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  • Simplex methods for optimizing the composition of composite building materials

    The article discusses the use of simplex methods of experiment planning to determine the optimal composition of composite building materials. Composite building materials are multicomponent systems, so their properties depend on a large number of factors that are diverse in nature and influence. The use of orthogonal plans is not able to adequately describe experimental data with a wide range of varying factors. Therefore, the article proposes to use simplex-lattice Scheffe's plans. A complete third-order model was developed to determine the optimal composition of the filled cement composite, and a regression equation was written. The adequacy of the equation was confirmed at the control points of the plan using the Student's criterion. The proposed planning method can be used to optimize the composition of multicomponent systems.

    Keywords: multicomponent system, optimization methods, composite building material, experiment planning, simplex plans, Scheffe's polynomial, regression equation

  • Water resistance of concrete fabric

    Increasing the energy efficiency of the construction process involves the use of materials with the lowest material intensity, including thickness, as well as with a reduced content of Portland cement clinker while maintaining or improving the technical characteristics of the products. In this regard, the use of textile concrete products, including concrete sheets, is promising. The development of a composite binder containing components that reduce nega-tive pressure in hardening concrete, and consequently shrinkage deformations and cracking, made it possible to obtain products with the following waterproofness indicators: determined by the ""wet spot"" method: 1.2 MPa; with a filtration coefficient of 5-7×10-11 cm / s; the concrete waterproof grade W12

    Keywords: textile-concrete, concrete web, water resistance, shrinkage during hardening, cracking, fine concrete

  • Argillite of Nekrasovskoye deposit as a promising raw material for production of clinker ceramic tiles

    Clinker tiles are one of the most popular types of roofing materials. Compared to other roof coverings, clinker tiles have higher strength, resistance to aggressive environments and aesthetic indicators. The relevance of the production of clinker tiles due to the fact that at present architects and builders are showing great interest in such an elite roofing material such as clinker tiles. However, the main trends in the production of ceramic tiles are to increase its strength while reducing weight by reducing the thickness. The conducted research has shown that the production of clinker tile on the basis of argillites Nekrasovskogo deposit is possible at a fractional composition of 0-0,08 mm, 0-0,05 mm and firing temperature of 1050 ˚C.

    Keywords: argillite, tile, clinker, research, chemical composition, mineral composition, ceramic products, properties, technology

  • Development of compositions of bitumen-mineral open mixtures for the Novoselovsky district of the Krasnoyarsk Territory

    This paper is aimed to present the produced compositions of bitumen- mineral open (BMO) mixtures for the Novoselovsky district of the Krasnoyarsk Territory. The Federal Road M53 runs through the area and in this district in particular it is characterized by steep ascents and descents. To ensure the required adhesion properties of road asphalt concrete pavements with car wheels for thepurpose of traffic safety in the area under study, the construction of rough wearinglayers or toppings from BMO mixtures has been suggested. Compositioncalculations were carried out using local mineral materials and BMO mixtures,after which test samples were prepared in laboratory conditions. It has beenestablished that the developed BMO mixture compositions meet all regulatory requirements. Recommendations are developed for the factory technology ofpreparing bitumen-mineral open mixtures and the design of rough wearing layers.Instructions for technical control during the preparation of BMO mixtures aregiven. The Road Repair and Construction Department of the Novoselovsky districthas already introduced the obtained compositions into the practice of road construction.

    Keywords: bitumen-mineral open mixtures, rough wearing layers, toppings, roads, asphalt concrete, bitumen, crushed stone, sand, compositions, technology

  • Assessment of the adhesion strength of colored masonry mortar in masonry

    Expert work has been carried out to determine the causes of the low adhesion strength of hand-molded ceramic bricks with Maxpol colored masonry mortar. The tests were carried out in accordance with GOST 24992 on 6 series of samples aged 7 and 28 days of hardening. The adhesion strength in the series of tested samples at 7 days of age, which were washed with running water, is 54% higher compared to the samples that were not treated.The compressive strength of Maxpol colored masonry mortar meets the requirements of technical specifications 23.64.10-001-79211444-2017 . The adhesion strength in the masonry meets the requirements of technical specifications only in a series of hand-molded bricks that have been treated with running water at the age of 28 days.

