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  • Chemically resistant material for repair of exterior walls of non-ferrous metallurgy buildings

    The structures of the external walls of buildings of non-ferrous metallurgy enterprises are destroying under the influence of an aggressive production environment. The results of scientific research on the development of material for partial or complex repair of the external walls of buildings of non-ferrous metallurgy enterprises are presented. The material developed by the author belongs to the group of polymer silicate compositions. It is lightweight polymer silicate shungizit concrete (LPSHС). This material is highly resistant to acidic wet gas production environment, typical for non-ferrous metallurgy enterprises. Building structures made of this material do not need to be additionally protected with chemically resistant materials. Shungizite gravel was selected as a lightweight porous aggregate. This lightweight porous aggregate is obtained by firing a chemically resistant shungite mineral. Several polymer silicate compositions have been selected. The properties of compositions affecting the durability, chemical resistance and energy efficiency of exterior walls have been studied. The article presents the results of comprehensive studies of the physico-mechanical properties of a material, its chemical resistance, and thermal performance. It is also shown that the reinforcement in LPSHC is well preserved. Studies have shown that the use of the developed material can provide high operational reliability of the external walls of buildings of non-ferrous metallurgy enterprises. According to regulated quality indicators and a combination of properties, LPSHС meets the requirements for exterior walls of non-ferrous metallurgy enterprises. The article also provides a list of production workshops for the application of LPSНС. The material can be used in other industries with similar aggressive environments.

    Keywords: exterior walls, durability, non-ferrous metallurgy, acidic wet gas production environment, polymer-silicate shungizit concrete, physical and mechanical properties, energy efficiency of wall structures

  • Investigation of the physico-mechanical properties of a low-density polymer insulation coating

    The results of a study of the development of a polymer heat-insulating coating for the insulation of heated metal surfaces of industrial and engineering equipment, industrial plants, building structures, working surfaces of pipelines operated at low (up to 1000C) temperatures are presented. The coating was developed on the basis of a polymer binder, which is a mixture of styrene-butadiene rubber and acrylic polymer, hollow carbon microspheres, pigment and water. The use of hollow carbon microspheres in this coating as a filler in an amount of 20.0 to 30.0 parts by weight reduces the thermal conductivity of the coating, compared with the known containing hollow glass or ceramic microspheres.

    Keywords: thermal insulation coating, polymer binder, hollow carbon microspheres, thermal conductivity, tensile strength

  • Development of a polymer heat-insulating fire-resistant coating filled with industrial waste

    The results of the development of a polymer coating with high heat-insulating and fire-resistant characteristics containing waste from galvanic production are presented. This coating is designed for thermal insulation and fire protection of concrete and metal surfaces of various building structures and industrial equipment. The coating is developed on the basis of siloxane rubber, K-18 catalyst, hollow carbon microspheres and industrial waste - galvanic sludge used as a flame retardant. The use of hollow carbon microspheres provides an increase in the strength and thermal insulation properties of the coating. The use of galvanic slurry in the amount of 5-15 parts by weight it allows to obtain the effect of self-extinguishing of the heat-insulating coating, reducing the burning time without compromising the operational properties - strength, adhesion, while solving another important problem - the safe disposal of galvanic sludge. Studies have shown that the use of this composition allows you to get a relatively inexpensive, but quite effective polymer coating with good thermal insulation, flame retardant and physico-mechanical properties.

    Keywords: polymer coating, siloxane rubber, hollow carbon microspheres, galvanic sludge, thermal conductivity, strength, self-extinguishing effect, safe disposal

  • Development of the methods of drainage for the device modified bases

    In order to speed up consolidation, vertical drainage has proven to be a good option for the construction of modified bases . A set of experimental field studies was conducted to study the influence of self-forming vertical sand drains on the process of consolidation of water -saturated soil. Experimental equipment for the construction of vertical sand drains for work in Western Siberia has been developed.

    Keywords: water- saturated soil, peat, consolidation, deep vibration, drainage agent, sand drains, modified base

  • The use of industrial waste for the production of slag-lime-gypsum binder

    The use of industrial waste for the production and production of slag-lime-gypsum (SHIG) binder is considered. A binder based on blast furnace slag of the Novolipetsk Metallurgical Combine (NLMK), supplied to the KCR for the “Tsemzavod” of the republic, phosphogypsum dihydrate (FGD) of JSC “Nevinnomyssky Azot”, lime and sand quarries of the KCR for use in the local region has been developed. A comparative analysis of the compositions of the initial mixtures to obtain the SHIG of the binder, the mechanochemical activation of the mixtures in a drum mill, and the study of the physicomechanical and construction-technical properties of the binder were performed. The normal density, the setting time, the uniformity of the volume change, the tensile strength of the SHIG binder are determined. Using research methods, it was found that the resulting slag - lime - gypsum binder can replace cement in the technology of stone and plastering, with screeds and preparations for floors, as well as in the manufacture of small-sized wall blocks for the construction of cottage-type buildings.

