROTECTIVE STRUCTURES
The intensification of military operations on the territory of Ukraine, which are accompanied by missile attacks and bombing of territories, requires the use of reliable protective structures. Modern codes require the provision of each new building with storage facilities that guarantee the safety of life and health of citizens, so the correct determination of all loads on the structural elements of protective structures is an urgent issue. Taking into acoount the fact that the previous codes were somewhat outdated and had limited access for a long time, a significant event was the adoption in 2023 of new codes for the design of protective structures of civil defence. The main requirements and recommendations of SBC B.2.2-5:20023 were taken into account when conducting research on determining the loads on buried walls of bomb shelters. Such structures, as we know, perceive a constant load from the lateral pressure of the soil, which during an explosion is supplemented by an episodic load from the action of an air wave. Modern specialized literature contains rather limited information on scientific research and development in the field of design of protective structures. An actual issue is also the study of the influence of determining factors on the intensity of the load on the walls of buried protective structures and the possibility of its adjustment in order to reduce it. Taking into account the nature of the distribution of loads on the underground walls of bomb shelters, a dependence was obtained to determine the resulting active pressure and quasi-static load caused by the action of an air wave. The pressures from the soil and the blast wave at different orientations of the contact wall and for different types of soil environment were studied. The loads in contact of a smooth and rough wall with sandy, sandy and loamy soils with different indicators of physical and mechanical characteristics were considered. The obtained results indicate a significant influence of the geometric parameters of the wall and the features of the contact soil on the resulting pressure, which can vary depending on the studied factors by 10-20%, which indicates the possibility of reducing the load on protective structures, operating with the considered indicators.
quasi-static load from the action of an air wave.
METHODS AND PRACTICES FOR IMPLEMENTING AND APPLYING DIFFERENT TYPES OF ARTIFICIAL INTELLIGENCE AND DATA SCIENCE TO SOLVE PROBLEMS IN WATER INFRASTRUCTURE
The subject of the study in this article was the practice of implementing and applying various types of artificial intelligence and data science to detect leaks from water supply networks, to monitor freshwater conditions and to detect pollution, clean freshwater bodies from waste from industrial and mining enterprises, control freshwater flow and develop more efficient water filtration methods. The article identifies the advantages and disadvantages of the practice of introducing and applying various types of artificial intelligence and data science technologies to automate traditional methods of monitoring, control and related work in the water industry. The article addresses the following objectives: to substantiate the effectiveness of implementation of various types of artificial intelligence technologies and data science methods and their practical application with software and hardware technologies to automate traditional methods of performing work in the water industry. To solve the tasks set, the methodology used was based on general scientific and special research methods, such as theoretical methods (analysis, explanation, generalisation, comparison). The use of this approach allowed us to obtain the following results: the features that affect the accuracy of the analysis of collected data used by technologies of various types of artificial intelligence and data science methods were identified. Practices and methods for more efficient and accurate application of this technology are reflected. Scientific data are analysed. The study allowed identifying the practical opportunities and problems of this technology. Recommendations for the effective use of this technology have been developed. The factors that influence the effective use of this technology in industry are identified.
ANALYSIS OF MODERN SCIENTIFIC AND PRACTICAL RESEARCH IN THE FIELD OF WATER DISTRIBUTION SYSTEM
Solving the problem of ensuring the reliable functioning of drainage systems is important not only for Ukraine, but also for scientists around the world. Since these systems are critically important for life support, their uninterrupted operation is of strategic national importance. The issue of preservation and restoration of existing underground communications is gaining particular relevance due to increased environmental requirements. To protect groundwater from contamination with aggressive reagents, it is important to understand the reasons for the destruction of underground communications structures and effective methods of their repair. The article analyzes scientific works related to the problems of ensuring the trouble-free operation of objects that are part of the complex of constructions of sewer tunnels of the city. Grouped according to the direction of research work: research on the corrosion process in water drainage networks; analysis of modern ones; materials, laboratory tests; technologies for restoring drainage networks. Analysis of studies of the condition of structures of objects; research of materials and methods of repair and restoration of sewage tunnels and inspection shafts, which are currently used with high efficiency in domestic and foreign practice; development of technological and organizational solutions and restoration of destroyed sewage structures of drainage networks. The analysis of the researches of domestic scientists showed that the sewer tunnels of large cities of Ukraine are worn out as a result of long-term operation, ineffective solutions to protect structures from the influence of an aggressive environment, low-quality materials and structures used during construction. Restoring normative operational characteristics, increasing the durability of sewage tunnels is a costly and technically complex task, the solution of which is urgently needed to prevent accidents, including those with serious environmental consequences. Existing modern technologies of work performance, materials and structures used for repair and restoration works with different efficiency solve these problems, at the same time, the need to reduce costs for repair and restoration works requires the search for cost-effective materials, structures and methods of work performance. The analysis of the conducted studies shows that the problem of increasing the durability of sewage network structures should be solved comprehensively, taking into account the current situation.
