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Field thermovision study of externsl enclosure for multi-storey residential building under climatic conditions of Northern Kazakhstan

https://doi.org/10.58224/2618-7183-2024-7-1-1
Abstract
An in-place thermovision study was carried out in a multi-apartment apartment building of high comfort in a cold period of the year, located in the Northern part of the Republic of Kazakhstan in the work. The study result showed the presence of significant problems on thermal protection at the edge and inner corner fences where the temperature difference between the inner surface of an enclosure and the internal temperature was 6.4 - 19.4ºC. An analysis of thermograms of window joints in living rooms also showed a significant temperature drop from -9.3ºC to 18ºC, where total vulnerable area was up to 10%. Thermograms of window-sill joints of living rooms also showed a temperature drop to -21.1 ºC with an area of 15.7 %. The temperature on a reinforced concrete column’s inner surface showed a value of 6.5 ºC, which is typical for an area of 34.8 %. An analysis of outside and inside temperatures showed that as the temperature drops from -7 ºC to -23 ºC during the day, the inside temperature of the room remains relatively stable at 25.3 - 26.1 ºC, although there are problems with the thermal protection of the enclosures, which indicates overconsumption of heat energy. Moreover, the internal air temperature exceeds the permissible temperature for living rooms by 1.3 - 2.6 ºС. An analysis of air humidity also showed unsatisfactory values, which during the day varied from 17.4% to 21.2%. The deviations identified during the survey indicate the presence of problems on thermal pro-tection of external enclosures, which require additional surveys aimed at further development and op-timization of external enclosure designs to obtain optimal values in the issue of energy saving, consid-ering the climatic characteristics of the Kazakhstan regions.
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Processing of nonlinear concrete creep curves using nonlinear optimization methods

https://doi.org/10.58224/2618-7183-2024-7-1-2
Abstract
The article proposes a method for determining the rheological parameters of concrete based on creep curves at various stress levels using the theory of V.M. Bondarenko. Using the proposed methodology, the experimental data presented in the work of A.V. Yashin is processed. The problem of searching for rheological parameters is posed as a nonlinear optimization problem. The sum of squared deviations of the experimental values of creep strains from the theoretical ones is minimized. The interior point method is used as a nonlinear optimization method. Four different expressions for the creep measure are considered, including the creep measure by N.Kh. Harutyunyan, creep measure by A.G. Tamrazyan, a creep measure in the form of a sum of two exponentials, and McHenry’s creep measure. It has been shown that the best agreement with experimental data is provided by the McHenry’s creep measure. An expression has been selected for the nonlinearity function, which describes the nonlinear relationship between stresses and creep strains. It is shown that the instantaneous nonlinearity of deformation and the nonlinearity that manifests itself over time cannot be described by a single function.
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Stress-strain state during the formation of normal cracks in three-layer bendable reinforced concrete elements under the action of longitudinal and transverse forces

https://doi.org/10.58224/2618-7183-2024-7-1-3
Abstract
Most wall panels in operating multi-storey residential buildings are in a complex stress-strain state under the influence of vertical and horizontal loads, such as their own weight, wind, etc. These features must be taken into account in the calculation in order to ensure operational safety. The combination of vertical and horizontal forces acting simultaneously for three-layer bending elements leads to the fact that the boundary between the compressed and tensile zones not only moves from one layer to another, but also has a different geometric shape depending on the ratio between the vertical and horizontal load. The stress-strain state during the formation of normal cracks in three-layer bendable reinforced concrete elements is caused by the impact on layers of different concretes. The formation of normal cracks occurs due to the achievement of ultimate tensile strength by the most stretched concrete under the influence of external loads. Since three-layer reinforced concrete elements consist of two outer layers (reinforced concrete) and a middle layer (lightweight concrete), when such an element bends, the outer layers are subject to compression, and the middle layer is subject to tension. The boundary of the compressed zone can be located either in one of the outer layers or intersect the middle layer, which falls into both the compressed and stretched zones. To analyze the stress-strain state during the formation of normal cracks, it is necessary to take into account the fol-lowing parameters: geometric characteristics of the element (dimensions and shape of the section, layer thickness, etc.), physical and mechanical properties of concrete (compressive and tensile strength, elastic modulus, Poisson's ratio, crack resistance coefficient, etc.), characteristics of reinforcement (class, diameter, pitch of bars, etc.) and its location in the section.
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Calculation of monolithic buildings structures taking into account the nonlinear operation of reinforced concrete

