Table of contents

ADVANCED TRENDS IN CIVIL ENGINEERING 2021 (ATCE 2021)

The 1^st International Conference ADVANCED TRENDS IN CIVIL ENGINEERING 2021 (ATCE 2021) was held from 13 to 14 September, 2021 in Belgorod (Russian Federation), on the basis of Belgorod State Technological University named after V.G. Shukhov, Belgorod, Russia.

It is one of the conferences for presenting novel and fundamental advances in the fields of Material Science and Physics. Within the framework of the international conference, the participants will present reports reflecting the latest achievements of using and application of materials science; technologies for their production and processing; ecological and economic efficiency of their application in various fields of modern production, as well as to discuss recent developments in the area of Physics.

The idea of the conference is for the scientists, scholars, engineers and students from the Universities all around the world and the industry to present ongoing research activities, and hence to foster research relations between the Universities and the industry. This conference provides opportunities for the delegates to exchange new ideas and application experiences face to face, to establish business or research relations and to find global partners for future collaboration.

As a result, there is a real opportunity among a wide range of scientists, teachers, industry representatives, and students in various fields related to material science and physics, to exchange ideas, share knowledge and establish close cooperation. The successful organization and holding of the conference are evidenced by the wide geography of the participants, as well as the high level of the reports presented. With its high quality, it provides an exceptional value for students, academics and industry researchers. It also provides a premier interdisciplinary platform for researchers, practitioners and educators to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the fields of Material Science and Physics.

List of EDITOR, ORGANIZING CONFERENCE COMMITTEE, SCIENTIFIC CONFERENCE COMMITTEE are available in this pdf.

ADVANCED TRENDS IN CIVIL ENGINEERING (ATCE 2021)

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Single-blind/Double-blind/Triple-blind/Open/Other (please describe): Double-blind.

Papers must be submitted electronically via: https://scopus-conf.ru/en/advanced-trends-in-sivil-engineering/. All submissions must come in PDF format, conform to the Conference Publishing template, and not exceed 14 pages (including figures, appendices and references). We also welcome survey papers with an increased page limit of up to 15 pages. Together with papers authors also must submit the registration form. Every participant in the conference served by this site, "in any capacity," must maintain a login and password. The same login must be used for all conferences. Follow the link to register a login, to check and update your personal information, or to retrieve your password. To comply with the General Data Protection Regulation, the first time when you login to a new account, you will be directed to the required opt-in consent form before you can use your account in any capacity for products and services offered through this site. All papers submitted to the conferences supported by this site need to be prepared as compliant PDF files and must be formatted according to the template.

• Conference submission management system: the papers were submitted via conference website

• Number of submissions received: 61 submissions received

• Number of submissions sent for review: 54 submissions were sent for review

• Number of submissions accepted: 28 submissions were accepted

• Acceptance Rate (Number of Submissions Accepted/Number of Submissions Received X 100): 45,9%

• Average number of reviews per paper: 3

• Total number of reviewers involved: 40

• Any additional info on review process: All the papers submitted to the ADVANCED TRENDS IN CIVIL ENGINEERING (ATCE 2021) conferences pass the procedure of reviewing according to the order established by editorial board. All papers are reviewed three times by experts in relevant field. The reviewing process took 40 days. The revised papers were also checked by Editors. All accepted papers meet the following criteria:

- Scientific merit and quality of data presented;

- Relevance of study to the conference topics;

- No plagiarism and autoplagiarism;

- Adequate paper structure;

- Good English.

Members of the editorial board and leading Russian and international experts in corresponding areas of life sciences, invited as independent readers, perform peer reviews. Conference Editors choose readers for peer review. In the case of the manuscript relevance to the conference profile, established rules and requirements, it is accepted by the editorial board and is sent for the reviewing. Otherwise the article is rejected without further reviewing. Reviewers prepare reviews of articles on a voluntary basis. Reviewers should submit their reviews in a scanned form. The reviewer makes a conclusion about the possibility of publishing an article:

• "recommended for publication"

• "recommended taking into account the correction of the comments made by the reviewer"

• "article must be sent for revision"

• "not recommended for publication".

The articles are reviewed and accepted only after at least two positive reviews of three reviewers. After making a decision by the editorial board of the conference to admit the article for publication, the author is informed about it.

