bluuebunny/crossref_metadata_2025_split huggingface dataset:
DBN Concrete and reinforced concrete structures intended to operate under elevated and high temperatures
Authors: Fomin S L , Bondarenko Y V , Butenko S V , Plakhotnikova I A 
Published: December 2019

Abstract
Current codes and regulations are applied to the design of concrete and reinforced concrete structures intended to operate under conditions of systematic exposure to elevated and high technological temperatures. It is proposed to develop a statutory instrument to replace the SNiP 2.03.04-84 changing its status for the DBN one. The purpose of the project is to create a new national regulatory instrument, which is based on the modern achievements of science, machinery and technology, advanced domestic and foreign experience of design and construction and at the same time uses theoretical and experimental studies of the updated version of SNIP 2.03.04-84. This regulatory instrument is extremely necessary for the development of national production of Ukraine. The calculation of “Concrete and Reinforced Concrete Structures for High and High Temperature Exposure” begins with the definition using Eurocode 2 EN 1992-1-1:2005 at normal temperature of 20°C, then is followed by improvements using a mathematical model of the ratio “stress-strain” of concrete at elevated temperatures, refinement of the load-bearing criteria of concrete structures in EN 1994-1-2:2004. The determination of the maximum strain on the basis of the energy approach allowed us to formulate its adjusted dependence on temperature, the values of the parameters of the stress-strain diagram. According to these data, the stress-strain diagrams of concrete during compression and heating according to Eurocode EN 1992-1-2:2004 are calculated using the formulae of the first stage.
Mathematical model of concrete strain diagram under heating
Authors: Fomin S L , Butenko S V , Spirande K V , Iakymenko M V 
Published: December 2019

Abstract
New regulatory documents have been adopted and they have significant differences. Firstly, this is a new concept of calculation, a nonlinear deformation model, and secondly, new approaches to the assessment of reliability, loads and impacts, methods of construction. The calculation consists of two stages. The first begins with the determination of the concrete class at temperature of 20ºC. At the second stage, the calculation is carried out at high temperatures according to Eurocode 2 part 1-2. Comparison of the “stress - strain” diagram of concrete class at compression and temperature of 20ºC by two formulae showed their big gap. There was a need to improve the mathematical model of the ratio of stress-strain of the concrete under elevated temperatures. The method of determination of maximum strain based on energy approach has been developed in the work and allowed to formulate the adjusted dependence of the limit strain on temperature, dependence of maximum strain on temperature, values of the parameters of stress-strain diagram.
Small mobile fortification system for quick installation
Authors: Gasii G M , Hasii O V , Shushkevych V I , Sribniak N N 
Published: December 2019

Abstract
Unfortunately, today local armed conflicts practically do not fade in many points of our planet. Also Ukraine is among such points. The nature of the armed conflict happening in the similar “burning” points received the name of «hybrid» war. In such war there is no obvious front line, deeply echeloned defence and other attributes «classical» wars of the last years. Such war is characterized, in addition, separate armed collisions in the most various, sometimes absolutely unexpected, places. Problem of protection of the military personnel, which have necessary in accordance with the circumstances should be defended not the equipped dominating height with rocky or frozen soil, still remains unresolved. Today attention of the scientific different countries (the USA, Great Britain, Poland) working as in the sphere of individual protection of the military personnel, (bullet-proof vests, helmets and so forth), and in the sphere of small fortification and protection of military equipment, so-called «non-Newtonian» liquids attract. It occurs owing to their specific properties which it was today possible to use for increasing of bulletproof of a barrier. In this aspect authors solve a problem of development of the mobile parapet of fast expansion.
Thermal physical properties estimation of high-rise building fencing construction
Authors: Haponova L V , Hrebenchuk S S 
Published: December 2019