https://doi.org/10.58224/2618-7183-2024-7-1-4
Abstract
Buildings and structures made of reinforced concrete are currently designed, as a rule, under the assumption of linear work of the material. However, in accordance with the requirements of modern standards, it is necessary to take into account the nonlinear operation of concrete and reinforcement in calculations. In the research presented in the article, using the example of a building with a wall structural system, the influence of taking into account the physical nonlinearity of reinforced concrete on the operation of its structures was considered. It was received that due to the nonlinear operation, there is a prospect of a possible reduction in the calculated forces affecting the strength and width of crack opening, and, consequently, the reinforcement consumption. In addition, when taking into account the work of reinforcement in the zone of yield stresses in ceilings and walls, local plastic areas may form that require reinforcement, which are not fixed in linear calculations.
The calculations were performed in the LIRA-CAD 2021 software package. The results of the calculations showed that taking into account the nonlinear operation of reinforced concrete when considering the floors of a building allows reducing the design efforts compared to calculations performed in a linear formulation by about (3 - 30)%, and when calculating walls, on the contrary, taking into account the physical nonlinearity of reinforced concrete, internal forces increase in some cases more more than twice. Taking into account the physical nonlinearity of reinforced concrete work also leads to a more correct assessment of floor deflections.
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Molding properties of clay mixtures in the soft mud brick manufacture

https://doi.org/10.58224/2618-7183-2024-7-1-5
Abstract
The article reveals physical and mechanical characteristics of clay mixtures in the soft mud brick manifacture. Considering that currently Russia has no advisory or regulatory documents on the selection of raw materials for soft mud bricks and requirements for their physical and mechanical properties, this issue is quite relevant. The authors, based on their extensive practical experience, present data on acceptable ranges of clay mixtures deformation and critical compressive stress in the soft mud brick manufacture, as well as the results of studies on the influence of electrolyte additives on these indicators. The findings of how the mineral composition of clay raw materials and moisture con-tent influence the critical compressive stress and stickiness of clay mixtures are also presented. Thus, it has been experimentally established that the critical compressive stress of clay mixtures for soft mud bricks should be in the range of 0.2 – 0.8 kg/cm2, and the deformation degree of raw bricks should be in the range of 3 – 5 units. Moreover, even within such narrow limits, depending on their variation as well as on the method of molding and the composition of clay mixtures, it is possible to obtain differ-ent structures of the brick front surface: granular, tuberculate, grooved, wavy, corrugated, spotted, scaly, and their combinations. The moisture content of clay mixtures, depending on the type of clay raw material, can vary within very wide limits: from 20 to 38 per cent. The data obtained will make it possible to develop methods for selecting raw materials for soft mud bricks, which in turn will con-tribute to the organization of its wide production in various regions.
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Stereotypical ideas in the perception of spatial marginality of urban outskirts

https://doi.org/10.58224/2618-7183-2024-7-1-6
Abstract
According to the territorial-regional development policy of Russia, a rigid structuring of the country's space is applied through the prism of a hierarchical management system. As a result, the structure of the space of the entire country was fixed through a system of boundaries, the markers of which highlight management objects at the national level, subject of the Russian Federation, territory, region, district. This article will present the main stereotypes that influence the creation of the perception of new territories in the nature of marginality. As is known, the formation of marginal communities can be traced throughout the history of civilizations. It is important to separate geographical marginality from spatial marginality. In geography, there is the concept of “marginal territories”, which can be considered those located on the remote periphery of the region or in isolated places. Such a phenomenon as spatial marginality is characterized precisely by the prevailing stereotypes in society about a specific area. Urban spatial perception critically influences human behavior and emotional responses, emphasizing the need to align urban spaces with human needs to improve the quality of urban life. However, the classification of urban architecture based on functionality is subject to biases stemming from discrepancies between objective representation and subjective perception. These biases can lead to city planning and designs that fail to adequately meet the needs and preferences of city residents, negatively impacting their quality of life and the overall functionality of the city. In this study, we apply machine learning to uncover these biases in urban spatial perception research using a three-step methodology: objective mapping, subjective perception analysis, and perceptual bias assessment. Our results show that machine learning can reveal hidden patterns in this area of research with significant implications for urban planning and design. Of particular note, the study found significant discrepancies in the distribution centroids between commercial buildings and residential or public buildings. This result sheds light on the spatial organization characteristics of urban architectural functions, serving as a valuable guide for urban planning and development. Moreover, it reveals the advantages and disadvantages of different data sources and methods for interpreting urban spatial perception, paving the way to a more complete understanding of the subject. These results highlight the importance of integrating both objective mapping and subjective perspectives when classifying the functionality of urban architecture.
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Structure and properties of modified shungite concrete during electrode heating

https://doi.org/10.58224/2618-7183-2023-6-6-1
Abstract
Concrete composition modifying by different electrically conductive components is one of less laborious but relatively effective methods between wide variety of electrode concrete heating effectiveness improvement methods. The purpose of this study is investigation of special aspects of cement systems modified by powdered shungite (Ssp 400 m2/kg) in combination with active mineral and plasticizing admixtures that harden under electrode heating at below zero temperatures. By the method of differential thermal analysis anomaly of exothermic reaction of cement stone specimens was discovered, that is due to formation of hydrated calcium silicate С2SH (A) discovered by the method of quantitative XRDA, and is verified by results received from scanning electron microscopy method, which among other factors provides higher strength and low permeability to these composites. Stabil-ity of cement systems modified by shungite and curing under electrode heating has been proved.
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Study of the characteristics of pavement elements made of rein-forced soil with the use of secondary resources