    Keywords: ceramic brick, colored masonry mortar, adhesion strength, compressive strength, separation area

  • Radiation-thermal changes in serpentinite concretes of “dry” shield of Water-Water Energetic Reactors of NPP during extension of their operation

    Calculation and analytical studies have been carried out on the influence of the duration of operation of nuclear power plants (NPP) when extending their service life on radiation and radiation-thermal changes of volume and compressive strength in serpentinite concrete of “dry” radiation-thermal shield (hereinafter referred to as “dry” shield) of Water-Water Energetic Reactors (WWER /VVER) different power. Concrete based on typical serpentinite aggregate from the Bazhenov deposit, used for the production for concrete of “dry” shield, is considered. It has been established that with increasing operating duration, radiation changes of the serpentinite concretes in “dry” shield of NPPs with VVER will generally increase monotonically and, in terms of volume changes, can become commensurate with or even exceed permissible values. In this regard, radiation changes in the concrete of «dry» shield should be taken into account when extending the operating life of nuclear power plants. It has been shown that radiation changes in the concrete of “dry” shield for NPPs with VVER-440 are 2 - 4 times more significant than of “dry” shield concrete for NPPs with VVER-1000. Radiation changes in the concrete of "dry" shield increase with decreasing average operating temperature. Thermal changes in serpentinite concretes of "dry" shield when exposed to operational and emergency temperatures increase with temperature and make a significant contribution to radiation-thermal changes in dry-shield concretes. The results obtained can be used to establish the permissible period for extending the operation of nuclear power plants with reactors of the VVER 440 and VVER-1000 types based on radiation-thermal changes in serpentinite concrete of "dry" shield.

    Keywords: radiation, thermal, radiation-thermal changes, serpentinite concrete, “dry” radiation-thermal shield, water-water energetic reactors, extension of the operating life of NPP

  • Mineral composition for soil stabilization

    The urgency of creating systems to stabilize and strengthen soils is due to the need to build buildings, structures and roads in regions where clay soils, as well as loams and sandy loams are widespread. The article formulates the main technological and technical requirements for stabilized soils. The principal possibility of applying a complex modification of the soil by introducing a composite composition of quicklime and finely ground granulated blast furnace slag in combination with mechanical compaction is considered. The results of studies of soil modification by composite composition are presented, the purpose of which is to make the soil suitable not only for the installation of anti-filtration curtains in soils during the development of pits, but also for foundations and basements. The results of studies of the properties of stabilized soil are presented.

    Keywords: unstabilized soil, soil modification, loam, quicklime, ground slag, analytical optimization

  • Optimization of slag-alkaline binder compositions during the reconstruction of the built and constructed building

    The main properties of slag-alkaline binders were studied to determine their optimal composition. The possibility of controlling the properties of binders developed on the basis of phosphorus and blast furnace slag by introducing corrective additives into the aluminosilicate component of slag-alkaline binders, as well as by changing the type of alkaline component, has been experimentally proven. The conducted studies confirm the effectiveness of the use of sulfate-containing alkaline components for the production of slag-alkaline binders. As a result of the conducted experiments, slag-alkaline binders with an activity of 30 to 110 MPa were obtained. The possibility of regulating the properties of the developed slag-alkaline binders has been established. The required binding strength is achieved by adjusting the composition of the aluminosilicate component by introducing additives and the type of alkaline component.

    Keywords: alkali-silk binders, slags, optimal composition, basicity, chromium peak, construction materials, reconstruction, work technology

  • Optimization of gypsum-cement- pozzolana binding agent composition through designing an experiment

    There has been studied the influence of gypsum-cement-pozzolana binding agent composition on its key strength properties. The study was aimed on the definition of such consumption of gypsum-cement-pozzolana binding agent components, which could allow maximum ultimate compression strength with minimum consumption of Portland cement provided. As the components of gypsum-cement-pozzolana binding agent, there have been used plaster, Portland cement, and the most wide-spread in the region pozzolana additive. An experiment design was developed to fulfil the work. The research was held in correspondence with the design, and the acquired results made it possible to estimate and analyze descriptive statistics, and expose the influence of components on strength properties of gypsum-cement-pozzolana binding agent. In the course of the analysis it was specified that pozzolana additive consumption factor, and interaction of consumptions of plaster and Portland cement exert a positive influence on strength properties of gypsum-cement-pozzolana binding agent. There have been acquired mathematical models of the influence of gypsum-cement-pozzolana binding agent components consumption on ultimate compression and bending strength of gypsum-cement-pozzolana binding agent. The said model allow forecasting gypsum-cement-pozzolana binding agent composition to have a desired ultimate compression strength. An optimization was carried out and there was acquired a composition of gypsum-cement-pozzolana binding agent with maximum ultimate compression strength with minimum consumption of Portland cement provided.

