33407
2304-6295
Construction of Unique Buildings and Structures
7
105
2022
1-60
RAR
RUS
10501-10501
O-6995-2019
6508103761
0000-0002-1196-8004
Vatin
Nikolai Ivanovich
Peter the Great St. Petersburg Polytechnic University
vatin@mail.ru
St. Petersburg, Russian Federation
0000-0003-2626-2626
Kotov
Evgeny Vladimirovich
Peter the Great St. Petersburg Polytechnic University
ekotov.cfd@gmail.com
St. Petersburg, Russian Federation
Horobrov
Svyatoslav
Analytical solution of the problem of flow in a porous rectangular bulkhead
The object of study is an unsteady pressureless filtration flow in a porous isotropic medium, in which the region of motion is limited from above by a free surface, on which the fluid pressure is constant and equal to the external atmospheric pressure. Such currents are characteristic of groundwater filtration through hydraulic structures (dams, water drawdowns, drainages, foundations, pits during their drainage). The aim of the study is to solve the problem of non-stationary gravitational flow of a fluid in a scalar porous medium with two-dimensional filtration motion in a vertical plane. To achieve it, the limiting problem of non-stationary filtration theory (Boussinesq) for a scalar porous medium is formulated using dimensionless factorization, which allows solving groups of problems for areas with similar domains of definition. The Boussinesq limit problem is reduced to a typical limit problem for Crocco's ordinary differential equation. Crocco's limiting problem is formulated and solved. An analytical solution of the limit problem for a rectangular bridge is obtained. The solution is used to determine the depth of the filtration flow in the downstream of the cofferdam. The paper proves that the limiting problems of non-stationary filtration in the vertical plane are identical to the limiting problems of the stationary theory of the boundary layer in the von Mises variables - the longitudinal coordinate-current function.
doi: 10.4123/CUBS.105.01
69
unsteady filtration flow
Boussinesq limit problem
reduction
Crocco equation
rectangular bridge
https://unistroy.spbstu.ru/article/2022.106.1/
10501.pdf
RAR
RUS
10502-10502
AAH-4480-2020
6506522453
0000-0001-8114-1187
Abdikarimov
Rustamkhan Alimkhanovich
Tashkent Institute of Architecture and Civil Engineering
rabdikarimov@mail.ru
Tashkent, Uzbekistan
O-6995-2019
6508103761
0000-0002-1196-8004
Vatin
Nikolai Ivanovich
Peter the Great St. Petersburg Polytechnic University
vatin@mail.ru
St. Petersburg, Russian Federation
Khodzhaev
Dadakhan
Tashkent Institute of Architecture and Civil Engineering
Tashkent, Uzbekistan
Free vibrations of a viscoelastic isotropic plate with a negative Poisson's ratio
Vibrations of viscoelastic isotropic rectangular plates of an auxetic metamaterial are considered in a linear formulation. The problem is described by a linear integro-differential partial differential equation with initial and boundary conditions. The weakly singular relaxation kernel of Koltunov-Rzhanitsyn is used. Using the Bubnov-Galerkin method, the resulting equation is reduced to a linear ordinary integro-differential equation with respect to the time function. This equation is solved by a numerical method based on the use of quadrature formulas, eliminating singularities in the relaxation kernel. The effect on the amplitude-frequency characteristic of vibrations of a viscoelastic isotropic rectangular plate of a metamaterial with a negative Poisson's ratio is studied.
