Using simulation and finite element method calculations of stress-strain state of monolithic concrete support for underground structures with non-circular outlines made of fast-hardening concrete are carried out in the paper. Based on the obtained results, the maximum stress zones and their magnitude in the reinforced concrete support are established. The stresses are compared with circular-form supports. The factors influencing the stress state of the support are determined.

Keywords: Underground structures; soils; concrete support; voltage; the experiment plan; modeling; finite element method

High cost and shortage of cement in the construction market of the Russian Federation determines the need to find ways to save it. One of the promising directions of improving the technology of concrete, providing the opportunity for significant savings of cement is the production of concretes of new generation. Such concretes are of high quality or highly functional. Mandatory element of the technology of such concretes is the introduction in their composition of organic additives (OMD). Using the methods of the experiment planning theory in the developed compositions of organic additives depending on the fineness of the mineral component and dosage of superplasticizer. It is established that the use of the proposed organic-mineral additives will allow to save from 15 to 30% of cement without loss of concrete strength.

Keywords: saving of cement, superplasticizer, mineral component, organic additive, the strength of concrete, design of experiments

Density distribution, equivalent hydraulic radius, similarity criterion, statistical probability, pore space, fine-dispersed filler, differential porosity.

Keywords: Density distribution, equivalent hydraulic radius, similarity criterion, statistical probability, pore space, fine-dispersed filler, differential porosity

Abstract: field application of lignosulfonate as a chemical additive for use in gypsum compositions. The influence of lignosulfonate on the physical and mechanical properties of pigmented plaster. The work studied the effect of lignosulfonate on properties of gypsum as strength properties, water absorption, softening coefficient and the changing colors of the material. Established that the application of lignosulfonate to a considerable extent not only improves the physico-mechanical properties of the material, but also its operational durability of pigmented gypsum, which expands the scope of these materials.

Keywords: lignosulfonate, pigmented plaster, physico-mechanical properties, strength properties, water absorption, coefficient of softening, change of color, long service life

The physicochemical properties of bitumen samples of road oil improved have been studied. It is established that the samples submitted for testing meet the regulatory requirements practically throughout the entire range of tests, except for the values ​​determined after heating the binder in a thin film according to the procedure of EN 12607-2 (EN 12607-1), which, apparently, indicates the insufficient stability of these bitumens to thermal and oxidative aging. The influence of the adhesive additive on the intensity of bitumen wetting of the surface of mineral materials was studied

Keywords: bitumen petroleum road improved, resistance to thermal and oxidative aging, regulatory requirements

From the pilot section of the gas pipeline, after ten years of operation, specimen-witnesses were seized. The gas pipeline consists of reinforced polyethylene pipes with an average adhesive reinforcing layer. The results of mechanical tests of model samples are given in the article. Investigations of the deformation-strength properties of the witness specimens show a decrease in the temperature of the viscous-brittle transition to -15 ° C. These results indicate a deterioration in the adhesion between the outer layers of PE80 and the middle technological layer. Good adhesion led to the emergence and development of a fragile crack. Stability tests at constant pressure showed satisfactory results, not a single sample collapsed. According to the research data, the reinforced polyethylene pipe did not deteriorate its deformation-strength properties for ten years of operation of the gas pipeline under pressure.

Keywords: Reinforced polyethylene pipe, specimen-witnesses, adhesion, stretching, viscous-brittle transition, resistance at constant internal pressure

Discusses actual problems of determination of the resistance and protection of concrete structures – slabs, produced by standart adopted in the Russian Federation and the United States. Studied national and international experience of evaluation and quality control, measures to preserve the integrity and stability of structures to various types of exposure. The focus is on those conclusions that must be made from the analysis of the causes of destruction in order to avoid future repetition of mistakes and miscalculations that are allowed currently in the design and construction of engineering structures and which often lead to the occurrence of accidents.

Keywords: methods of quality control, concrete structures, failures of engineering structures

The composition of non-autoclaved aerated concrete with blast-furnace granular slag was developed and optimized, which was introduced in an amount from 5 to 15% instead of a part of the silica component (quartz sand) into aerated concrete. By the results of optimization by the method of least squares, the basic regression equations were obtained in the form of polynomials of the second degree and the optimal compositions of non-autoclaved cellular concrete with the addition of blast-furnace granular slag. In this case, the most effective is a dosage of 15%, which has a positive effect on the increase in strength of cellular concrete in comparison with the control composition and does not lead to an increase in the average density.