    Keywords: natural gypsum - dihydrate; phosphogypsum - dihydrate (FGD); granulated blast furnace slag; lime - fluff; slag - lime - gypsum binder; average density; fineness of grinding; normal density; uniformity of volume change; strength

  • Comparative analysis of the structure of sheet and modified cellulose

    An impact on mechanochemical activation on morphology and structure of wood cellulose was examined. A comparative analysis of structure of sheet cellulose and fluffed cellulose was made using infrared spectroscopy and scanning microscopy. It was given that the cellulose I tranformed into a modification of cellulose II with more reacting power as a result of pulping. It ascertained that mechanochemical activation of the cellulose can increase the physical and chemical indicators of technical carboxymethylcellulose.

    Keywords: cellulose, mechanochemical activation, carboxymethylcellulose

  • Assessment of the quality of paving slabs based on Portland cement, produced by vibropressing technology

    The physicomechanical properties of paving slabs produced by vibropressing technology are determined. The compositions of fine-grained concrete using quartz fine-grained sands and very fine sands are proposed. The obtained results confirmed the possibility and effectiveness of the use of substandard fine-grained raw materials of the local raw material base, which ensure a reduction in the cost of production.

    Keywords: fine-grained concrete, vibrocompression, raw material base, substandard sands, ground sand, active rheological matrix

  • On the issue of the joints strength for wooden glued structures

    The results of testing a series of 18 samples of joints for chipping along wood fibers are considered. The samples are made of glued wooden beam, intended for use as a supporting structure of the floor. To assess the strength of the adhesive joint in accordance with standard 33120-2014 “Wooden glued structures. Methods for determining the strength of joints”, statistical processing of test results was carried out, temporary shear resistance, coefficient of variation, range of variation series and the minimum probabilistic value of tensile strength were determined. Indicators are given to standard wood moisture content W = 12%. It was determined that the strength of the adhesive joint is less than the value established by current standards, by 18.5%.

    Keywords: glued wood, wooden glued beams, adhesive strength, temporary chipping resistance, tensile strength, minimum probabilistic value of tensile strength, coefficient of variation, chipping during bending, standard wood wetness

  • The use of modern building materials and technologies in the device roofs

    One of the most complex structural elements of the building is the roof. It protects the building from the external environment: precipitation, temperature changes, solar radiation, wind effects, as well as from air pollution. The main element of the roof is the roof, as the condition of the roofing depends on the condition of the other elements of the roof and in this article will be considered modern building materials used in the device of roofs.

    Keywords: roofing, roof, modern roofing, metal, profiled flooring, Ondulin, membranes, slate, tile

  • Study of the acoustic activity of vibroforming equipment of concrete products factories

    This article is devoted to a comprehensive study of noise generation processes in the industrial production of reinforced concrete products. The relevance of acoustic research of industrial equipment is substantiated. The authors of the article cite and analyze the experimental results of studies of noise generation processes in existing workshops. The paper presents graphs of noise spectra of the most common molding equipment. In conclusion, the authors draw conclusions about the advantages and disadvantages of vibration equipment for the manufacture of reinforced concrete products of various types and make recommendations for its use.

    Keywords: acoustics, acoustic activity, vibroforming equipment, industrial production, safety equipment, labor protection, noise, vibration, working conditions, vibration installations

  • Research of properties and characteristics of foam glass broken stone application in road constructions

    This article describes the territories of the northern regions of the Russian Federation, the problems of the distribution of permafrost soils (MMG), and discusses the difficulties encountered in the construction of roads in difficult geocryological conditions. The introduction of heat-insulating layers of foam glass rubble into the design of pavement is proposed. The basic physical and technical characteristics have been analyzed, and the key properties of foam glass rubble are determined. The article describes the process of production of foam glass, the advantages that allow the use of this material in various fields of construction. Typical road structures made of soil are considered. A comparison is made of a typical construction of pavement made traditionally from soil (high embankment) with a construction with a heat-insulating layer of foam-glass rubble. The advantages have been listed when using structures using foam glass rubble in road construction.