10.4123/CUBS.105.02
69
Viscoelasticity; Creep; Galerkin Methods; Numerical Methods; Integrodifferential Equations; Bubnov-Galerkin Method; Nonlinear Equations; Thin Walled Structures; Dynamic Stability; Linear Vibrations; Plates; Equations of Motion; Аusthetics
https://unistroy.spbstu.ru/article/2022.106.2/
10502.pdf
RAR
RUS
10503-10503
Vdovin
Evgeny
Bulanov
Pavel
Mavliev
Lenar
Physical and mechanical characteristics of soil stabilized with quicklime for road bed
The object of research is the stabilization of clay soils of the road bed. The purpose of this work is to study the physical and mechanical characteristics of stabilized clay soil with quicklime. The influence of quicklime ground lime in an amount from 1% to 10% on the change in the basic physical properties and compressive strength of clay soil is considered. Method. As a soil, heavy silty loam with a Index of plasticity of 14.63 and a content of dust and clay particles of 79.92 % was used. The strength and physical properties of stabilized soil with quicklime ground were studied for the following indicators: compressive strength of water-saturated samples at 7 days of age, water uptake, moisture at the limit of liquidity, moisture at the limit of plasticity, index of plasticity, content of dust and clay particles.Results. Stabilization of the soil with quicklime ground lime in an amount of 1 % to 5 % improves the workability and workability of clay by increasing the optimum moisture content by 2.4-13.5 % and reducing the maximum density – 0.6-4.4 %. With the introduction of quicklime ground lime in an amount of 1 % to 10 % in clay soil, the compressive strength of water-saturated samples at 7 days of age increases from 0.05 MPa to 1.34 MPa. It has been established that with the introduction of quicklime in an amount of 1 % to 10 % into the soil, there is a decrease in the degree of heaving and swelling due to a decrease in water absorption by weight from 24.85 % to 13.34 % and a decrease in the amount of dust and clay particles from 79.92 % to 46.29 %.
***ARTICLE IN PRESS***
10.4123/CUBS.105.03
69
Soil stabilization; Quicklime; Road bed; Road; Index of plasticity; Maximum density; Optimum moisture content
https://unistroy.spbstu.ru/article/2022.106.3/
10503.pdf
RAR
RUS
10504-10504
Vdovin
Evgeny
Bulanov
Pavel
Mavliev
Lenar
Modification of bituminous binders with styrene-butadiene- styrene copolymer and sulfur
The object of research is bituminous binders modified with styrene-butadiene-styrene and sulfur. The purpose of this work is to study the physical and technical properties of polymer-bitumen binders modified with sulfur. The influence of styrene-butadiene-styrene and sulfur on the physical and technical properties and short-term aging of the polymer-bitumen binder is considered. Method. Tests of bitumen and polymer-bitumen binders were carried out according to the following indicators softening point, dynamic viscosity at 105 °C, 135 °C and 165 °C, penetration at 25 °C, extensibility at 0 °C, Fraas brittleness temperature, as well as the difference in softening temperature after aging in the RTFOT oven. Results. The dependences of the influence of sulfur on high-temperature and low-temperature properties, as well as on the short-term aging of bitumen and polymer-bitumen binder based on styrene-butadiene-styrene copolymer have been established. It was found that with an increase in the sulfur content in bitumen, the difference in softening temperature after aging in the RTFOT furnace increases. However, the modification of the polymer-bitumen binder with sulfur gives the opposite effect, up to negative values due to the destruction of polysulfide bonds as a result of thermal exposure and dynamic shear.
***ARTICLE IN PRESS***
10.4123/CUBS.105.04
69
Polymer-modified bitumen; Modification; Styrene-butadiene-styrene copolymer; Sulfur; Aging
https://unistroy.spbstu.ru/article/2022.106.4/
10504.pdf
RAR
RUS
10505-10505
Khaliullin
Marat
Gilmanshina
Alsu
Plaster cement dry mixes with a complex organomineral additive
The objects of the research is plaster cement dry mixes with a modifying organomineral additive. The additive includes ground expanded clay dust as a pozzolan component and high-molecular polyethylene oxide PEO-S as a water-retaining component. The purpose of this work is to investigate the basic properties of plaster cement dry mixes with the use of a modifying organomineral additive in order to identify the effectiveness of the application of the additive. Method. Preparations of the organomineral additive were carried out by grinding the components in a laboratory planetary mill. Tests of dry plaster mixes were performed as per standard methods to GOST 33083, GOST 31357, GOST R 58277. The additive composition was optimized via the method of central composite rotatable design during of a two-factor experiments. Results. The dependences which indicate the impact of the additive components upon the compressive strength and the bonding strength to the base of dry plaster mixture-based solutions have been established. The increase in compressive strength and adhesion strength to the base of plaster mortars with an optimal content of ground expanded clay dust is explained by its high pozzolan activity; high-molecular polyethylene oxide PEO-S with a molecular weight of 4×106 provides a water-retaining effect. The dependencies that were established have served as the basis for developing dry plaster mixes which conform to regulatory requirements and are competitively viable as compared to other industrial counterparts owing to a reduction in the consumption of expensive Portland cement achieved through replacing a portion of it with ground expanded clay dust - industrial waste - and also thanks to the application of a water-retaining additive of locally produced high-molecular polyethylene oxide PEO-S instead of more expensive imported water-retaining additives.
