A review of the literature concerning the molding of centrifuged concrete products was carried out. The peculiarities of centrifugation of concrete, in particular, the manufacture of centrifuged pipes, have been studied. The main parameters and indices of the quality of concrete and the centrifuged tubes themselves are considered. The traditional mode of forming non-pressure pipes is described. The calculation formulas for the parameters of the centrifugation process and their graphical dependences are given. Based on the calculated data, it is concluded that the traditional modes of shaping of non-pressure pipes are characterized by the rotation speed of the mold from 82 to 300 rpm in the stages of loading and distribution of the concrete mixture. At the sealing stage, the control of the rotation speed of the mold varies over a very wide range and depends largely on the viscosity of the concrete mix and the pressing pressure: from 825 to 4400 rpm for concrete pipes with a diameter of 100 to 300 mm. Modeling the parameters of the molding regime during the centrifugation of ring-shaped products in a laboratory installation at a maximum compaction pressure of p = 2.16 kg/cm2 will allow us to refine the obtained data and study their effect on the variability of the concrete structure

Keywords: centrifugal force, centrifugation parameters, charging speed of the mold, speed distribution of the shape, sealing speed of the mold, pressing pressure, centrifugation time, ring-shaped products

Advantages of concrete paving slabs (CPS) are shown in front of asphalt pavements. The problem of preservation of decorativeness and durability of CPS in connection with porous structure of concrete is revealed. The need to reduce the capillary water saturation of CPS, including through the use of water repellents, is established. Field and laboratory studies of a number of hydrophobizing preparations have been carried out. The order of application of hydrophobizators and evaluation of properties is characterized. The results of a quantitative and scaled assessment of the properties of CPS after application of the preparations are presented. Hydrophobizers, which minimize the water saturation and water absorption of CPS, increase the resistance to UV radiation, alternating and elevated temperatures and reduce the peel strength of the frozen sample of concrete are determined.

Keywords: paving slab, concrete, paving elements, decorativeness, durability, porosity, capillary water saturation, hydrophobizing preparation, water absorption, peel strength

The purpose of this paper is to identify to main areas of application of fibrous concrete based on the overview of foreign scientific works published over the last year. It is found that the studies are mainly focused on possible applications of fibrous concrete that are aimed at strengthening brick, concrete and wooden structural elements as part of building reconstruction. Part of the studies discusses the issue of recycling construction waste, especially glass and concrete, and using it to produce fibrous concrete. This approach allows maintaining the environmental balance, as the issues of industrial waste disposal remain topical for all countries of the world.

Keywords: Application of fibrous concrete, recycling of construction waste, environmental conservation

The experience of applying centrifugation as a molding and compacting method has opened new prospects for the production of highly efficient reinforced concrete products. The experience of production of centrifuged power line supports at one of the enterprises of the Socialist Republic of Vietnam is analyzed. The studies aimed at studying the change in the composition of the mixture during centrifugation and the kinetics of the strength of centrifuged concrete were carried out. The dependence of the ultimate strength of centrifuged concrete on compression on the value of B / W after HMT (heat and moisture treatment) and at the age of 3-7 days was studied. Conclusions are made on the correction of the known quantitative regularities of the change in the strength of vibrating concrete from the value of B / W and the porosity, taking into account the heterogeneity of the structure of the centrifuged concrete over the cross section.

Keywords: centrifugation, heavy concrete, concrete mixture, power line supports, additives to concrete, enterprises for the production of reinforced concrete products

In the article features of work of monolithic overlap on the profiled flooring, leaning against steel I-beams, reinforced by pre-stressed bar reinforcement are considered. Often, when changing the functional purpose of a building or redevelopment, strengthening the structure of the floor is required to ensure strength. In addition, at spans of more than 7 meters, deflections exceeding the limit values may develop, which lead to a decrease in reliability and durability, and a deterioration in the appearance of the overlappings. The purpose of this study is to find the optimum reinforcement of the floor beams. To strengthen the proposed installation of prestressed reinforcement in the lower girdle of the beam, which increases the strength and reduces the deflections of the beams. In such ceilings, the bending moment from external loads is distributed between the structural elements: the beam and the reinforced concrete overlap, in accordance with the ratio of the stiffnesses of these components. As a result of the study, the optimal diameters of prestressed reinforcement for steel beams by spans from 6 to 9 m were determined and for the calculated linear load from 5 to 30 kN/m. The proposed reinforcement option allows to increase bearing capacity, reduce deflections, reduce labor costs for building reconstruction, and also increase the reliability and durability of the structure.

