Introduction.The purpose of the study is to investigate the influence of the impregnation degree of a non-woven needle-punched fabric with aqueous polyurethane dispersions of varying compositions on the formation of the porous structure of composite materials for construction applications.Materials and methods.The object of the study is a non-woven needle-punched fabric made of polyethylene terephthalate fibers (Technical Specifications TU 6-13-0204077-95-91) with a linear density of 0.33 tex (diameter 20-25 m), impregnated with aqueous polyurethane dispersions of different compositions.The fibrous web was formed by mechanical means and strengthened with a primary needle-punching density of 180 cm -.The impregnation process employed aqueous dispersions of anionically stabilized polyurethane: the brand IMPRANIL DL 1380 (China), based on an aliphatic diisocyanate with a polymer concentration of 385%; and the brands Aquapol-11 and Aquapol-21, based on aromatic diisocyanates, produced by LLC "NPP 'Makromer' named after V.S. Lebedev", Vladimir, with a polyurethane concentration of 402%.Results and discussion.The influence of the aqueous polyurethane dispersions on their distribution pattern on the fibers during impregnation was determined.Materials with an optimal porous structure were obtained, which governs the heat and mass transfer processes while maintaining the required physic-mechanical properties.Conclusion.At an impregnation degree of less than 0.1 or a porosity coefficient of 0.8, fragmentary structures of the IMPRANIL DL 1380 polyurethane form on the fiber surfaces.This results in strong composite materials whose air permeability is practically the same as that of the original non-woven fabric.The development of such materials is of interest for thermal and sound insulation in building structures.When using Aquapol-11 and Aquapol-21 dispersions for impregnation, the polyurethane binder almost completely fills the space between the fibers.This leads to a decrease in the overall porosity of the composite, making it promising for use as a waterproofing material in road construction.

Introduction.Self-compacting concrete offers broad potential in construction due to its operational reliability and durability.However, the high cost of self-compacting concrete and the technological complexity of its production require the development of new concrete mix designs and improved placement technologies.When selecting concrete mix designs for self-compacting concrete, chemical additives can be used to reduce cement consumption and improve the concrete's properties.Materials and methods.To ensure the rheological and technological properties of the concrete mix, fly ash, a dry polycarboxylate-based superplasticizer, and ultrafine additives were used.The ultrafine additives were produced by hydrolysis, using pure Portland cement as a precursor, with the concentration in the solution varying from 1 to 5%.The cement hydrolysis reaction results in the formation of a multicomponent sol containing silicic acid, aluminum hydroxide, iron hydroxide and calcium hydroxide.Results and discussion.Experiments were conducted to modify self-compacting concrete with an ultrafine additive obtained using sol-gel technology.An optimal composition of modified cement containing an ultrafine additive with an average particle size of up to 100-150 nm was developed.The use of the ultrafine additive accelerated the cement hardening kinetics and improved the physical and mechanical properties of cement stone by 1.4-1.8times compared to cement without the additive due to water accumulation, an increase in the volume of cement gel, and a decrease in capillary porosity.Based on an assessment of the technological and rheological properties of concrete mixtures containing fly ash as a microfiller and a modifying additive, compositions corresponding to strength classes B40-B60 were established, containing 7.5-44% fly ash and an additive in an amount of 0.1% of the cement weight on a dry matter basis.It has been established that the introduction of ultrafine fly ash and fly ash into the concrete mix reduces segregation by 17-19%, increases viscosity by 13% to 20%, and reduces flowability only slightly by 5-10%.It has been established that self-compacting concrete with the combined use of fly ash with medium pozzolanic activity, a chemically active ultrafine additive, and a polycarboxylate-based superplasticizer is characterized by intensive strength gain within 1-3 days of curing and an increase in strength by 15-17% within the design curing period.Conclusion.As a result of the research, a low-temperature method for producing a modifying additive using sol-gel technology was developed.This method is simple to synthesize, does not require complex process equipment, and can be added along with mixing water and uniformly distributed throughout the concrete mix.Concrete mix formulations for self-compacting concrete of strength classes B40-B60 were developed using an ultrafine additive, which improves the process properties, quality indicators, and physical and mechanical properties of the concrete.

