The article considers the process of relaxation of fibrous material after the action of the load on it is completed. A simple model of the relaxation process is constructed in the form of an exponential function, which describes this process quite accurately. It is determined that the relaxation time estimates are robust with respect to the parameter distributions. The constructed relaxation models make it possible to estimate the magnitude of the residual relative strain corresponding to the plastic strain of the material.

Keywords: relaxation, deformation, fibrous material, robustness, Monte Carlo method, exponential model, regression

The paper presents the results of a study conducted for chemically and thermally resistant ceramics obtained from low-plastic clay using boric acid as a melt, zirconium oxide and galvanic sludge as functional additives. The studied ceramics were obtained by semi-dry pressing technology at a maximum firing temperature of 1050 оC. The dependences of the physical and mechanical properties of ceramics on the content of zirconium oxide and galvanic sludge in the charge are established. Zirconium oxide promotes liquid-phase sintering, compaction and strength enhancement, and galvanic sludge exhibits a pore-forming effect due to calcium carbonate and heavy metal hydroxides in its composition. At the same time, the effect of galvanic sludge on the physical and mechanical properties is lower than that of zirconium oxide. The quantities of the studied additives have been established, which make it possible to obtain high values of operational properties and apply the resulting ceramics in the production of lining and other ceramic products for special purposes.

Keywords: heat-resistant ceramics, acid-resistant ceramics, self-glazing, low-plastic clay, galvanic sludge, zirconium oxide, boric acid

The results of the technical inspection of the building structures recognized as dilapidated and subject to reconstruction with a positive conclusion of the construction-technical expertise are presented. The program of complex technical diagnostics, including the regulations of the necessary expert and verification work, methods and techniques of examination, recommendations on the choice of modern technical means of measurement and instrumentation is developed. The category of the technical condition of the building was established, and recommendations for strengthening the monolithic reinforced concrete floor slabs were developed.

Keywords: construction expertise, technical inspection, defects, nondestructive testing methods, expert opinion

This paper provides the results obtained from the studies of polymer-bitumen binder (PBB) used for the production of polymer-modified asphalt cements (PMA). Thermoplastic elastomers produced at Voronezh Synthetic Rubber Plant, as well as at Chinese and Korean production units have been studied in order to obtain PBB. It has been established that locally-produced thermoplastic elastomers of DST-30 grade demonstrate the best performance indicators. To reduce the costs, speed up the preparation process and improve the properties of PBB, a new technology for incorporation of DST into bitumen was developed. It is suggested that DST should first be dissolved in industrial oil of the trademark IM-20, and after that the polymer solution should be incorporated into bitumen. Furthermore, the limiting concentrations of DST additive in oil were determined, which range from 10 to 30%. The influence of the DST additive on the properties of the domestically produced bitumen of the Achinsk Oil Refinery grade BND 90/130 was revealed. Studies have found that the inclusion of additives leads to an increase in extensibility, elasticity and a decrease in the brittleness temperature of bitumen, which indicates an increased deformability of the polymer-bitumen binder. Using the method of experiment planning, the optimal composition of PBB was determined: the ratio of DST and oil stands at 19% DST and 81% oil; the amount of polymer solution in the binder equals 9%. This composition was prepared in laboratory conditions, its properties were determined and compared with the requirements. The prepared composition of the PBB was recommended for industrial implementation to the roadway maintenance bodies of the city of Krasnoyarsk and the Krasnoyarsk Territory.

Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production

Decorative materials currently used to give architectural expressiveness to buildings and structures have various compositions, including cement, fillers, pigments. To obtain products with high decorative indicators, it is necessary to choose components in such a way that, as a result of operation, the decorative properties that ensure the quality of the facade surface are preserved. The quality of aggregates and the technology of production of products are important at all stages of production.