• Contact person for queries:

Name: Sergey Klyuev

Affiliation: Candidate of Engineering Sciences (PhD), Associate Professor, Belgorod State

Technological University named after V.G. Shukhov

Email: Klyuyev@yandex.ru

To assess the impact on human health of the sonic boom that occurs when an aircraft is flying at supersonic speed, and, accordingly, to solve the problem of noise reduction by optimizing the aircraft design, it is proposed to evaluate the shock wave energy using the TNT equivalent of a cylindrical explosion. An example of calculating the shock wave energy during flights of F4 and F18 aircraft at different altitudes is considered. To calculate the evolution of an acoustic pulse during its propagation from the boundary of the shock wave transition to the acoustic one, the wave equation and its solution are used, taking into account the inhomogenei-ty of the atmosphere, nonlinear effects, absorption and expansion of the wave front, as well as the results of ground-based measurements of acoustic pulses. The results of calculations of the dependence of the explosion energy on the flight altitude, as well as on the type of aircraft are explained on the basis of the formula for the atmospheric resistance force.

Industrial wastes are widely involved in the building ceramic production. Sewage sludge ashes are promising secondary sources for building ceramics production. However, sewage sludge ash application for building ceramic materials production is limited by unsatisfactory molding properties. According to modern concepts, coagulation structure formation processes can be controlled by adjusting ceramic mass compositions by highly dispersed modifying additives. In this study, the drinking water treatment sludge filtrate generated in pumping and filtering stations was used as a highly dispersed additive. The purpose of study was to assess the drinking water treatment sludge filtrate effect on rheological properties of ash-clay molding mixtures.

Using the photo sedimentation analysis, X-ray phase analysis, calorimeter method and parallel-shifting plate plastometry the drinking water treatment sludge filtrate additive effect on rheological properties of ash-clay mixtures was established.

It was found that ash-clay mixture modification with the drinking water treatment sludge filtrate promotes a slow elastic deformations percentage increase from 3-17% to 7-34%. Apparently, this is due to the drinking water treatment sludge filtrate highly dispersed particles adsorption on coarse ash and clay particles that promotes the growth of their hydrophilic properties. Ash-clay mixtures molding properties improvement makes it possible to increase the ceramic blanks density.

Information on the effect of thermal activation of silicate and aluminosilicate rocks used as a filler in dry building mixtures on their reactivity of interaction with lime binder is presented. The change in the distribution of acidic Bronsted and Lewis centers on the filler surface as a result of thermal activation is shown. It was found that the number of Bronsted and Lewis acid centers on the surface of fired clays exceeds the number of the same centers on the surface of unbaked clays. The number of adsorption centers at pKa from 0 to 7 and pKa> 13 on the surface of fired diatomite is 2.435 * 10-5 mol/g, and on the surface of unbaked diatomite -1.678 * 10⁻⁵ mol/g. The heat treatment of diatomite at low temperatures (200⁰C and 300⁰C) does not significantly affect the values of the compressive strength of the mortar. An increase in the firing temperature to 7000C leads to an increase in strength characteristics up to R = 4.38 MPa. However, the greatest effect is achieved when diatomite is fired at a temperature of t = 900⁰C. The value of the ultimate strength in compression was R = 5.1 MPa.

Based on the knowledge that exists today, it is generally accepted that there are basic parameters and characteristics to obtain effective mixtures for their use in 3D printing. Rheological behavior and setting time (initial and final) are those characteristics that determine workability, as well as the speed and nature of hardening of the molded pastes and, as a result, the final framework and the integrity of the resulted structure. Among the promising options for 3D printing, the literature often contains information on alkali-activated binders. In this work, an alkali-activated binding system based on electrometallurgical slag, as well as citrogypsum, a waste of the industrial production of citric acid, was studied. Some rheological characteristics of experimental binders were considered: the nature of the mixture flow under the action of torsional loads and their initial and final setting times. It was found that the joined use of both components in the experimental system "slag - water": an alkaline activator and citrogypsum, promotes the transition of the character of the system from thixotropic to mixed: dilatant-thixotropic (for the Na₂SiO₃ activator) and dilatant (for the NaOH activator). It was found that the addition of alkaline activators and citrogypsum to the binding system separately in both cases helps to reduce the initial and final setting times from 18 and 22 hours to 1 hour and 1.5 hours. Also, experimental results have shown that the jointed action of both components: an alkaline activator and cytogypsum, has a synergistic effect on the setting time.