    Keywords: gypsum-cement-pozzolana binding agent, optimization of composition, ultimate strength, experiment design, descriptive statistics, superposed diagram, correlogram, ternar chart

  • Durability of the anchor attachment of the hinged ventilated facade, based on the calculation of the iciness coefficients for the northern and southern walls

    The results of the coefficients of iciness for the northern and southern walls, in the attachment points of the frame of the ventilated facade for wall fences made of three-layer reinforced concrete panels with an internal thermal insulation layer are presented. The durability of the anchor attachment of the hinged ventilated facade is determined, depending on the frost resistance of the outer layer of the three-layer wall panel and the orientation of the wall to the north or south.

    Keywords: hinged ventilated facade, reinforced concrete three-layer panel, attachment point of the hinged facade, ice coefficients, durability

  • Overview: Advances and Challenges in Analyzing and Diagnosing Product Defects by Digital Methods

    The article provides an overview of the analysis and diagnosis of product surface defects, evaluated using digital image processing. The search for scientific publications was carried out mainly in the Scopus and RSCI scientometric bases for the period 2019-2023. The purpose of this article is to determine the best methods for assessing the destruction of materials using digital images. The main methods of processing and analyzing digital images are considered. The perspective of unification of segmentation modes by digital image acquisition sources and combining images from various recording sources to obtain objective information on the nature of material destruction is shown. To reduce the time for assessing the degree of destruction of materials, it is proposed to gradually use the methods of segmentation, filtering digital images of defects in metal products with subsequent calculation by a neural network.

    Keywords: defect, control, digital image, neural network.

  • 3D-printing and reinforcement of concrete mix

    The article discusses the issues of 3D-printing and reinforcement of concrete mix with an automated reinforcement integration system, analyzes the effect of the mixture on the dynamics of the construction printer. During the work of the construction 3 D-printer, data was obtained from the accelerometer in the form of graphs of the oscillation frequency of the construction printer, which characterize the main operating parameters. The valve feed was arranged in such a way as to ensure application with virtually no stress. A roller feeder for the rear of the nozzle has been developed for this purpose. Experimental curves of force dependence on displacement for 40 × 40 mm samples with reinforcement reinforcement are presented.

    Keywords: construction 3D printer, concrete mix, vibration pattern, accelerometer, reinforcement integration

  • "Construction Materials Based on Gypsum Hydrate Cakes Obtained from Krastsvetmet JSC "

    The paper presents the results of research on the application of gypsum hydrate cakes, the waste products of the refining process at the Krastsvetmet non-ferrous metals plant, for the production of construction materials. The study examined pasty cakes for use in building mortars, and after drying and grinding, the resulting cake powder was further used as a fine filler in asphalt concrete mixes. The optimal composition of the construction mortar was determined using a mathematical method of experimental design. The construction mortars were prepared based on cement and local mineral materials. The study demonstrated that it is possible to get construction mortars of the required strength based on the cakes. The cake powder obtained after drying was examined as a mineral powder for asphalt concrete. Tests showed that the cakes met the requirements for grade MP-3 mineral powders in all aspects. Asphalt concrete incorporating the cakes also met the regulatory standards for its key properties. Based on the research results, the optimal compositions of mortars and asphalt concrete were recommended for implementation to construction companies in the Krasnoyarsk Krai.

    Keywords: waste products, cakes, construction mortars, compositions, properties, regression equations, durability, water retention capacity, segregation, mineral powder, asphalt concrete

  • Selection of the composition of fine-grained concrete with the use of various plasticizers

    The article examines the influence of various superplasticizers on the performance characteristics of concrete. A series of tests of samples-beams of fine-grained concrete modified with plasticizers of various types was carried out. The optimal amount of the introduced additive was experimentally determined to compare the plasticizing effect of the cement-sand mixture. Experimental data are given indicating the main operational characteristics of the material depending on the additive used. The most effective additive "Polyplast SP-3" has been determined.

    Keywords: concrete, fine-grained concrete, mixture, lignosulfonates, polycarboxylates, naphthalene sulfonates, plasticizer, superplasticizer, water demand, plasticity

  • Activated dry mix for the preparation of mortars and fine-grained concrete

    This article presents the developed compositions of dry mortar mixtures for the preparation of fine-grained concrete. For the preparation of these mixtures, the technology of electromagnetic action on the dry components of solutions was applied. As a result of the use of a magnetic field to activate and increase the reactivity of the mixture, the physical and mechanical characteristics of fine-grained concrete have significantly improved. The increase in the compressive strength of the samples reached more than 70% compared to the strength of samples prepared using conventional technology without the use of magnetic treatment of dry components of the mixture.

    Keywords: dry mix, magnetic treatment, linear induction rotator, fine-grained concrete, strength

  • Effective gypsum-free Portland cement binders with low water demand for building materials and structures

    The article shows the possibility of reducing the water demand of clinker binders based on gypsum-free cement with a multicomponent additive of technical lignosulfonate and an aqueous solution of sodium silicate. The possibility of obtaining composites based on modified gypsum-free cement with improved properties for building structures has been demonstrated.