Keywords: reinforced concrete floor, gain, prestressed reinforcement, I-beams, overlap on profiled flooring

Studied the possibility of disposing of chromium waste galvanic production, their use in the manufacture of ceramic products and production of building materials based on hydraulic binders. The plasticizing effect of galvanizing is revealed and it is established that at use of slurries in the form of additives in concrete and solutions leads to decrease in consumption of cement at equal durability.

Keywords: electroplating sludge, industrial waste, chromium-containing waste, recycling, concrete additive, plasticizing effect

Short data on efficiency of a fibrobeton on the basis of heavy quartz sand are provided in work. Taking into account existence of huge reserves of natural porous fillers (the tufa, pumice, pummitsit, etc.) in various regions of Russia and also the fillers received on the basis of industry waste the relevance of a research of a stalefibrobeton with easily concrete matrixes is proved. Experimental selection of optimum composition of concrete on the basis of tuff filler of the Kamensk field of Kabardino-Balkar Republic regarding his use as a matrix of a stalefibrotufobeton (SFTB) is executed . The picked-up structure has been used for creation of skilled combined and monolithic samples of beams which should be tested. During formation of beams control samples of a stalefibrotufobeton have been selected and tested. Results of tests of control samples for compression, stretching and a bend demonstrate that fiber reinforcing exerts significant positive effect on strength and deformativny properties of a tufobeton. Data of experimental research confirm a possibility of using tufobeton in the stalefibrobetonnykh designs.

Keywords: Stalefibrotufobeton, steel fiber, matrix, volume percent of fiber reinforcing, stretching, compression, bend, dynamic influences, zone placement

"he article gives a technical and economic comparison of the calculation results for two grades of steel VSt3ps4 and 16G2AF. The features of steel grades are analyzed. The comparison of the weight and cost of belts of curved rafter trusses is given. The results show that the use of increased strength in the steel structures under investigation is not only less metal-consuming, but also more economical. Despite the fact that the cost of 16G2AF steel pipes is 25% higher than the cost of Bst3pc4 steel pipes, a total cost saving of belts of 28% was obtained. This is explained by the significantly lower weight of belts made of 16G2AF steel. This research is relevant in that the result of the work done demonstrates which mark has become more appropriate to choose for large span farms in the design. The above engineering calculations confirm that the use of steel 16G2AF for metal curvilinear trusses, 48m flight is more economically advantageous. The weight of the belts for 16G2AF steel is almost half that of VST3PS4. As a result, the analysis of the performed calculations allows us to draw the following conclusions: Due to the fact that the design resistance Ry of steel 16G2AF is 67% higher than the design resistance of steel VSt3ps4, the metal savings due to the reduction of the cross-sectional area of the belts in the amount of 47% were obtained.

Keywords: curved truss, technical and economic comparison, steel grade, high-strength steel

The optimum coefficients for the use of materials for combined beams in a wide range of loads are obtained in the article. The principles of designing and calculating the strength of Steel Reinforced Concrete slabs are outlined in accordance with SR 266.1325800.2016 ""Steel Reinforced Concrete Structures. Design rules"". Strength calculations are performed, the results of a numerical experiment are compared and analyzed. The optimal utilization factor of materials obtained in accordance with the specified regulatory document was established. The results obtained can be used in the design of combined beams of different cross-sections and spans. The purpose of this study is to find the optimum reinforcement of the floor beams. To strengthen the proposed installation of prestressed reinforcement in the lower girdle of the beam, which increases the strength and reduces the deflections of the beams. In such ceilings, the bending moment from external loads is distributed between the structural elements: the beam and the reinforced concrete overlap, in accordance with the ratio of the stiffnesses of these components. As a result of the study, the optimal diameters of prestressed reinforcement for steel beams by spans from 6 to 9 m were determined and for the calculated linear load from 5 to 30 kN/m. The proposed reinforcement option allows to increase bearing capacity, reduce deflections, reduce labor costs for building reconstruction, and also increase the reliability and durability of the structure.