10.4123/CUBS.105.05
69
plaster dry mixes; organomineral additive; expanded clay dust; high-molecular polyethylene oxide; pozzolan additive; water-retaining additive
https://unistroy.spbstu.ru/article/2022.106.5/
10505.pdf
RAR
RUS
10506-10506
Gayfutdinov
Rustem
Baimukhametov
Gadel
Khafizov
Eduard
A new method to evaluate the abrasion resistance of asphalt-based concrete
Abrasion wear of composites is one of the reasons of material failure. Based on the current needs in construction and mechanical field it is necessary to evaluate estimation methods of abrasion wear of composites. The object of research is to gain a new method of abrasion resistance calculation for asphalt-based concretes. Method. For this study 101 asphalt samples have been prepared using Marshal compactor and tested. Grading of mixes, saturation value, Nordic abrasion value of aggregate and Prall Test abrasion value of asphalt for the samples were obtained. Based on existing methods for calculating the wear of composites, the abrasive wear of asphalt concrete was analyzed, and a principle was proposed for calculating the wear resistance of asphalt concrete based on the mixture properties and parameters of the materials. After entering the necessary coefficients, they were searched by regression analysis based on the maximization of the determination coefficient. Results. The result of the study is an equation for the abrasion resistance of asphalt concrete calculation. Coefficient of determination for this formula is 0.98. Obtained technique meets the necessary accuracy requirements for predicting the wear of asphalt concrete. It allows to increase the efficiency of designing asphalt concrete mixtures and similar asphalt-based materials.
***ARTICLE IN PRESS***
10.4123/CUBS.105.06
69
Composites
Abrasion wear
Asphalt
Prall Test
Wear model
Rutting
Aggregate
https://unistroy.spbstu.ru/article/2022.106.6/
10506.pdf
RAR
RUS
10507-10507
Loginova
Olga
Roundabouts on the same level
The object of research is the junction of highways at the same level with its further transformation into a roundabout at the same level. The purpose of this work is to analyze the design standards for roundabouts designed according to domestic and foreign methods. The choice of the type of roundabout is based on the reduced traffic intensity calculated from the results of field measurements. Method. The traffic intensity is measured at characteristic points using a video camera. The values of the current intensity are reduced to the reduced intensity of vehicles per day. Using a nomogram to determine the type of intersection, a roundabout in one level is selected. Results. By designing roundabouts, it was found that with the same initial data - two traffic lanes, the estimated speed, differences were found only in the outer diameter of the roundabout. The width of the carriageway on the ring according to the considered methods has a slight difference of 0.7 m. The alignment of the plans of the ring intersections shows their identity.
***ARTICLE IN PRESS***
10.4123/CUBS.105.07
69
Roundabout; Design; Highways
https://unistroy.spbstu.ru/article/2022.106.7/
10507.pdf
REP
RUS
10508-10508
Stroganov
Victor
Amelchenko
Maksim
Emel’yanova
Darina
Эксплуатационные характеристики строительных стирол-акриловых полимерных покрытий с дисперсным наполнителем
Объектом исследования является каолин, активированный в аппарате вихревого слоя, который использован в качестве наполнителя стирол-акриловых лакокрасочных покрытий. Выполнен сравнительный анализ эксплуатационных характеристик покрытий, наполненных исходным и активированным каолинами. В качестве методов исследования выбраны дисперсный анализ, который позволил установить, что обработка наполнителя в аппарате вихревого слоя обусловливает увеличение его дисперсности до 6 мкм. У наполненных лакокрасочных покрытий определяли изменение показателей смываемости, водо-/влагопоглощения, адгезионной прочности, а также стойкость к действию агрессивных сред, в том числе модельных, имитирующих процесс биологической коррозии. Изменения в результате воздействия жидких сред осуществляли путем контроля цветовых характеристик покрытий и состояния их поверхности – микроскопирование. В результате установлено, что наполнение активированным каолином обеспечивает увеличение уровня эксплуатационных характеристик покрытий – смываемость в 3,5 раза, водопоглощение в 2,5 раза и адгезионной прочности в 1,5 раза, а также стойкость к действию агрессивных сред.
