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Vol. 5 Issue 3

Archives Journal Construction Materials and Products Vol. 5 Issue 3

DESIGNING THE COMPOSITION OF ASPHALT CONCRETE BY THE CALCULATION METHOD

https://doi.org/10.58224/2618-7183-2022-5-3-5-16
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 5-16 p.
Abstract
The article proposes a promising technology for designing asphalt mixes based on the method of "irregular packing" of figures of different sizes and shapes. The calculation has been improved and adapted to deter-mine the bulk density of asphalt concrete depending on the content of bituminous binder. A detailed algorithm for designing asphalt mixes based on the "irregular packing" method is described. MS Excel spreadsheets have been created with calculation formulas for converting the grain composition of the mineral part of the asphalt concrete mixture, the content of bituminous binder by volume and recalculating the bulk density of asphalt concrete, the content of air voids, voids in the mineral aggregate and voids filled with bituminous binder. In order to justify the application of the "irregular packing" method of figures of different sizes and shapes in determining the bulk density of asphalt concrete, the results of the calculated data were compared with laboratory tests of control samples during the preparation of ShMA-16 and A 16Vn asphalt concrete mixes at the plant, as well as cores taken from the coating on highway. As a result of the comparison, it was found that the discrepancy between the obtained experimental and calculated values in terms of bulk density does not exceed 0.02 g/cm3, and in terms of the content of bituminous binder, less than 0.2%.
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TECHNOLOGICAL FEATURES OF THE CONSTRUCTION OF A DEMOUNTABLE FOUNDATION FOR TOWER STRUCTURES

https://doi.org/10.58224/2618-7183-2022-5-3-17-26
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 17-26 p.
Abstract
The paper proposes a new type of modular demountable reinforced concrete foundation for the construction of tower-type structures. Numerical modeling and design features of the manufacture and installation of the foundation, implemented under patent 2633604 “Demountable foundation for support” for a real tower with a height of 30 meters and a power of a 150 kV wind power plant, are given. The reduction of material consumption is achieved due to the formation of a cavity in each typical module and filling it with soil or any inert material. The result of the proposed solution is to increase the bearing capacity of the foundation as a whole, increase the strength and rigidity of its main joints, as well as simplify installation in comparison with traditional approaches to design. Moreover, the foundation modules, where maximum stresses occur, can be made of fibre concrete.
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SOLID CARBIDE TOOL WASTE RECYCLING TECHNOLOGY

https://doi.org/10.58224/2618-7183-2022-5-3-27-34
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 27-34 p.
Abstract
Carbide materials are widely used in various industries. However, due to the limited world reserves of tungsten and cobalt, as well as the accumulation of hard-to-process waste of solid carbide materials, the question arises about alternative sources of raw materials. So a large amount of waste is generated by the manufacturing industry. The main methods of processing require a significant consumption of reagents and energy, are distinguished by the toxicity and aggressiveness of working media, and a variety of special equipment. Electrochemical methods make it possible to significantly simplify the technological scheme and hardware design of the process, reduce the duration of recycling waste and improve environmental performance. The paper presents a technique for the disposal of carbide tools by the electrochemical method. Comparison of the compositions of electrolytes and current sources is carried out. Under comparable conditions, the highest current efficiency during oxidation of WC/Co alloys is achieved in nitric acid electrolytes. However, when using nitric and hydrochloric acids, harmful substances are released during electrolysis. Further experiments were carried out using sulfuric acid. The optimal reducing agent has been determined - hexamethylenetetramine. Powders of anode sludge were obtained, which were investigated by thermal analysis and energy dispersive methods. The chemical composition of the sludge has been established, which is defined as 20% oxide and 80% tungsten carbide.
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CREATING GROUND CONCRETE AND STRENGTHENING SUBSTRATES USING MINING WASTE