Introduction.Currently, barium sulfate is actively used in various industries, including paper manufacturing, construction, paints and coatings, rubber, chemical, metallurgical, and electrical engineering industries, as well as in agriculture and medicine.Literature analysis has shown that the composition and properties of barium sulfate depend on its deposit.Different processing technologies have been developed for barium sulfate, including methods for producing materials for a wide range of applications.Particular attention is given to creating radiation-resistant and radiation-shielding materials, including radiation-resistant concretes and ceramics.Methods and materials.In Kyrgyz Republic, there are more than 40 barium sulfate deposits.Among them, the "Arsy" deposit stands out particularly, with sufficient reserves.The chemical composition of barium sulfate from the "Arsy" deposit was analyzed using atomic emission spectrometry, X-ray fluorescence method, and silicate chemical analysis.The analysis results showed that the chemical composition of barium sulfate includes barium sulfate (BaSO) at about 89-91%.The remaining components are impurities: calcium (Ca) -8-8.4%,silicon dioxide (SiO) -1.6-1.8%,aluminum oxide (AlO) -0.1-0.13%, and iron oxide (FeO) -0.15-0.25%.Micro-silica is a fine-dispersed powder consisting of silicon dioxide (SiO) particles ranging from 0.1 to 0.3 micrometers in size.Its SiO content is approximately 85-98%.It also contains impurities: aluminum oxide (AlO) -0.2-0.8%,iron oxide (FeO) -0.1-0.5%, and calcium oxide (CaO) -about 0.5%.The chemical composition of bentonite from the Abshir deposit is characterized by the following component contents: silicon dioxide (SiO) -65.84%, aluminum oxide (AlO) -14.8%, iron oxide (FeO) -4.35%, calcium oxide (CaO) -2.85%, magnesium oxide (MgO) -1.76%, loss on ignition (LOI) -2.72%, and other impurities -7.68%.For processing barium sulfate powder, a hydrocavitator was used, which ensures effective treatment of liquid media through a combination of cavitational and mechanical effects.Results.To develop the technology and optimize the composition and properties of the ceramic composite, bentonite clay, finely ground barium sulfate, and micro-silica were used as raw materials.The experiment was conducted based on a four-factor plan B4.Regression equations describing the dependence of the material's density, water absorption, strength, and shrinkage on the varying levels of the factors were constructed from the levels of factor variation and the experimental data obtained.Corresponding nomograms reflecting the influence of the studied factors within the experimental plan were developed based on these equations.Optimal parameters ensuring high strength of the ceramic composite were identified: barium sulfate content of about 20-25%, micro-silica content of approximately 5%, firing temperature around 850 C, and heat treatment duration of 30-45 minutes.Subsequently, the barium sulfate powder was processed using a hydrocavitator, after which the technological modes and physical-technical characteristics of the powder after cavitation treatment were determined.The composition and properties of the barium sulfate powder were analyzed using X-ray diffractometry, performed on an AL-27MINI diffractometer within the 2 range of 10 to 70.Fourier-IR spectra were recorded on an IRSpirit-T spectrometer equipped with a QATR-S accessory, within the range of 400-4000 cm -1 .Conclusion.Optimization of the composition and properties of the ceramic composite based on the analysis of mathematical models indicates that it is advisable to use barium sulfate powder in an amount of about 20-30% and micro-silica up to 10%, at a firing temperature of 850-900 C and a heat treatment duration of 30-45 minutes.Such a composition allows achieving high strength and water resistance of the material.After cavitation treatment, barium sulfate powder changes its chemical activity and can be used in the composite in an amount up to 20% by mass relative to the bentonite.Adding more than 20% of barium sulfate powder causes intense chemical reactions due to the presence of sulfur, leading to the destruction of the material's structure.Therefore, it is recommended to limit the barium sulfate content to a maximum of 20% to avoid undesirable effects, including explosive or destructive processes within the ceramic composite structure.

