75504 2712-8172 Magazine of Civil Engineering 6 98 2020 1-140
RAR RUS 9801-9801 Institute Mechanics and Seismic Resistance of the Structures named M.T. Urazbaev Academy of science of the Republic of Uzbekistan Sagdiev Khamidulla imssan@mail.ru
Tashkent, Republic of Uzbekistan
 Institute Mechanics and Seismic Resistance of the Structures named M.T. Urazbaev Academy of science of the Republic of Uzbekistan Teshabayev Zohidjon imssan@mail.ru
Tashkent, Uzbekistan
 Institute Mechanics and Seismic Resistance of the Structures named M.T. Urazbaev Academy of science of the Republic of Uzbekistan Galiaskarov Viktor instmech@uznet.net
Tashkent, Republic of Uzbekistan
 Institute Mechanics and Seismic Resistance of the Structures named M.T. Urazbaev Academy of science of the Republic of Uzbekistan Yuvmitov Anvar anvar.sayfullaevich@mail.ru
Tashkent, Uzbekistan
 Centrifugal modeling of underground polymer pipes under temperature effect Experimental study of underground polymer pipes under temperature effect is developed in this paper by the method of centrifugal modeling to study the process of polymer pipes elongation depending on the depth of laying and physical and mechanical properties of soil. The method is based on the use of centrifugal installation with PC and software. The experiments were carried out in a centrifuge with an effective radius of centrifuge rotation at a working scale of modeling n = 40. Experimental studies were carried out at various laying depths of the underground polymer pipes. In the process of conducting experiments, the polymer pipe model was subjected to various temperature influences. The temperature effect on the polymer pipe model was created using an electric spiral. As a result, it is established that the process of polymer pipes elongation over time under soil pressure and temperature factor has a non-linear character; the value of the absolute strain depending on the laying depth and the temperature factor may differ by several times. 10.18720/MCE.98.1 centrifugal modeling polymer pipes temperature effect pipe-soil interaction structure model scale factors experiment technique measuring complex strain gauge sensor https://engstroy.spbstu.ru/article/2020.98.1/
RAR RUS 9802-9802 56688180600 0000-0003-0657-9159 Can Tho University Huynh Trong-Phuoc htphuoc@ctu.edu.vn
Can Tho City, Viet Nam
 0000-0001-6233-3888 VSB Technical University of Ostrava Ho Nguyen-Trong ntrong.ho@gmail.com
Ostrava, Czech Republic
 0000-0001-9443-2397 Ho Chi Minh City University of Technology Bui Phuong-Trinh buiphuongtrinh@hcmut.edu.vn
Ho Chi Minh City, Viet Nam
 0000-0003-3024-2150 National Taiwan University of Science and Technology Do Ngoc-Duy dongocduy29@gmail.com
Taipei City, Taiwan
 57203962119 0000-0001-9723-5161 National Research Moscow State Civil Engineering University Nguyen Trong-Chuc ntchuc.mta198@gmail.com Mechanical-thermal characteristics of foamed ultra-lightweight composites Turning waste into construction materials recently gets much attention from researchers in the world due to the advantages of not only the eco-friendly environment but also the positive enhancement of material characteristics. Thus, this study investigates the feasibility of the use of a ternary mixture consisting of cement, ground granulated blast-furnace slag (GGBFS), and fly ash (FA) for producing foamed ultra-lightweight composites (FULC) with the designed dry density of approximately 700 kg/m3. The FULC specimens were prepared with various FA/GGBFS ratios (16/24, 20/20, and 24/16) and foaming agent/water ratios (1/60, 1/80, 1/100, and 1/120). The constant water-to-binder ratio of 0.2, cement content of 40 % by mass, and superplasticizer dosage of 0.2 % by mass were applied for all FULC mixtures. Properties of the FULC specimens were evaluated through laboratory tests of compressive strength, dry density, thermal conductivity, water absorption, and thermal behavior following the relevant ASTM standards. Additionally, both the microstructure observation and cost analysis of all FULC mixtures was performed. Test results show that reducing GGBFS content resulted in a reduction in the compressive strength, dry density, thermal conductivity, and cost of the FULC. A similar trend could be observed when reducing the concentration of foam in the FULC mixtures. As the results, the 28-day compressive strength, dry density, thermal conductivity, water absorption, and cost of the FULC were in the ranges of 4.41–5.33 MPa, 716–729 kg/m3, 0.163–0.182 W/mK, 41.5–48.5 %, and 15.3–20.9 USD/m3, respectively. Furthermore, the FULC exhibited excellent performance under fire conditions as the maximum temperature at the internal surface of the FULC and the normal brick walls were 122 °C and 3180°C after 120 minutes of firing, respectively. Consequently, both GGBFS and FA had enormous potential for the production of FULC. 10.18720/MCE.98.2 composite cement fly ash compressive strength thermal behavior microstructure https://engstroy.spbstu.ru/article/2020.98.2/
RAR RUS 9803-9803 12782293300 Military Space Academy named after A.F. Mozhaysky Sychova Anastasia amsychova@yandex.ru
