Introduction. Presents a method for modeling a two-dimensional stationary temperature field in a layered rod. The peculiarity of the structure of the rod is the presence of discontinuity of the width of the cross section in the direction of heat flow and multilayer. Identification of the temperature field in such rods is a necessary step in solving the problem of thermoelasticity. The relevance of the problem lies in the development of analytical methods for analysis layered rods of complex geometric shape with thermal effects, with acceptable computational complexity and necessary accuracy. Materials and methods. For a multilayer rod, a method for constructing an approximate solution of the Dirichlet stationary heat conduction problem with a transverse heat flow direction is considered. Within each layer, the temperature distribution function is represented as a sum of two functions. The first function, linear in the direction of the heat flow, reflects the exact solution of the problem for a rectangular layered section. The second function is the correction nonlinear function of two variables. It describes the nonlinear distortions of the temperature field due to the presence of discontinuities in the width of the cross section. The correction function, according to the Fourier method, is represented as a product of a given coordinate function and the sum of the sought amplitudes caused by the width breaks. The functions of the effect of breaking the width on temperature fields in adjacent layers are introduced. An approximate formulation of the Dirichlet problem with integral conjugation conditions on interlayer boundaries is formulated. Results. The parameters of the stationary temperature field were calculated for a seven-layer section of a T-shaped form with alternating layers of carbon and steel. Testing the results of the Ansys program showed good qualitative and quantitative correspondence of two-dimensional temperature fields. Conclusions. The obtained solution satisfactorily describes the temperature field in the cross section of a layered rod in the vicinity of its geometric features. The method is characterized by acceptable laboriousness and accuracy suitable for solving the problem of thermoelasticity of a layered rod.

Introduction. Conducted is to the evaluation of the stress-strain state of the steel-concrete beams with thin-walled section. In recent times, steel-reinforced concrete structures have become widely used in civilian buildings (beams, slabs, columns). Thin-walled section have not found wide application in steel concrete structures, unlike steel structures. Presents the results of numerical studies of beams consisting of concrete, anchors and steel beams. Two investigating of the location of anchors are given. Numerical investigations are presented of steel-concrete beams with thin-walled section based on numerical studies. Testing procedure and test result are given. Results of calculations, comparison of numerical and experimental studies are presented. Materials and methods. For full-scale experiments, steel I-beams with filling of side cavities with concrete were adopted, screws are used as anchor ties, with varied both the lengths and their location (vertically and obliquely). As steel curved C-shaped steel profiles were used steel profiles from the range of the company “Steel Faces”. ANSYS software package was used for computer modeling. A total of 16 steel concrete beams were considered, for which the results of strength and stiffness evaluation were obtained in ANSYS. Results. The data of the stress-strain state of beams on the basis of computer simulation are obtained. The results are used for the production of field samples. Data of computer simulation are compared with the indicators of field experiments. Conclusions. The stress-strain state of steel-concrete structures was studied on the basis of numerical and experimental data. The proposed calculation method gives good convergence with the experimental data. Anchor connections made from self-tapping screws can be used in studies for modeling in steel-concrete beams structures and other anchor devices, ensuring the joint operation of concrete and steel profiles in structures.

Introduction. Researched methods of accounting for the nonlinear operation of reinforced concrete structures on the example of an industrial structure, when exposed to an air shock wave using modern software systems based on the finite element method. The calculation of reinforced concrete construction to the impact of an air shock wave, if no increased requirements for tightness are presented to it, in accordance with current regulatory documents, must be carried out taking into account the elastic-plastic work, crack opening in the stretched zone of concrete and plastic deformations of reinforcement are allowed. Reviewed by new coupling approach to determining the dynamic loads of a shock wave, implemented in the LS-DYNA software package, which allows to take into account the effects of a long-range explosion and wave-wrapping around a structure. Materials and methods. The study of the stress-strain state of the structures was carried out using numerical simulation. For the nonlinear equivalent-static method, a step-by-step calculation algorithm is used, with gradual accumulation and distribution of stresses, implemented in the LIRA-SAPR software package. For the nonlinear dynamic method, the Lagrangian-Eulerian formulation is used using the methods of gas dynamics in the LS-DYNA software package. Results. As a result of numerical simulation, the following was done analysis of existing methods of nonlinear calculations; analysis of the existing loads during the flow of shock waves around the structure; analysis of the forces and movements in the bearing elements, as well as pictures of the destruction of concrete and reinforcement. Conclusions. According to the results of the comparison of the two approaches, conclusions are drawn about the advantages and disadvantages of the methods. Advantages of nonlinear dynamic calculation methods are noted compared to the equivalent-static ones. Use of the combined approach to the description of the shock wave front gives a reduction in time and allows us to describe the interaction of the wave with the structure with sufficient accuracy. The findings indicate the relevance of the study and provide an opportunity to move to more reasonable computational models.

