It describes the material CLT, which is used for the manufacture of floor slabs. The required floor thickness is calculated from the condition of rigidity under a load of 2.4 kN / m2 for various spans. The values of deflections are determined from the stiffness condition. The calculated deflection values are compared with the standard values. Based on these results, the recommended floor thickness is assigned for each span.

Keywords: cross-laminated timber, timber constructions, floor, deflection, rigidity

The article investigates the physical and mechanical properties of fine-grained fiber-reinforced concrete with metal, polypropylene and polyamide fibers, using Portland cement, hyperplasticizer. Comparison of strength characteristics of fiber-reinforced concrete made using metal fiber, polypropylene and polyamide fibers is carried out. A technical and economic comparison of the efficiency of using fibers of various origins has been made. According to the cost calculations, the use of polyamide fibers is cost-effective, since the cost of materials is lower than the cost of fiber-reinforced concrete materials based on polypropylene fibers of this composition.

Keywords: fiber concrete, hyperplasticizer, fiber, microsilica, tensile strength, nature of destruction, mechanical property, polypropylene fiber, polyamide fiber, cement, reinforcement, adhesion, monolithic structure, cost

The results of the development of compositions and technologies for their preparation for use in the structures of marine gravity oil and gas production platforms and underwater oil and gas pipelines are presented. The efficiency of using basalt fiber fibers, plasticizing additive "Sika ViscoCrete 5-800" and soot waste from thermal power plants in the manufacture of fine-grained concrete is proved. As a result of the experiments, the strength characteristics of fiber concrete were determined depending on the amount of superplasticizer and soot waste introduced when using equal-moving mixtures. An increase in the compressive and Flexural strength of samples modified with basalt fiber, superplasticizer and industrial waste is shown, which contributes to an increase in the operational characteristics of oil and gas offshore structures by increasing the parameters of frost resistance and water resistance of structural materials.

Keywords: oil and gas facilities, fiber-reinforced concrete mixture, the superplasticizer basalt fibre, particulate waste strength

This article discusses the problem of increasing the load-bearing capacity of bored piles. The technology of injecting fixing solutions into the ground under the foundations of a two-story building in the city of Azov to increase the load-bearing capacity of bored piles was described.

Keywords: structurally unstable soil, pile Foundation, load-bearing capacity, soil consolidation, silicatization, camouflage broadening, driving piles, bored piles, screw drilling, concreting

The use of laser radiation for welding aluminum alloy AD33 can improve the quality of welded joints and process performance. At the same time, most of the welded structures in production are performed using automatic laser welding installations, which allow ensuring the necessary quality of welded joints, including due to the constancy of the technological process modes. However, there are a number of industries where manual laser welding installations are indispensable and in high demand. At the same time, a distinctive feature of the manual laser welding process is the problem of ensuring the constancy of the duration of exposure to laser radiation on the surface of the workpiece when the speed of the laser beam changes. The paper presents the results of a comparative study of the dependence of the quality of the AD33 aluminum alloy welded joint on the change in the speed of the laser beam for manual and automatic laser welding conditions.

Keywords: aluminum alloy, laser radiation, welding, welding bath, technological process, microstructure, AD33, laser beam, manual laser welding, Al–Mg–Si, aluminum thermal deformation coefficient, vacuum chamber, pulsed laser

The results of scientific and experimental research on determining the width of the crack opening in concrete under the influence of mechanical load are presented. In the process of scientific research, a simultaneous complex measurement by tensometric and acoustic methods of the load of deformation, the width of the crack opening, the total count of acoustic emission was carried out to obtain complete diagrams of concrete deformation. As a result of the experiments, regression equations were obtained and the correlation dependence between the crack opening width and the total acoustic emission count was established.

