The expediency of using a finely ground mineral additive from burnt mudstone clay for the production of heat-resistant expanded clay concrete based on Portland cement with a rational dose of the additive of 30...50% by weight of the binder is shown. Compositions of heat-resistant expanded clay concrete with a maximum permissible application temperature of I10 classes in compressive strength up to B15 and an average density of up to 1500 kg/m3 have been developed. The efficiency of the technology for obtaining heat-resistant expanded clay concrete using pre-forced electric heating of the concrete mixture up to 60°C is substantiated and rational technological parameters of electric heating are determined. The residual strength of heat-resistant expanded clay concrete obtained using the developed technology, after short-term heating to 1000oC, exceeds 0.65 of the initial, which is higher than the values for analogues according to SP 27.13330.2017. The coefficient of linear temperature expansion of the developed heat-resistant expanded clay concrete in the temperature range of 200...1000oC varies within 2 ...5,8ˑ10-6 1/oC. The increase in the coefficient of thermal conductivity of the studied concretes with an increase in temperature up to 1000°C is up to 34%. The heat resistance of heat-resistant expanded clay concrete at 800oC, obtained using the technology of pre-forced electric heating of the mixture, was 12, 14 and 15 air heat changes, respectively, at a temperature of pre-forced electric heating of 60, 80 and 90 оC.

Keywords: heat-resistant expanded clay concrete, fine-ground mineral additive, mudstone, thermal conductivity coefficient, coefficient of linear thermal expansion, residual strength

The increasing complexities in the development of new fire-protective coatings hinder the attraction of private investments and impede the progress of innovation. The review provides an overall picture of the research and specifically illustrates the extraordinary diversity of their directions and explains the inherent reason for such diversity. The goal of this review is to establish an information foundation for a critical analysis of the feasibility of private investments in developments in this field and to show some possible ways. The wide range of choices for specific components in fire-protective coatings and the diversity of mechanisms they employ result in a factorial number of possible combinations. The variety of properties of these components and the complexity of their interactions make it difficult to assess the outcomes of their selection unequivocally without conducting experiments during the development of new materials. Therefore, confident prediction of the results of new research is extremely challenging. As a consequence, there is a broad spectrum of directions and sub-directions in ongoing developments. Summing up the results of these investigations is further complicated by the difficulty of testing materials for aging parameters and resistance to external influences. The wide range of choices for specific components in fire-protective coatings and the diversity of mechanisms they employ result in a factorial number of possible combinations. The diverse properties of these components and the complexity of their interactions prevent a definitive evaluation of the results of their inclusion in the composition prior to conducting experiments in the development of new materials. Therefore, confident forecasting of the results of new research is extremely challenging. As a consequence, there is a broad range of directions and sub-directions in ongoing developments. Summing up the results of these investigations is further complicated by the difficulty of testing materials for aging parameters and resistance to external influences. The high uncertainty in forecasting the prospects of specific developments stimulates the advancement of simulation methods for compositions and coating manufacturing technologies, as well as the prediction of their effectiveness, etc. However, these methods only provide a partial increase in the reliability of expectations. A more thorough execution of a feasibility study is recommended to substantiate venture investments. One of the additional approaches capable of enhancing its credibility is the utilization of non-traditional specialized methods for researching patent information.

Keywords: fire-protective coatings, specifically illustrates the extraordinary diversity, prospects of specific developments stimulates, simulation methods for compositions and coating manufacturing technologies

The article is devoted to the issue of increasing the efficiency of ventilation systems through the use of a new type of air ducts. The main advantage of microperforated textile air ducts is the possibility of supplying fresh air with laminar micro jets to the human breathing zone. The need to adapt the existing methods for calculating the main parameters of jets for the laminar regime is noted. The article presents the results on the development of a mathematical model of a stationary boundary layer for the numerical calculation of the movement and heat and mass transfer of air in a laminar microjet. A discrete analog of the generalized differential equation is derived, on the basis of which a software package is developed that allows one to determine the main parameters of laminar microjets. Verification of the developed software package was carried out, the discrepancy with the known engineering method was less than 3%.