In this work, the study of integral and differential strength and deformation characteristics of centrifuged and vibrating centrifuged concrete on activated Portland cement was carried out. Mechanical activation of cement was carried out using a specialized grinding unit. Manufacturing of centrifuged and vibrating centrifuged samples was carried out on an experimental laboratory centrifuge. All samples were made of concrete of the same composition. The optimum values of technological parameters of centrifugation and vibrating centrifugation are given. The scheme of obtaining small-size specimens from a common annular section to determine the strength and strain characteristics was developed. According to the results of the study it was found that the improvement of integral and differential strength and strain characteristics when using activated Portland cement is observed for both centrifuged and vibrating centrifuged specimens. However, the samples made by vibrating centrifugation technology have better strength and strain characteristics than the samples made by centrifugation. According to the results of the study, it was found that the activation of Portland cement at its rational values is the best way to enhance variatropy.

A unified methodology for assessing the ability of a material to heal itself does not exist at present. It is due to the absence of criteria characterizing the ability of a material to independently respond to conditions in a controlled manner and to take measures to eliminate an adverse effect on the properties or structure of the material. Usually, the self-healing ability is assessed using the coefficient of relative change of a measured indicator (for example, strength), which does not allow for two parameters: residual strength, which depends on the number of not broken bonds after the test, and the binder's own potential for recovery. The paper proposes a method for calculating the healing efficiency, taking into account the relative difference in the loss of strength, material with the use of an encapsulated modifier and without it. The proposed recovery factor reflects the effect of the encapsulated modifier on the change in the strength of the composite under study; therefore, to assess the efficiency of a self-healing material, it is also necessary to take into account the properties in the initial period of time and their stability under operating conditions. The problem of choosing the optimal indicator of material properties for assessing the recovery effect and improving the calculation method taking into account the duration of the recovery period is not solved and requires additional large-scale studies.

Nowadays, the researchers of materials sciences area, use direct and indirect methods such as microscopy, porosimetry, etc. for studying structural characteristics of materials. X-ray computed tomography is among one of the modern and widely used research analytical methods that provides 3D images of solid materials without any preliminary preparation, such as crashing of sample, and violation of its structural integrity. To demonstrate the potential possibilities of X-ray computed tomography, in this research matrices with cellular structure using portland cement-based cellular concrete was studied as an example. The study showed that the pore structure of cellular concrete is dominated by capillary pores with a diameter of up to 200 um. The majority of pores did not exceed 1.6 mm in diameter, that formed during the foaming process. The calculated average size of the volumetric distribution of air voids was 0.95 mm. About 80% of large pores of a cellular concrete specimen with an average size of about 1 mm determines high porosity of the composite which is consistent with its average density values. The study of interpore structure partition using X-ray computed tomography allows for evaluation the difference in thickness from 10 um to 0.6 mm in the zones of "confluence" of large pores. The porosity of cement matrix, including individual pores with sizes from -30 to 250 um, was about 16.5%. The cement matrix is dominated by the products of cement hydration with capillary and "gel" pores. There are few nonreacted cement particles that are evenly distributed throughout the volume of the composite. To obtain more complete information about the structure of cellular concrete or any other composite, it is necessary to perform complex studies applying not only X-ray computer tomography technique, also scanning electron microscopy for evaluation of chemical analysis to identify mineral phases present and correlate them with absorption intensity of X-ray radiation on tomographic images.

Poly (diethylene glycol adipate) is an important product of chemical technology. Several grades of polyesters (P-9, P-9A) are produced in the industry, in which poly(diethylene glycol adipate) is the main component. These composites are used in production of binders of mixed rocket solid fuels, as well as consumer goods. Poly(diethylene glycol adipate) is obtained by polycondensation of diethylene glycol and adipic acid. Usually, the polycondensation is carried out using catalysts. The use of catalysts complicates this process: requires further purification process or in solvent free system might slow reaction rate due to the limiting diffusion between reactants and mass transfer limitations. Therefore, it was proposed to use low-intensity ultrasound, which allows to influence the kinetics of the process without complicating the system. In this work, the reaction of polycondensation of diethylene glycol and adipic acid in low-intensity ultrasound was studied. The results of applying low-intensity ultrasound to the preparation of poly(diethylene glycol adipate) showed an increase in the reaction rate of the formation of a high-molecular compound and a change in the thermal regime. Application of low-intensity ultrasound provides synchronization of vibration and rotation of self-organizing dissipative structures, which leads to the decrease in energy consumption for mass transfer, thereby increasing the reaction rate. The low-intensity ultrasound demonstrated to be an effective method to intensify the polycondensation reaction.