    Keywords: composite, gypsum-free cement, composition, technical lignosulfonate, concrete, Portland cement, sodium silicate, strength

  • Analysis of the applied methods for calculating the strength of a normal section of multilayer bending structural elements

    The article discusses the existing methods for calculating the strength of a normal section in multilayer bending structures. The experience of Russian and foreign researchers was analyzed, the approaches described in domestic and foreign regulatory documents were compared, and key differences were identified. At the same time, special attention is paid to the mathematical description of the work of concrete as a material. It was concluded that further research is expedient to find the most optimal method for calculating multilayer structures.

    Keywords: concrete, reinforced concrete, multilayer structures, calculation method, bending element, normal section, stresses, high-strength concrete, stress diagram, description of concrete work, bending moment, neutral axis

  • Dispersion-filled composite on carbon black

    The article shows the possibility of producing a composite using carbon black as a filler. Trivalent chromium oxide was chosen not only as a pigment component, but also as a light stabilizer. The results obtained allow us to say that the dispersed composition is efficient. Compositions based on carbon black and containing trivalent chromium oxide in an amount of 1% exhibit electrically conductive properties.

    Keywords: pyrolysis carbon, chemical composition, structural and morphological characteristics, elemental composition, energy dispersive spectrum, micrograph, epoxy binder, polyethylene polyamine, trivalent chromium oxide, thermal conductivity, electrical conductiv

  • Study of the Physical-Mechanical and Wave Characteristics of Porous Fibrous Materials

    This article is a study of the physical and mechanical characteristics and wave parameters of porous fibrous materials (PFM) used in providing sound insulation and vibration protection of buildings and structures. In the work, the classification of porous-fibrous materials according to the initial raw material and various degrees of rigidity is carried out, the main physical and mechanical characteristics and wave parameters of porous fibrous materials, and theoretical methods for their determination are presented. The results of laboratory measurements of the physical-mechanical and wave characteristics of PFM samples (glass and stone bases of various density and thickness) are presented. An extensive experimental study has been carried out in order to evaluate the main relationships between the sample material, its density, feedstock, structure, size, and its acoustic, physical-mechanical and wave characteristics. The results of the study are of great practical importance for the development of acoustically effective building materials and their optimal use in construction and engineering systems.

    Keywords: acoustic measurements, acoustic design, building materials, characteristics of porous-fibrous materials, sound insulation, vibration protection of buildings and structures

  • Investigation of the effect of adding pulverised stone processing waste on the strength properties of concrete

    Utilisation a waste of stone processing in production of other kinds products is an actual task for stone-cutting enterprises. In this study, the possibilities of using basalt dust generated during sawing, grinding and polishing of basalt and related minerals in the manufacture with concrete are studied. Three groups were prepared with different content of basalt dust - 0 %, 5 % and 20 %. After the final hardening performance of the concrete, the compressive strength testing was conducted on the specimens. The results showed that the addition (5%) added basalt dust practically did not reduce the strength ratio practically, the increase of basalt dust content up to 20% caused an average 16% reduction in the strength of the specimens. The fracture character that occurred in the specimens containing basalt dust corresponded to the fracture character that happened to similarly shaped concrete products.

    Keywords: concrete, stone waste, strength, basalt

  • Numerical analysis of residual welding stresses of butt welded joint of plate steel

    Welding is the main method of joining plate steel. Its use leads to significant residual welding stresses. Residual stress can significantly affect the load-bearing capacity of long-span steel bridges. In this work, a finite element calculation of residual welding stresses of steel sheets up to 100 mm thick was carried out, and the distribution of surface residual stresses and the influence of sheet thickness on the residual surface stress were identified.

    Keywords: steel bridge, plate steel, welding residual stresses, finite element method, welded joint, stress distribution

  • Experimental study of the impact of microwave radiation on the physical and mechanical characteristics of concrete