Keywords: non-autoclaved aerated concrete, active mineral additive, medium density in the dry state, compressive strength, blast-furnace granular slag, least-squares method, regression equation, silica component

The methods of directed formation of the variational structure of concrete products and structures are considered in the article. The experience of Russian scientists in the issues of obtaining articles of different density over the section has been studied. The problems of the technology of obtaining articles of different density along the section are considered, the main principles of shaping the variational pore structure of aerated concrete for monolithic enclosing structures, the optimal schemes for forming two-layer wall products from concrete of various densities, forming a structure with a double skeleton - mineral and polymeric - by sintering the polystyrene grains, the formation of variational structure of magnesian foam concrete, which involves sequential laying of foam masses with various average, perspectivity of the use of reinforced concrete constructions of a variational structure.

Keywords: Variational structure, concrete products and structures, reinforced concrete, aerated concrete, foam concrete, expanded clay concrete, density, fire resistance

The material of the C-profiles in question, manufactured by the continuous rolling method, is galvanized steel up to 3.0 mm thick. Thin-walledness and the shape of the cross-section, causes a number of features of the profiles under load. The valid design norms in addition to the basic geometric parameters of the cross-sections used in calculating the longitudinal and bending forces (A is the cross-sectional area, Sx, Sv are the static moments of the section, Ix, Iv, Ixy are the axial and centrifugal moments of inertia) , Suggest the use of sector-specific characteristics. These characteristics are peculiar only to thin-walled rods and are determined on the basis of the notion of a sectorial area. The problem of determining the geometric characteristics of a thin-walled C-shaped profile is considered. The center of the bending is taken to be the point with respect to which the moment from the tangential forces arising during transverse bending or torsion in the cross section is zero. The position of the bending center does not depend on the forces acting on the rod, but depends only on the shape and dimensions of the cross-section of the thin-walled rod.

Keywords: steel structures, calculation of structures, thin-walled, profile, c-shaped, geometric characteristics, bending center

For a research of features of formation of temperature and high-speed fields in volume of the electrosteel-smelting shop at various ways of distribution of stitched air the three-dimensional non-stationary model is used. By results of the made numerical experiment for the description of spatial distribution of air and thermal streams in the shop it is established that the most rational way of supply of stitched air in the considered shops is the way of "flooding of a working zone".

Keywords: microclimate, all-exchange ventilation, air distributor, convective streams, stitched streams, electrosteel-smelting furnaces, speed, temperature

The influence of dropping out of kamnedrobleniya and mineral filler, included in its composition, the fine-grained characteristics of self-compacting concrete.Studies have shown the efficacy of combined use in the composition of the fine self-compacting concrete dropping out of kamnedrobleniya fractions of 2.5-5 mm, and mineral filler mixture fractions 0-2,5 mm. At the optimum dosage of the products of kamnedrobleniya and modifying additives in the composition of fine-grained mixtures ensure the required flow characteristics of the concrete mix achieved the required strength of the concrete. Mineral filler – dust component of dropping out of kamnedrobleniya allows to increase the total volume of the test binder, sufficient to fill the intergranular voids and coating grains of a filler, and contributes to water-holding capacity and the persistence of the mixture.

Keywords: kamnedrobleniya screenings, mineral filler, fine self-compacting concrete, superplasticizer, water-retaining additive, the spreadability of the mixture, keeping the mixture, the strength of concrete

The paper presents the design procedure and the appointment of the composition of the molding mixtures, which is based on computational-experimental approach to the determination of the composition taking into account the quality of the used raw materials and requirements to the properties of concrete manufactured products

Keywords: Raw materials, grain structure, concrete, svezheulozhennye mix, precast products, hard pressing, block diagram

The influence of viscosity modifier brand BASF on rheological properties of self-compacting mixtures and the kinetics of curing of concrete. When determining the spreadability of the mixture with the locking ring installed, that the use of the modifier with water-retention effect increases the fluidity of the mixture, despite the presence of obstacles. During the complex introduction of superplasticizer and viscosity modifier was an increase in water demand of the mix, resulting in a loss of concrete strength. The possibility of obtaining smart dynamic concrete and the effectiveness of the use of the viscosity modifier in combination with various additives should be set on the utilization of cement in concrete.To ensure the competitiveness of the smart dynamic concrete viscosity modifier it is necessary to design the composition with the lowest specific consumption of cement due to the rational grain composition of the filler and the optimum dosage of chemical additives.