Annually enterprises in the field of manufacturing of products from aerated concrete generate from 5000 to 10000 m³ of solid production waste. One of the perspective and under-investigated direction is the practical application of solid waste using a porous aggregate in structural-heat-insulating lightweight concrete in the production of construction materials. The aim of this study was to evaluate the possibility of using crushed aerated concrete as a large aggregate in lightweight concrete for structural and thermal insulation purposes and to establish optimal conditions for obtaining products with the best characteristics. There were defined the qualitative indicators of crushed aerated concrete, analyzed factors influencing on the preservation of the properties of concrete in time, selected the composition of concrete aggregates from crushed concrete, studied the structure and properties of the obtained samples in the research. It has been found that to obtain effective constructive insulating lightweight concrete using waste production of aerated concrete as an aggregate is possible due to the fractionated pre-treatment of the aggregate with water dispersion of deep-penetration acrylic copolymers, insertion excess sealing water to concrete mixture, including optimization of the rheological properties of the concrete mix due to insertion of polycarboxylate hyperplasticizer.

The ZrB₂-45MoSi₂-10Al coating was prepared by a Robotic complex for detonation spraying of coatings equipped with a multi-chamber detonation accelerator on surface of carbon/carbon composites without adhesion sublayer. The coating has a lamella-type structure typical for gas-thermal coatings, well connected with C/C composite substrate without sublayer, and composed of m-ZrO₂, t-ZrO₂, t-MoSi₂, some h-ZrB₂, and c-Al phases. Heat treatment of the samples at 1500 °C for 1, 3 and 6 h was carried out in air. The effect of heat treatment on the microstructure and phase composition of the ZrB₂-45MoSi₂-10Al coating was investigated by X-ray diffraction and scanning electron microscopy. The c-ZrO₂ and h-(α-Al₂O₃) were formed after oxidation at 1500 °C for 6 h. The uniform distribution of ZrO₂ ceramic particles and the formation of a-Al₂O₃ enhanced the thermal stability of the coating. The coating after heat treatment (1, 3 and 6 h) exhibited structure without cracks and low porosity. The dense microstructure of the coating contributed to its good oxidation-resistant property at high temperature.

Verification of validity of different manifolds of chemical reactions and coefficients in Arrhenius formulae was made for numerical simulation of deflagration appearing in hydrogen-air gas mixes. Kinetic model of branching chain reaction was tested for initial stage of detonation of this kind of mixes. One dimensional numerical simulations of deflagration initiation where provided for small closed heat isolated region. The next problem was solved numerically:in small closed volume, initially filled by hydrogen-air mix with atmospheric meanings of gas dynamics parameters at moment t=0 temperature rising till meaning, at which reaction of deflagration should begin. Numerical experiment consist of calculation of thermodynamics parameters of gas mix in small isolated volume. Meanings of molar concentration of components of gas mix where calculated by implicit numerical method of Gir for numerical decision. Calculation where provided till zero concentration of hydrogen or not appearing of deflagration at all. Characteristic feature of hydrogen-air gas mix deflagration is appearance of sudden explosion after long period of induction. In this induction period grows of radicals H, O and OH appears. Mass of radicals, nevertheless stay small, and one radical component transverse to the others. This explosion mechanism is branching chain reaction introduced by N.N.Semenov. In agreement with branching chain reaction theory during process of branching chain reaction radicals H, O, OH many times initiates reaction with other components of the mix. Nevertheless mass of radical components preserve small during the reaction, them almost fully disappeared in every time of the process. That's why method of "quasi - stationary concentration" is treated to components O, OH (velocity of changing of this components concentration is equal to zero). For concentration of component H one simplified differential equation is treated. Speed of changing H essentially grater then speed of changing "slow" components H₂, O₂, H₂O, that's why equation for H should be solved separately. Algorithm was developed for numerical simulation of hydrogen-air mixes on the basis of theory branching chain reactions. Calculations provided demonstrate applicability of developed algorithm for numerical simulations of initial stage of deflagration of hydrogen-air mixes.