Keywords: mathematical modeling, air exchange, microperforated textile air duct, microperforation, laminar jet, control-volume method, round jet, micro jet

A promising direction for improving the durability and transport and operational performance of road pavements is the use of modifiers, including those based on sulfur as a component of the asphalt concrete mixture. However, sulfur and its toxic gases are active substances that can enter into chemical interactions with fillers to form water-soluble calcium and magnesium sulfides CaS and MgS. This process leads to the destruction of the dispersed phase and a decrease in the water resistance of sulfur asphalt concrete. A promising direction that has received wide approbation in the manufacture of polymer composites is the finishing of the filler surface, which makes it possible to prevent the formation of water-soluble sulfides. The coupling agents form a shell impermeable to sulfur, which prevents its chemical interaction with the dispersed phase. The following components are offered as coupling agents: Polymethylsiloxane (PMS-100), SKDN-N rubber, silicic acid sol in a medium containing Fe(OH)3 nanoparticles, and iron (III) hydroxide sol.

Keywords: sulfur asphalt concrete, asphalt concrete, water resistance, strength, sulfur bitumen binders, nanoscale additive

The results of research permissible longitudinal axial and fiber tensions are given for various characteristics of gas distribution and gas consumption systems.

Keywords: polyethylene gas pipeline, longitudinal axial tension, longitudinal fiber tension, gas pipeline deformation, optimal gas pipeline bending radius

The paper presents the results of studies of the characteristics of a polymer coating for the protection of steel and concrete surfaces based on low molecular weight dimethylsiloxane rubber SKTN-A. For cold curing of the binder and its modification, the MSN-7-80 hardener was used, an additional functional additive was galvanic sludge calcined at 1000 °C and crushed to a particle size of no more than 40 microns. It was found that polymethylsilazane, which is part of MSN-7-80, increases the strength characteristics of the coating, especially its cohesive strength, while reducing water absorption by increasing the hydrophobicity of the surface. In turn, galvanic sludge increases the mechanical strength upon impact. The ecological safety of the obtained material was confirmed by the method of biotesting on the mortality of Daphnia magna Straus. As a result of comparison with a protective coating similar in composition and purpose, it was revealed that the coating obtained in this work surpasses it in strength and adhesion characteristics. The developed polymer composition can be used to protect steel and concrete surfaces in construction and mechanical engineering from shock and moisture, including in extreme conditions of high or low temperatures and in contact with aggressive media.

Keywords: polymer composition, protective coating, organosilicon binder, electroplating sludge, polymethylsilazane, cold curing

The article presents a feasibility study of the use of the izoproflex-115A pipeline based on thermal and hydraulic calculations of existing thermal networks in Saransk. When modeling two variants (pipe networks made of steel in polyurethane foam insulation and polymer pipelines "izoproflex-115") of pipelines, the same technique was used. Analysis of the calculation results of the longest section of the heat network showed that ISOPROFLEX pipes, on average, have a three-fold capacity reserve in relation to a steel pipe. The use of modern izoproflex-115A pipeline systems will ensure high-quality and uninterrupted heat supply to consumers, increase energy security and energy efficiency, reduce the accident rate of heat supply systems and improve the financial performance of heat supply organizations.

Keywords: heating networks, pipeline, reserve, capacity, heat supply, consumer, insulation, electronic model, isoproflex-115A, Zulu Thermo

Insulating materials are widely used in the petrochemical, energy and other industries. Thermal insulation materials play an important role in the energy saving of district heating systems and in the construction sector. In this work, the influence of the wetting and drying cycle on the thermal conductivity and density of the heat-insulating material is determined by the experimental method. The thermal conductivity of the insulating material was determined by the protected hot plate method. It has been established that after four cycles of wetting and drying, the thermal conductivity and density of the heat-insulating material increase up to 2 and 2.5 times, respectively.