Keywords: concrete, finishing materials, artificial stone, mortar, decorative cladding, deformation, pigments, placeholder

One of the important components of building mixtures and concretes is sand. Sand is the most readily available raw material. In many countries sand mining is environmentally damaging or in short supply. Some countries have to buy sand. To replace building sands, various wastes are offered during crushing and grinding, screenings of concrete and brick scrap. Desert sand is not always suitable for building mixes due to its physical properties. Technogenic sands are very different in their origin, formation conditions, chemical and mineral composition, structure and properties. To determine the applicability of a sand substitute, it is required to conduct research on technogenic sand and products based on it.

Keywords: sand extraction, technogenic sands, concrete scrap crushing screening, brick scrap crushing screening, enrichment waste

The main reasons for the weakening of wooden structures, as well as the main requirements for strengthening wooden structures, are considered. Various methods for strengthening structures are being analyzed. Strengthening with carbon fiber is highlighted separately, the main advantages and disadvantages of this method are considered.

Keywords: analysis, causes, methods, reinforcement, wooden structures, wood, reconstruction, carbon fiber, composite, strength, deformability

Compositions and their properties for protective coatings based on liquid ebonite and water dispersion of CSPE were described. The experimental data of different testing are confirmed their high effectivity for corrosion protection.

Keywords: corrosion protection, liquid ebonite mixtures, oligobutadiene, water dispersion CSPE, service properties

The problem of physical deterioration values of residential buildings for a given period of time for practical purposes is considered. A review of the existing normative and technical documents for determining the physical deterioration of residential buildings has been carried out. Various methods for predicting physical deterioration for a given period of time are considered. The conclusion is made about a linear increase in physical deterioration with an average annual increase of 1%. Recommendations are given on the use of the data obtained in the planning of operational measures for the repair and maintenance of residential buildings .

Keywords: predicting, physical deterioration, residential building, building management, average annual increase, technical inspection, chronological age method, expert method, service life, technical condition assessment

The article presents the experience of automating the process of secondary sludge preparation in autoclave aerated concrete technology. It is proposed to use a non-cut non-isotope density meter of domestic production as a recording sensor. The algorithm of the system operation and the scheme of the technological process fragment are presented.

Keywords: automation, control system, production process, autoclave aerated concrete, secondary sludge, algorithm, density meter, quality of the finished product, sludge pool, density

The purpose of this article is to consider the concept of "polymer concrete", its classification, features of its use, role in modern construction and the likelihood of replacing traditional building materials. Also studied and structured theoretical material on the topic "concrete based on polymer binders", classification of polymer concrete according to V.V. Paturaev ,practical experience of its application. The possibility of using polymer concrete in modern realities and in the future is considered. General conclusions are made about the expediency of its widespread use from a practical and economic point of view.

Keywords: polymer concretes, polymer, binder, filler, reinforcement, resins, thermosetting, thermoplasticity , thermoplastic substances, thermosetes, polymer concrete (PO)

The effect of redispersible polymer powders on the change in the properties of building mortars after 60 cycles of heating to 60 ° C and cooling is investigated. An increase in the compressive strength from 11 to 27% was revealed at a dosage of RPP from 1 to 3%, and the introduction of an air-entrapping additive into the composition does not contribute to an increase in the compressive strength. A significant increase in the ratio of the tensile strength "flexural tension" has been established/compression", while the tensile strength of building mortars during bending practically does not change with an increase in the dosage of RPP, and the increase in tensile strength during bending occurs to a lesser extent than that of building mortars without RPP, and the presence of an air-entrapping additive contributes to an increase in the tensile strength during bending. A decrease in the initial modulus of elasticity was found almost independently of the dosage of the RPP to values of 0.82 – 0.84, and in the presence of an air-entrapping additive to 0.9 relative to normal hardening conditions. A decrease in the adhesion strength to the concrete base to values of 0.59 – 0.75 relative to normal hardening conditions was revealed. The presence of an air-entrapping additive leads to an increase in the adhesion strength after cyclic heating-cooling by more than 4 times.