***ARTICLE IN PRESS***
10.4123/CUBS.105.08
69
Аппарат вихревого слоя; каолин; активация наполнителя; стирол-акриловые сополимеры; лакокрасочные покрытия
https://unistroy.spbstu.ru/article/2022.106.8/
10508.pdf
RAR
RUS
10509-10509
Grishin
Ilya
Petropavlovskikh
Olga
Ibragimova
Aniia
Stress-strain state of asphalt concrete pavements of steel bridges
The object of research is the stress-strain state of asphalt concrete pavements of steel bridges with an orthotropic slab under traffic load. The necessity of research is due to the fact that one of the main problems of steel bridge deck pavements is the formation of longitudinal cracks in asphalt concrete above the main beams of superstructures. At the same time, there are no instructions in the engineering standards to prevent the appearance of such a cracks. This, in turn, is due to the fact that the stress-strain state of the roadway of metal bridges has its own, insufficiently studied, features. Method. The main research method is use of software package that implements the finite element method. During modeling, shell finite elements are used to model the metal span, and three-dimensional finite elements are used to model the protective-cohesive and asphalt concrete layers. A three-axle truck was considered as a wheel load under various loading schemes. In addition, the physical and mechanical parameters of the protective layer and asphalt concrete were considered at different temperatures, on which they largely depend. Results. As a result of modeling superstructure section, it was found that tensile stress do indeed occur in the upper fiber of asphalt concrete above the main beam. And the closer the wheel is to the main beam, the greater this stress are, which can lead to cracks in the future. However, a phenomenon has been found that at sufficiently high temperatures, the highest tensile stresses in the top fiber of asphalt concrete occur near the wheel, while at sub-zero temperatures, the highest tensile stresses always occur above the main beam. Taking into account that cracks in asphalt concrete arise as a result of gradual accumulation of damage and assuming that the traffic load moves mainly along the wheel path zone, it can be concluded that the spacing of wheel path and walls of the main beams in space can lead to an increase in the service life of asphalt concrete pavements of metal bridges.
***ARTICLE IN PRESS***
10.4123/CUBS.105.09
69
Asphalt; Steel bridge; Finite element modeling; Bridge deck pavement; Cracks in asphalt
https://unistroy.spbstu.ru/article/2022.106.9/
10509.pdf
RAR
RUS
10510-10510
Kareeva
Juliya
Gabdrafikov
Rustam
Верификация численной модели течения конвективной струи у бокового отсоса
The object of research is a free convective jet located near the side hood. The aim of the study is to choose a calculation model that most adequately describes the development of a free convective jet above the definition of a heat source and a convective jet near a side hood located at a certain height above the heat source. Method. The problem is solved numerically using the Fluent software package. At the first stage, modeling of a free convective jet is proposed. For comparison, a number of problems are solved with a combination of turbulence models and near-wall functions. On the tendency to switch the flow of the convective jet at the side hood. Results. As a result of the numerical solution, the velocity and temperature distributions along the axis of the convective jet are obtained. The results are compared, calculated with the construction of theoretical data. A combination of turbulence and wall function models is chosen, which most accurately describes the flow of a convective jet near the side hood.
