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NONLINEAR TRANSVERSE VIBRATIONS OF COMPOSITE RODS UNDER THE ACTION OF A STATICALLY APPLIED TRANSVERSE LOAD

https://doi.org/10.34031/2618-7183-2021-4-2-29-37
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 29-37 p.
Abstract
Nonlinear transverse vibrations of composite rods pre-loaded with lagging arranged symmetrically on both sides of the axis of the composite rod under the action of a statically applied transverse load are investigated. The cases of attaching the lagging only to the ends of the composite rod, as well as when the laggings are continuously attached to the composite rod along its entire length, are considered. The results of the study of nonlinear transverse vibrations of composite rods under the action of a statically applied transverse load are presented. When conducting studies of transverse vibrations of composite rods, solutions of differential equations of vibration of prestressed through beams and stiffening cores of high-rise buildings are obtained. The obtained differential equations of vibration of composite rods allow us to determine the dynamic characteristics of prestressed through beams under various linear and boundary conditions. A method for composing differential equations of free and forced oscillations of prestressed through beams and stiffening cores of high-rise buildings and solving differential equations under various linear and nonlinear boundary conditions is developed.
Expressions are given for determining the longitudinal forces and torques at the ends of the rod at any location of the lagging from the axis and at any different stiffness of the lagging.
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UTILIZATION OF GYPSUM-BEARING WASTES IN MATERIALS OF THE CONSTRUCTION INDUSTRY AND OTHER AREAS

https://doi.org/10.34031/2618-7183-2021-4-1-5-17
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 5-17 p.
Abstract
Rational environmental management is one of the priorities of the technological development of the Russian Federation and most countries of the world. Particularly important in this area is the work undertaken with previously generated and accumulated waste, a whole group of which is gypsum-bearing wastes (GBW), which includes by-products of various industries: phosphogypsum, borogypsum, chlorogypsum, ferrogypsum, citrogypsum, vitamin gypsum, etc. GBW features are similar compositions, prevalence, perennial volumes of stored reserves with stable dynamics of annual growth. This determines the relevance of research on the development of a unified methodology for converting GBW of various types into target products particularly for construction purposes, providing maximum energy efficiency and minimal generation of secondary waste. The starting point of the research is the monitoring of approaches developed by the scientific community which are presented in the article. It is shown that researchers are exploring several main areas of GBW conversion: components of Portland cement and clinker; single and multicomponent binders; direct raw materials for the production of building materials; and road construction. The latter two directions have the greatest potential capacity for the consumption of GBW. The general level of research on the issue is not exhaustive, but has the potential to improve on existing methods of processing and application and promote the search for new and more efficient methods.
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COMPARISON OF CAD AND BIM TECHNOLOGY EFFICIENCY WITH THE USE OF A MATHEMATICAL MODEL

https://doi.org/10.34031/2618-7183-2021-4-1-18-26
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 18-26 p.
Abstract
The article reveals definitions and the entity of computer-aided design and building information modeling. The content and effect of using information modeling at various phase of the life cycle of a real estate object are described in the article. The level of BIM applying in Russia is analyzed, data is obtained that the majority of AEC organizations do not use information modeling. A comparative evaluation of the applying of various CAE systems using mathematical modeling in the MATLAB environment using the Fuzzy Logic Toolbox extension package is carried out. Based on the obtained results, we can make a conclusion about the effectiveness of using building information modeling. The information in this article is relevant for designers, real estate investors, and leaders of AEC organizations. The obtained evaluation of project technology is able to induce stakeholders to analyze alternative technology of project and estimate the expediency of Russian enterprise's transition to the use of BIM technology.
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ANALYSIS OF THE INFLUENCE OF INDUSTRIAL WASTE IN THE FORM OF CERAMIC CHIPS CRUSHING DROPOUTS ON THE MAIN PROPERTIES OF CEMENT COMPOSITES

