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

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 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 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 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