    Heat treatment of concrete, along with steaming, is one of the main methods for accelerating the hardening of concrete and achieving its transfer, stripping and design strength. These concrete processing technologies are more often used in factories in the manufacture of mass-produced concrete and reinforced concrete products in curing chambers of periodic and continuous action, under portable hoods on stands and other installations, or in special thermoforms, thermal packs, cassettes, etc. However, there is an increasing need acceleration of concrete strength gain at the construction site at the time of construction and installation works associated with new construction, repair or reconstruction of existing buildings. The aim of the study is to study the acceleration of the strength development of concrete subjected to heat treatment using the energy of an electromagnetic field of microwave frequencies. The article presents the results of an experimental study of concrete samples for compression treated with microwave energy and the control group of samples gaining strength in natural conditions. The experimental data obtained indicate an increase in the strength of the treated concrete samples by 72.94% on day 1, by 27.83% on day 2, by 14.23% on day 3, and by 1.1% on day 7 in comparison with samples not subjected to microwave exposure. From the 14th day, a gradual drop in strength begins in comparison with the samples not subjected to heating with the help of electromagnetic fields, so on the 14th day the strength of the treated concrete samples decreased by 2.45%, on the 21st day by 32.17%, on the 28th day by 25.61%. As a result of the analysis of the obtained experimental data, it was concluded that microwave exposure to the concrete solution significantly increases the strength of concrete in the early stages, but negatively affects the design strength of concrete as a whole.

    Keywords: microwave radiation, microwave, concrete, heat treatment, strength, construction

  • On the issue of resource saving in the construction industry and construction

    Factors affecting the limited mineral resources of the planet and requiring the expansion of the raw material base of the construction industry are considered. The negative impact of overburden dumps on the ecological state of the habitat was noted. The importance of their processing into a useful product was emphasized in connection with the need to implement the industry program of the Russian Federation ""Involvement of overburden and containing rocks classified as production waste in economic circulation for 2022-2030."" The properties of sand and opoka as raw materials for making foam concrete were analyzed. The result of the analysis made it possible to formulate a list of restrictions, as a result of which it is undesirable to use opoku in concrete of a cast-in-place structure and a list of reasons, based on which it is possible to predict the feasibility of its use in foam concrete. The results of experimental studies are presented, reflecting the influence of the individual properties of sand and opoka on the density of foam concrete mixtures, the density of solidified foam concrete and the kinetics of their plastic strength during three hours of hardening from which it follows that replacing sand with opoka allows significantly improving the technological properties of foam concrete mixtures without compromising the achievement of their design density. It follows from the analysis of experimental data that the structural features of the foam concrete mixtures have a positive effect on the technological properties of foam concrete mixtures, which accelerate the gain of plastic strength of foam concrete mixtures after their placement into molds. The most important reason for the achieved result should be considered mesopores located in the volume of dispersed particles of aggregate from opoka. The established scientific facts make it possible to predict the expanded use of overburden rock - opoki in order to save resources in the construction industry and construction.

    Keywords: resource saving, sand, opoka, foam concrete mixture, plastic strength

  • Study of the rheological properties of cement compositions with a complex of additives

    The article presents the results of a study of the rheological properties of cement compositions with a polycarboxylate-based plasticizer and stone flour from carbonate rocks of the Saratov region.

    Keywords: cement, rheological matrix, powder-activated concrete, superplasticizer, hyperplasticizer, finely dispersed additive, stone crushing waste, stone flour, water-cement ratio, water-reducing effect

  • The effect of redispersible polymer powders and holding conditions on the shrinkage of building mortars

    The influence of the type and dosage of some redispersible polymer powders on the shrinkage deformation of building mortars obtained from dry building mixes, including for underfloor heating, after exposure at a temperature of 70 ° C in accordance with GOST R 56387-2018 was investigated. The introduction of admixtures 4042N, E06RA, 5603 into the mixtures did not lead to an increase in shrinkage deformations when maintained according to GOST R 56387-2018 relative to the additive-free standard, regardless of the type and dosage of the admixture, while with these admixtures, regardless of their dosage, within 1-3%, the values of shrinkage deformations were less than 1.5 mm / m. The greatest influence of the type and dosage of the redispersed polymer powders on the shrinkage change is manifested at the heating stage, which is due to their influence on the kinetics of dehydration and the magnitude of the E-modulus. Depending on the type of cement, type and dosage of the admixture, the moisture loss values by the end of heating to 70oC ranged from 0.114 to 0.629 relative to the total moisture loss by the end of holding. Naturally, a change in shrinkage by the end of heating from 0.027 to 0.595 relative to complete shrinkage by the end of aging was noted, while a proportional relationship between moisture loss and shrinkage was revealed. In some formulations, an expansion of up to 0.469 mm/m was recorded by the end of heating. For a comprehensive assessment of the degree of influence of admixtures on changes in the deformation and strength properties of mortar at a holding temperature of 70 ° C according to GOST R 56387-2018, an indicator of the conditional stress level is proposed, varying depending on the holding stage, type of cement, type and dosage of the additive in the range from 0.489 to 3.05.

    Keywords: Shrinkage, building mortars, dry building mixes, redispersible polymer powders, underfloor heating