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2023

Archives Journal Construction Materials and Products Vol. 6

Optimization of Rectangular and Box Sections in Oblique Bending and Eccentric Compression

https://doi.org/10.58224/2618-7183-2023-6-5-2
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Abstract
The article presents a solution to the problem of finding the optimal ratio of the height of the cross-section to the width for a rectangular and box-shaped section in the case of oblique bending and eccentric compression. Optimization is performed according to the strength criterion, and for the case of oblique bending of a rectangular beam, a solution was also obtained from the condition of a minimum full deflection. For a rectangular section, the solution is made analytically, and for a box section, numerically using the MATLAB environment and the Optimization Toolbox package. As a numerical method of nonlinear optimization, the interior point method is used. To simplify the solution, the box section is assumed to be thin-walled, i.e. it is assumed that the wall thickness is significantly less than the height and width of the cross section. An estimate of the error of such an assumption is also performed. It has been established that in the case of oblique bending of a rectangular beam, when optimizing according to the strength criterion, the optimal ratio of the cross-sectional height to width is equal to the cotangent of the angle between the force plane and the vertical axis, and when optimizing according to the rigidity criterion, it is the square root of the cotangent of this angle. In the case of eccentric compression of a rectangular beam with eccentricities in two planes, the optimal ratio of the height of the cross section to the width is equal to the ratio of the eccentricity along the vertical and horizontal axes. For a box-shaped section, graphs of the change in optimal parameters depending on the angle between the force plane and the vertical axis in the case of oblique bending, as well as depending on the ratio of eccentricities along the axes in the case of eccentric compression, are plotted.
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Research Trends in the Mechanoactivation of Clay Minerals Used in Obtaining Geopolymers

https://doi.org/10.58224/2618-7183-2023-6-5-3
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Abstract
The article is an attempt to review scientific achievements in the field of obtaining aluminosilicate geopolymers and current research trends in the field of mechanical treatment (mechanical activation or mechanoactivation, as the term is used in the article) of their predecessors. A geopolymer, also referred to in the literature as geopolymer resin and geopolymer cement, is a mineral binder resulting from geopolymerization, the main step of which is the polymerization (or polycondensation) of precursors in an alkaline or acidic medium. This review focuses on geopolymers whose precursors are natural aluminosilicates, i.e., clay minerals, because, firstly, clay minerals are widespread and available worldwide, and secondly, geopolymers based on heat-treated kaolinite (or metakaolin) have a number of advantages that make kaolinite attractive for further study in terms of reducing energy consumption and carbon footprint in their manufacturing. On the other hand, the review considers the potential of mechanoactivation of clay minerals in an air medium and establishes that mechanoactivated kaolin clays have the potential to replace metakaolin.
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Study of the Influence of Hydrothermal Treatment Parameters on the Properties of Lightweight Silicate Bricks Using Aluminosilicate Microspheres and Substandard Clay Rocks

https://doi.org/10.58224/2618-7183-2023-6-5-4
Abstract
This article investigates the influence of various parameters of hydrothermal treatment on the properties of lightweight silicate bricks obtained using substandard clay raw materials, construction lime and aluminosilicate microspheres. It was found that it is possible to obtain products with the required performance characteristics at a minimum hydrothermal treatment pressure of 0.2 MPa. With an increase in pressure to 0.4 MPa, it is possible to reduce the time of isothermal exposure while main-taining the required properties, which helps to reduce the energy intensity of production. The optimal amount of CaO depends on the specific parameters of hydrothermal treatment. So in order to achieve maximum strength indicators, the content of CaO is 10 wt. % at a pressure of 0.2 MPa and 15 wt. % at a pressure of 0.4 MPa, respectively. The addition of aluminosilicate microspheres makes it possible to significantly reduce the average density and obtain a lightweight silicate brick with this indicator from 930 to 1610 kg /m3. The rational time of isothermal exposure, ensuring the formation of a cementing compound of optimal composition, and as a result, obtaining a material with high physical and me-chanical properties at a pressure of 0.2 MPa is 8 hours, and at a pressure of 0.4 MPa is 6 hours. Math-ematical models are proposed for the selection and optimization of lightweight silicate brick compositions based on construction lime, substandard clay rocks and aluminosilicate microspheres.
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Development of Public Spaces: the Impact of Metro Stations Construction on the Formation of the Structure of the Adjacent Territory