https://doi.org/10.34031/2618-7183-2021-4-1-27-34
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 27-34 p.
Abstract
During the implementation of the program to restore the housing stock of the Chechen Republic, as well as during the planned demolition of dilapidated housing, significant volumes of technogenic raw materials were generated, in particular, large volumes of brick and concrete scrap. Enterprises for the production of building materials and products also produce significant volumes of production defects, which accumulate over the years at landfills. Ceramic broken brick and broken brick dropouts are used to fill the roadbed, and the main part still goes to the dump and landfill, which is also an environmental problem. One of the promising ways to use dropouts and broken brick itself is to use them as secondary aggregates in concrete and mortars. This article discusses the issues of improving the quality of ceramic concrete mixtures, choosing the optimal composition and technology for mixing concrete mixtures using dust fractions of dropouts for crushing ceramic brick bricks.
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DETERMINATION OF THE TRANSSHIPMENT CAPACITY OF THE RAILWAY STATION AND MEASURES TO ENSURE IT IN THE REQUIRED VOLUME BY INSTALLING TEMPORARY LOADING AND UNLOADING DEVICES

https://doi.org/10.34031/2618-7183-2021-4-1-35-44
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 35-44 p.
Abstract
In view of the fact that recently the economic cooperation between Russia and Iran in a number of production areas of the raw materials sector is expanding its program, the provision of mineral extraction with specialized and auxiliary equipment is being carried out. The paper deals with the organization of the delivery of cranes of Russian production on the automobile base of the type "Ivanovets" KS-6476 in the composition of 40 units to the objects of ore mining. Transportation of cranes by rail on the route: St. Petersburg (Russia)-Julfa (Azerbaijan) – Bandar Abbas (Iran) is justified. For transportation on the railways of Russia, the paper considers long-wheelbase platforms of model 13-491, on bogies of 1520 mm gauge. In order to comply with the dimensions on the railways of Iran, the transporters with a reduced floor level of the model 14-T116 on trolleys of 1435 mm gauge were selected. The reloading of equipment is planned to be carried out at the Julfa railway station of the Azerbaijan Railway. The results of the research, in our opinion, are certainly of practical importance for the transport industry, as the developed and proposed designs of loading and unloading devices allow for the reloading of equipment without the use of crane equipment using always available stocks of materials at cargo stations.
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INCREASING IN IMPACT VISCOSITY OF FIBER-ASH-CONCRETE

https://doi.org/10.34031/2618-7183-2020-3-6-5-16
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 5-16 p.
Abstract
The trend in building materials science is to replace the different proportions of Portland cement in the binder. Therefore, the paper proposes the principles of controlling the static and dynamic strength of fiber-reinforced concrete, consisting in the complex effect of the hydro-removed ash and slag mix and basalt fiber on the processes of structure formation of the cement composite. A four-stage purification system for the hydro-removed ash and slag mixture has been developed, including disintegration, flotation and two-stage magnetic separation. It was found that the density of the fresh mix from the dose behaves naturally, and the density of solid samples at low doses slightly decreases. High early strength of the developed composites is noted, in particular, for specimens with ASM, one and a half increase in compressive strength is traced in comparison with non-additive specimens. Combinations of "fiber + ASM" with a quadrupling of strength have a significant effect on bending strength. Successful approximations of the compressive strength and bending strength on the ASM dose for different ages (1, 7, 28 days) are traced with the regular behavior of the coefficients in the power dependences. Revealed a multiple increase in the impact strength of the developed compositions. The use of the results will lead to the possibility of designing high-strength concretes, including for special structures.
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INCREASING THE BONDING STRENGTH OF THE PLASTERING COATING TO THE BASE

https://doi.org/10.34031/2618-7183-2020-3-6-17-26
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 17-26 p.
Abstract
The strength of plaster coatings depends on the quality of adhesion of the applied plaster layer with the base. The bases for applying plaster coatings are necessarily prepared, the technology of preparing the bases may differ depending on the coating applied. It is established that the closer the initial structures are in structure, the higher the quality of the plaster coating as a whole. According to geonics, the relationship of structures in building composites is based on basic properties, general physical and mechanical indicators, which equally apply to both the building plaster solution and the base. At the same time, a contact binder is allowed between the base and the plaster layer with similar indicators, the presence of which guarantees reliable adhesion and strength of the resulting coating. The use of plaster solutions on enriched fine substandard sands with complex modified additives makes it possible to improve the technological qualities of the mortar mixture, the physical and mechanical characteristics of plaster solutions and optimize the technology of applying the plaster coating. Successive application of plaster layers on technogenic sands with different size modulus allows creating a base rough coating on the base, which closes the main defects and creates the base for the next layer of plaster solution. The Chechen Republic has extensive reserves of very fine and fine local sands, which in their basic properties are inferior to medium- and coarse-grained sands, but with a rational selection of composition, enrichment of grain composition can be used to produce high-quality construction composites. To enrich the grain composition of fine local sands, it is proposed to use dropouts of concrete scrap crushing, the volumes of which are significant on the territory of the Chechen Republic. Dropout of concrete scrap crushing by chemical composition is suitable for enriching local fine sands and when selecting the composition of the plaster solution increases the physical, mechanical and technological properties of the mortar mixture.
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INCREASING THE RESISTANCE OF MACADAM-MASTIC ASPHALT CONCRETE TO RUT FORMATION DUE TO THE USE OF POLYMER MODIFIERS