THE ROLE OF CaCO3 IN THE FORMATION OF STRENGTH AND DECORATIVE PROPERTIES OF POWDER ALKALINE-ACTIVATED SLAG CEMENT CONCRETE
The article discusses approaches to the formation of compositions of alkali-activated decorative Portland slag cements containing Portland cement type CEM1 5...45% with high performance and decorative properties. The optimization of the compositions of decorative alkali-activated Portland slag cements was carried out using statistical methods for designing experiments. Finely dispersed TiO2 and CaCO3 additives with a whiteness of 90% were used as bleaching components. The alkaline component is sodium metasilicate in the form of a non-hygroscopic powder. The research carried out made it possible to obtain decorative Portland slag cements with a whiteness of 45...77%, which allows them to be used to produce colored cements with a wide range of colors from white to black. It has been established that alkali-active decorative Portland slag cements have an activity of 37...59 MPa at the age of 28 days. All compositions have good hardening dynamics and, based on the strength at the age of 2 days - 22...36.6 MPa, they can be classified as fast-hardening. Based on them, it is possible to produce dry construction mixtures. All mortar compositions based on alkali-active decorative Portland slag cements demonstrate fairly high frost resistance - F200. This allows them to be used for the manufacture of products and solutions both for indoor use and when exposed to atmospheric influences without loss of design characteristics and decorative appeal. The inherent shrinkage strains of decorative alkali-activated Portland slag cements are 0.51...0.61 mm/m, which eliminates cracking and premature destruction of products. The use of the CaCO3 additive is especially effective for controlling the shrinkage deformations. Thus, the CaCO3 additive performs the functions of not only a decorative component, but also a structure-forming component. Concrete and mortar mixtures can be used to produce decorative products using the traditional method, extrusion, 3D printing on construction printers, etc. And not too long setting times and a rapid increase in strength make it possible to produce products without thermal treatment or with minimal consumption of thermal energy.
alkali-activated decorative Portland slag cements
COMPUTATIONAL EXPERIMENTS WHEN STUDYING MATERIALS PROPERTIES INFLUENCED BY "MIXTURE" FACTORS
Short information on computational materials science is given, with the methodology of material properties fields, in composition and process coordinates, as the part of it and as the background of the study presented in this paper. One of the main means of the methodology is random scanning the whole and local fields. These tools were developed and used to solve many problems in materials science related to the properties defined by mutually independent factors. The purpose of the study presented in this paper has been to develop the tool for random scanning the fields of properties effected by "mixtures" of q components, linearly related portions of components in rangers from 0 to 1, with their sum equal to 1. In these cases, the factors domain (or subregion of it) presents the simplex. The special designs of experiments to get reduced polynomials describing the fields in simplex coordinates are used. Two procedures for generating any number of uniformly distributed points on the simplex have been developed. These points define the virtual mixtures simulated in computational experiments. The procedures were tested by scanning the fields of two rheological characteristics of lime suspension filled with "short", “medium", and "long" cellulose fibers. Experimental-statistical models in the form of reduced polynomials for effective viscosity at shear rate equal to1 s-1 and for the rate of destruction of liquid structure (parameters of power-law model of flow, K = η1 and m) obtained in previous study are used to determine the levels of these characteristic for each of simulated mixture. Computational experiments were carried out, in which the fields of η1 and m in whole simplex domain and in some of its zones were scanned, allowing the generalizing indices of the fields and different correlations between η1 and m in different zones of mixture triangle to be estimated. The developed tools, the procedures of generating random points, which would define the simulated compositions of the "mixtures", make significant contribution to the progress of the methodology of recipe-technological fields of properties and to computational materials science.