https://doi.org/10.58224/2618-7183-2023-6-5-5
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Abstract
The article aims to study the development potential of local urban centers around the rapid transit system with due regard to the historical traditions of urban development and modern urban planning principles. To attain this end, the authors use a set of methods, including site analysis, data collection, classification, and project proposal development. The paper presents the tradition of forming a peripheral public space within the historical boundaries of the city. It is demonstrated that the current development of local public spaces based on peripheral rapid transit stations can be considered a continuation of this tradition at a new historical and technological stage. The authors select metro stations suitable for the formation of local urban centers. To determine the possibility of placing a pub-lic space in the vicinity of metro stations, calculations are made for territories included in forty-three metro zones of the peripheral part of the city and thirteen zones of the middle part of the city. Based on a group of indicators for the selected stations, the authors conduct an analysis and compile a table that characterizes the territories near each rapid transit station. As a result, the density and floor space index, passenger traffic per day, and the balance of the adjacent territory for each station were deter-mined. There are draft projects for the development of territories, layouts, and visualizations of the proposed options for building open public spaces. The authors consider scenarios for the placement and transformation of public centers near metro stations. The study reveals how the construction of each metro station affects the adjacent territory. It is worth mentioning that new stations affect not only the lifestyle of citizens, with improved transport accessibility, the status of the territory increases, new centers of social activity, and new public spaces emerge.
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National Artistic Traditions in the Formation of a Model of Architectural Development of City Limits

https://doi.org/10.58224/2618-7183-2023-6-5-6
Abstract
The study considers the planning of Russian estates from both architectural and social perspectives, as well as their influence on the modern construction of urban outskirts, which is necessary for the development of city limits. The article examines the planning and organization of socio-cultural space as exemplified by the Russian estate at the turn of the 18th and 19th centuries. By analyzing the architectural complexes of the Russian estate and developing surroundings in this period, the authors propose a model for organizing the socio-cultural space of city limits. The article dwells on the historical architectural ensembles of Arkhangelskoye and Abramtsevo, as well as various types of Russian estates, whose territories are being developed as city outskirts. The study considers modern opinions and assessments of planning territories bordering historical architectural monuments through various research methods. The obtained results allow the authors to develop a model of a socially sustainable architectural ensemble, including its socio-cultural, artistic, and educational functions.
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Recycling of Municipal Solid Waste in Construction

https://doi.org/10.58224/2618-7183-2023-6-5-7
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Abstract
This article discusses a promising direction focused on the use of recycled municipal solid waste in construction. In Russia, there are problems related to municipal solid waste management, which necessitates the modernization of this process and confirms the relevance of the issues raised. Analysis and use of the experience of foreign countries in the processing of municipal solid waste and its secondary use in Russia contributes to the search for a more environmentally responsible approach that entails both economic and social benefits. The use of solid municipal waste recycling products in construction is aimed at minimizing the negative impact on the environment and is a step towards the transition to a circular economy, where waste is turned into valuable resources.
The article reflects on the various methods of recycling municipal waste and analyzes the priority areas for the processing of municipal solid waste. In addition, examples of successful building projects using recycled products are given, and the challenges and prospects of this approach, as well as its significance for sustainable development and environmental responsibility in the construction industry, are revealed.
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Circumpolar Aspect in the Development of Urban Environment Organization in Russian Cities

https://doi.org/10.58224/2618-7183-2023-6-5-8
Abstract
The purpose of the paper is to examine the effect of the Arctic Hectare program on the development of Russian cities in the Arctic region. In particular, the study analyzes the role of the program in changing the borders of settlements and the possibility of their regulation. The research employs a qualitative approach, including the collection of data from government documents, research literature, and electronic resources associated with urban development, regional development, and the Arctic Hectare program. Data analysis shows that most Arctic cities continue to compress: with preserved infrastructure, entire houses and areas of settlements go empty. In contrast, the Gulf of Ob shows an increase in settlements, as its mining areas actively expand. The area demonstrates a principle characteristic of circumpolar urban development, e.g., a fractal system of settlement growth with the development of the next branch of the city tree. The restart of empty suburbs outside the zone of active mining is attributed to the stage program of Arctic Hectare. As a result, the authors identify two concepts of urban planning: one that emphasizes development along outbound highways, and another that assumes the development of satellite cities. In the near future, the familiar urban landscape may change, as its outskirts may be supplemented by low-rise development. A large share of applicants use the Arctic Hectare to solve the housing problem. It becomes clear that the suburbs are a realistic way of habitation in the Arctic region. The researchers argue that the sustainability theory can allow pre-dicting urban development in the territory based on adaptive cycles.
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The Influence of High Frequency Plasma Treatment Reduced Pressure Induction Discharge to Improve the Adhesive Characteristics of Fiberglass