https://doi.org/10.58224/2618-7183-2022-5-3-35-44
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 35-44 p.
Abstract
The study examines the theoretical aspects of the structure formation of reinforced cohesive soils. The analysis of the most promising methods of chemical strengthening of soils with mining waste has been carried out. The paper provides information on the selection of the composition of a complex binder based on lime-clay soil. The relevance of the study is due to the fact that the construction industry needs areas suitable for development. This paper describes the methods of mineralogical and chemical analysis, X-ray diffraction analysis, electron microscopic examination and fluorescence analysis, and also shows a new technology for strengthening clay soils with lime, simplified compared to the mechanical activation method. In the course of the research, it was possible to determine the optimal composition of soil concrete. This work also confirms the possibility of using these compounds in 3D technology in construction.
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INVESTIGATING THE EXTERNAL AND INTERNAL STABILITY FOR CSG DAMS

https://doi.org/10.58224/2618-7183-2022-5-3-45-54
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 45-54 p.
Abstract
Due to the increasing human demand for dam building, as well as the progress and development of this industry, engineers are always trying to move in the direction of two factors: cost reduction and environmental protection. Dams with Symmetrical profile dams (trapezoidal plate) made of material (cement sand and gravel - CSG) are a new types of dams that have been used widely in countries in recent years. Cement, sand and gravel are used in dam bodies presenting properties between concrete dams and earth dams. The raw materials used in these dams include riverbed sand, drilling debris and aerated rocks, and so on. Indicating that the choosing of aggregates among these materials is not very strict and there is no necessity for equipment for grain sorting. As a consequence, this not only reduces resource consumption and environmental degradation, but also reduces operating costs. So the dam is called “zero emission dam” (dam without pollution) in abroad, and has been known as a kind of environmental protection hydraulic structures. Distinctive features of this type of dam are “material rationalization”, “construction rationalization” and “design rationalization”. The specialized design of these dams is a combination of finite element design and dynamic analysis method. Because these two methods can simultaneously provide a di-rect and reasoned assessment of internal and external stability. For the basic design of a trapezoid-shaped CSG dam, strength and modulus of elasticity in linear range are used as material properties of CSG. , Nevertheless, taking account of plasticity of CSG, the trapezoid-shaped CSG dam is considered to have enough safety margin against stress generated during earthquakes. In this article, introduction of a trapezoid-shaped CSG dam, result of stress analyses and dynamic properties of CSG confirmed by cyclic loading tests are described. From the test results, it is confirmed that a stress-strain curve clearly showed non-linearity compared with concrete. The elasticity of stress- strain relationship was confirmed by cyclic loading tests under conditions that the maximum compressive stress did not exceed the linear range of CSG.
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ANALYSIS OF COMFORT OF THE LIVING ENVIRONMENT IN ST. PETERSBURG DURING THE SOVIET PERIOD OF HOUSING CONSTRUCTION FROM 1926 TO THE 1980S.

https://doi.org/10.58224/2618-7183-2022-5-3-55-65
 55-65 p.
Abstract
The article examines the architectural and urban environment of St. Petersburg.
The aim of the work is to analyze and classify (typology) housing of the Soviet period (from the 1930s to the 1980s) to determine the compliance with the sustainable development of the territory (comfort and favorable urban environment), which is necessary for further reconstruction of the development of St. Petersburg.
The article considered the Kirovsky district (Nevskaya Zastava), as an example of the residential environment of St. Petersburg, as one of the oldest districts of the city, but with modern quarters present in it. Various types of living environment are widely represented at each of the stages of its development in the area. But the most capacious of the periods is the Soviet one from the 1930s to the 1980s, it is distinguished by a variety of types of housing development not only in this area, but throughout the city. This confirms the correctness of the period chosen for the analysis.
To achieve this goal, the existing systems for assessing the stability and comfort of the territory were analyzed, their main shortcomings and problems in use were described. International examples of urban areas that have a high rating or score in these systems are considered. The positive characteristics of the quarters from the point of view of the architectural and urban planning aspect are highlighted.
The results obtained make it possible to develop a model of a comfortable quarter or district and apply it as an assessment or methodology for determining the conformity between the comfort and favorableness of the urban environment. Which was clearly described on the example of the Soviet period of building up the quarters of the Kirovsky district in the city of St. Petersburg.
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