Keywords: redispersible polymer powder, adhesion strength, modulus of elasticity, compressive and bending strength, cyclic heating-cooling

The paper presents the results of studying the dependences of the physico-mechanical properties of facing ceramics on the use of molybdenum trioxide. The additive together with boric acid is introduced into a charge based on low-plastic clay. The studied ceramic material was obtained by semi-dry pressing at a maximum firing temperature of 1050 ° C. Both additives used are fins, contributing to liquid-phase sintering and the effect of self-glazing of the surface of the material. At the same time, molybdenum trioxide also makes it possible to reduce the viscosity of the vitreous phase and increase its degree of crystallinity. The optimal amount of molybdenum trioxide has been established, which allows to effectively increase the strength and frost resistance of ceramics. The practical application of the developed composition of the charge will allow the use of low-quality raw materials for the production of facing construction ceramics with high performance characteristics.

Keywords: facing ceramics, molybdenum trioxide, low-plastic clay, boric acid, melting, liquid-phase sintering, self-glazing

GRP horizontal tanks are used for wastewater treatment. This material can be used for 50 years or more, which exceeds the lifetime of reinforced concrete sewage treatment plants. However, when designing the products, it is necessary to determine whether the tank should be manufactured using the continuous winding method or the spiral-crossflow method. The main problem in selecting the manufacturing method is to determine the stability of the structure against vertical loads from the soil mass. The continuous winding method provides high circular stiffness, hence resistance to various influences, while the spiral cross winding method deteriorates circular stiffness and reduces the cost of the product. The article examines constructed GRP structures made using different methods and located at different depths. The tests are carried out to study the strength characteristics of the material on the basis of the Plant of composite materials, the ring stiffness and the modulus of elasticity are determined according to GOST R 54925-2012, to confirm the data obtained, a comprehensive calculation is performed in the Midas GTS NX software using a work model (structure + soil). The Mohr-Coulomb model was selected as a model to describe the soil, the material characteristics were set according to the data obtained from the tests. The results of surveys and calculations proved the inability to use GRP containers manufactured by the spiral cross-winding method because of low circular stiffness resulting in loss of load-bearing capacity of the structure and further ingress of soil inside the container.

Keywords: GRP gorizontal containers, continuous winding method, spiral cross winding method

The overlapping time of the layers during the layer-by-layer laying of the concrete mixture during the construction of massive monolithic reinforced concrete structures is an important technological parameter of concreting, linking the rate of concreting, the thickness of the laid layers and the design parameters. For traditional concrete mixtures compacted by vibration, this parameter is determined by the persistence of the concrete mixture, taking into account its temperature. When using self-compacting concrete mixtures, the time of overlapping layers, in addition to traditional factors, significantly depends on the period of formation of the "elephant skin". The influence of the overlapping time of the layers on the strength of their adhesion, depending on the properties of the concrete mixture and the method of its laying, was studied. The ultimate tensile strength in bending was used as a criterion for adhesion strength. It has been confirmed that when using a traditional concrete mix compacted by vibration without superplasticizing additives based on polycarboxylate esters, the overlapping time of the layers of 2 hours provides a seam of equal strength with the main body. For self-compacting concrete mixes using vibration when laying subsequent layers after the first, the overlapping time corresponds to the storage index and increases to 6 hours, and when layered without vibration, the adhesion strength decreases by about 20%, 70% and more than 90% with an overlapping time of 2.4 and 6 hours, respectively.

Keywords: self-compacting concrete mixes, massive reinforced concrete structures, overcoating time, "elephant skin"

One of the most massive polymer waste of consumption is car tires that are going out of service. The disposal of such tires at a solid waste landfill is an extremely inefficient way of their disposal, entailing an increase in the area of landfills and an increase in negative environmental impact. The least financially and labor-intensive way of processing automobile tires is grinding into fractional crumbs. To reduce the costs of sorting and further grinding of tires, a shredder with a dispersion of 3 mm is used. The article suggests the use of rubber crumbs as a binder when laying highways. Studies of indicators affecting the operational parameters of asphalt pavement at different values of the mass of rubber crumbs in comparison with a clean sample were carried out and the optimal specific mass of the added crumbs was determined, which was 15-20%.