The paper presents the results of experimental studies of solid particle erosion resistance of 20GL structural steel samples with two different variants of surface modification based on the boriding process. Characteristics of modified layers such as depth, composition, microhardness were determined. Tests were carried out according to ASTM G76-13 standard at air-abrasive flow rate of 170 m/s, flow attack angles of 30º and 90°, sample surface temperature of 25ºC. It was found that both considered options of surface modification at an angle of attack of 90 ° flow do not worsen the abrasion resistance of 20GL steel samples, and at flow attack angle of 30 ° increase not less than 8 times. A change in the wear pattern of boriding samples with an increase in the angle of attack from 30° to 90° is noted. As after the boriding process surface embrittlement was observed, the angle of maximum wear for 20GL steel with boriding became equal to 90° in contrast to steel without treatment, where the maximum level of wear is observed at 30°. Thus, the change of fracture type from plastic to brittle was revealed, which should be taken into account in full-scale operation of the treated parts. The obtained results indicate that the process of boriding of pump parts made of 20GL steel will increase their solid particle erosion resistance and extend their overhaul period.

The results of high-temperature tribological tests of carbon-containing material in friction on heat-resistant stainless steel 40X13 in the temperature range from 20 to 700 °C under atmospheric conditions are presented. Friction surface modifiers "Argolon-2D" material improve antifriction properties and decrease friction coefficient value. Friction coefficient when using Ni-Se-PTFE modifier at load of 0.67 MPa and speed of 0.16 m/s is less by 5% than at speed of 0.05 m/s, and at speed of 0.25 m/s friction coefficient is less by 13% than at speed of 0.05 m/s. At 500 °C and a load of 0.67 MPa the friction coefficient when using Ni-Se-PTFE modifier is 30% higher than when using InSb-PTFE modifier, and the friction coefficient when using CuO-PTFE modifier is 1.2 times higher than when using InSb-PTFE modifier.

Today, modification of metal surfaces using laser radiation (laser ablation) is one of the most common processing methods in various scientific studies. At the same time, there is no unified approach to estimating the energy of laser radiation impact on the metal surface, which significantly complicates the comparison of the results of studies performed at different parameters of laser radiation. In the present work, a universal method of calculating the energy density of laser radiation impact on the surface is presented. The formation of relief with identical geometric characteristics at different parameters of laser radiation, but with the same energy density of radiation effect on the surface being modified, was experimentally confirmed.

The effect of electron radiation on the physical and mechanical properties of Sontara nonwoven fabric produced using spunlace technology has been studied. The initial raw material for the manufacture of materials using this technology, as a rule, are viscose, polyester, polypropylene and cellulose fibers. Such nonwovens are highly breathable and are therefore used in disposable surgical gowns and suits. Since radiation can be used to sterilize disposable surgical gowns, it is important to assess the resistance to ionizing radiation. It was found that the Sontara brand material is resistant to the effects of ionizing radiation - the physical and mechanical characteristics of the material (breaking load and relative elongation) in the longitudinal and transverse directions of the web do not significantly change when irradiated with absorbed doses up to 60 kGy. It should also be noted that a cloth with a basis weight of 68 g/m² has a significant smell of strength after radiation sterilization.

In this article, new composite coatings ZrB₂-35MoSi₂-15Al were deposited on the surface of a carbon-carbon composite using a multi-chamber detonation accelerator. The evolution of the phase composition of ZrB₂-35MoSi₂-15Al coatings was analyzed with differential scanning calorimeter (DSC) and X-ray diffractometry (in situ HT-XRD) at temperatures from room temperature (∼ 25°C) to 1400°C (normal atmosphere and pressure). The coating before annealing according to X-ray diffractometry data is tetragonal (t-ZrO₂) and monocline (m-ZrO₂) zirconium dioxide, monocline silicon oxide (m-SiO₂), hexagonal zirconium diboride (h-ZrB₂), tetragonal molybdenum disilicide (t-MoSi₂), cubic aluminum (c-Al) and cubic yttrium oxide (c-Y₂O₃). It was found that the coating crystallizes in m-ZrO₂ at 460ºC, and then mullite with rhombic crystal lattice appears at 960ºC. When the temperature reaches 1050ºC the m-ZrO₂, ZrSiO₄, t-ZrO₂, m-SiO₂ and mullite phases formed in the coating. At 1400 º C, cubic zirconium dioxide appears in the coating. Experimental results can become the basis for the application of ceramic coating ZrB₂-35MoSi₂-15Al, which can improve the properties of carbon-carbon composites in an oxygen-containing environment at elevated temperatures.