https://doi.org/10.58224/2618-7183-2023-6-4-5-14
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 5-14 p.
Abstract
The article presents the results of studies confirming the advantages of plasma treatment in the production of glass-filled composite materials based on polyamides, which consist in environmental friendliness, resource saving and no dependence on chemical solutions that plasma treatment offers compared to traditional methods. By optimizing processing parameters, the study also explores how plasma processing can manipulate surface layer characteristics and material structure to improve cer-tain glass fiber characteristics without sacrificing other properties.
As part of the study, experiments were carried out to study the effect of low-energy ions generated by high-frequency plasma on the technological characteristics of glass fibers. Previous studies have shown that plasma treatment in various gaseous media (argon, air, propane-butane mixture) makes it possible to remove the lubricant from the fiberglass surface, activate its surface, and increase adhesion in the polymer-filler system.
Capillarity tests were carried out to evaluate the adhesion characteristics of the plasma-treated glass fibers. The results showed a direct relationship between the increase in the capillarity index, the dura-tion and intensity of the plasma treatment. As a result of the study, the optimal processing parameters were determined to achieve the desired adhesive characteristics, as a result of which the adhesive strength increased by 1.5-1.7 times.
The results of the study confirmed the persistence of the effect of plasma treatment over time, and therefore, it is recommended to use modified glass fibers to reinforce polymer matrices during the first 10-25 days after treatment.
The data obtained make it possible to recommend plasma treatment for the modification of glass fibers in the production of reinforced polymer composites.
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Injection mortars based on composite cements for soil fixation

https://doi.org/10.58224/2618-7183-2023-6-4-15-29
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 15-29 p.
Abstract
The fixation of subsidence soils is an important practical scientific and technical task, which makes it possible to carry out construction and repair work on weak (subsidence) base soils. Composite cements (CC) have been developed, including aluminosilicates (AS), obtained by enrichment of ash and slag mixture (up to 65 wt.%), Portland cement clinker and gypsum. Based on the developed CC, a wide range of injection solutions with water-binding ratios from 1.0 to 2.0, including screening of crushed granite from 0.7 fineness modules, has been created. The developed injection mortars are capable of effectively fixing the soils of the foundations of underground structures, providing the strength of the soil-concrete mass up to 25.6 MPa with a deformation modulus of 10.1 GPa. According to the sedimentation analysis of solutions, it can be seen that these materials have a percentage of water separation from 22.5% at W/B=1 to 36.5% at W/B=2. At the same time, the viscosity indicators of these materials indicate a high penetrating ability, since the time of the expiration of mortars through a Marsh viscometer for mortars IR5 and IR6 is 39 and 40 seconds at W / B = 1.5 and W/ B = 2, respec-tively. The effect of increasing the density of injection mortars on composite cement at the age of 28 days was maximum at an AS dosage of 45% by weight, then it decreased with an increase in the con-tent of the aluminosilicate component. There are high ratios of the values of strength properties on the second day to similar indicators in the 28-days age: for compressive strength 0.24 (0.20-0.22 for addi-tive-free clinker compositions), for flexural strength 0.16 (0.15 for additive-free clinker compositions; while increasing the AS content above 45%, this ratio decreases to 0.14). High early strength makes it possible to effectively use injection mortars for urgent fixing of soils during the repair of underground structures.
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Radar absorbing materials based on sealant “Abris”

https://doi.org/10.58224/2618-7183-2023-6-4-30-41
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 30-41 p.
Abstract
The article discusses the creation of elastic self-adhesive radio absorbing materials for the frequency range of 4.5 – 6.0 GHz. In recent decades, technologies related to the emission of electromagnetic energy into the environment have been rapidly developed. In 1996, the World Health Organization first introduced the concept of "Electromagnetic environmental pollution". The electromagnetic field is a biologically active, biotropic factor that, under certain conditions, can cause pathological changes in the functioning of the human body. An effective way to meet the requirements of electromagnetic ecology and safety is to reduce electromagnetic radiation to an acceptable level through the use of protective materials. Analyzing the composition of existing protective materials, it is obvious that the shielding (reflecting) properties dominate over the absorbing ones. Under the conditions of the modern magnetic environment, the need for absorbing materials is great, which is explained by the need to exclude the influence of re-reflections on the complication of the structure of the electromag-netic field, which leads to an increase in the total surface irradiation of the object. In this regard, based on the ethylene-propylene sealant "Abris" produced by LLC "Plant of sealing materials", Dzerzhinsk, Nizhny Novgorod region, a radio-absorbing material was developed. To absorb electromagnetic radia-tion, UFM-4HD carbon fiber and metal scale are introduced into it. It is shown that their introduction into the composition of the composite leads to the absorption of electromagnetic radiation by 75-78%. The material is designed to protect premises and equipment from electromagnetic radiation.
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