https://doi.org/10.34031/2618-7183-2020-3-6-27-34
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 27-34 p.
Abstract
Rutting is an important problem in Russia today. One of the ways to improve the properties of asphalt concrete mixtures and reduce wear on road surfaces is to modify the binder with polymer additives. The aim of the work was to test the selected compositions of MMAC mixtures containing bitumen modified with the addition of sevilene and rubber for rutting resistance, which make it possible to predict the formation of plastic rut. It was revealed that when using sevilen in its composition, with an increase in the concentration of vinyl acetate, the depth of the track increases in comparison with the industrial polymer-bitumen binder. It is shown that with the introduction of a complex additive based on sevilen and rubber into the binder composition, its rutting decreases and the service life of the road surface increases, which indicates a high elasticity of the complex-modified binder. In this work, the calculation of the service life of the coating before the formation of a critical rut requiring repair of the coating is carried out. It was found that in terms of the slope of the rutting curve and the proportional depth of the rut, the compositions with sevilene and rubber are not inferior to traditional industrial PBB.
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RELIABILITY OF REINFORCED CONCRETE STRUCTURES TAKING INTO ACCOUNT THE CONCRETE CREEP FACTOR

https://doi.org/10.34031/2618-7183-2020-3-6-35-43
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 35-43 p.
Abstract
In the process of inspection of reinforced concrete structures being in long-term service, deflections of beams and slabs beyond the standard values are often detected, which is attributable to concrete creep occurring in the case of the early dismantling of shuttering. At the same time, any visual signs of their reduced load-bearing capacity are absent. Taking into account the high degree of uncertainty of the factors influencing the long-term strains of the concrete, the safe service life of such structures can vary within a rather wide range, and its actual value can be assessed only through probabilistic methods of the reliability theory. The paper presents the results of the investigation of the influence of concrete creep caused by the early dismantling of the shuttering on the reliability of prefabricated reinforced concrete floor beams of a three-storey building. The data obtained through the instrumental verification of the mechanical characteristics of the beam materials and their deformed state were used for design modelling. The authors carried out the probabilistic creep analysis of the beam through the method of statistical modelling taking into account the variability of concrete strength for various values of the relative humidity of the ambient air and the age of concrete at the moment of the load application. The statistical characteristics of the stress-strain modulus and the beam deflection values with various levels of probability were obtained. Due to con-crete creep, the safety analysis showed a 2,4 times reduction in the beam reliability index at the service life of a structure of 70 years.
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PERFORMANCES OF HIGH POROUS CELLULAR CONCRETE

https://doi.org/10.34031/2618-7183-2020-3-5-5-14
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 5-14 p.
Abstract
The widespread use of cellular concrete for enclosing structures forces researchers to develop ways to improve their performance and durability. Compositions of aerated and foam concrete with the use of waste heat power engineering have been developed. The optimal formulation ratios have been identified that contribute to the creation of a rigid interpore matrix and water-repellent pore protection. The regularities of the synthesis of aerated concrete and foam concrete were established, which consist in optimizing the processes of structure formation through the use of a polymineral cement-ash binder and a pore-forming agent. The mix composition intensifies the process of hydration of the system, which leads to the synthesis of a polymineral highly porous heterodispersed matrix. The increased activity and granulometry of aluminosilicates predetermine an increase in the number of contacts and mechanical adhesion between particles during compaction, strengthening the framework of the interpore partitions. The mechanism of the influence of the composition of the concrete mix on the microstructure of the composite is established. The calculated sound insulation of airborne noise shows sufficient characteristics for using aerated concrete blocks as enclosing structures. One of the main advantages of aerated concrete is its low thermal conductivity, which is especially important from the point of view of ensuring the energy efficiency of buildings and structures. Even in spite of the high values of open porosity of the developed aerated concrete, the rigid frame makes it possible to achieve almost 2 times higher frost resistance characteristics than that of the reference specimen.
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