    Keywords: foam-glass rubble, road construction, automobile road, heat-insulating layer, frost, north, glass, construction, soil, materia

  • Dependence of frost resistance of fine-grained concrete modified by polymers on the ratio of conditionally closed and open capillary porosity

    GOST 10060-2012 as the main criterion of frost resistance for all concretes, including fine-grained, established the ratio of the compressive strength of the main and control samples is not less than 0.9, taking into account the coefficient of variation of strength in the series. There are numerous studies in which the dependence of the frost resistance of concrete on the nature of its porosity is revealed, and the criteria of frost resistance in the form of, for example, the ratio of open and conditionally closed porosity are proposed. The article examines the impact of indicators of porosity on frost resistance of mortar (fine aggregate concrete), the basic criterion GOST 10060-2012, and also for frost resistance of the contact zone according to GOST 31357 - one of the normalized indicators of quality of solutions and fine-grained concrete obtained from dry mixes. The purpose of this study is to identify the dependence of changes in the compression and bending strengths, as well as changes in adhesion to the base of polymer-modified fine-grained concrete on the nature of porosity. The frost resistance of 36 compositions obtained using three different Portland cements and three redispersible polymer powders with a dosage from 0 to 3% by weight of the dry mixture was studied. In addition to polymers, low-modulus inclusions in the form of ash microsphere or entrained air are introduced into a number of compositions. The main samples were tested after 75 freeze-thaw cycles according to GOST 31357.

    Keywords: dry mixes, frost resistance of the contact zone, open porosity, adhesion to the base

  • Prospects for enrichment of natural sands of the Usklyayskoye deposit of the Republic of Mordovia for cement concrete and mortar

    The article discusses the possibility of improving the physicotechnical properties of the sand of the Usklyaysky deposit of the Republic of Mordovia for the production of cement concrete and mortar. The prospects of their enrichment due to preliminary screening and washing with water are proved.

    Keywords: Building sand, cement concrete, mortar, particle size modulus

  • Increasing the operational life of steel ropes by forming solid lubricant coatings on the surface of the rope during its production

    The article presents materials on the study of increasing the operational life of steel ropes. The methods of lubrication of steel ropes, as well as the resistance characteristics of the applied lubricants, under various operating conditions, were studied. An experimental study of the effect of molybdenum disulfide on the operational characteristics of steel ropes. The concept of a useful model for the formation of a surface layer of a solid lubricant coating based on molybdenum disulfide on steel ropes in the process of their production is proposed.the mode of operation of the Elevator equipment in each cycle. The structure of the algorithm for the formation of accumulated loads and their equivalent value during a given period of operation is substantiated. The proposed method can be used as a simulation model in determining the required amount of repair impacts in the maintenance of passenger elevators

    Keywords: steel rope, rope lubrication solid lubricants, vibration mechanochemical solid lubricant coating, molybdenum disulfide, utility model

  • Highly effective plasticizing additives with nanostructures for modifying the properties of cement mixtures, mortars and concrete

    The article discusses the possibility of increasing the rheological properties of cement raw mixes for concrete and mortar by modifying them with plasticizing additives with metal / carbon nanostructures, manufactured by SIC IEMZ Kupol JSC. The introduction of ultra-small amounts of nanostructures into a plasticizer based on polycarboxylate esters contributes to an additional 20–40% increase in the rheological ability of plasticized cement raw mixes.

    Keywords: Metal / carbon nanostructures, carbon metal-containing nanostructures, cement binder, plasticizing additive, superplasticizer

  • Separate concreting in the manufacture of centrifuged reinforced concrete products

    When forming in the process of centrifugation an annular section by the method of ""separate"" concreting with the formation of a section of the product at the first stage from the original, including fine-grained concrete mixture, and with the introduction of a coarse aggregate at the second stage into the formed circular section, followed by the final formation of the section and compaction of the concrete mixture by centrifugation, the speed, calculated for the compaction stage, increases, depending on the section zone, the concrete compressive strength from 20% up to 47%, the initial modulus of elasticity from 6 to 19% relative to single-stage centrifugation. The ratio vint / vext of ultrasonic pulse velocities for surface sounding along the inner (vint) and outer (vext) faces of a centrifuged annular section can be considered as a conditional indicator of the uniformity of the concrete structure over the cross section of a centrifuged product. Key words: centrifugation, separate concreting, structure homogeneity, strength and deformation properties, porosity.

    Keywords: centrifugation, separate concreting, uniformity of structure, strength and deformation properties, porosity

  • The use of microwave energy for the modification of rubber-bitumen binders

    The article describes the use of recycled rubber raw materials for the preparation of a suspension. The use of the resulting suspensions as a binder for asphalt concrete and concrete waterproofing.