Introduction. The approach to the creation and development of the system of separate collection and pre-treatment of municipal solid waste (MSW) and bulky waste. At present, Russia is lagging behind in the level of waste disposal, the expedient use of secondary resources. One of the main reasons is the lack of a cost-effective system for managing waste and secondary resources. Despite the deteriorating environmental situation, the closure of landfills for municipal solid waste, the growth of unauthorized landfills, there has been a trend of growth in tariffs for removal and disposal of municipal solid waste (MSW) and bulky waste affecting the entire population of Russia. This problem determines the need to find new scientific and methodological approaches and practical solutions for planning not only the placement of industrial waste disposal infrastructure, but also creating a system for separate collection and pretreatment of MSW and bulky waste in the sources of their formation, justification and optimization of the standards for the accumulation of this waste for citizens. Materials and methods. Materials for conducting a scientific research are: legal acts, standards, guidelines and recommendations, regulatory and technical documentation in the field of waste management, published materials of domestic and foreign scientific research. The methods of scientific research are based on the use of factor, comparative, expert types of analysis. Results. Optimization of the system for calculating the standard of accumulation of MSW and bulky waste is proposed; reducing the financial burden on citizens in terms of tariffs for garbage collection; economic incentives for the population to separate the collection of MSW with the pretreatment of the components of this waste to the level of demanded secondary resources. Conclusions. The introduction of the proposed system will allow achieving socio-economic, environmental, natural resource, political effect, consolidating the society to solve the problem of resource conservation, the use of secondary resources.

Introduction. Analyzes innovative methods of cost accounting for their use in a construction organization. The main stages and stages of construction activity are described, their comparison is made, problematic issues are identified, for the solution of which it is necessary to apply the data that is formed in the enterprise accounting system. The characteristics of the creation of a management accounting system, which involves the integration and linkage of various innovative concepts for cost management, including calculations on the full life cycle of the company’s products, are given. Analytical tools are considered and variational models of organization of management accounting are recommended, ensuring the adoption of effective management decisions of the construction company. The subject of the study is one of the main management functions - information and analytical support of the organization for making assessment, operational and strategic management decisions based on the use of effective information created in the management accounting system of the construction company. Purpose of the study - was to assess the feasibility of applying innovative management accounting methods in the construction sector, to study the changes in the work of the respective companies caused by them, to optimize cost management for all stages of the life cycle of the products produced. Materials and methods. Dialectical method as a general approach to the scientific knowledge of the subject under investigation acts as a methodological basis. Scientific apparatus of management accounting was used, as well as standard methods for evaluating and analyzing various data (grouping, methods of system analysis, comparisons, index). Results. The rationale for the use of management accounting methods to maximize the effective management of costs at different stages of the life cycle of construction products, which will achieve the highest results. Conclusions. The issues discussed in this paper can be used as recommended methodological approaches for applying innovative methods of management accounting that will improve the management of costs of construction companies.