In the difficult conditions of modern construction, the use of concretes with a combined aggregate, if the composition is rational and the formulation and technological factors act rationally, will allow solving many existing problems. In this paper, studies were carried out on the choice of a rational formulation of lightened concrete based on foamed slag, natural crushed stone and granulated blast furnace slag by varying the volume content of a porous coarse aggregate and a fine aggregate in relation to the volume of the mixture. In total, 9 series of prototypes and 1 series of control samples were manufactured and tested. One series of samples includes three cubes with dimensions of 10x10x10 cm. All samples are tested for density, compressive strength and the coefficient of constructional quality. According to the results of the study, it was concluded that the introduction of foamed slag into the composition of heavy concrete instead of a part of a dense coarse aggregate and the replacement of a fine dense aggregate with granulated blast furnace slag leads to an increase in the coefficient of constructional quality, that is, the decrease in compressive strength of concrete is compensated by an even more significant decrease in the density of the material, and therefore a decrease in mass. The increase in the coefficient of constructional quality of concrete based on foamed slag, natural crushed stone and granulated blast furnace slag in comparison with the control composition was 14%.

Analysis of various studies has shown that one of the most promising ways to reduce hydraulic resistance in pipelines during transportation of liquid fluid is a method based on changing the wettability of functional surfaces, i.e. hydrophobization. This paper presents the results of experimental studies of the effect of hydrophobization of pipe surfaces on hydraulic losses. For this purpose, experimental tube samples of steel (20Kh13) were made, on the surface of which a spiral relief was formed using laser equipment, resulting in a hydrophobic state, and the value of the contact angle was 160.7°. From the analysis of the results of experimental studies, the dependence of hydraulic resistance on Reynolds number was obtained, from which it follows that the use of hydrophobic surfaces during water transportation helps to reduce the hydraulic resistance to 9.7%.

The percentage of wooden buildings damaged or even lost due to the lack or insufficient technical measures for their preservation is growing every year. This fact makes it mandatory to treat the surface of wood building materials with protective and decorative agents. Within the framework of this study, a multifunctional protective composition for wood was developed that can increase its physical and mechanical properties. Modification of the wood surface with organomineral compositions leads to an increase in its density, hardness and strength. The hardness of the treated wood is 24% higher and the compressive strength along the fiber is 20% higher than that of untreated wood. After treatment, the surface of the wood darkened and slightly yellowed, which does not prevent its use in the construction and reconstruction of buildings. The results of measuring the color coordinates of the surface of the modified samples indicate the stability and durability of the developed protective coating even after 4 months of exposure to atmospheric conditions. Judging by the slight return of the color coordinates of the treated wood back to values of the original wood, it can be concluded that the composition is partially washed out.

The article discusses a promising conductive composite material such as carbon-plastic. This material has significant strength, not inferior to metal, has a low specific weight and has interesting electrophysical characteristics. For a wider use of the material in various structural products, it is necessary to consider its unique characteristics. The work is devoted to the study of the conductive properties of carbon fiber under the influence of lightning currents and the development of criteria for its destruction. Based on two models of destruction of CFRP by lightning currents, a theoretical analysis of its destruction has been carried out. The first model considered the composite material as a continuous medium with anisotropic-conducting properties. The solution of the Laplace equation with the Neumann boundary conditions made it possible to find the distribution of current densities over the material and theoretically determine the radius and depth of damage. The second model, the layered structure model, took into account the structure of real CFRP. The dynamics of layer-by-layer destruction is considered on the basis of the equivalent circuit of carbon fiber reinforced plastic, which takes into account the longitudinal and transverse resistivity of the composite. The distributions of the radial current density along the radius and depth of the material are constructed and the analysis of the spreading of currents at various degrees of material anisotropy is carried out. Strong anisotropy, leading to the release of total energy in the first layer. Destruction of the upper layer changes the distribution of currents in the rest of the layers. The results of numerical modeling of layer-by-layer destruction of CFRP for five layers are presented. The process of destruction under the action of large current pulses is considered. The fracture criteria for various degrees of material anisotropy are obtained and refined. The resulting formulas contain values that are reproduced in the experiment. The calculation results are in good agreement with experiment. In conclusion, it is concluded that the criteria are applied to predict the effects of lightning and optimize lightning protection at the design stage of an aircraft.