    Keywords: suspension, rubber crumb, oil pitch, fuel oil, bitumen, microwave energy

  • Investigation of the loss factor and the strength of damping materials based on ethylene-vinyl acetate modified with rubbers

    This article is devoted to the problem of development of damping polymer materials with high damping properties in a wide temperature range. The purpose of this article is to study the loss factor and strength of polymer materials based on ethylene-vinyl acetate when additional polymers in the form of rubbers are added to them. The leading method to investigate this problem is the method of dynamic mechanical analysis, which allows to obtain information about changes in the dynamic properties of polymeric materials subjected to oscillating loads depending on frequency and temperature. According to established experimental dependences, it was possible to define the type of additional polymer expanding the temperature range of effective damping and increasing tensile strength of composites based on ethylene-vinyl acetate. The percentage content by volume of the additional polymer was established at which its efficiency on the dynamic and mechanical properties of composites on ethylene-vinyl acetate basis will be greatest.

    Keywords: ethylene-vinyl acetate, polymer, chlorobutyl rubber, nitrile butadiene rubber, strength, damping, glass temperature, dynamic mechanical analysis

  • Investigation of influence of fillers and modifiers on damping properties of pva-based material

    The modern world is impossible to imagine without means of technical movement, broad mechanization and automation of production processes. Mechanisms exude harmful noises and vibrations that adversely affect the human body. Many materials have been created that absorb harmful noises and vibrations. Vibrating materials are widely used in everyday life. They are applied to the parts of cars, hulltrains of trains and aircraft from the inside. Anti-corrosion coating helps to protect the bottom of the car and train. It can serve as another level of protection against noise and vibration. At the heart of the vibrating material, as in the anti-corrosion coating, is a viscous layer, which, in turn, is modified by the introduction of fillers and plasticizers. The difference between vibrating material and anti-corrosion material is that for a greater increase in its vibrating properties, the material is sometimes reinforced. The article presents the results of studies of the mastmaterial material with such fillings as mica ground flogopit SMF-123, calcium formiat, melflux 1641F, melflux 4930F, melflux 6681F. A steel plate with a mast material applied to it has been selected as the object of the study. The matrix material was based on polyninilacetate, which injected epoxy resin and dibutylphthalate. The loss factor of the material was determined by a resonant method, the essence of which is to excite the sample of cross-range oscillations. Developed vibrating mastics, selected effective fillers and plasticizer for it. The dependence of vibrating properties on the amount of epoxy resin injected, plasticizer and the influence of thickness of layers is represented.

    Keywords: polyvinyl acetate, epoxy resin, vibration-absorbing mastic material, damping, loss coefficient

  • The Paving Slab Market Analysis and Development Prospects in the Rostov Region

    The paving slab market analysis and development prospects for the Rostov Region are given in this article. The market prospects are considered from the point of view of paving slab manufacturers on their participation in government programs of a modern urban environment formation and improvement. The main changes in the product specifications requirements are considered taking into account the enactment of GOST 17608-2017 instead of GOST 17608-91. We analysed the pricing policy of large manufacturers of paving slabs operating in the Rostov Region. Then we also considered the prospects of paving slab sales for municipal projects and in the private segment. We also reviewed the government programs for creation of a comfortable urban environment and their financing in the Rostov Region, as well as cooperation prospects between the municipal government and business in terms of concession agreements. Finally, we defined the main consumer categories for the paving slabs and the consumption structure of the paving slabs market.

    Keywords: paving flag, paving slabs, improvement, modern urban environment, the formation of a modern urban environment, paving

  • On the dependence of "stress-strain" and "modulus of strain-loading level" for concretes with organomineral modifiers

    It is shown that the given ratio of the modulus of deformation and the initial modulus of elasticity of concrete depends not only on the type of the function ε = f(𝜎), and from the initial modulus of elasticity of the concrete, i.e. concrete with different values of initial modulus at equal strength, for example, with the introduction of the composition of concrete organo-mineral modifiers, the dependence of the ratio E𝜎/E0 from the loading level will vary. To describe the "stress-strain" or "modulus of deformation-level of loading" for concretes with organo-mineral modifiers, it is advisable to use The sargin diagram, taking into account the influence of modifiers on the main deformation constants: the initial modulus of elasticity, the coefficient of elasticity, the relative deformation corresponding to the short-term strength limit. The nature of deformation of concretes with organo-mineral modifiers at a loading level above 0.9 may differ from the known patterns for traditional concretes, in connection with which this issue requires special study.

    Keywords: modulus of deformation, stress-strain diagram, modified concretes, loading level, modulus of elasticity

  • Crack resistance test of samples from polyethylene pipes

    The article presents the results of testing samples of welded joints of polyethylene pipes for crack resistance at various temperatures. It is shown that in the weld zone a decrease in the stress intensity factor is observed up to 27% compared with the base material.

