75504 2712-8172 Magazine of Civil Engineering 1 93 2020 1-155
RAR RUS 3-12 56662851300 0000-0001-8407-8144 Ogarev Mordovia State University Erofeev Vladimir al_rodin@mail.ru 57191249816 0000-0002-8080-9808 Ogarev Mordovia State University Rodin Alexander al_rodin@mail.ru LLC “Kombinat teploizolyacionnyh izdelij” Bochkin Viktor sovelitnew@mail.ru 57206900881 0000-0002-8892-4085 Ogarev Mordovia State University Yakunin Vladislav vladisjakunin@yandex.ru https://orcid.org/0000-0002-2560-0948 Ogarev Mordovia State University Ermakov Anatolij anatoly.ermakov97@mail.ru
Saransk, Respublika Mordoviya, Russia
 Lightweight geopolymers made of mineral wool production waste Reducing industrial slags and developing building materials on its basis is one of the priority areas for the development of the construction industry. The problem of obtaining cellular concrete from mineral wool production waste (lightweight geopolymers) is considered within the framework of the researches, the results of which are presented in the article. The research purpose was to establish the impact of composition of the raw material mixture and technological production features on the physical, mechanical and thermophysical properties of light geopolymers based on mineral wool production waste. Light geopolymers were obtained by preparing a mixture of ground slugs (specific surface is 400±20 m2/kg), alkaline activator (NaOH), water, a gas-forming additive (aluminum powder), fine aggregate and a water-holding additive. The resulting mixture was placed in the form without vibration. Molded products were steamed in order to accelerate hardening. The mobility of mortar mixtures was studied during the work, the average density, compressive strength, and thermal conductivity was studied for hardened samples. The compositions of lightweight geopolymers with an average density from 610 to 1,130 kg/m3, compressive strength from 1.7 to 5.4 MPa, and a thermal conductivity from 0.144 to 0.345 W/m∙°C were obtained. The application of the results will contribute to the expansion of the raw material base for obtaining light geopolymers, thereby reducing the amount of waste generated during the mineral wool production. The developed materials can be used for the construction of walling, and also as the insulation of the roof and floor of industrial and civil facilities. 10.18720/MCE.93.1 geopolymers slags caustic soda concretes compressive strength thermal insulation https://engstroy.spbstu.ru/article/2020.93.1/
RAR RUS 13-26 Perm National Research Polytechnic University Kashevarova Galina ggkash@mail.ru Perm National Research Polytechnic University Tonkov Yuriy 95081@mail.ru
Perm, Russia
 Technical diagnostics of reinforced concrete structures using intelligent systems The results of the development of an effective intelligent system for technical diagnostics of reinforced concrete structures are presented. The category of technical condition is the main criterion in deciding on the degree of accident or the need to take measures to bring it to further safe operation of a building construction. For the purposes of this study, an expert system was developed based on the mathematical apparatus of the theory of fuzzy sets and fuzzy logic, which can take into account the scatter of individual opinions of experts, significantly reduce the examination time and improve the quality of the diagnostics. A hierarchical structure of the organization of expert knowledge is proposed for assessing the technical condition of building structures taking into account the universality of information and the possibility of its expansion based on ontological analysis. Moreover, a technique was developed for formalizing expert information using membership functions for input and output control parameters. To implement a fuzzy logical inference, an algorithm adapted to the given problem is developed. A computer program has been developed that implements the method of identification of the category of technical condition of building structures on the basis of fuzzy knowledge bases. The results of using this program in a survey of a real industrial building are given. The results of the technical state evaluation examined structure, obtained using the expert system, are confirmed by expert opinions of specialists who did not participate in the creation of the program and have extensive experience in examining the building structures. The present work is motivated by a need to transfer knowledge from the technical books and experienced experts in the domain field of diagnostics of building structures to make that knowledge and expertise available to practicing engineers. 10.18720/MCE.93.2 buildings and structures diagnostics reinforced concrete structures technical condition category expert system fuzzy logic ontological analysis https://engstroy.spbstu.ru/article/2020.93.2/