St. Petersburg, Russian Federation
 Military Space Academy named after A.F. Mozhaysky Zarin Sergey sergeyzarin27091989@gmail.com
St. Petersburg, Russia
 Military Space Academy named after A.F. Mozhaysky Matskevich Andrey andmats@yandex.ru
St. Petersburg, Russia
 Theory of determining the frequency of natural oscillations of span structures The article is devoted to the development of mathematical dependence of determination the natural oscillation frequencies of reinforced concrete span structures according to the physical, mechanical, geometric and energy characteristics of their elements and materials. Carrying out and processing the results of the experimental studies as well as the analysis of literature revealed the ways of reducing the error of the existing mathematical dependences in determining the natural oscillation frequencies of the span structures. The use of Griffith’s energy approach, the account of the nonlinear law of stiffness changes and the subsequent approximation of the experimental data made it possible to reduce the error of the mathematical dependence in the process of determination the natural oscillation frequencies of span structures by 4.4 times. The effect obtained makes it possible to apply the developed mathematical dependence to monitor the technical condition of the reinforced concrete span structures and the numerical determination of the boundaries of their technical condition categories. 10.18720/MCE.98.3 cracks reinforced concrete span structure vibrodiagnostics natural oscillation frequency Griffith energy approach https://engstroy.spbstu.ru/article/2020.98.3/
RAR RUS 9804-9804 56504969400 0000-0001-8879-1190 Kazan State University of Architecture and Engineering Ibragimov Ruslan rusmag007@yandex.ru
Kazan, Russia
 37099331400 0000-0003-0815-4621 Moscow State University of Civil Engineering (National Research University) Korolev Evgeniy korolev@nocnt.ru
Moscow, Russia
 6602522532 0000-0003-2714-519X Kazan National Research Technological University Deberdeev Timur deberdeev@mail.ru
Kazan, Russia
 Mechanical activation in the production of lime-sand mixtures This paper presents a review of the author’s research of the effect of different grinding units’ on the physical and chemical profile and geometry of quartz powders. Thus, when quartz sand is being treated in a vortex layer machine for 3–5 minutes, the mean particle size decreases from 235 to 6–7 μm, and the maximum size – from 498 to 81–77 μm. In this case, the specific surface area of the quartz powder, determined by the BET method, is 1.14–1.5 times larger than that of the powder obtained in other grinding units. It was shown that only the treatment of quartz sand in the vortex layer machine allows identifying this process as mechanical activation. The same positive results were obtained when treating building lime in the machine. There is an intensification of the building lime hydration process observed. The rational treatment time of the lime-sand compounds mixture in the vortex layer machines is 5 minutes. For compounds obtained from such mixtures at the age of 28 days, an increase in compressive strength by 209 % and bending strength by 172 % is observed. A decrease in the porosity of the compounds by 24 % was also found. Increasing the time of treatment of a lime-sand mixture in the vortex layer machine for more than 5 minutes has shown a slight effect on the physical and mechanical properties of the materials obtained. 10.18720/MCE.98.4 aggregates mortar mechanical properties hydration energy efficiency https://engstroy.spbstu.ru/article/2020.98.4/
RAR RUS 9805-9805 AL-QASIM Green University Marshdi Qosai qusaymarshdi@gmail.com
Babylon, Iraq
 Al-Qasim Green University Al-Sallami Zainab z198995@yahoo.com
Babylon, Iraq
 0000-0001-8067-9137 Donbas National Academy of Civil Engineering and Architecture Zaichenko Nikolai zaichenko_nikola@mail.ru
Makiyivka, Ukraine
 Effect of multicomponent modifier on the properties of cement pastes formulated from self-compacting concrete The article presents the results of studies of the influence of multicomponent modifier on the properties of cement pastes and self-compacting concretes. To reduce the cost of self-compacting concretes as well as to enhance their properties in fresh and hardened state the multicomponent modifier has been developed. It consists of ground granulated blast furnace slag, superplasticizer on the base of sulphonated naphthalene formaldehyde condensate, shrinkage-reducing admixture based on the polypropylene glycol derivative, and sodium sulphate set accelerator. The workability of SCC mixtures is considered from the rheological properties of cement pastes formulated from self-compacting concrete. The properties of fresh SCC have been tested according to EFNARC Committee’s suggestions. A partial replacement of Portland cement with granulated blast-furnace slag decreases hydration activity of the cementitious material resulting in contributing to higher flowability of cement paste. Shrinkage-reducing admixture in a combination with superplasticizer provide the effect of decreasing apparent viscosity of Portland cement-slag pastes. Sodium sulphate set accelerator coupled with superplasticizer and shrinkage-reducing admixture increase both the apparent viscosity of cement-slag paste and slump retention of SCC mixture. The multicomponent modifier provides an improvement of the properties of fresh (increased slump flow and slump retention) and hardened (28-day compressive strength comparable to control sample and decreased drying shrinkage) SCCs. 10.18720/MCE.98.5 self-compacting-concrete cement paste superplasticizer ground granulated blast-furnace slag shrinkage reducing admixture set accelerator rheological properties https://engstroy.spbstu.ru/article/2020.98.5/