    Keywords: Polymer, polyethylene, pipe, stretching, crack resistance, low temperatures, brittle failure, crack, welding, welded joint, fusion zone

  • On the question of assessing the frost resistance of concrete on the strength criterion

    Durability of concrete, including fine-grained, with alternating cyclic temperature effect of the external environment is normalized according to GOST 26633 mark on frost resistance, and frost resistance criterion for all concrete in accordance with GOST 10060-2012 is the ratio of ultimate strength on compression of the main and control samples not less than 0.9 with a coefficient of variation of strength in the series, while for concrete road and airfield pavements is another additional criterion is the loss of mass. In the previous edition of GOST 10060, the ratio of the compressive strength of the main and control samples not less than 0.95 was adopted as the criterion of frost resistance for all concretes. GOST 31357 normalizes the indicator "frost resistance of the contact zone" for a number of mortars or fine-grained concretes obtained from dry building mixtures. This indicator characterizes the ability of the solution or fine-grained concrete to maintain the strength of adhesion to the concrete base after a certain number of freeze-thaw cycles. For the brand for frost resistance of the contact zone from Fkz25 to Fkz100, the number of cycles is taken, after which the decrease in the adhesion strength to the base does not exceed 20% according to GOST 31356, and in this case the coefficient of variation of the clutch values measured in the series is not taken into account. Due to the limited information on the change in the in-series coefficient of variation of strength after cyclic freezing-thawing, as well as the ratio of frost resistance by the criterion of compressive strength and adhesion strength to the base, the purpose of this study was to identify patterns of change in the in-series coefficient of variation of strength and adhesion strength to the base of fine-grained concretes obtained from dry building mixtures based on various Portland cements with the content of various redispersible polymer powders from 0 to 3%. The studies were carried out on the basis of 75 freeze-thaw cycles. This paper presents the results on the change in the coefficient of variation of strength after cyclic freezing-thawing and the ratio of frost resistance coefficients

    Keywords: frost resistance of concrete, coefficient of variation of strength, coefficient of frost resistance, fine-grained concrete, dry mixes

  • Electrical conductivity and piezoresistive properties of cement paste with addition of carbon nanotubes

    Paper presents a review of scientific works investigating of effect of carbon nanotubes (CNT) concentration on electrical conductivity and pizeresistive properties of concrete. Different values of the percolation threshold for nanomodified concrete obtained by different authors are given. Recommendations for specifying the favorable concentration of nanotubes in composites are considered. As a result of review a need for additional dedicated research for the assessment of relation between favorable CNT concentration and their characteristics, method for the producing of composite and conditions of its application is stated.

    Keywords: concrete, sensor, carbon nanotubes, percolation threshold, electrical conductivity, monitoring of stress-strain state

  • The effect of redispersible powders and low modulus inclusions on the properties of fine-grained concrete after repeated freezing-thawing

    Low-modulus inclusions in the form of entrained air or ash microspheres in the composition of fine-grained concrete practically do not affect the ratio of the ultimate strength in bending and compression during hardening of concrete under normal conditions. After 75 freezing-thawing cycles, the ratio of the flexural and compressive strengths of fine-grained concrete with ash microspheres did not change, and in concretes with involved air, the influence of factors such as the type and dosage of redispersible powder and the type of cement increased sharply. Low-modulus inclusions have practically no effect on the ratio between the initial elastic modulus and the compressive strength of fine-grained concrete during hardening under normal conditions. After 75 cycles of freezing and thawing in concrete with entrained air, the influence of such factors as the type and dosage of redispersible powder and the type of cement on the ratio of the initial elastic modulus to compressive strength increases sharply. The cyclic freezing-thawing does not affect on the ratio of module and strength in concretes with an ash microsphere. Regardless of the presence of low-modulus inclusions, there is no clear relationship between adhesion to a concrete base and flexural strength of fine-grained concrete. In concretes with entrained air, the increase in adhesion to the concrete base after 75 freezing-thawing cycles, depending on the type of cement and dosage of redispersible powder, was up to 82%, and for compositions with an ash microsphere, up to 62%. Regardless of the presence of low-modulus inclusions, after 75 freeze-thaw cycles, adhesion to the base corresponds to class C-1. With an increase in the dosage of redispersible powder from 0 to 3% in compositions with low-modulus inclusions, an increase in adhesion to the base was noted up to 62%.

    Keywords: dry mortar mixes, redispersible polymer powders, low modulus inclusions, adhesion to the base, elastic modulus, tensile strength, freezing and thawing cycles