Introduction. Researched is conducted to determine the possibility of using an alternative method - laser cleaning. Laser systems have proven themselves in many areas and are a high-tech and effective solution for many construction problems. Despite this nowadays sandblasting is the most common method of processing contact surfaces of high-strength bolted joints - an outdated technology, with high equipment wear and even dangerous to people’s health. Materials and methods. Sandblast and laser-treated specimens were tested for shear. Before testing, the roughness of the contact surfaces and the tension force of high-strength bolts were tested. During the test, the readings of the meter and dial-indicator were taken. The experiments were carried out on a hydraulic press IPS-500, the samples were provided in a processed form. Results. According to the data obtained, strain graphs were plotted and the shear forces of the samples were calculated. Calculated efforts were compared with standard values. The results show the compliance of samples with the requirements of SP 35.13330.2016 “Bridges and pipes” in terms of strength characteristics. Samples with laser surface cleaning have a safety margin value similar to sandblasted samples. Conclusions. Comparison of the strength characteristics proves the possibility of using laser cleaning of the contact surfaces of friction joints. After the transition from outdated technologies, the process of surface preparation can be made economical and environmentally friendly. The obtained values and data can be entered into a number of regulatory documents, including SP 35.13330.2016 “Bridges and pipes” for future research and the widespread application of the method.

ABSTRACT Introduction. The question of a comparative assessment of the quality of images obtained as a result of scanning test composite materials exposed under the cyclic effects of positive and negative temperatures is considered. The samples are sorted relative to the reference numerical metric expressed as a percentage. Materials and methods. The compared composites differ in composition relative to the control sample. Periodic scanning of the tested composites is carried out during several control points of time. A comparative analysis of the image quality of test composites was carried out both during the entire exposure time and at the control points of time. On the basis of the existing algorithm Structural Similarity Index for measuring image quality (SSIM), percentage indicators of sample quality were determined depending on the composition and exposure time. The results obtained allow the selection of composite materials in accordance with the level of structural similarity in structural color characteristics. According to the SSIM algorithm, the resulting metric values are in the range [-1; +1]. Full structural similarity corresponds to a value equal to one. It is proposed to express the SSIM metric as a percentage with the transformation that the change in the color structural difference of the relative control sample can vary from zero to 100 %. Results. For the proposed method of comparing images of scanned samples of composite materials, ten samples of composite materials of different composition were used. Numerical results of the experiment with their graphical visualization give a clear idea of the nature of the change in color characteristics relative to the control sample. Consistent evaluation at the exposure points shows the nature of changes in the properties of materials from the duration of exposure to cyclic changes in positive and negative temperatures. Conclusions. The proposed benchmark image quality assessment based on the existing SSIM algorithm allows you to quickly investigate groups of materials, the change in properties of which is caused by their exposure in adverse operating conditions.

Introduction. The use as a binder in the manufacture of silicate paints polysilicate solutions obtained by mixing liquid glass and silica sol is considered. To regulate the rheological properties of the paint, improve the filling and prevent the pigment part from sagging, it has been proposed to introduce glycerin into the binder composition. The results of studying the interfacial interaction between the paint and the substrate are given. Materials and methods. In developing the formulation of silicate paints based on polysilicate solutions, MK-2 microcalcite, marshalite, diatomite and talc of MT-GSM grade were used as a filler, and titanium dioxide as a pigment. Polysilicate solutions were obtained by reacting stabilized solutions of colloidal silica (sols) with aqueous solutions of alkali silicates (liquid glasses). Nanosil 20 and Nanosil 30 silicic acid sol were used, produced by the Promsteklocentr PC. Used potassium liquid glass with module M = 3.29. A thermodynamic method was used to assess the interfacial interaction. Results. Shown that the introduction of glycerol into the formulation of a sol of silicate paint promotes a decrease in the interfacial surface tension and a better wetting of the surface of the mortar substrate. An increase in wetting coefficient is observed. Coatings based on sol silicate paints with the addition of glycerin are characterized by increased crack resistance. An increase in tensile strength, maximum tensile properties, and decrease in the elastic modulus of paint membranes based on the composition with glycerol has been established. The values of the free surface energy of the coating based on the sol of silicate paint and the ratio of the polar to the dispersion component of the free energy of the surface are given. Coatings based on sol of silicate paint with the addition of glycerin are characterized by a large value of the free energy of the surface. In the process of moistening a decrease in the free surface energy is observed due to a decrease in the dispersion component. Conclusions. Studies have shown that the introduction of an additive of glycerin in the formulation of a silicate paint sol contributes to an increase in the performance properties of coatings based on it.