RAR RUS 27-34 https://orcid.org/0000-0001-8101-4698 Mien Tay Construction University Ngo Van Thuc nvthuc34@gmail.com
Vinh Long city, Vietnam
 57207950600 0000-0003-3142-428X Mien Tay Construction University Lam Thanh Quang Kha lamthanhquangkhai@gmail.com
Vinh Long city, Vietnam
 57209972900 0000-0001-6869-8941 Mien Tay Construction University Do Thi My Dung dothimydung1983@gmail.com
Vinh Long city, Vietnam
 57203962119 0000-0001-9723-5161 National Research Moscow State Civil Engineering University Nguyen Trong-Chuc ntchuc.mta198@gmail.com Increased plasticity of nano concrete with steel fibers High strength concrete or nano concrete, it is often brittle, so it is necessary to study the solutions to increase the plasticity to obtain the structure to ensure the bearing capacity. The main advantage of steel fibers concrete is that it makes concrete with high flexibility, high tensile and compressive flexural strength, with bending components such as beams, the tensile area makes the concrete easier to form cracks and makes the structure quickly damaged. In this paper used the experimental method in order to determine the mechanical properties of nano concrete such as the tensile bending strength, the splitting tensile strength, for nano concrete samples with steel fibers and without steel fibers. In addition to the study also identified the deformation stress state of the two types of nano concrete and nano concrete with steel fibers. The use of steel fibers in nano concrete in the experiment made nano concrete increase plasticity, increase tensile bending strength, increase the splitting tensile strength and further enhance the advantages of new materials: steel fibers nano concrete materials. 10.18720/MCE.93.3 nano concrete high strength concrete steel fibers plasticity of concrete increased plasticity https://engstroy.spbstu.ru/article/2020.93.3/
RAR RUS 35-49 56644930600 https://orcid.org/0000-0003-4478-5041 St. Petersburg State University of Architecture and Civil Engineering Guzeev Roman guzeev.roman@gmail.com
St. Petersburg, Russia
 https://orcid.org/0000-0002-2383-0766 ALLPLAN Infrastructure GmbH Domaingo Andreas adomaingo@allplan-infra.com
Graz, Austria
 Long span bridges buffeting response to wind turbulence The buffeting response of the cable-supported bridges is studied. Several wind turbulence models are summarized and wind field models for practical application in bridge and structural engineering is proposed. The wind turbulence model comprises the mean wind and turbulence intensity profile, power spectral density and coherence functions. The dynamic response of the structure is governed by random vibration theory of stationary random process. The simplified method of analysis using the mode decomposition method is proposed where the only main modes are considered and the aerodynamic damping is introduced by means of flutter derivatives. The method of cable system coherence analysis is presented. The calculation procedure of generalized power spectral densities of wind turbulence load for different structural component is proposed. This procedure takes into account the effects of all three orthogonal components of wind turbulence. The contribution of the wind velocity components into total dynamic response and their correlation for different structural elements is studied. 10.18720/MCE.93.4 cable stayed and suspension bridges buffeting response turbulence model bridge deck structural design coherence random vibration numerical models https://engstroy.spbstu.ru/article/2020.93.4/
RAR RUS 50-59 0000-0002-4577-8794 Petersburg State Transport University Belash Tatiana belashta@mail.ru “B.E. Vedeneev VNIIG”, JSC Ivanova Tatyana IvanovaTV@vniig.ru
21, Gzhatskaya St., Saint Petersburg, Russia, 195220