This paper presents data on obtaining a composite coating by radio frequency (RF) magnetron sputtering of a Ni-Cr-B₄C composite target in an inert gas (argon) environment. To make the target, Ni-Cr-B₄C composite powder was applied to the copper base of the target by detonation gas-thermal spraying. The obtained targets served as a source of coating material during high-frequency magnetron sputtering. This method of coating production ensures the reproducibility of their properties, as well as the uniformity of coating thickness and good adhesion to various target backings.

The data of the study of the structure and morphology of the composite coating are presented. The resulting composite coating Ni-B/Cr₇C₃ with a thickness of 2 microns has a dense homogeneous structure with expressed textured polycrystallinity. The surface of the resulting coating is represented by nanoscale and homogeneous grains. There is no columnar crystal growth in the coating, which has a positive effect, as the columnar structure reduces the mechanical characteristics of the coatings due to faster oxygen diffusion along the grain boundaries. It is established that the combined use of the Ni-B and Cr₇C₃ binary phases in composite coatings leads to an increase in operational properties.

Information on the effect of a polysilicate solution obtained by mixing liquid glass with a silicic acid sol on the structure formation of lime compositions is presented. It was revealed that the amount of specific heat released when lime is wetted with a polysilicate solution is greater than when lime is wetted with water. This is due to the additionally released heat due to the chemical interaction of lime with polysilicate solution. It was found that the introduction of a polysilicate solution accelerates the development of plastic strength. For comparison, we used liquid glass and a sol of silicic acid as an additive. The synergistic effect of the influence of the polysilicate solution on the structure formation of lime finishing compositions was established, which manifests itself in the acceleration of the set plastic strength in comparison with silica sol and water glass. It has been established that the introduction of a polysilicate solution into the lime mixture formulation contributes to an increase in the resistance to slipping of the finishing layer. The optimal thickness of the finishing layer was determined, which is 20 mm, at which sliding from the vertical surface is not observed.

Increasing the volume of road construction is one of the priority areas of infrastructure development in any country. When building roads, it is preferable to use local materials to reduce the cost of their transportation, therefore, it is advisable to build the roadbed on local soils. It is worth noting that clay water-saturated soils are the most common, which complicates the construction of the road due to some features of this type of soil. The object of the study is a water-saturated clay with the following characteristics: natural humidity from 25.3 % to 28.1% by weight, optimal humidity from 11.8 % to 16.7% by weight, the number of plasticity from 0.118 to 0.153. Clay soils have a number of features: waterlogged soils are difficult to compact and develop, it is quite problematic to dry them, and thixotropy is also characteristic of clay soils. In this regard, it is most advisable to use the method of complex mineral binders to optimize their physical and mechanical properties. In the course of laboratory studies, compositions of soil compositions with the addition of lime waste and superplasticizer P-17 were developed. The dependence of the strength on the consumption of mineral binders and surfactants is established: the maximum compressive strength of the soil being fixed is achieved at a lime content of 25 wt.% and at a P-17 content in the range of 0.10-0.5 wt.%.

At the moment, there is a wide range of bulky nonwovens for various purposes on the market. One of the important areas of using such materials is healthcare. In particular, bulky nonwoven materials are intended for the manufacture of wound dressings, evacuation kits for newborns. Disposable medical devices of this kind are usually subjected to radiation sterilization. As is known from earlier studies, radiation sterilization significantly affects the performance of nonwovens. In this regard, for nonwoven materials for medical use, an important characteristic is the stability of indicators after exposure to radiation sterilization. As a result of the study of bulk nonwovens Holofiber ® after radiation radiation in the dose range from 20-60 kGy, there were no significant changes in operational performance. The stiffness increased by an average of 3-10%. The stiffness indicators after ionizing radiation according to GOST 24684 also meet the requirements. The value of electrification increased due to an increase in the static field under the action of ionizing radiation. It is worth noting that the values of electrification are within the norm established by GOST 32995. The breaking load varies from 1-5%. Thus, non-woven materials Holofiber ® PROFI, article P 35191, Holofiber ® SOFT, article P 5197, Holofiber ® SOFT, article P 5200 are recommended for the production of medical devices.