Introduction. This study focuses on the use of silica fume partially replacing cement with 0, 5, 7.5, 10, 12.5 and 30 % constant replacement of fly ash by weight of cement in concrete. Concrete is probably the most extensively used construction material in the world. But the conventional concrete is losing its uses with time and high-performance concrete (HPC) is taking that place. HPC has superior mechanical properties and durability to normal strength concrete. Because of, the microstructure of HPC is more homogeneous than that of normal concrete (NC) due to the physical and chemical contribution of the mineral admixtures as well as it is less porous due to reduced w/c ratio with the addition of a superplasticizer. The inclusion of additives helped in improving the properties of concrete mixes due to the additional reduction in porosity of cement paste and improving the particle packing in the interfacial transition zone (between cement paste and the aggregates).In this experimental investigation the behavior of HPC with silica fume and fly ash with and without quartz powder were studied. The water-binder ratio was kept 0.3 and 20 % quartz flour as partial replacement of fine aggregate for all cases. Materials and methods. Used materials in Vietnam, as follow, Sulfate-resisting Portland cement - PCSR40 (type V) of company Luks Cement (Vietnam) Limited was used in the work. Crushed granite of fraction 9.5…20 mm - as coarse aggregate, Natural sand from Huong river of 0.15…2.5 mm fraction with the fineness modulus of about 3.0 and quartz powder with an average particle size of 5…10 μm were used as fillers; Sika® Viscocrete®-151 is a superplasticizer based on a blend of 3rd generation PCE polymers was used as a plasticizing admixture. The flg ash from Pha Lai thermal power plant and Sika silica Sikacrete® PP1 (particle size < 0.1 μm) was used as a mineral active admixture. The study of strength and technological properties of high-performance concrete was performed by using standard methods. Results. Established by icate that, the workability and strength increase at a certain level and after that, they decline with further increase in the replacement level of silica fume is 12.5 %, on the basis of 30 % FA replacement, the incorporation of 10 % SF showed equivalent or higher mechanical properties and durability compared to the reference samples. Conclusions. HPC consists of mineral admixtures such as silica fume and fly ash use combine quartz powder and superplasticizer helped in improving the strength and durability of concrete mixes due to the additional reduction in porosity of cement paste and an improved interface between it and the aggregate. With 30 % fly ash is optimum dosage used to replacement of cement, incorporation 10 % SF (by weight) and combine of partial replacement of fine aggregate by 20 % quartz powder. On the other hand, a few mathematical equations can be used to derive the durability properties of concrete based on its compressive strength.

Introduction. Neutralization methods (including composting) are widely used in the technologies of chemical and biothermal oxidation of organic matter. A promising method of waste management is their biothermal composting using controlled gas flows. The methods of process intensification are described: the introduction of inoculating additives, increasing the homogeneity of the mixture, recycling of composts, natural and forced low-pressure and high-pressure aeration, and several others. One example of the implementation of these technologies is the disposal of oil-contaminated soils. Materials and methods. The description of the implemented complexes of biothermal composting of oil-contaminated soils: functional zoning, design solutions. The main functional zones are shown: input control section, intermediate placement area, continuous forced aeration zone (inoculation), periodic forced aeration zone (stacked cavalier biodegradation), and natural aeration zone without mixing (ripening zone). The main element of the complex is the combined aeration system (forced from blower devices and natural mechanical mixing). The expediency of using high-pressure forced aeration to intensify the composting process is shown. Results. The developed mode of operation of the aeration system of the composted mass is described: the initial process of incomplete oxidation of organic matter in stacks of inoculation with a constant air flow and the final decomposition of organic matter with a periodic air flow. The constructive design of the high-pressure forced aeration system used to intensify the composting process is given. Aerobic biothermal composting is performed in aerated piles, which are formed on sites with a waterproof coating. Aeration, necessary to accelerate the decomposition of organic matter in the composts, is carried out in natural (mixing with a ladle) and artificial (purging) conditions. For purging use a system of perforated pipes and blower station. Describes measures to protect pipelines (ducts) from aggressive environmental exposure and increase their service life, to ensure the efficiency of the aeration system in an emergency. Conclusions. The possibility of practical implementation of gas flow control technology in the design, construction and operation of biothermal treatment of waste is shown. The implementation of the projects described in the article showed the need to create a generalized mathematical model that would describe in general terms the behavior of gas flows in heterophase wastes.