***ARTICLE IN PRESS***
10.4123/CUBS.105.10
69
numerical method
turbulence models
wall functions
convective jet
local exhaust ventilation
side hood
https://unistroy.spbstu.ru/article/2022.106.10/
10510.pdf
RAR
RUS
10511-10511
Vdovin
Evgeny
Konovalov
Nikita
Activated mineral fillers for the modification of cement composites
Объектом исследования являются активированные минеральные наполнители, применяемые для модификации цементных композитов. Модификация активированными наполнителями цементных композитов обеспечивает возможность повышения уровня прочностных показателей дорожно-строительного материала, а так же сокращения содержания основного вяжущего вещества. В качестве минерального наполнителя использовался доломит. Механическая активация наполнителей проводилась в аппарате вихревого слоя Vortex 297, при различном времени воздействия. Для обеспечения эффективной активации определены оптимальный коэффициент наполнения размольной камеры и размеры ферромагнитных частиц. Исследован характер распределения дисперсности частиц минерального наполнителя на лазерном анализаторе в зависимости от времени активации. Проведена оценка состояния поверхностей минерального наполнителя после активации, методом кислотно-основных взаимодействий с определением свободной поверхностной энергии, уровень показателей которой характеризует способность поверхности к межфазовому взаимодействию. Установлено влияние времени активации и содержания минерального наполнителя на прочность при сжатии образцов цементного камня. Определено оптимальное время активации минерального наполнителя в аппарате вихревого слоя.
***ARTICLE IN PRESS***
69
Минеральные наполнители
механоактивация
аппарат вихревого слоя
свободная поверхностная энергия
дисперсность
https://unistroy.spbstu.ru/article/2022.106.11/
10511.pdf
RAR
RUS
10512-10512
Fomin
Alexey
Khomyakov
Alexander
Asphalt concrete based on bituminous polysulfide binder, designed according to the volumetric method
The purpose of this study is the development of new asphalt mixes in the system of volumetric - functional design, using bituminous polysulfide binders (hereinafter - BPV) in their composition. Research methods. At the first stage, research was carried out on the BPV of various grades to determine the brittleness temperature by the Fraas method and the softening temperature using the ring and ball method. At the second stage, studies of BPW were carried out in order to establish its compliance with the requirements for binder grades according to PG. The following indicators were determined: flash point using the Cleveland open crucible method; dynamic viscosity, which is defined as the ratio between the applied shear stress and the shear rate of the bituminous binder; shear stability using the DSR dynamic shear rheometer, the method of determining which is to evaluate the shear stability of the bituminous binder by oscillating shear deformation of the sample and determining the values of the complex shear modulus and phase angle; bitumen and determining the effect of this impact on bitumen by comparing the physical and chemical parameters of bitumen obtained before and after exposure; aging temperature according to the PAV method, which consists in exposing samples of bituminous binders to elevated temperature and pressure in order to simulate aging processes during a period of operation in the pavement from 5 to 10 years; fatigue resistance, which is determined on a bituminous binder aged by the PAV method; low-temperature resistance, the method of determining which is to evaluate the low-temperature properties of the bituminous binder by determining the complex shear modulus in the frequency range at different temperatures and determining the stiffness values S(t) and the parameter m. At the final stage, the compositions of the asphalt concrete mix were selected and tests were carried out for resistance to rutting by rolling a loaded wheel over a test sample at the required temperature and determining the rut depth after 10,000 load cycles (20,000 wheel passes) or until the limit value was reached. Results. Synthesized organic polysulfides based on sulfur and mixtures of higher fatty acids (hereinafter referred to as PS). The softening temperature of BPV with a polysulfide content of 25 and 40 wt.% is 50 and 54°C, and the brittleness temperature is -22 and -25°C, respectively. The combination of bitumen with PS makes it possible to obtain binders of a new composition with a set of property indicators corresponding to grades PG 58-40 and PG 52-34. The compositions of the SP-16 asphalt concrete mix based on industrially produced and bitumen-polysulphine binders have been selected. Comparative tests of asphalt concrete were carried out to determine their resistance to rutting by rolling a loaded wheel. It has been established that the depth of the rut of the control composition on the binder PG 70-28 is 1.26 mm, on bituminous polysulfide binders, depending on the content of polysulfide, it varies within 1.87 ... 2.62 mm. The obtained values of indicators meet the requirements of regulatory documents. It has been established that the introduction of polysulfide into bitumen makes it possible to lower the lower temperature limit PG of the binder, to increase its softening temperature and the upper limit PG, respectively. The rut depth indicators of asphalt concrete on BPV meet the requirements for asphalt concrete used in extreme and difficult conditions.
10.4123/CUBS.105.12
69
Modification; Sulfur; Bitumen; Asphalt concrete; Asphalt concrete mixture; Volumetric functional design system; Polysulfides
https://unistroy.spbstu.ru/article/2022.106.12/
10512.pdf