RAR RUS 9806-9806 0000-0002-6275-8381 Karaganda State Technical University Shaikezhan Amankeldi shikg_a@mail.ru
Karaganda, Republic of Kazakhstan
 0000-0001-6799-5792 Karaganda State Technical University Anuarova Ayaulym anuarova_ayaulym@mail.ru
Karaganda, Republic of Kazakhstan
 6505983238 0000-0003-2467-3384 Vilnius Gediminas Technical University Antonovic Valentin Valentin.antonovic@mail.ru
Vilnius, Lithuania
 Cement slurry from electro-phosphoric slag Possibility to obtain high alite Portland cement of alternative raw materials was established by complete replacement of clay component with electro-phosphoric (EPS) slag. This technology allowed disposal of considerable volume of slag with production of high grade cement and reduction of CO2 emissions. Fuel saving was about 15 % increase in productivity of kiln was 10−15 %. It was detected after industrial tests that some rheological properties of slag were unknown. We studied properties of limestone-residual slag, aimed at production of clinker with alite content 69.6 and 65.4 %. EPS slag was weak structuring element at the initial stage of coagulative structuring. An increase in the volume concentration of solid phases led to an increase in viscosity, dynamic shear stress, and plastic strength. With an increase in concentration by 3 % from 35 to 38 %, fluidity decreased by 20 mm, and mobility by 1.3 times. Increase of bulk concentration of solid phases led to increase in viscosity, dynamic stress viscosity, and plastic strength. With the increase in concentration by 3 % from 35 to 38 %, fluidity had been decreased by 20 mm, and mobility by 1.3 times. Further growth of concentration led to reduction of these indicators by an order. Coarse limestone-residual slag with moisture content 37 % preserved its mobility during 26 days. Under static conditions, critical structural strength (100 g.cm2) of slag was achieved during 24 days. In case of proper mixing, duration of slags’ mobility shall be increased. Therefore 37 % can be recommended for lower limit of slag moisture. 10.18720/MCE.98.6 Portland cement phosphoric slag limestone rheology alite https://engstroy.spbstu.ru/article/2020.98.6/
RAR RUS 9807-9807 55516020800 Northeast Forestry University Zhao Qianqian 492954791@qq.com
Harbin Heilongjiang, China
 0000-0002-0414-9051 Northeast Forestry University Zhang Hetong 2586762756@qq.com
Harbin, Heilongjiang, China
 57199850188 0000-0002-2279-1240 Far Eastern Federal University Fediuk Roman roman44@yandex.ru
8. Suhanova St. Vladivostok, st. Octyabrskaya. 690950. Russia
 0000-0002-5953-8919 Harbin Dongan Automobile Engine Manufacturing Co. Wang Jianwu nihaone@163.com
Harbin, Heilongjiang, China
 Antiskid prediction model for cement pavements in seasonal frost regions The antiskid performance of the cement concrete pavement in the seasonal frost regions is an important factor determining the safety of road use. However, due to the low efficiency and high cost of on-site detection, it is very important to reasonably predict it. Five key factors such as ice film thickness, tire pressure, tire load, driving speed, and structural depth were determined. The response surface test was performed to determine the corresponding range of the five factors when the model was optimally predicted. A prediction model of antiskid performance for cement concrete pavement in the seasonal frost regions was created, the goodness of model fitting and the normal distribution of the model were tested, and the applicability of the model was verified. The results show that when the thickness of the ice film is 1.5 mm ～ 3 mm, the tire pressure is 180 kPa ～ 240 kPa, the driving speed is 40 km/h ～ 80 km/h, the structural depth is 0.24 mm ～ 0.62 mm and the tire load is 3250 N ～ 4000 N , the prediction level of the model is the best; SRI can be interpreted by the model accounting for 98.5 %, and the regression model has a high degree of fit, which meets the assumption of normal distribution; the model's SRI predicted value fits the field measured SRI value to 0.995, and the degree of fit is high. The prediction model of antiskid performance is of great significance to prolong the service life of cement concrete pavement in seasonal frost regions. 10.18720/MCE.98.7 concrete pavement numerical model temperature optimization https://engstroy.spbstu.ru/article/2020.98.7/