Keywords: lightweight concrete, crack width, tensometric method, acoustic emission, deformation diagrams

Increased concrete strength due to early loading is one of the priorities of concrete technology. Many articles contain data on changes in compressive strength after early loading. The first person to test early concrete loading was Satalkin. He tested bridge supports for static and dynamic loads. The results of his work became the basis for further research in the field of early loading of concrete. The objective of this work is to study the tensile strength in bending after early loading and to check the influence of the orientation of the samples under load. Also we considered the effect of active mineral additives on this parameter. The object of study is samples of cement-sand dough prepared on a Portland cement binder of various manufacturers. We noted a difference in the strength characteristics in bending by changing the orientation of the samples when testing them after early loading. The maximum increment of strength is noted in a plane perpendicular to the direction of compressive force. The use of a mineral additive with the replacement of a fraction of cement gave the attenuation of the observed effect.

Keywords: anisotropy of strength properties, early loading of concrete, cement composite, flexural strength, mineral additive

The results of optimizing the composition of concrete based on aggregates from crushed concrete are presented. With the help of mathematical and natural modeling matched the composition of the expanding agents sulfoaluminate type, the optimal percentage of components of the modified cement required for producing a material with improved performance characteristics, the mathematical model construction and technical properties of the concrete and the kinetics of their changes to take into account the time factor and strength and weathering.

Keywords: mathematical modeling, expanding additive, factor experiment, influencing factors, level of variation, experiment planning matrix

The search for technological solutions for the organization of lean production at precast concrete enterprises was carried out. Options for rational use of rock crushing screenings as a filler and filler for self-compacting fine-grained concrete are considered. The optimal dosage of limestone crushing screenings in the composition of fine aggregate for the preparation of self-compacting mixtures has been determined. It was found that the enrichment of very fine Sands with large fractions of Sandstone crushing screening in an optimal amount reduces the intergranular voidness and reduces the water demand of the fine-grained mixture.

Keywords: lean production, rock crushing screenings, optimization of grain composition of aggregate, self-compacting fine-grained concretes, superplasticizer based on polyaryl and polycarboxylate esters

A scheme and procedure for carrying out emanation tests of radon-protective coatings on standard concrete samples are proposed. The results of testing the material "Silor-Ultra" as an effective radon protective coating are shown.

Keywords: radioactivity, radon, radiometer, concrete, standard sample, antiradon protection, radon protection coating, radon insulation, emanation tests

The analysis is made of the use of expanded clay gravel in cement-sand mortar in order to reduce ice at the boundary between the pile and the mortar. The application of expanded clay concrete in block-modular buildings is considered. Lightweight design and reduced heatloss are proven.

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

Fiber-reinforced concrete is a promising type of concrete, which in the near future may take a fairly large share in the total volume of concrete produced. Dispersed reinforcement fibers are a versatile material that can be introduced into various types of concrete. This additive may later be as common as plasticizers for modern concrete mixes. Fibro fibers can be used for the production of concrete products in stationary reinforced concrete plants or on-site installations for the production of ready-mixed concrete. The paper examines the influence of parameters on the index of bending strength of the material, as the main one, which is aimed at the introduction of fiber. The results of the influence of the characteristics of dispersed reinforcement on the effectiveness of the introduction of these additives and the final construction and strength properties of heavy concrete are described.

Keywords: dispersed reinforcement, basalt fiber, polypropylene fiber, fiber concrete, prismatic strength, Flexural strength

This study presents the results of the development of a polymer composite material with good dielectric properties, which allows it to be used in the radio and electrical industries. This material is based on epoxy resin, polyethylene polyamine, hollow glass microspheres and gallium oxide. The use of hollow glass microspheres in the composition in an amount of 5-20 wt. h. reduces the dielectric losses, and the use of gallium (III) oxide in an amount of 5-15 wt.h. it makes it possible to increase the stability of the dielectric characteristics when working in the microwave radio range and reduce the dielectric loss. Studies have shown that a sufficiently effective composite polymer material with high physical, mechanical and dielectric properties can be obtained on the basis of the developed composition.

Keywords: composite material, epoxy resin, hollow glass microspheres, gallium oxide, permittivity, dielectric loss tangent

Geopolymers are a promising building material that can become an alternative to Portland cement. They are distinguished by the possibility of using industrial waste, in particular metallurgical slags as well as inexpensive liquid glass. These resource-efficient binders can be used for the production of concrete products in stationary factories or workshops. The paper provides general directions for regulating the structure formation and properties of geopolymers based on metallurgical slags mixed with activators. The mechanism of geopolymer hardening based on the interaction of non-active slag components with an alkaline activator is briefly described; it is a three-stage physical and chemical process that leads to the formation of a solid stone structure. The influence of raw material properties on the final product characteristics is described.