Abstract
Presentation and realization of according to the calculations, it is established that the process of water vapor condensation occurs in the three-layer structure of the outer wall for three months: December, January, February. The condensed moisture evaporates in the other months of the year. The increase in material humidity in the thickness of the structure in which moisture condensation can occur during the cold season is estimated. In this case, the layer is moistened because it is adjacent to the condensation zone on the inner surface of the wall by Δw=1.05%. The estimated increase in the construction material humidity in the cold season Δw=2.2%, exceeds the allowable for thermal insulation characteristics. Also, the distribution of fencing construction partial pressures at an outside air temperature of -23°C indicates moisture accumulation on almost the entire surface of the structure. Numerical implementation was carried out with the development of a constructive solution: the proposed air layer with the mandatory layer ventilation provision (convective air exchange). For this reason, given the inertia of the combined concrete wall, it is permissible to decide on the need for the wall interior of aerated concrete blocks.
Study of the vibration influence on load-bearing floor structures in case of machinery operation
Authors: Ilnytskyy B M , Kramarchuk A P , Bula S S , Bobalo T V 
Published: December 2019

Abstract
In this article, the impact of vibration loads on load-bearing floor structures is investigated. These loads were caused by machinery operation process in the five-storey factory building. Within this case study, examination of the structure was performed to measure the real vibration level and evaluate the damages to the structure. The analysis of the results has shown overloading the structures by machinery vibrations. The paper reflects a reasonable approach to rapid estimating of amplitude limits for floor structures avoiding complex calculations. Measured experimental values of amplitudes and precipitations under various productivity levels are given in this study. Theoretical and experimental data comparison appeared slabs subjected to vibration overloading and dynamic deflections. Some control points have shown significant exceeding amplitude limitations. Provided investigations of structure damages, in this case, also confirmed critical areas. It was revealed that incorrect machinery service entailed excessive vibration loads on the structures. Subsequent reinforcement works were provided to eliminate the cracks in structures.
Accounting of the dynamic pressure of bulk on the side surface in the world practice of designing building structures
Authors: Kalmykov Oleg , Khalife Rabie 
Published: December 2019

Abstract
This paper contains research of the seismic effects on the design of retaining walls. The present state of the technique of determining the pressure of the bulk medium on the side surface is analyzed. The basic theory of soil pressure on the retaining walls in static formulation is the Coulomb theory, according to which the pressure of the bulk medium on the lateral surface is determined by the condition of static equilibrium of a rigid wedge formed in the layer between the rear face of the structure and the sliding surface. In the works of Okabe and Mononobe, the proposed theory has evolved in the direction of dynamic influence accounting. To date, these studies are at the heart of current regulations. the issue of seismic component consideration in the calculation of retaining walls in the world design practice was analysed. The differences between the calculated dependencies of the US, Ukraine and Eurocodes codes are given. The reasons for the analyzed differences are identified and recommendations for their correction are offered.
Impact of low-cycle loads on deflections and width of crack opening of concrete beams with different types of reinforcement
Authors: Koval P M , Polyuha R I , Stoyanovych S V , Hrymak O Y , Komarov K O 
Published: December 2019

Abstract
The article presents the studies of the impact of low-cycle loads on experimental samples of concrete beams with different types of reinforcement – unstressed steel bars; steel pre-stressed reinforcement and unstressed reinforcement (mixed reinforcement); basalt-plastic reinforcement. Influence of low-cycle loads on the width of cracks opening and deflections of concrete beams were established. The research results of beams with steel reinforcement without pre-stressing, with pre-stressing and the beams with basalt-plastic reinforcement have shown interrelated proportional relative increase of the width of cracks opening and increase of deflections. Suggestions for consideration of the impact of low-cycle loads during the calculation of bending concrete beams reinforced with steel or basalt-plastic reinforcement by the second group of limit states were proposed. Coefficients determined experimentally for calculating the deflections and the width of cracks opening of the beams were introduced into the equation. Taking into account the impact of low-cycle loads during the calculation of bending concrete structures reinforced with steel or basalt-plastic reinforcement will provide higher reliability of such structures performance.
Methodology for assessment of the fire-resistant quality of reinforced-concrete floors protected by fire-retardant coatings
Authors: Kovalov A I , Otrosh Y A , Kovalevska T M , Safronov S O 
Published: December 2019