RAR RUS 9808-9808 57209803918 0000-0002-6056-5498 Peter the Great Saint Petersburg Polytechnic University Gerasimova Ekaterina katyageras17@gmail.com
St. Petersburg, Russia
 57194431559 0000-0003-4992-2084 Peter the Great Saint Petersburg Polytechnic University Galyamichev Alexander galyamichev@yandex.ru
Polytechnicheskay, 29
 0000-0003-4901-4967 Istanbul Okan University Dogru Selcuk seltrue@hotmail.com
Istanbul, Turkey
 Stress-strain state of Insulated Glass Unit in structural glazing systems Article presents the analysis of classical and structural ways of fastening of the glass unit subjected to uniformly distributed wind load under the various conditions: modification of the fixing step in horizontal and vertical direction, change of gas-filled gap and glass panel thicknesses. Calculation is performed in FEM-based SJ Mepla software for three most common types of glass units of the size of 1200×1200 mm, 2400×1200 mm and 3600×1200 mm. On the basis of obtained results, it is possible to conclude that modification of the fixing step in horizontal direction and glass panel thickness have a significant influence on the stress and deformation values; in contradistinction, modification in vertical direction and gas filling thickness do not noticeably impact stress-strain state of a plate. Default fixing step between two adjacent supports, which is often adopted by manufactures of IGUs without preliminary calculation for actual applied load, has to be verified in each case in terms of deformation in order to satisfy the conditions of SLS. The table of recommended values of maximum distance between supports is presented. 10.18720/MCE.98.8 glass structural optimization finite element method stiffness stress-strain state Limit State Design https://engstroy.spbstu.ru/article/2020.98.8/
RAR RUS 9809-9809 0000-0002-9541-4737 Department of Civil Engineering, University of 20 august 1955 Derabla Riad rderabla@gmail.com
Skikda, Algeria
 0000-0003-3933-2793 Department of Civil Engineering, Ahvaz Branch, Islamic Azad University Sajedi Fathollah sajedi@iauahvaz.ac.ir
Ahvaz, Iran
 Behavior of heat treated self-compacting mortar cured in seawater The acceleration of the hardening of self-compacting concrete (SCC) using the process of heat treatment is widely used in the field of prefabrication. Because mortar serves as the basis for the workability properties of SCC, these properties could be assessed by self-compacting mortars (SCMs). This paper has the purpose to study the behavior of heat-treated SCM based on two different mineral additions in marine environment. The additions are used as micronized powder to substitute 20 % and 40 % of cement. They are as ground granulated blast furnace slag (GGBFS) and limestone filler (LF). The cycle regime of heat treatment process used achieves a temperature of 60 °C and total duration of 24 hours. The research was conducted through the study of the physical and mechanical properties of elaborated SCMs under two curing regimes as freshwater and seawater. The obtained results indicate that the incorporation of LF seemed more effective in standard treatment process but it is advisable to limit its use to levels of less than or equal to 20 % as it develops resistance levels lower than those obtained by GGBFS. The incorporation of GGBFS especially with high amount of 40 % is very beneficial to improve physical-mechanical properties of heat-treated SCMs and it has many advantageous for obtaining stable and resistant SCMs against aggressive environment. 10.18720/MCE.98.9 GGBFS limestone mortar heat treatment mechanical properties seawater https://engstroy.spbstu.ru/article/2020.98.9/
RAR RUS 9810-9810 6504446571 0000-0001-6981-7420 Jordan University of Science and Technology Al-Rousan Rajai rzalrousan@just.edu.jo
Irbid, Jordan
 The shear behavior of CFRP strengthened RC beams The primary objective of this paper is to study the effectiveness of using externally applied CFRP composites as a method of shear strengthening. The parameters investigated in this study included CFRP amount and distribution (i.e., sheet versus strips), bonded surface (i.e., web sheet versus U-wrap), and fiber orientation (i.e., 90° fiber direction versus 45° fiber direction). Firstly, a novel Nonlinear Finite Element Analysis (NLFEA) model is created and validated. Then, five RC beams (150×225×1500 mm) have been constructed. The overall behavior of the NLFEA beams loaded up to failure, the onset of the cracking, and crack development with increased load and ductility were described. The NLFEA results showed that externally bonded CFRP increased the shear capacity of the strengthened RC beams significantly depending on the variables investigated. The beams strengthened with 90° CFRP U-wrap sheet provided a large increase in the ultimate load carrying capacity compared to beams strengthened with 90° CFRP web strips of 50 mm width. Decreasing the spacing between the strips is also efficient, while using 45° strips rather than 90° strips does not produce a remarkable increase in the shear capacity. The externally bonded CFRP can increase the shear capacity of the beam significantly by 34−62 % than that of the control beams, depending on the variables investigated. The inclination of the primary shear crack influenced the shear strength contribution of the external strengthening. Finally, an inclusive assessment of the NLFEA results, as well as three other well-known shear strength models, is conducted using a large test database. It is shown that the proposed shear strength, Chen and Teng, and the Chen et al. models give consistently good correlation with test data with an acceptable coefficient of variation as well as ACI Model shows unsatisfactory performance probably owing to its empirical nature and the use of an inappropriate model for the effective FRP bond length. 