Keywords: self-compacting concrete, smart dynamic concrete, a superplasticizer, a viscosity modifier, a locking ring, the spreadability of the mixture, the rheological characteristics of the mixture, the strength of concrete, the utilization rate of cement

The paper describes the role of inert mineral additives in concrete technology. It was found that inert mineral additives are expediently use together with superplasticizers for the preparation of concrete mixtures with high workability at low cement consumption. It was shown that the negative effect of inert additives on strength decreases with a decrease in the water-cement ratio due to an increase in the proportion of cement hydration products and a reduction in the pore volume in a cement stone prepared with the use of inert mineral additives. There was established that the most promising direction of using these materials is the production of high-fluidity and self-compacting concretes of low and medium class with high frost resistance, water resistance and corrosion resistance

Keywords: "concrete, inert mineral additive, superplasticizer, workability, strength "

Abstract: Among the variety of modern mineral binders occupy a special place gypsum binder, which has many positive properties: efficiency of production in comparison with cement, quick hardening, architectural expressiveness of features with the use of pigments, abundance of raw materials and high technology. However, its application is limited by low resistance of the material. The paper presents a brief analysis of the main methods of improving the water resistance developed at the moment in construction: increasing the density of products, improvement of water resistance by impregnating the surface of various materials, the use of various chemical additives, a decrease in the solubility in water of calcium sulphate, the use of combined methods of improving the water resistance, the creation of composite

Keywords: Keywords: gypsum binders, improvement of water resistance, impregnation, chemical additives, composite materials.

In the article the problems of the technology of aerated concrete products of non-autoclaved hardening are considered and the literature data concerning the study of the influence of various factors on manufacturing technology are analyzed. The results of experimental studies devoted to the study of the role of additives of various types in the formation of aerocrete structure are presented. The influence of three factors was investigated: the type of surfactant introduced into the aerated concrete mix; presence of caustic soda additive; the consumption of aluminum powder on the process of structure formation and the properties of non-autoclaved aerated concrete. The obtained data made it possible to take a detergent powder as a surfactant in further experiments. It has been experimentally confirmed that exclusion of caustic soda from the composition of the aerated concrete mix leads to a decrease in alkalinity, and accordingly the gas release reaction proceeds much more slowly, which leads to an increase in the density of aerated concrete, the appearance of defects on the surface of products, and a significant increase in rejects. The optimal content of aluminum powder in the composition of aerated concrete is determined, which corresponds to grade PAP-1 - 5.75 g.

Keywords: Non-autoclaved aerated concrete, additive, surfactant, caustic soda, aluminum powder, gasifier, gassing

This article considers the influence of a structuring additive on the physical and mechanical properties of aerated concrete. As a structuring additive, a by-product was introduced into the composition of the aerated concrete mixture by cutting the top layer of the "gorbuschka" in an amount of 10 to 30%. Comparative analysis of the results of physical and mechanical tests of aerated concrete samples with different amount of structuring additive showed that its introduction increases the compressive strength, while simultaneously increasing the density of aerated concrete. At the same time, the value of the constructive quality factor in GB4 (with 20% of the "gorbuschka") is 20.4% higher than in GB2 (with 30% of the "gorbuschka") and 31% higher than for the aerated concrete base composition GB1 (control) that allowed us to take him for the optimal composition in further research.

Keywords: "gorbuschka", structuring of aerated concrete, non-autoclaved aerated concrete, structuring additive, swelling process, plastic strength of the structure, constructive quality coefficient, average density in the dry state, compressive strength

Abstract: the main applications of pigments in the building and abroad. This paper studied the influence of pigments on the physico-mechanical properties of gypsum - strength properties, water absorption, softening coefficient and the capillary suction material. It is established that one of the important characteristics of gypsum composite is a capillary suction material, which determines to a considerable extent not only the physico-mechanical properties of the material, but also its operational durability.