Introduction. A primary geotechnical challenge pertains to the stabilization of unstable soils due to their inadequate deforma tion, physical, mechanical, and filtration characteristics, which, in turn, can result in abnormal settlements, the destabilization of the soil mass under external loads, or even its own weight. The advent of chemical technologies on a global scale, along with their development within the Russian Federation, has precipitated the utilization of advanced equipment in conjunction with novel, innovative technologies. This confluence has given rise to novel methodologies and the fabrication of new materials, which have been instrumental in addressing a myriad of geotechnical challenges. The predominant methods of soil stabilization with mineral compounds (predominantly based on Portland cement) possess clear advantages; however, they do not always permit work to be conducted in soils with high water saturation, under conditions of high filtration, or in soils with low deformation indices. Conse quently, issues pertaining to cementation stabilization periodically emerge. These issues manifest, for instance, in water-saturated rock soils under high hydrostatic pressures, in various fractured soils complicated by the presence of karst depressions, in dispersed, silty, and organo-mineral structurally unstable soils. Materials and methods. The employment of innovative polymer materials, such as polyurethane-based materials, facilitates the injection of mixtures with optimized strength gain, thereby addressing the issue of soil reinforcement within this process or enhancing the criteria for constraining the propagation of injection mixtures for subsequent cement grouting. Results and conclusion. Laboratory tests and analysis of a number of completed projects allow us to consider this technology effective and practical in complex engineering and geological conditions and beyond design-basis parameters for underground construction projects. The present study was carried out using the material and technical resources of the Main Regional Center for Collective Use of Scientific Equipment and Installations of the Moscow State University of Civil Engineer ing, with the support of the Ministry of Science and Higher Education of the Russian Federation (agreement No. 075-15-2025-549).

Introduction.Flexible elements made from various materials such as films, papers and geotextiles, coated with an electrically conductive coating containing carbon nanoparticles, have the potential for creating intelligent structures.To rationally choose, design, and apply electrically conducting components, it is necessary to objectively assess their behavior throughout the life cycle of these objects.Currently, there are no objective methods for evaluating such components.Methods and tools are needed that can not only evaluate initial electrical conductivity values of components but also predict dynamics of changes over time.Methods and Materials.The samples were tested under cyclic multi-axial stretching conditions.After each stretch, the strain, thickness, and electrical resistance of the samples were measured.Different materials were selected for the study, including films, nonwoven fabrics, and fabrics which differ in composition, structure, and properties.A composition with carbon nanoparticles was applied to the materials using screen printing.Results and discussion.The tests showed that the irreversible part of deformation of the sample ranged from 8% to 75%, while thickness varied from 6% to 100% depending on the structure of materials.Electrical resistance ranged from 25 Ohms to 5 KOhms, depending on test parameters and composition of coating-substrate composite.Correlation analysis confirmed strong correlation between electrical resistivity and sample deformation with correlation coefficient ranging between 0.6 and 0.78.An approximation was used to derive empirical equations that can be used to predict the reliability of flexible, electrically conductive elements under cyclic stretching conditions, which simulate operating conditions.Conclusion.A comparative analysis of test results under these conditions allowed us to recommend nonwoven fabrics and fabrics with a thickness of 0.5-0.7 mm for use as flexible electrically conducting elements.This method is recommended for objective assessment of changes in the properties of these components in intelligent building structures.