10.18720/MCE.98.10 reinforced concrete structural strength shear flexural strength fiber reinforced polymer nonlinear finite element analysis https://engstroy.spbstu.ru/article/2020.98.10/
RAR RUS 9811-9811 Peter the Great Saint Petersburg Polytechnic University Sabri Mohanad Muaya mohanad.m.sabri@gmail.com
Polytechnicheskay, 29
 6507787139 OOO “PI Georekonstruktsiya” Shashkin Konstantin cshashkin@yandex.ru The mechanical properties of the expandable polyurethane resin based on its volumetric expansion nature The expandable polyurethane resin is an innovative material used in the field of soil stabilization and foundation restoration. The injection technology using the expandable polyurethane resin is an effective way that raises the foundations rapidly, strengthening the soil beneath. Nevertheless, different technical aspects have not been studied yet, which might affect the lifting and stabilization process, such as the density of the resin formed in the massive of the injected soils. The density of the resin formed in the massive of the injected soils during the injection process is varied due to the expansion nature of the resin when mixed proportionally controlled by the amount of the injected resin, the injection pressure, the injection temperature, and other factors. Obviously, the differences in resin densities lead to a variation of the resin mechanical properties; consequently, it affects the desired lifting and strengthening results gained. The article demonstrates the results of a laboratory experiment that has been conducted to investigate the mechanical properties of an expandable polyurethane resin consists of two components based on its volumetric expansion ratios controlled by the amount of the injectable resin. The density of the resin gained for each expansion ratio has been obtained and given in this article. The stress-strain diagrams of the resin for various densities and expanding ratios are incorporated. The results were interpreted, and the strength-density relationship of the resin has been established and introduced. 10.18720/MCE.98.11 soil injection technology expandable polyurethane resin mechanical properties soil compaction foundation lifting foundation settlement resin expansion nature https://engstroy.spbstu.ru/article/2020.98.11/
RAR RUS 9812-9812 25637856200 0000-0003-4513-809X Kyiv State Technical University of Construction and Architecture Yurchenko Vitalina vitalinay@rambler.ru
Kyiv, Ukraine
 25637832500 0000-0001-7028-9653 Lviv Polytechnic National University Peleshko Ivan ipeleshko@hotmail.com
Lviv, Ukraine
 Improved gradient projection method for parametric optimisation of bar structures Numerical optimization and the finite element method have been developed together to make possible the emergence of structural optimization as a potential design tool. The main research goal of this paper is the development of mathematical support and a numerical algorithm to solve parametric optimization problems of structures with orientation on software implementation in a computer-aided design system. The paper considers parametric optimization problems for bar structures formulated as nonlinear programming ones. The method of the objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations has been used to solve the parametric optimization problem. Equivalent Householder transformations of the resolving equations of the method have been proposed. They increase numerical efficiency of the algorithm developed based on the considered method. Additionally, proposed improvement for the gradient projection method also consists of equivalent Givens transformations of the resolving equations. They ensure acceleration of the iterative searching process in the specified cases described by the paper due to decreasing the amount of calculations. The comparison of the optimization results of truss structures presented by the paper confirms the validity of the optimum solutions obtained using proposed improvement of the gradient projection method. The efficiency of the proposed improvement of the gradient projection method has been also confirmed taking into account the number of iterations and absolute value of the maximum violation in the constraints. 10.18720/MCE.98.12 parametric optimization bar structures nonlinear programming gradient projection method finite element analysis https://engstroy.spbstu.ru/article/2020.98.12/