 Earthquake resistance of buildings on thawing permafrost grounds A feature of the structural solution of the building is the presence of a solid underground foundation in the form of a three-dimensional rigid reinforced concrete platform. The building will be erected on thawing grounds; thawing takes place during the entire period of operation. Theoretical analysis of stress-strained building structures exposed to static and seismic loads has been carried out. Seismic load was determined by a specified response spectrum method. The calculation was carried out taking into account the presence of a thawing basin under the foundation with the size of the bowl varying from 6 m to 27 m. It was found that the building structures exposed to a seismic load are subject to increased stress and strain as compared with the static load exposure. Evaluation of the obtained values has shown that they did not exceed the permissible limits for the accepted strength properties of structural materials even in conditions of a maximum thawing basin. Foundation settlement is gradual. The adopted foundation structure design ensures the required earthquake resistance of the building in the given construction conditions. 10.18720/MCE.93.5 thawing permafrost ground seismic survey stresses strains settlement foundation platform https://engstroy.spbstu.ru/article/2020.93.5/
RAR RUS 60-70 Riga Technical University Vasiljevs Romans rominz@bk.ru
Riga, Latvia
 6508223358 Riga Technical University Serdjuks Dmitrijs Dmitrijs.Serdjuks@rtu.lv
1 Kalku Street, Riga LV-1658, Latvia
 Riga Technical University Buka-Vaivade Karina karina.buka.vaivade@gmail.com Riga Technical University Podkoritovs Andrejs andrew-next@inbox.lv
Riga, Latvia
 M-6585-2013 6508103761 0000-0002-1196-8004 Peter the Great Saint Petersburg Polytechnic University Vatin Nikolai vatin@mail.ru
Polytechnicheskay, 29
 Load-carrying capacity of timber-concrete composite panels Timber-concrete composite panels, due to its benefits, are one of the most popular alternatives to common slabs of pure timber or concrete. In the analyse of load-carrying capacity for timber-concrete composite panels, subjected to flexure, the important component is connection system between concrete layer and timber, which affects the stress distribution and the deformations of the structure. Possibility to increase effectiveness of structural materials use and load-carrying capacity of the timber-concrete composite structural members, with the rigid timber to concrete joint, was evaluated in this research. Consequently, possibility to develop rigid timber to concrete joint by the using of the crushed granite pieces as the keys was checked by the experiment. Development of rigid timber to concrete joint enables to increase effectiveness of the structural materials use in timber-concrete composite panels in comparison with the compliant once. Behavior of the timber-concrete composite panels were analysed by the transformed section method, finite element method and by experiment for the purpose of this study. Four timber-concrete composite panels were statically loaded till the failure by the scheme of three-point bending. Variants of composite panels with the rigid and combined timber-concrete joints were investigated. The rigid timber-concrete joint was provided by the pieces of crushed granite, which were strengthened on the surface of the timber boards by epoxy glue. Dimensions of the crushed granite pieces changes within the limits from 16 to 25 mm. Moreover, the combined timber-concrete joint was provided by the screws and by the crushed granite pieces. The screws were placed under the angles equal to 45 degrees relatively to the direction of fibres of the timber layers in accordance with the literature recommendations. As a result, it was stated, that load–carrying capacity of timber-concrete composite panels is up to 1.9 times higher than the same of cross-laminated timber panels. The maximum load-carrying capacity in 43 kN was obtained for the variant of timber-concrete composite panel with the rigid timber to concrete joint at the same time. 10.18720/MCE.93.6 rigid timber to concrete joint bending test composite structures structural analysis timber fasteners fiber-reinforced materials failure(mechanical) https://engstroy.spbstu.ru/article/2020.93.6/
RAR RUS 71-82 https://orcid.org/0000-0003-2493-7255 Peoples' Friendship University of Russia (RUDN University) Galishnikova Vera galishnikova-vv@rudn.ru
Moscow, Russia
 0000-0002-5347-5443 Peoples' Friendship University of Russia (RUDN University) Abdo Shamseldin eng.shamseldin13@hotmail.com
Moscow, Russia
 0000-0001-5577-1513 Alexandria University Fawzy Ahmed engahmedfawzy90@yahoo.com
Alexandria, Egypt
