In the article there was considered a possibility of off-grade materials utilization for making fine concrete with a multicomponent complex additive applied. Use of fine sands as raw material for fine concretes is actual for many regions in Russia because of deficiency of sands of necessary fineness modulus. There was considered the issue of utilization of fine sand and stale cement for reducing cost (loss), widening materials’ assortment for low-rise building, and energy- and resource-saving. To achieve the assigned purpose a multicomponent complex additive was applied. The research was carried out in full correspondence with the adopted design of the fractional factorial experiment. The acquired results were subject to a preliminary analysis and processing, and consequently dependences of strength properties upon varying factors were obtained. The obtained dependences made it possible to select optimal ingredients’ proportion of the complex modifying additive in order to increase strength properties of fine concrete based on off-grade materials. It was established that the use of optimal consumption of the complex additive components allows increase strength properties by 25-30% in comparison with the reference composition.

Keywords: fine concrete, fine sand, stale cement, complex additive, fractional factorial experiment, strength

The factors affecting the strength of the interlayer bond of 3D concrete, as well as factors affecting the ability of the printer nozzle to produce a controlled concrete thread of a particular composition, which is being investigated in the process of 3D printing technology, the main characteristics of the suitability of compositions for printing on a 3D printer, requirements for rheology, hydration and strength in an uncured form, are considered 3D concrete, the main mechanical test methods for determining the adhesion strength in concrete printed on a 3D printer. The possible shapes and nominal sizes of the samples used in the methods for determining the strength of concrete are given.

Keywords: 3D concrete, anisotropy of mechanical properties, extrusion, cold connection, interfacial coupling, deflocation, thixotropy, initial static viscosity, curing, three-point bending

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

The article presents a model for the formation of a thermodiffusion layer on steels. Thermodiffusion coatings on 45 steel and HVG steel were obtained by a chemical-thermal method in a powder mixture. Studies of layered X-ray diffraction phase and microrentgenospectral analysis of the studied coatings have been carried out. on steel. The obtained results of X-ray diffraction and microrentgenospectral analysis of diffusion coatings confirm the correctness of the model of formation of the diffusion layer and the theoretical prerequisites outlined. The results of the study can be used in the preparation of mixtures for thermal diffusion saturation.

Keywords: diffusion layer, diffusion chrome plating, diffusion coating

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

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

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

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

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

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

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

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

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.

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

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

The impact of the alkali NaOH on the structure and morphology of cellulose has been considered. Using X-ray spectroscopic microanalysis and electron microscopy, it has been determined that treatment of wood cellulose with aqueous solutions of NaOH allows to reduce the content of lignin in cellulose and significantly improve the topography of the fibers. A comparative analysis of alkali cellulose samples was conducted, obtained during treatment with NaOH solutions of 13.7% and 12.3% concentration for a process duration of 5.5 hours, at a temperature of 124 °C. It has been established that at the considered concentrations of NaOH, approximately ~75% and ~50% of lignin is removed from the original cellulose, respectively. The results of infrared spectroscopy indicate an increase in the amorphization of alkali cellulose. Alkali cellulose, formed at a NaOH concentration of 13.7%, exhibits superior morphological uniformity and a lower lignin content.

Keywords: wood cellulose, chemical treatment, alkalinity, lignin, X-ray spectral microanalysis, electron microscopy

The influence of secondary crushed stone on the strength and shrinkage of concrete was studied. The results showed that when granite coarse aggregate is replaced with crushed recycled concrete, the compressive strength of concrete is reduced by an average of 20% and the flexural strength by 3-10%. Concrete on recycled crushed stone has a high shrinkage. The shrinkage of concrete with a minimum consumption of recycled aggregate differs slightly from the shrinkage of concrete on granite crushed stone.

Keywords: demolition waste, concrete scrap, recycling, recycled aggregate, compressive strength, flexural strength, shrinkage

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

The article presents the results of the effect of replacing a part of cement with volcanic ash on the strength of cement stone in building mortars. Pozzolan additives have hydraulic properties. Volcanic ash from Kabardino-Balkaria deposits can be used in building mortars and concrete mixtures as an active mineral additive.

Keywords: volcanic ash, active mineral additive of natural origin, building mortars with active mineral additives, cement stone, flexural and compressive strength

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

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

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

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

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

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