Keywords: rubber crumb, tires, asphalt mix, optimal weight

Portland cement based materials occupy leading position in the construction industry nowadays. The constantly growing volume of construction and the development of modern technologies requires to provide new multifunctional characteristics to traditional cement composites. Thus, the introduction of various kinds of admixtures into the cement composition can affect its structure formation, improve physical and mechanical characteristics or give special properties to cement stone. Admixtures can be classified as accelerating, water reducing, retarding, etc, some of them are capable of providing extraordinary properties to the surface of the cement stone, some of them combine several functions at once. With the development of nanotechnology the particles of admixtures can be of nano scale. Many studies has been performed to create biocide admixtures: compounds capable of eliminating bacteria, viruses and fungi with various mechanisms of activity. The list of additives is constantly updated with new compounds and formulas. Ultrafine titanium oxide doped with bismuth can be considered as a promising admixture to cement systems with accelerating, biocide and photocatalytic properties. This article is a brief review of admixtures with biocidal activity.

Keywords: construction materials, portland cement, biocides, fungicides, fungi, titanium dioxide, photocatalysis

To solve environmental problems related to the disposal of broken bricks, the preparation of new places for building residential complexes, as well as the expansion of the resource base for the production of building materials, clay brick scrap after the renovation of buildings is considered as a major substitute for concrete mixtures. The main physical and mechanical properties of concretes were studied. It has been established that concretes obtained on the basis of coarse aggregate from brick scrap have the properties of concretes based on natural aggregates of the M250-350 grade. The use of scrap clay bricks as fillers requires a special technology for preparing the latter in order to reduce its water demand. The conducted studies have shown that it is expedient to design concrete mixtures based on secondary resources based on a complex binder consisting of Portland cement, finely ground clay brick cullet and hyperplasticizer.

Keywords: clay brick scrap, coarse aggregate, renovation, binder, hardening, concrete mix, concrete, strength

Computational and analytical studies of the influence of the duration of operation of nuclear power plants during the extension of their operation on the radiation changes in the concrete of the shaft of water-water power reactors (VVER) on various aggregates have been carried out. The studies were carried out using the existing experimentally tested methods for the analytical determination of radiation changes in concrete and their components. It has been established that during the extension of the operation of nuclear power plants with VVER reactors, the radiation changes in the concrete of the reactor shaft can be commensurate with the allowable changes in concrete or exceed them. It is shown that the radiation changes in the concrete of the reactor shaft increase with an increase in the duration of operation and depend on the power of the reactor (440 or 1000 MW), the thickness of the "dry" shield around the reactor, and the material of the concrete filler used. Radiation changes in all concrete of the NPP shaft with VVER-440 reactors will be more significant than in the concrete of the NPP shaft with VVER-1000 reactors. It has been established that the radiation changes in the concrete of the reactor shaft and the maximum duration of operation when using aggregates from various rocks differ significantly. It is noted which concretes (on which aggregates) have the smallest, largest and intermediate radiation changes. It is shown that with an increase in the operating temperature, the radiation changes in concrete will decrease, and the allowable operating time of the NPP will increase.

Keywords: radiation changes, reactor shaft concretes, concrete aggregates, rocks, water-water power reactors VVER-440 and VVER-1000, extension of NPP operation

The problem of controlling stepper motors of a road printer using the method of neuro-fuzzy control is considered. An algorithm for developing an intelligent control system for stepper motors is described. A training sample is obtained according to the data of variables determined as a result of modeling an automatic control system with a continuous proportional-integral-differentiating (PID) regulator. Training of the adaptive neuro-fuzzy output system by the hybrid method was performed using the MATLAB program. Transient characteristics of the control system with continuous and neuro-fuzzy PID regulators have been built. Direct indicators of the quality of the considered control systems of stepper motors have been determined, and an analysis of these results has been carried out. The use of neuro-fuzzy-PID control of stepper motors made it possible to obtain a high-quality transient process, confirmed as a result of a computational experiment.