Keywords: thermal conductivity of heat-insulating materials, density of heat-insulating materials, dampening of heat-insulating materials

In the article, it is proposed to take the density of soil particles as the maximum density, the determination of which does not require sophisticated equipment, is determined in the laboratory using a pycnometer, while the density of soil particles is a fairly stable value, depending only on the composition of the soil. As a result, a more advanced method has been developed for assessing the degree of compaction of sandy soils by using the density of soil particles and statistical dependencies as the maximum soil density without directly determining the maximum density and optimal soil moisture in the laboratory according to GOST 22733-2016. Based on the research of BeldorNIA, it is proposed to take the density of soil particles as the maximum density, the determination of which does not require the presence of complex equipment.

Keywords: highway, soil, soil compaction, soil composition, road surface, road defects, trackage, road construction, method, pycnometer

The experience of standardization of modular construction and factory-ready buildings of China, the USA, Canada, Great Britain, France, the Netherlands, Germany and others is considered. The analysis of the existing profile regulatory and technical documentation (RTD) in the Russian Federation. The analysis of domestic and foreign RTD showed that there is no unified approach to rationing of the considered subject area. At the present time it is necessary to update the Russian RTD in the field of modular construction. Based on the results of the analysis and synthesis of the world practice in the field of modular construction, recommendations and suggestions for working with terms and definitions, the variants of development of normative and technical documentation of the Russian Federation in the field of modular construction and themes of work for the development of modular construction regulation were developed.

Keywords: modular construction, quickly erected buildings, prefabricated buildings, technical documentation

The influence of the properties of the base and the holding conditions on the adhesion strength to the base of modified building mortars obtained from dry building mixes with a content of 1-3% of redispersible polymer powders has been investigated. A decrease in the adhesion strength of the modified mortar with a standard concrete base was revealed to an average of 0.45-0.8 relative to normal hardening conditions when maintained at elevated temperatures according to GOST R 56387-2018 and to 0.4-0.55 when cyclically heated to 60 ° C, depending on the properties of cement, type and dosage of RPP. The relative strength of adhesion to granite under the same conditions was 0.3-0.65 and 0.2-0.8, respectively. The adhesion strength of modified mortars during hardening under normal conditions relative to the adhesion strength with a standard concrete base is approximately: with silicate brick from 30 to 50%, with ceramic brick from 65 to 80%, with aerated concrete about 50%, with granite from 9 to 18%. The recommended initial dosage of redispersible polymer powders for dry building mixes for heated floors is 1.5%.

Keywords: modified building mortars, redispersible polymer powder, adhesion strength to the base, bending strength, temperature

Annotation: The possibility of quality assessing of paint coatings by using the products surface conditions analysis through the use of digital technologies is shown. In the conditions of industrial enterprise, the comparative analysis of АК-1301 and Tikkurila Metallista coatings condition, exposed to aggressive environments: water, gasoline is carried out. From digital images of the surface, adhesive strength and the porosity of the coatings before-and-after the effects of the environments were assessed. It is shown that АК-1301 enamel has the highest adhesive strength and chemical resistance to water and gasoline.

Keywords: paint coating, adhesion, surface porosity, corrosive environment, digital image, pixel

The paper presents the results of research into the road polymer-modified asphalt (PMA) concrete, which is supposed to be used in the Siberian region, in particular, in the city of Krasnoyarsk and the Krasnoyarsk Territory. For the preparation of asphalt concrete, a polymer additive was used in the form of DST-30 grade thermoplastic elastomer. In addition, the results of studies using IR spectroscopic methods of the processes of interaction between bitumen and DST dissolved in industrial oil are presented. It has been established that the change in the physical properties of bitumen when DST is added to its composition is a consequence of chemical interaction in the studied composite binder. On the previously developed composition of the polymer bitumen binder, hot asphalt polymer concretes were prepared, which were studied for the main physical and mechanical indicators. The resulting compositions meet the regulatory requirements. When compared with the properties of asphalt concrete on "pure" bitumen, it was found that the introduction of a polymer additive leads to an increase in durability at 20 and 500C, water resistance and strength reduction at 00C, which indicates an increased crack resistance at a negative temperature of polymer-modified asphalt concrete compared to regular asphalt concrete. Recommendations on the factory technology for the preparation of asphalt concrete are given. The resulting compositions are proposed for industrial implementation by road maintenance bodies and firms in the city of Krasnoyarsk.