Abstract
In the work, the tests have been analysed for fire-resistant quality of hollow-core reinforced-concrete floors with fire-retardant plaster covering. A two-dimensional physical model and computer model have been developed in the ANSYS FLUENT software environment, which includes a system of equations and boundary conditions, taking into account the thermal conductivity in the coating and concrete, as well as complex convection-radiation heat transfer in air voids. A one-dimensional multilayer mathematical model has been developed, equivalent to a two-dimensional model of the thermal state of hollow-core reinforced-concrete floor with fire-retardant plaster covering, with the specific these layers’ thicknesses. A methodology has been developed in the article, based on solving the direct and inverse heat conduction problems, with the help of which it is possible to assess the fire-resistant quality of hollow-core reinforced-concrete floors with and without fire-retardant coatings. The developed methodology was applied to determine the thermophysical (heating constant and specific heating capacity per unit volume) and fire-retardant characteristics of the studied plaster covering according to the results of tests for fire-resistant quality of reinforced-concrete floors with this fire-retardant coating. The conclusion was made about the effectiveness of this coating and the boundaries of using the fire-retardant coatings to ensure normalizable values for the limit of the fire-resistant quality of hollow-core reinforced-concrete floors.
Deflections of continuous reinforced concrete elements
Authors: Krantovska O M , Ksonshkevych L M , Petrov M M , Synii S V , Ksonshkevych S M 
Published: December 2019

Abstract
The results of experimental investigations of deflections of continuous reinforced concrete elements are obtained, empirical dependences are deduced. Comparison of the deflection values with the results of calculations by the author’s method of NIISK (Bambura A.M.), adapted deformation model of OSACEA, what was realized with the help of the mathematical program MATLAB and also the algorithm of theoretical calculations of the finite element method was developed using the mathematical-graphical environment of the LIRA-SOFT software complex. The results of experimental investigations of deflections of continuous beams were compared with theoretical data (graphical representations of displacements in the form of isofields were obtained).The finite element calculation allowed to monitor the stress-strain state of the test beams at all stages of work, which made it possible to compare the obtained experimental values of the deflections with the designed ones. The performed experiments confirmed the feasibility of taking into account the shear deformations on the supporting sections in determining the deflections of reinforced concrete beams.
The research of carrying capacity of reinforced concrete walls under uneven warming
Authors: Nuianzin O , Tyshchenko O , Zhartovskyi S , Zaika P , Peregin A 
Published: December 2019

Abstract
The purpose of this article was to determine the dependence of the values of the boundary of the fire resistance of the bearing walls on the temperature dispersion on their heating surfaces as a scientific basis for improving the efficiency of the evaluation of the results of fire tests. In this paper, the problem of strength was determined to determine the bearing capacity of a reinforced concrete wall in a fire. During work, computational experiments using CFD and the finite element method were used. As a result of the studies, the dependence of the design values of the fire resistance of the reinforced concrete wall on the value of the maximum temperature dispersion on the heating surface of the structure during the fire tests and the error of the definition of the fire resistance limit was obtained, as well as the recommendations for creating new and improving existing furnace chambers from the tests on the fire resistance of the vertical reinforced concrete building constructions.
The criteria of estimating risks of spreading fire to adjacent building facilities
Authors: Nyzhnyk V V , Tarasenko O A , Kyrychenko O V , Kosiarum S O , Pozdieiev S V 
Published: December 2019