Keywords: Key words: pigments, physico-mechanical properties, strength properties, water absorption, softening coefficient, capillary leak, long service life

The paper describes the effect of dosage of polypropylene fiber on mixture consistency, flexural strength and compression strength and impact strength of fine-grained concrete. It was established that introduction of fiber leads to a certain decrease of consistency of the mixture, but bleeding are significantly decreases. It was found that the reason for the decrease in strength characteristics of concrete with addition of fiber can be related to heterogeneity of distribution of additive in material volume. Therefore, in order to increase the efficiency of use of fiber, necessary to use methods for preparing mixtures with fiber, which ensure a high uniformity of distribution of the additive in material. It was shown that micro-reinforcement increases impact resistance, even with insufficient quality mixing

Keywords: fine-grained concrete, propylene fiber, flexural strength , compressive strength, impact strength, heterogeneity

In the article the main types of corrosion of concrete, such as chloride, sulfate, acid and carbon dioxide, are considered, the mechanism of cement stone damage is given. The danger of leaching of concrete is shown. Protection of bridges from penetration of aggressive moisture is waterproofing. Materials used for the device of waterproofing in our country are given, their advantages and disadvantages.

Keywords: Waterproofing bridges, carbon dioxide corrosion, chloride corrosion, acid corrosion, concrete leaching, waterproofing materials, adhesion

To date, almost none modern construction site can do without the use of cement. Ease of use and financial accessibility make this material indispensable for most construction works. Therefore, it is very important that the cement stone obtained during construction meets the necessary requirements when erecting construction projects. The theoretical aspect of the issue of dependence of the water-cement ratio on strength is considered in the article. A number of experiments were performed, taking into account the experience of other researchers with the aim of determining the reliability of data, obtained earlier. The results obtained during the experiment confirmed that the increase in water-cement leads to a decrease in the strength of the cement stone.

Keywords: Cement, water, water-cement ratio, active cement, concrete, sand, strength, compression, dispersion, Portland cement

V stat'e rassmatrivajutsja problemy zhelezobetonnyh proletnyh stroenij dlinoj menee 35m. provoditsja analiz otechestvennyh i zarubezhnyh balok proletnyh stroenij, pri analize uchityvajutsja takie harakteristiki balok kak, ves konstrukcii, mezhremontnyj srok sluzhby proljotnyh stroenij, rastjagivajushhie naprjazhenija, vosprinimaemaja nagruzka, dolgovechnost', sul'fatostojkost' balki.

Keywords: tipovoe proektirovanie, balki, zhelezobetonnye konstrukcii, proljotnye stroenija mostov, tipovoj proekt, ramno-nerazreznoj, mosty, nagruzka, mezhremontnyj srok, prochnost', dolgovechnost

The article notes the need to ensure the quality of road surfaces by using modified bituminous binders. It is emphasized that this problem is typical not only for Russia, but also for other countries. Areas of application of modified bituminous binders are described. Compositions and technology of hot asphalt-concrete mixtures with the use of modified bitumen are proposed. It is pointed out that asphalt mixes prepared on the basis of modified bitumen give high strength parameters and meet the requirements of existing state standards. The results of experimental and theoretical studies, published by the authors, will allow us to study in more detail the properties and technologies of other types of asphalt-concrete mixtures in the future

Keywords: Road surface, modified bitumen, adhesion, additive, technology, composition, strength, rutting, crack resistance.

Air pollution in residential areas near industrial plants is one of the most significant problems of modern ecology. The resulting dust is one of the important factors in assessing the adverse impact on the environment. Studies show that the greatest danger to the human body is particles up to 10 microns in size. When analyzing the dispersion of dust in the residential and industrial areas, it is possible to estimate the percentage of particles PM10 and PM2.5 from the total amount that is necessary to effectively control the effects of dust on human health. The article gives a comparative analysis of the results of studies of the dispersion composition and dust concentration in the air of the working zone and the urban environment.

Keywords: sources of pollution, atmospheric air, dispersed analysis, PM10, PM2.5, dust, microscopic method, laser method, concentration, sanitary protection zone