Keywords: polymer bitumen binder, asphalt polymer concrete, thermoplastics, compositions, properties, experiment, industrial oil, regression equations

The article describes ways to equalize temperature differences in the material after preheating in the heating zone. A mode for changing the temperatures of the material and the furnace channel has been developed. The optimal length of the firing zone and the time of passage of the material were established, at which a constant temperature is maintained on the surface of the material. Values for optimizing the main parameters are given.

Keywords: firing, tunnel kiln, temperature equalization

The paper presents the results of a study of the effect of cerium oxide on the sintering process and the basic physico-chemical properties of ceramics based on low-plastic clay with the addition of boric acid. The developed ceramics were obtained by semi-dry pressing at a maximum firing temperature of 1050 ° C. The combined introduction of cerium oxide with boric acid promotes liquid-phase sintering, self-glazing of the ceramic surface and effective filling of pores and voids in it with the vitreous phase. At the same time, cerium oxide increases the refractoriness and chemical resistance of the vitreous phase and equalizes the coefficients of thermal expansion between the crystalline and amorphous phases in the composition of ceramics. The amount of cerium oxide has been determined, which makes it possible to optimally increase the heat resistance, chemical resistance and strength of ceramics. The practical application of the developed composition of the charge makes it possible to use raw materials of low plasticity in the production of high-quality ceramics for lining apparatuses and equipment, lining of industrial buildings and structures, etc. products experiencing mechanical stress with repeated and abrupt temperature changes, as well as in contact with aggressive media.

Keywords: ceramics, heat resistance, chemical resistance, self-glazing, low-plastic clay, cerium oxide, boric acid

A research of fibrous gypsum modified with a complex additive has been undertaken. The objective of the research was to identify influence and dosage of complex additive components upon fibrous gypsum water absorption. To fulfil the work there were used gypsum plaster and a modifying complex additive which consisted of the following components: polypropylene fibre, fine-dispersed inert aggregate, super-plasticizer and redispersing polymerous powder. To undertake the research designing an experiment took place and the central composition plan was implemented. The obtained research result made it possible to calculate and analyze descriptive statistics. Positive influence of the researched factors on water absorption decrease was revealed. It was established, that consumption of fine-dispersed inert aggregate and, super-plasticizer promote decrease of fibrous gypsum water absorption. Analysis and processing of the research data allowed obtain a mathematical model of influence of complex additive components consumption on fibrous gypsum water absorption and reveal a fibrous gypsum composition with the minimal water absorption. The obtained model allowed forecast a composition with the minimal water absorption.

Keywords: fibrous gypsum, water absorption, complex additive, modified, central composition plan, model, additive efficiency.

The method of fixing soils is injection filling of voids, which is produced by binding materials - cements, clays, bitumen, etc., and sand, sawdust, loam, suspensions are used as inert fillers. It is possible to improve the quality of cement composite solutions through the use of reinforcing additives, which in the future will ensure a high degree of reliability, safe operation of facilities. The paper considers the possibility of involving nano-additives in grouting compositions, such as aluminosilicates, in particular boehmite. Studies of the hardening processes of composite solutions in the presence of bentonite grade P1T1 with different content of boehmite have been carried out. The concentration of boehmite at which the rate of hardening of the composite solution is maximal is determined. In order to save cement, the effect of the surfactant on the strength of the composite solution was investigated, it was found that the 20% introduction of the surfactant into the composite solution gives a strength that almost coincides with the zero sample.

Keywords: safe operation, plugging compositions, boehmite, surfactants, strength, structure formation, optimal concentration, nanosystem, modifier, cement

This article examines the impact of nanotechnology on the development of flame retardant materials in the field of construction. The general provisions of nanotechnology and nanocomposites, their characteristics and classification are described. Examples of the use of nanotechnology to create fire-resistant materials and their direct application in construction are presented. The main problems of nanocomposites are presented, the solution of which will allow to bring passive fire protection of buildings and structures to a new level.

Keywords: fire protection, fire-resistant material, nanotechnology, nanocomposite, composite material, composite, polymer, material

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