Keywords: geopolymer, geopolymer concrete, aluminosilicate component, alkaline activator, metallurgical slag, basicity modulus, strength

This paper presents results of development of heat-resistant dielectric composite material based on epoxy resins to create structural and electrical radio products, coating materials receiving and transmitting radio systems for the aerospace, naval and land equipment. Research results show that when adding 10 wt.h. polyethylene polyamine as a hardener, 10-30 wt.h. polymethylphenylsiloxane as a modifier to ensure homogeneity, 10-40 wt.h.ceramic hollow microspheres and 5-15 wt. h. alumina as fillers per 100 wt. h. epoxy resin can be obtained a material with low permittivity and high thermal stability at 150 °C.

Keywords: dielectric material, polymer binder, epoxy resin, polyethylene polyamine, polymethylphenylsiloxane, hollow ceramic microspheres, heat resistance, permittivity

The article deals with obtaining RDF fuel based on solid municipal waste. The expediency of using this type of fuel in the cement industry is justified, since its combustion in cement furnaces has less impact on the environment due to the high temperature level of the process. The composition of RDF fuel by elements is analyzed. Due to the fact that this fuel from different sources has a difference in the heat of combustion of two times or more, the heat of combustion of RDF fuel for the middle zone of Russia was experimentally determined and its compliance with GOST R 55127-2012.

Keywords: solid municipal waste, MSW, Recycle Derived Fuel, RDF fuel, lower combustion heat, ash content, alternative energy source, colorimetric bomb

The article is devoted to the relationship between the strength of cement composites and the fractal dimension of their structure. In solid state physics, fractal algorithms can accurately describe and predict their properties and can be used in modeling the structure of composite building materials. Determination of the material fractal dimension according to its structure image at the macrolevel allows to understand its microstructure, and its properties as the result. Using the methods of experiment mathematical planning, the study was carried out and the relationship between the strength of the cement composite and its fractal dimension was established. It has been found out that the lower the fractal dimension, the higher the strength of cement composites. However, there is an area on the function graph that shows the increase in strength at sufficiently large values of the fractal dimension. Presumably, this is due to a change in the parameters of material differential porosity. For example, such as the average pore size index, the coefficient of pores uniformity in size, and the coefficient of microporosity. Such circumstance arouses interest and conditions for further research.

Keywords: fractal dimension, microstructure, strength, cement composite, composite building material, experiment planning, three-component system, regression equation, regression coefficient

A method for increasing the production efficiency of ultra-lightweight refractory products is proposed, by optimizing the technology for preparing foam, which allows to release the products from the forms immediately after they are installed for drying. The plastic-viscous characteristics and stability of the foam can be increased by its mineralization, i.e. by introducing fine mineral substances into the foam-forming solution

Keywords: foam mass, mineralization, ultimate shear stress, plastic-viscous characteristics, ultra-light refractories, aluminum-potassium alum

The results of the development of a polymer protective coating based on oligopiperylene styrene binder for the protection of concrete and metal surfaces of structures of buildings and structures from the effects of adverse natural and technogenic factors are presented. Modification of this binder with tetraethoxysilane in an amount of 3-20 wt. including allows you to get a protective coating with good hydrophobic properties. Introduction to the composition of 1-12 wt. including tetraisopropyl titanate significantly improves the adhesive and strength properties of the protective coating, which is associated with the formation of bonds between oligopiperylene styrene and tetraisopropyl titanate, due to chemical interaction between the reactive groups of these compounds. The developed protective polymer coating provides good adhesion to the working surface, is easy to apply technologically, the curing of the coating occurs at room temperature, and the improvement of the strength and hydrophobic characteristics of the coating will significantly expand its field of application.