Abstract
The choice of heat flux receiver is justified in order to investigate the danger of spreading fire to adjacent building objects by the criterion of heat flux for measuring the heat flux density. It is suggested to use the heat flow receiver FOA-013-01. A technique was developed and experimental studies were conducted to determine the heat flux density acting on the elements of adjacent building sites. Measurements of heat flux values were performed by FOA 013-01 heat detectors, which were installed at distances of 2 m, 4 m and 6 m from the fire torch at a height of 1 m. The obtained heat flux density is, on average, for a distance of 2 m - 6.5 kW/m2, for distances of 4 m and 6 m - 1 kW/m2. Such data indicate a significant variability in the heat flux density over the observation period. Thus, experimental data call into question the possibility of using the “heat flux” criterion from a fire as a reliable criterion for evaluating the risk of fire spreading between adjacent building facilities. It has been suggested that the temperature criterion should be the basis for determining fire distance.
Estimation of fire resistance of bending reinforced concrete elements based on concrete with disperse fibers
Authors: Vasilchenko Alexey , Doronin Evgeny , Chernenko Oleksandr , Ponomarenko Ivan 
Published: December 2019

Abstract
The results of estimative calculations of bearing capacity, critical temperatures, and fire resistance ratings of reinforced concrete bending elements based on fiber concrete with disperse reinforcement of steel, basalt and synthetic fiber are presented. The calculations carried out on the example of a reinforced concrete rectangular beam both taking into account the percentage of reinforcement of each element and at a constant load corresponding to the condition of calculation adequacy showed that disperse reinforcement of a reinforced concrete bending element with steel, basalt and synthetic fiber increases its bearing capacity, but slightly affects critical temperature and fire resistance rating. Despite the fact that concrete with basalt fiber is the least sensitive to heat, concrete with steel and synthetic fibers turned out to be comparable in this indicator with ordinary concrete. The presented results of evaluative calculations allow predicting the use of bending reinforced concrete elements based on concrete with disperse fibers in conditions of increased fire hazard, depending on the percentage of reinforcement and on the workload.
Research of “influence area” parameters of the foundations arranged without soil
Authors: Zotsenko M L , Vynnykov Yu L , Pinchuk N M , Manzhalii S M 
Published: December 2019

Abstract
New relationships of shapes, sizes and properties formation for soils of the “influence area” of foundations and artificial bases, arranged without excavation, have been determined. The “influence area” parameters are decisive in assessing the stress-strain state of the system “base – foundation”. Field and laboratory methods of soil properties research of the “influence area” were improved: penetration; probing; rotational slip. A method of constructing the compaction area boundaries is considered, taking into account the shape, dimensions of the foundation cross-section and longitudinal profile, the type and properties of the base soil. For the first time, it is established that for soils with an angle of internal friction φ < 25°, the boundaries of the compaction area and the “influence area” are close to each other. When φ > 25° the boundaries of the “influence area” exceed the boundaries of the compaction area as more, the more the angle of internal friction of the soil. The relationship between the volume of the leading well and the soil compaction area diameter was also determined.
Physical and chemical research of the microstructure of the cement composite filled with allumosilicate and glass microphases
Authors: Bondarenko D O , Plakhotnikov K V , Kostuk T O , Dedenyova O B , Kalinin O A 
Published: December 2019

Abstract
Using the physical and chemical analysis, the possibility to obtain a dense and crack-resistant Portland cement-based composite material filled with aluminosilicate and glass microspheres and a complex additive which purposefully enhances each of the mentioned properties have investigated. During the molding of a composite material, in which particles of a filler and a binder have the same size in microns, micro-reinforcing fibrous additives will not be effective because their particles are larger than filler’s particles. To specify the conditions for the formation of a micro-reinforcing layer of etryngite needles and for increasing the density of the cement matrix structure, relevant theoretical and experimental studies were carried out and a complex additive consisting of calcium nitrate and chloride, carboxymethylcellulose and plasticizer was proposed. Based on the physical and chemical analysis performed, it has been found that adding a complex additive facilitates the compacting of the cement matrix structure through the additional synthesis of crystalline hydrates: ettringite, calcium hydrochloroaluminate, calcium hydroxychloride, and calcium hydrosilicates of the felt-like structure, which improves physical and mechanical properties of a Portland-based composite material.
Production of modified basalt fibre for heat-insulating products manufacturing
Authors: Gots V I , Berdnyk O Y , Rogozina N O , Maystrenko A A 
Published: December 2019