Keywords: Steel reinforced concrete, floors, combined beams, profiled sheet, coefficient of use of materials

The possibility of using an additive based on amorphous aluminosilicates in the formulation of calcareous dry construction mixtures as a modifying additive that increases the thermal insulation properties of the solution based on the mixture being developed is investigated. Several compositions of an aluminosilicate additive with different proportions of raw components have been considered. For determine the optimum mode of synthesis of the test additive, special attention was paid to the change in the porosity and compressive strength of the calcareous composite. Optimum content of aluminosilicate additive in the composition of calcareous composite was selected. The degree of influence of the magnitude of the liquid glass module used in the production of the aluminosilicate additive on the change in the strength of the calcareous composite with the use of a modifying additive was evaluated. The change in the strength, density, and porosity of a calcareous composite was studied in the presence of the additive being developed, depending on the temperature regime and the duration of the synthesis of amorphous aluminosilicates. It has been established that the temperature and heat treatment time of the aluminosilicate additive does not significantly affect the density of the cement composite. It was also found that the use of an additive based on amorphous aluminosilicates in the composition of calcareous dry construction mixtures leads to an increase in the porosity of the samples as compared to the control samples (without additive).

Keywords: amorphous aluminosilicates, dry building mixtures, lime, strength, synthesis, modifying additives, analysis

The article contains an analysis of the shortcomings of the majority of existing stabilizing additives for shale-mastic asphalt-concrete mixtures. In the paper, the results of the use as a stabilizing additive for blast-mastic asphalt-concrete mixtures of a composition consisting of cellulose fibers treated with organic binder and mineral fiber are considered.

Keywords: stabilizing additive, crushed-mastic asphalt concrete, cellulose fiber, mineral fiber, bituminous binder, road surface

The peculiarities of the deformation diagram under short-term central axial compression of concrete of the frame structure of class B60, obtained by immersing a large aggregate in a low-viscosity solution component, are revealed. The boundaries of microcrack formation of concrete are determined. A good correspondence of the main regularities of the change in the tensile strength and deformation properties of a concrete frame structure with some known data is shown. The possibility of an analytical description of the deformation diagram of a concrete frame structure known formula Sargine (Sargine) is confirmed. Data are presented on the change in the initial modulus of elasticity, the Poisson's ratio, the change in the volume of concrete and the propagation velocity of ultrasound in concrete, depending on the level of loading. The ratio of cubical and prismatic strength is given. The conclusion is made about the expediency of using concrete frame structure in reinforced concrete columns.

Keywords: concrete frame structure, tensile strength, modulus of elasticity, deformation diagram, parametric points, microcrack formation, superplasticizing additive

The possibility of determining the physical and mechanical properties of materials on the basis of measuring the fractal dimension of its structure is considered in the article. It is shown that there is a definite dependence between the composition of the cement composite and the fractal dimension, and, consequently, similar dependencies can be obtained for various physicomechanical parameters.

Keywords: Fractal dimension, microstructure, mathematical experiment planning, variable factors, three-component system, polynomial equation, regression coefficients

In this article the relevance of development of the wood concrete meeting the modern requirements for an ecological component and energy efficiency is considered. Features of the mechanism of structurization at hydration of the cement knitting and organic filler with use of the X-ray diffraction analysis are shown. Indicators of concentration of basic elements in the cement test without organic filler are defined and at his existence. The comparative analysis of structure of steam solution of wood concrete and structure of solution from quick-hardening cement with use of data of a rastroelektronny microscope is carried out.

Keywords: Ivashchenko Y.G., Laushkina V. A., Timokhin D.K.

The history of development and efficiency of application of pipe-concrete structures during the erection of buildings and structures of various technical purposes is considered. The application of pipe-concrete columns for the purpose of restoring the operational reliability and load-carrying capacity of prefabricated reinforced concrete structures of the production building during its reconstruction is considered. Calculation of the bearing capacity taking into account additional loads and checking the strength of sections of the pipe-concrete column according to the deformation model have been made.

Keywords: concrete, pipe-concrete, load-bearing capacity, reinforced concrete, building structures, reinforcement, constant load, strength, operational reliability, deformation

The article deals with the use of enamel for concrete surfaces as a pile coating to reduce their frictional interaction with the soil of the foundation. Conducting tests and processing the results.

Keywords: piles, friction interaction, frictional force

The paper presents the results of a study of the physico-mechanical properties of the granular colorless binder "Recofal" and polymer concrete prepared on its basis.