Keywords: protective coating, oligopiperylene styrene binder, tetraethoxysilane, tetraisopropyl titanate, adhesion, hydrophobicity, contact angle

The results of the development of a polymer fire-resistant heat-insulating coating containing waste from electrochemical production for thermal insulation of hot metal surfaces of industrial equipment and building structures, working surfaces of pipelines are presented. The coating is developed on the basis of acrylic binder, hollow carbon microspheres, antifoam, pigment and flame retardant based on waste electrochemical production - galvanic sludge. The use of hollow carbon microspheres as a filler in the amount of 14.0 to 38.0 wt. including reduces the thermal conductivity of the coating, and the use as a flame retardant additive, pre-dried and finely ground galvanic sludge in an amount of 5 to 15 wt. h., gives the cured heat-insulating coating fire-resistant properties. Studies have shown that the use of this composition allows you to get a polymer heat-insulating coating with good physico-mechanical and flame retardant properties, while another problem is solved - the safe disposal of galvanic sludge.

Keywords: polymer heat-insulating coating, waste from electrochemical production, flame retardant, hollow carbon microspheres, galvanic sludge, fire resistance, safe disposal

The reconstruction of the basement of a two-story brick building is considered. The reconstruction of the basement was preceded by a technical inspection of structures and elements, which revealed damage. The condition of the basement structures was assessed, the causes of damage were identified, and a project was developed to eliminate them. The main tasks of the reconstruction included: eliminating the facts of flooding by waterproofing the walls and floor of the basement, developing a recipe for dry mix for shotcrete, eliminating the identified damage and reconstructing the basement walls.

Keywords: basement, flooding, water resistance, strength of concrete under compression, cement, silica fume, organo-mineral complex additive

A survey of the frame-panel building was carried out, in which ecowool was used as the heat-insulating material. A study was made of the moisture state of wooden frame walls and attic floors. Ecowool samples were taken from various sections of the wall. No mold was detected on material samples. In this case, the sorption humidity was not more than 16%. The results of laboratory tests of ecowool showed high persistence of density and coefficient of thermal conductivity during long-term operation. Tests were conducted to determine the effect of moisture on the change in the physical and technical properties of ecowool. The research results were processed by statistical methods. As a result of the study, it was found that moisture does not accumulate in the ecowool layer of the examined frame walls and attic flooring, but goes out through the insulation and elements of the building envelope. The conducted studies allow us to predict the preservation of the heat-shielding properties of ecowool during operation for a long time

Keywords: ecowool, durability, sorption humidity, density, coefficient of thermal conductivity

The article describes an integrated approach to the replacement of heating appliances in residential buildings in the event of major repairs or mechanical wear of these devices. The conditions of use of different types of modern heating appliances in existing heating systems have been analyzed. Based on experimental data, an analysis has been conducted for the operation of an aluminium radiator in a single-pipe up-feed heating system with respect to various radiator connection options to the riser. Recommendations have been provided on usage of modern types of heating appliances in residential buildings.

Keywords: the heater, thermal comfort, the response time, a single-pipe heating system, the connection diagram of the heater to the riser.

This paper presents the results of the development of a heat-insulating coating based on a polymer binder for thermal insulation of hot metal surfaces of industrial equipment, process plants, pipeline surfaces, operating at temperatures up to 100 0C. The heat-insulating coating is based on a polymer composition containing a mixture of acrylic polymer and styrene-butadiene rubber, hollow phenol-formaldehyde microspheres, pigment and water as a binder. The use of phenol-formaldehyde hollow microspheres in this composition in an amount of 20.0 to 40.0 wt. % as a filler, it allows to reduce the thermal conductivity of the developed coating and increase its strength characteristics, in comparison with a similar coating containing carbon microspheres. The use of this composition allows to obtain a polymer coating with high thermal insulation and mechanical properties.

Keywords: heat-insulating coating, acrylic polymer, styrene-butadiene rubber, hollow phenol-formaldehyde microspheres, tensile strength, thermal conductivity

One of the most pressing problems in the oil and gas industry is numerous pipeline accidents that require innovative solutions. This article analyzes a promising method of repair using composite couplings, which include many advantages compared to steel structures. The strength characteristics of the couplings are also given and their installation process is described.

Keywords: Oil pipeline, overhaul, reinforcing composite coupling, composite materials