Abstract
As a result of the research flexible heat-insulating materials were developed based on basalt fiber with increased effectiveness, which can be achieved due to directed fiber microstructure forming through fusion modification. It is known that chemical composition of initial fusion not identically influences on physical and chemical and mechanical properties of basaltic fibres. Structural descriptions of fusion and basaltic fibre got from him appear main factors the nearer, than high speed of cooling. This index mainly depends on such constituents: a) ambient temperatures; b) coefficient of heat conducting; c) heat conducting of fusion; d) areas of surface. By researches influence of temperature of basaltic fusion was shown on the structure of fibres. Structural characteristics of the basalt fiber (number of active zones, coefficient of its distribution on the basalt fiber surface, as well as a correlation of three groups of active zones) depend on rheological properties of basal fusion, speed of drawing through the die plate and cooling speed.
Study of service properties of alkali-activated cement using wastewater treatment residues
Authors: Kovalchuk Oleksandr , Kochetov Genadiy , Samchenko Dmytro 
Published: December 2019

Abstract
The paper discloses the results of the study of treatment of galvanic wastewater residues by incorporation into the alkali-activated cement matrix. Leaching of heavy metals from the artificial stone was studied. It is set that immobilization level of the matrix is 99.96 % by mass of heavy metal (97.83 using traditional methods). Application of alkali-activated cement makes it possible to obtain compressive strength of compound up to 40 MPa even when 30 % of wastewater residues are involved. Immobilization level of alkali-activated cement matrix met requirements of the standard.
The effect of sodium aluminate on the properties of the composite cements
Authors: Kropyvnytska T P , Kaminskyy A T , Semeniv R M , Chekaylo M V 
Published: December 2019

Abstract
The effect of sodium aluminate activator on properties of the Portland-composite cement (clinker factor 65 %) was studied and the results are being discussed. It is shown that the introduction of sodium aluminate (Na[Al(OH)4]) leads to an increase in the water demand of cement and a decrease in its strength. The results showed that the sodium aluminate and polycarboxylate ether (PCE) admixtures ensure the production of higher strength cements. It has been found that the addition of Na[Al(OH)4] – PCE significantly increases the compressive strength of cement mortar, particularly at 10–48 h of hydration. XRD and SEM measurements confirm that the hydration of composite cement with the addition of Na[Al(OH)4] – PCE is greatly accelerated by the way of formation of intense lines ettringite. It has been shown that the introduction of a sodium aluminate into the cement mortars allows to accelerate hardening and increase early strength and using of composite cement will provide improved performance and suitability. The results have shown that alkaline accelerator and polycarboxylate were effective for decrease shrinkage of composite cements.
Disperse reinforced concrete with polycarboxylate additive on a mechanically activated binder
Authors: Ksonshkevych L M , Barabash I V , Krantovska O M , Synii S V , Sunak P O 
Published: December 2019

Abstract
The article discusses the properties of disperse reinforced claydite concrete on mechanically activated slag-portland cement with the addition of polycarboxylate superplasticizer Relaksol-Super PC. The idea of making a high-mobile claydite concrete mix with a settling of concrete cone 45 to 50 cm is substantiated. Particular attention is paid to the study of the effect of mechanical activation of the binder on the kinetics of the increasing in the strength of claydite concrete. The results of researches indicate that introduction of basalt fiber into slag-portland cement together with mechanical activation of binder allows to increase the impact strength of concrete by almost 1.7-1.9 times in comparison with the reference and to provide frost resistance of concrete at least than 350 cycles of alternating freezing and thawing.