Keywords: Road printer, stepper motor, travel printer, stepper motor, transfer function, adaptive neuro-fuzzy output system

The article contains the results of verification of the finite element design model of work on axial compression of reinforced concrete structures with combined reinforcement. Structures with combined reinforcement (with non-removable steel-fiber concrete formwork) are widely used in the construction of nuclear power plant structures. Steel fiber reinforced concrete, in comparison with heavy concrete, has increased strength and deformation characteristics, due to which it performs the function of a bearing element that perceives compressive and tensile forces. The study of the joint work of steel fiber concrete and heavy concrete is a promising area of research. The developed finite element model of a reinforced concrete structure with a fixed steel-reinforced concrete formwork with a high degree of reliability allows us to determine the stress-strain state, the redistribution of forces between the cross-section elements and the parameters of cracking during loading. The described modeling technique is recommended to be used in the study of the operation of such structures.

Keywords: NPP, nonremoveale formwork, structural testing, Ansys, stress-strain state diagram, steel fiber reinforced concrete, finite element method

The article considers the problem of continuous monitoring of the concentration of dust flow in air ducts at enterprises in the production of building materials. A spectral-timbre methodology for estimating dust concentration based on the analysis of acoustic emission signals is proposed. Two stages of adaptation of the simplified assessment of dust concentration on the bench model and in production conditions were carried out. In the process of adaptation, a piezoceramic sensor is used, an acoustic signal from which using a preamplifier is fed to a recording device called potentiometer with a circular daily diagram . The reference weight method was used to measure the actual dust concentration and simultaneously record the readings of an adapting dust meter.

Keywords: building materials, dust concentration, dust measuring equipment, acoustic methodology, acoustic emission signals, Fourier spectrum

The article discusses the various stages of the study of quarry sand as a component of the cement-sand mixture. Two large-scale stages are designated: drying and sieving. The drying stage for different layers (upper, middle, lower) of quarry sand is given. The results of moisture content of sand weighing from 100 to 5000 g for different layers are given. The screening stage for various layers of quarry sand is given. The granulometric (grain) composition of various layers of quarry sand was determined experimentally according to the normative methodology. The results of partial and total residuals for each layer of sand are given. Size moduli are calculated for different layers of sand. The equipment used for drying and screening quarry sand is illustrated. The experimentally theoretical necessity of the preliminary stages of preparation (drying and sifting) of quarry sand before using it as an integral part of the cement-sand mixture for the production of bricks has been confirmed experimentally.

Keywords: quarry sand, drying, drying, sifting, screening, cement-sand mixture, humidity, granulometric composition, particle size modulus

An analysis of existing ceramic materials for high-temperature thermal insulation is presented. The possibility of obtaining a composite based on zeolite-containing raw materials from the Sakhaptinsky deposit with additives for thermal insulation of industrial aggregates is shown. The results of the effect of additives (clay, microsilica, burnable additives and foam-forming emulsion) on the physical-mechanical and firing properties of the resulting products are presented. The main characteristics of the resulting porous ceramics were studied and the optimal limits for the use of the additives used were determined in accordance with the requirements of GOST 2694-78 for the analogical foam-diatomite brick. The effect of clay content in composites on the density, strength and additional linear shrinkage of samples was determined.An optimal composition has been obtained containing microsilica and burnable additives (sawdust) in the manufacture of porous ceramics used for high-temperature thermal insulation with the lowest density and appropriating the requirements of GOST for strength and additional linear shrinkage.

Keywords: zeolite, clay,microsilica, foam-forming emulsion, burnable additives, chemical composition, firing properties, physico-mechanical properties, porous ceramics, waste products, high temperature insulation

The article discusses the various proportions of the components of the cement-sand mixture for the production of bricks for the construction of private houses. Particular attention is paid to the values ​​of the draft of the cone, as one of the indicators of the mixture. Tables are given with a description of the different composition of the mixture for each component. The results of an experiment to study the effect of different ratios of components are presented. The equipment for manual and automatic molding and creation of finished products from the resulting mixture is illustrated. A conclusion is given on the possibility of using a specific mixture in the production of bricks.

Keywords: brick, cement, sand, water, cement-sand mixture, cement mortar, water-cement ratio, composition selection, construction, production