Keywords: Colored polymer concrete, granular binder "Recofal", physical and mechanical properties, polymers, pigments

The results of studies on the development of composition gypsum solution mixtures on the pumice with the application of a multifunctional additive D, are represented. Are proposed the compositions of mortars on composition gypsum that binding and ashes, that make it possible to substantially improve the physicomechanical properties of solution mixtures and solution. The introduction of multifunctional additive D -5 to solution mixtures makes it possible to improve the properties of composition solution mixtures. The developed composition gypsum solution mixtures correspond to requirements ALL-UNION STATE STAN. 28013–98 and have low prime cost due to the use of the pumice

Keywords: gypsum, portland cement, pumice, additive D -5, composition gypsum mix, transverse strength and compression, density, the coefficient of the softening

The influence of finely ground zeolite-containing rock on the properties of fine-grained concrete mixtures is considered and its interaction with cement. Defined optimal dosage of the zeolite-containing rock, which increases strength under bending and compression.

Keywords: fine-grained concrete, fine-grained concrete, zeolite-containing rock, finely ground filler, mineral additive

Some kinds of construction materials, notably rock is subjected to burning while producing construction materials. One of the materials is clay. The aim of the research is to ascertain if burning of clay rocks influences changes of specific and effective specific activity of natural radionuclides. The selected samples of clay were subjected to phasic burning. After each phase specific activities of natural radionuclides were establiched, and their effective specific activity was calculated. The undertaken research acquired data served a matter for further analysis and searching dependencies. The reserch results analysis having been made, it managed to establish, that there exists a correlation of different power degree berween burning temperature and specific activity. On the example of one of the clays researched there was drawn a polynomial regression pattern. When being aware of radiation characteristics and burning temperature of clay stock, the pattern will allow calculate radiation characteristics of the finished product. This will allow control (decrease) the radioactivity level of the finished product, i.e. ceramic materials and items.

Keywords: natural radioactivity, burning, clay rocks, radionuclide, correlation analysis, polynomial regression

The imbalance in the development of the forestry, with respect to the valuable and non-standard woods used by the construction enterprises, entails an ecological catastrophe in the regions. For the wide use of hardwood in the production of building materials and products, a technology has been developed to direct the development of operational properties. Modification of the structure of the wood due to volumetric impregnation of capillaries helps to reduce water absorption, increase fire resistance and biostability of wood, and also contributes to meeting the growing needs of producers of wood-based building materials in a cheap local raw material quickly renewable resource base

Keywords: wood, construction, fire resistance, hardwoods, modified wood, biosphere

The review of existing nanomaterials for stabilization of clay soils is carried out. The possibilities and limitations of the known nanotechnological approaches to the stabilization of clay soils are analyzed. The influence of nanomaterials on the physical and mechanical properties of clay soils is described.

Keywords: soil, clay mineral, bearing capacity, soil stabilization, nanomaterial

One of the most important strategic tasks, the solution of which is aimed at the development of the construction complex, is to improve the quality and competitiveness of construction products. In work the technique of an estimation of competitiveness of building production with the account of the criteria characterizing the basic properties and cost of considered objects is offered. The application of this methodology allows us to obtain not only reliable results of assessing the competitiveness of products, but also to determine the degree of improvement for each of the analyzed criteria after the corrective and preventive measures taken to improve the quality of products.

Keywords: quality, competitiveness, plastic window construction, profile system, weight ratio, integrated priority

The advantages of using polypropylene fiber in technology of geopolymer concrete were considered. It was established that the use of dispersed reinforcement makes it possible to improve the critical characteristics for this type of concrete: strength, crack resistance and shrinkage. It was shown that an important problem of using polypropylene fiber is obtaining of a homogeneous structure of concrete with fiber. The effectiveness of various ways of introducing polypropylene fiber VSM into fine grained geopolymer concrete mixture was studied. It was found that the most effective way of introducing fiber is pre-mix it with a moistened fine aggregate.

Keywords: "geopolymer, fine-grained concrete, disperse reinforcement, polypropylene fiber, mixing technology, compressive strength, flexural strength, homogeneity, granite, slag "

The article deals with the improvement of air quality in the environment through the use of self-cleaning building materials. The photocatalysis process is analyzed. Examples of realized objects with self-cleaning materials are given.

Keywords: urban pollution, air purification, self-cleaning building materials, photocatalysis, photocatalytic reactions, self-washing