Introduction.The work is devoted to the experimental and theoretical study of the technology and properties of composite materials based on soluble glass.The prospects for the manufacture of floor coverings and other products using frame technology and roller molding are shown.Materials and methods.The frame technology for the manufacture of building composites consists in the first stage of gluing grains of large filler to each other according to the shape of the future product, and in the second stage -filling the voids of the hardened porous frame with a solution component.Roller molding is used both when performing the operation of compacting the frame and when filling its voids with a matrix.The purpose of the work was to conduct an experimental and theoretical study of the manufacturing technology, physical and mechanical properties and chemical and biological stability of composites based on liquid glass.To analyze the mechanism of the stress-strain state of compacted mixtures, a rheological model is considered, in which the mechanical characteristics of the medium are determined by fundamental properties: viscosity, elasticity and plasticity.When conducting experimental studies, sodium liquid glass was used, sodium fluorosilicate was the hardener, and powders based on mineral and organic materials served as fillers.Furyl alcohol was used as a polymer additive.Results.The optimization of the compositions of frames and matrices for framed concretes was performed.The studies were carried out using mathematical methods of experiment planning.Three-factor matrices consisting of 10 experiments were considered.Discussion.The best strength characteristics are demonstrated by matrix compositions that include filler mixtures of quartz sand, pyrite cinders and diatomite, and the greatest strength of the framework is achieved by including granules of 5-10 mm in the composition -7%, 2.5-5 mm -23%, 1.25-2,5 -70%.The chemical and biological resistance of composites on silicate and polymer silicate binders was studied.Chemical resistance was determined in water, aqueous solutions of caustic soda, technological environments of soft drink factories, and biological resistance -in a standard environment of mycelial fungi.It was found that composites containing modifying additives are characterized by higher resistance rates.Conclusion.Scientific and technological foundations for managing the structure and properties of liquid glass framed composites of vibration-free roller molding have been developed, as well as scientifically based solutions for improving the compositions of frame and matrix mixtures by regulating the processes of chemical interaction between components, the grain composition of fillers and aggregates, and the introduction of special additives to ensure increased strength, chemical and biological resistance of concrete.

Introduction.The porous composite and nanocomposite materials discussed in this publication are metallized carbon-graphite materials, in particular carbon fiber materials (CFMs).At metallization of CFMs one of the actual problems is the task of applying uniform metal coating on the surface of CFMs fibers over the entire volume of the processed material.One of the most effective ways to coat CFMs with metals and their alloys is the galvanic method.This method allows, among other things, to optimize the process by optimizing both the design of the electrolyzer with flow-through three-dimensional electrodes (FTE) and the choice of electrodeposition modes, such as galvanic, concentration, and hydrodynamic.Materials and methods.Methods of mathematical modeling of porous medium metallization processes and previously published experimental data were used to solve problems on calculation of operating modes and elements of the electrolyzer design, in particular, the specific reaction surface of the UWM distributed over the thickness of the electrolyzer.Results and discussion.The development of mathematical models of the processes of electroplating metallization of CFMs is carried out.Boundary value problems of mathematical physics are formulated and calculation methods are proposed.Problems of optimization of distribution of specific reaction surface of CFMs by thickness of FTE on the basis of electrochemical theory of processes in porous medium are set, ways of their solution are presented.Specific technological problems are solved.The comparison of the most effective values of the distribution of specific reaction surface of CFMs over the thickness of FTE obtained as a result of modeling with the experimental data is given.The workability of models and methods for studying the process of copper electrodeposition from sulfuric acid electrolyte is shown.Conclusion.Calculation of regularities of electrochemical processes of metal extraction in FTE on the basis of the developed mathematical models allows to predict the results of electrolysis, determine the optimal modes of operation and elements of FTE design.The use of FTE for metallization of CFMs with properly distributed reaction surface contributes to obtaining composite materials with specified properties.