Titanium oxide coatings were obtained by magnetron sputtering on a glass substrate with different oxygen fraction in the plasma. Studies were carried out by scanning electron microscopy of the obtained coating samples establishing the role of oxygen in the process of crystallization of TiO_x-coatings. It was found that with increasing the oxygen fraction in the vacuum arc discharge plasma the crystal grain size increases, the time of coating on the substrate increases, and the crystal layer has a columnar structure. The presence of amorphous and crystalline phase for all coating samples was revealed, with the predominance of the former. On the surface microphotographs of the coatings microcraters were found, on the surface of the samples obtained at the concentration of O₂ in the plasma 14% of their concentration is maximum, this can be explained by changes in the state of the plasma, starting to occur at this concentration of reaction gas. Vacuum photonic annealing of the obtained coatings was performed. Vacuum radiation annealing in the furnace led to modification of coatings: sintering of coatings, increase of their crystallinity. An increase in crystallite size in a sample with an oxygen fraction of 12% was detected.

This article studies the corrosion behavior of the TiNi alloy in the coarse-grained and ultrafine-grained states. The study of the influence of the initial microstructure on the corrosion behavior of the TiNi alloy was carried out by the gravimetric method in the NaCl and H₂SO₄ solution for a month. Studies was shown that as a result of the action of a corrosive medium from a sample in a coarse-grained state, it undergoes greater destruction, pitting corrosion was observed, at the same time, in an ultrafine-grained sample only traces of corrosion products are observed on the surface of the samples. Investigations with an inverted light microscope in a dark field made it possible to observe corrosion products and determine their volume fraction. Evaluation of the corrosion rate showed that in the coarse-grained state it is 126 times higher than the corrosion rate in the ultrafine-grained state. Analysis of X-ray phase analysis showed that in the coarse-grained state after corrosion tests, a significant proportion of the TiNiH_1.4 phase is observed, while in the ultrafine-grained state all phases correspond only to the TiNi phases. The TiNi alloy contains an Ti₂Ni phase enriched Ti both in the coarse-grained state and in the ultrafine-grained state. Moreover, in a coarse-grained state, its share is 2 times higher.

The analysis of data obtained under studying scientific, technical and normative literature in the area of applying efficient concretes, in particular, fiber-reinforced concrete, in the world and national tunnel construction is presented herein. The European regulatory documents, standard metrologically certified methods and procedures for analyzing and testing, laboratory test equipment and measuring instruments are indicated. Steel fiber concrete studies was explored at the Scientific and Educational Center for Innovative Technologies of the Architectural and Construction Institute of the Ufa State Petroleum Technical University. Prism bending tests were made with different fiber content. In addition to laboratory tests, other tests were made in accordance with the Russian standards, where the prisms are tested without a notch. The correlation between the slope of the load-to-displacement curve of the crack mouth (CMOD - Crack Mouth Opening Displacement) and the length of the crack was used in the course of the study. The fiber content enabling to get an average residual bending strength of at least 1.5 MPa at 0.5 CMOD (equivalent to 0.47 mm center deviation) and an average residual bending strength of at least 1 MPa at 3.5 mm CMOD (equivalent to 3.02 mm of center deviation) is found. Statistical distributions of the Grubbs tests are analyzed by methods of statistical modeling. The regulatory framework for fiber concrete is not currently well developed in the Russian Federation, thereby reducing greatly the application of new generation concretes meeting the current knowledge. The application of fiber concrete in tunnel construction will prove to be economically justified and the areas of applying effective materials are to be developed in future with the wide participation of scientific, design, production, construction and other specialized organizations, as well as educational and training centers.

The paper presents data on the synthesis of phloroglucinol-furfural modifier (1,3,5-trihydroxybenzene-2-furaldehyde oligomer) based on 2-furaldehyde (furfural) and 1,3,5-trihydroxybenzene (phloroglucinol). The synthesis of a modifier with different molar ratios of phloroglucinol/furfural was carried out. It was found that an increase in the molar ratio leads to an increase in the plasticizing ability of the modifier. The optimal concentration of the catalyst was determined to be equal to 50% by weight of phloroglucinol. Two chemical forms of the modifier were obtained: H-form and Na-form. The structure of various forms of the modifier has been studied by scanning electron microscopy. It was found that the oligomers used in the work for the synthesis of the modifier, in addition to 2-furyl methyl alcohol, do not have plasticizing properties. Purified 2-furyl methyl alcohol has weak plasticizing properties. It is shown that to achieve the best plasticizing effect, it is necessary to gradually introduce a condensing agent into the reaction mixture. With gradual introduction, a complete condensation reaction occurs between the monomers, which affects the improvement of the plasticizing properties of the resulting product. The spread of the cement mixture when using 0.3% of the additive based on the mass of cement in terms of dry matter is 19 cm.