 Influence of silica fume on the pervious concrete with different levels of recycled aggregates The world nowadays is trying to find alternative approaches to be used in manufacturing instead of consuming raw materials. Using recycled aggregates in new concrete is one of these effective approaches, which in turn reduces the quantity of waste and reduces the required landfills. In this present work, an attempt was made to study the effect of using recycled aggregates as an alternative to raw aggregates in pervious concrete with different levels (0 %, 25 %, 50 %, 75 % and 100 %), in addition to the impact of adding 5 % and 10 % of silica fume as a replacement of cement weight on the pervious recycled aggregate concrete properties. The concerned properties are as follows: fresh and hardened density, fresh and hardened voids content, water permeability, compressive strength, splitting tensile strength, flexural tensile strength, and potential resistance to degradation of the pervious concrete. Additionally, relations between water permeability and other parameters of the pervious concrete were deduced. Experimental results generally showed that by increasing the recycled aggregates' percentages, there was a consequent deterioration in concrete properties. Whereas, the addition of silica fume enhanced the mechanical properties. It was observed that the addition of 5 % silica fume to concrete with 50 % recycled aggregate was subsequently accompanied by 4.2 % and 5.5 % increase in the fresh and hardened pervious concrete density, respectively, while a 17.5 %, 11.7 % and 17.2 % decrease in the hardened concrete voids content, concrete permeability and concrete degradation, respectively. Regarding the strength parameters, the pervious concrete’s 28 days compressive strength, 28 days splitting tensile strength and flexural tensile strength increased by 100 %, 20 % and 20.3 %, respectively, As follows, the addition of silica fume significantly improves the mechanical properties of the pervious concrete, with a slight decrease in the permeability parameters. 10.18720/MCE.93.7 pervious concrete recycled aggregates silica fume voids content permeability compressive strength tensile strength degradation https://engstroy.spbstu.ru/article/2020.93.7/
RAR RUS 83-96 6603316020 https://orcid.org/0000-0001-5285-3329 National Research Tomsk Polytechnic University Kazmina Olga kazmina@tpu.ru
Tomsk, Russia
 55210135000 https://orcid.org/0000-0002-1032-6077 National Research Tomsk Polytechnic University Mitina Natalia mitinana@tpu.ru
Tomsk, Russia
 55596796500 https://orcid.org/0000-0002-5389-5464 National Research Tomsk Polytechnic University Minaev Konstantin minaevkm@tpu.ru
Tomsk, Russia
 Lightweight cement mortar with inorganic perlite microspheres for equipping oil and gas production wells In this study lightweight cement mortar was researched. Low-density mortar is used for cementing high temperature, heavily watered oil and gas wells. ISO standard methods, X-ray diffraction analysis and electron microscopy confirm that hollow microspheres of perlite are an effective lightening component for cementing slurry. The results show that admixing microspheres reduces slurry density to 1400 kg/m3. Cement stone with the 3% perlite microspheres has an increased strength of 1.9 MPa due to actual interaction of the cement matrix with the aluminosilicate substance of microspheres, the self-reinforcement of the cement matrix by use of ettringite crystals. Cellular multi-chamber structure of perlite microspheres with the reactive surface enhances water-retention of cementing slurry. Use of the perlite microspheres as a facilitating additive for grouting slurry is preferable in comparison with glass microspheres. Low-density cement mortar with perlite microspheres is recommended a lightweight solution for cementing oil and gas wells. 10.18720/MCE.93.8 cement slurry well cementing hollow perlite microspheres cement stone strength https://engstroy.spbstu.ru/article/2020.93.8/
RAR RUS 97-120 7003880429 Institute of Mechanics and Seismic Stability of Structures Academy of Sciences of the Republik of Uzbekistan Sultanov Karim sultanov.karim@mail.ru
100125, Tashkent, 31, Dorman street
 https://orcid.org/0000-0002-2617-6931 Tashkent Institute of Architecture and Construction Kumakov Jakhongir sultanov.karim@mail.ru
Tashkent, Republic of Uzbekistan
 Institute of Mechanics and Seismic Stability of Structures Academy of Sciences of the Republik of Uzbekistan Loginov Pavel lopavi88@mail.ru
100125, Tashkent, 31, Dorman street
 https://orcid.org/0000-0001-9306-0798 Institute of Mechanics and Seismic Stability of Structures of the Academy of Sciences of the Republic of Uzbekistan Rikhsieva Barno barno.khusanova@mail.ru
Tashkent, Repulic of Uzbekistan