Introduction. Currently, the development of science and technology requires the creation of new polymer composites with high technical characteristics for various industries. One of the primary methods to improve the physical and technical characteristics of polymer composites based on thermoplastic elastomers is by incorporation of natural fillers. In the Kyrgyz Republic, there is particular interest in using fine mineral fillers extracted from local natural resources. The minerals and rocks found in the region are charac terized by high availability, extensive reserves, and a variety of properties. The accumulated experience in research and practical application opens up prospects for using these materials to create polymer composites with unique characteristics. This opens up new possibilities for using the cavitation process in various industrial applications, including the grinding of materials. Methods and materials. An experimental hydrocavitation mill has been developed to produce fine powders from minerals and rocks intended for use as fillers in polymer composites. The physicochemical properties of polymer composites and their raw materials were studied using modern instruments and equipment. The fractional composition and physical and technical characteristics of some minerals and rocks used to obtain active fillers for polymer composites are given. Results and Discussion. The fractional composition of crushed fillers with a particle size of less than 0.31 mm is distributed as follows: finely ground basalt – 7.3%, wollastonite – 44.6%, marble dust – 50.26%, brown coal powder – 47.56%. The analysis shows that among the studied fillers, finely ground basalt contains the smallest amount of fine fractions, which is due to its high hardness compared to other minerals such as wollastonite, marble, and coal. Physical and mechanical studies of the resulting polymer composites showed that when finely ground basalt is added, an uneven distribution of basalt powder in the polymer matrix is observed, which leads to a decrease in the strength characteristics of the composite. Therefore, to obtain a more durable material, it is necessary to grind minerals and rocks to the level of microparticles using the cavitation effect. For this purpose, a laboratory mill was created that operates based on the cavitation effect. Fillers at the level of micro- and nanoparticles were obtained using the developed hydro cavitation mill. The physical and technical characteristics of polymer composites with additives of the resulting nanofillers have been determined. The compressive strength of composites with mineral fillers (fraction less than 0.31 mm, content of wollastonite filler in the composite – 25.2%) was 5.47 MPa, with basalt f iller – 5.2 MPa, and with leather powder (dust) – 4.25 MPa. Fillers at the level of micro- and nanoparticles were obtained using the developed hydro cavitation mill. The physical and technical characteristics of polymer composites with additives of the resulting nanofillers have been determined. The compressive strength of composites with mineral fillers (fraction less than 0.31 mm, content of wollastonite filler in the composite – 25.2%) was 5.47 MPa, with basalt filler – 5.2 MPa, and with leather powder (dust) – 4.25 MPa. The compressive strength of the composite with the addition of carbon filler (13.2%) was 4.2 MPa. The introduction of up to 14.2% of mineral fillers into the composition of the composite increases its heat resistance: when adding basalt filler – up to 106 °C, and wollastonite – up to 114 °C. Conclusion. The fractional composition of mineral fillers based on inorganic raw materials studied for their use in creating polymer composites. A hydro cavitation mill was made and a method for processing fillers from minerals and rocks was developed. New polymer composites were obtained with the addition of basalt, wollastonite, marble, and leather industry waste. Studies have been carried out on the physical and technical characteristics of these polymer composites depending on the content of fillers, such as basalt, wollastonite, marble and leather industry waste.

Introduction. The article briefly discusses the state of scientific research in the field of mathematical modeling of physical systems with distributed parameters. Mathematical modeling in elasticity theory. The initial boundary value problem of linear elasticity theory is formulated. It is shown that using measured and unmeasured variables, it is possible to construct a positive definite energy relationship, which allows not only to use the variational technique to find an approximate solution, but also to design objective es timates of its quality. Two-dimensional problem of elasticity theory (static case). Using the example of solving a two-dimensional static problem of linear elasticity, the advantages of the proposed approach are discussed in detail. Mathematical modeling in fluid theory. The variational principle in fluid theory is formulated. Optimal pressure control. Using the example of solving the problem of the motion control for ideal and viscous fluids in pipeline systems, the issues of finding an approximate solution and estimat ing its accuracy are discussed. Energy principle in the heat transfer problem. The variational principle in the linear heat transfer problem is formulated. Two-dimensional heat transfer problem. The features of constructing a solution to a control problem in a two-dimensional heat transfer theory are discussed in detail. Generalizing principle. A generalizing principle of the actual state of a physical system is formulated, which can be effectively applied for a detailed description and analysis of physical processes.