https://doi.org/10.58224/2618-7183-2023-6-6-2
Abstract
The importance of using secondary resources on the basis of industrial waste is understood by both governments of developed countries and business (production of Portland cement using ground metallurgical slag as a mineral additive at Novotroitsk, Magnitogorsk, Sterlitamak, Katav-Ivanovsk and other plants in the South Urals). The use of secondary raw materials requires the creation of technological infrastructure for processing of secondary raw materials, the costs of which can be quickly recouped due to the cheapness and availability of industrial secondary raw materials and freeing the territory from environmental pollution. In order to recoup the costs of the infrastructure, it is necessary to guarantee full compliance of the quality of pavement elements with the requirements of GOST R 59120-2021. Secondary raw materials have a great variety and laboratory analysis of the quality of pavement elements is required in order to design compositions with the best quality, satisfy-ing all regulatory requirements. In our work the authors present the results of laboratory research and evaluation of the possibility of using clinker-free lime-slag binder based on the mineral product of so-da production and metallurgical slags to strengthen and stabilize soils for their use in pavement struc-tures in the construction of roads for various purposes and climatic zones.
It is experimentally shown that the addition of lime-slag binder in the amount of 8-10% of the dry weight of both cohesive (loamy soil, loamy sand) and non-cohesive (fine sand) soil allows to obtain reinforced soil with improved strength and elastic-deformative characteristics, which can be used in-stead of scarce natural crushed stone and gravel in the construction of underlying layers of pavements in the construction and reconstruction of highways. This technology can be used not only in the Rus-sian Federation, but also in a number of other countries, including those with hot dry climates (e.g., the Republic of Egypt).
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Technology for the production of road bitumen modifier using aluminosilicate microspheres extracted from ash and slag energy waste

https://doi.org/10.58224/2618-7183-2023-6-6-3
Abstract
The results of research on the development of technological solutions for the production of a new rubber-bitumen binder for asphalt concrete based on the use of industrial waste: used car tires, used car oil and microdispersed aluminosilicate spherical particles obtained from the processing of ash and slag waste (ASW) from thermal power plants are presented. The proposed technological solutions make it possible to obtain high-quality polymer additives for modifying the properties of road bitumen. The elements of novelty of the developed approach include the use, to obtain a granular modifier, of micro-sized hydrophobized aluminosilicate spheres, which are extracted as an additional product during the complex processing of ASW. The positive economic efficiency of technological solutions is ensured by the use of large rubber crumb (more than 8 mm) or rubber chips, their devulcanization together with hydrocarbon fractions of used engine oil and petroleum bitumen at a given temperature to form a gel-like mass, which is further subjected to mechanical grinding in a mill.
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Features of the pyrolysis process of waste batteries using carbon black as an additive in the construction industry

https://doi.org/10.58224/2618-7183-2023-6-6-4
Abstract
The paper discusses the technology for recycling used lithium-ion batteries. At the same time, one of the important components in the technology for processing such waste is the recycling of anode material with the extraction of graphite or carbon black, which can be used in the production of fire bricks. It has been shown that materials and compounds contained in lithium-ion batteries are sources of hazardous waste of the second hazard class. At the same time spent accumulators are a source of valuable secondary material resources and contain in their composition up to 16 % wt. % of graphite.The paper proposes to consider the process of processing anode materials of lithium-ion bat-teries in order to obtain graphite and carbon black from them by pyrolysis. Experimental studies were carried out on the process of decomposition of cathode and anode materials of lithium-ion batteries separately, as well as their mixture by pyrolysis. When studying the kinetics and mechanism of pyrol-ysis of carbon-containing materials, thermogravimetric analysis of the following materials was carried out: 1) powdered graphite grade GAK-2 (GOST 10273-79); 2) graphite released from the anode dur-ing manual disassembly of the LKIT; 3) mechanically activated powders containing cathode material LiNiMnCoO2. The characteristics of the pyrolysis process were assessed using thermogravimetric and differential thermogravimetric analyses. Pyrolysis characteristics demonstrate that organic substances contained in batteries can decompose at a pyrolysis temperature of 500 °C for cathode materials and 450 °C for anode materials. This subsequently leads to higher efficiency in the extraction of valuable components with shorter grinding times. It has been shown that the decomposition of a mixture of lith-ium-ion battery materials removes a larger amount of organic components than the pyrolysis of anode and cathode materials separately. In this case, the rate of decomposition of the mixture of materials occurs more slowly. The activation energy values for lithium-ion battery materials after the pyrolysis stage were determined. The content of components in powder obtained after the pyrolysis stage was determined using the method of atomic emission spectrometry with inductively coupled plasma.
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