 Strength of underground pipelines under seismic effects A brief analysis of calculation methods to assess underground pipeline earthquake resistance, their advantages and disadvantages are given in the paper. The analysis of the models of underground pipeline-soil interaction under seismic (dynamic) effect is given. The coupled problems of underground pipeline-soil interaction at seismic wave propagation in a soil medium with embedded pipeline are set. One-dimensional non-stationary wave problems for the soil medium and the pipeline are solved numerically using the method of characteristics and the finite difference method. Numerical solutions are obtained in the form of a change in longitudinal stresses over time in various sections of the pipeline. An analysis of the obtained numerical solutions shows a significant dependence of longitudinal stresses on wave processes in the soil medium, dynamic stress state of soil and mechanical properties of soil and the pipeline material. A factor of a multiple increase in longitudinal stresses in the underground pipeline under its dynamic interaction with soil is revealed. It is shown that the main reason for this increase in stresses is the dynamic stress state of soil around the pipeline under its interaction with soil. The results obtained are the grounds for the development of a new regulatory calculation of underground trunk pipeline strength under seismic effect. 10.18720/MCE.93.9 strength earthquake-resistance pipeline soil interaction mechanical properties numerical methods strain rate stress https://engstroy.spbstu.ru/article/2020.93.9/
RAR RUS 121-133 7004452338 0000-0001-8759-6318 National University of Water Environmental Engineering Dvorkin Leonid dvorkin.leonid@gmail.com
Rivne, Ukraine
 The influence of polyfunctional modifier additives on properties of cement-ash fine-grained concrete The object of the study is the properties of cement-ash concrete with the addition of a polyfunctional modifier (PFM) intended for floors of industrial enterprises. The PFM composition includes a naphthalene-formaldehyde type superplasticizer and a vinyl acetate-vinylversatate copolymer. A prerequisite for the use of PFM additives in cement-ash concrete is the ability to actively influence the structure formation processes and, as a consequence, the properties of concrete with it. Using well-known chemical and physical methods, experimental data have been obtained on the effect of PFM additives on the degree of cement hydration, the kinetics of changes in the plastic strength of cement-ash stone during hardening. It was found that the introduction of the PFM additive allows one to reduce the open porosity and average pore sizes of cement-ash stone and also increase the pore size uniformity index. To study the properties of cement-ash concrete with PFM additive, the method of mathematical planning of experiments was applied, as a result of which a complex of mathematical models of water demand, water separation, volume of air involved, concrete strength under compression and bending was obtained. The models make it possible to quantitatively evaluate the effect on the indicated properties of concrete of water and ash-cement ratios, the content and ratio of PFM components, as well as design the compositions of cement-ash concrete with desired properties. The studies, the results of which are presented in the article, showed the possibility, with the help of PFM additives, to significantly improve the properties of cement-ash concrete, which are important when using them for floors of industrial enterprises and, in particular, reduce ultimate shrinkage deformations by 30–50 %, reduce by 1.5–3 times their abrasion and up to 20 % increase resistance to shock. 10.18720/MCE.93.10 ash strength shrinkage abrasion additives superplasticizer structure https://engstroy.spbstu.ru/article/2020.93.10/
RAR RUS 134-146 57200793249 0000-0003-4851-1822 Beirut Arab University Jahami Ali ahjahamy@hotmail.com
Beirut, Lebanon
 0000-0001-8576-5544 Beirut Arab University Temsah Yehya ytemsah@bau.edu.lb
Beirut, Lebanon
 6701635056 0000-0002-4393-6728 University of Wolverhampton Khatib Jamal j.m.khatib@wlv.ac.uk
Wolverhampton, United Kingdom
 0000-0002-4854-0247 Beirut Arab University Baalbaki Ossama obaalbaki@bau.edu.lb
Beirut, Lebanon
 https://orcid.org/0000-0002-8341-4043 Beirut Arab University Darwiche Mohamad m.darwich@bau.edu.lb
Beirut, Lebanon
 https://orcid.org/0000-0002-9729-9023 Beirut Arab University Chaaban Sandy s.chaaban@bau.edu.lb
Beirut, Lebanon
 Impact behavior of rehabilitated post-tensioned slabs previously damaged by impact loading Accidental rockfalls are common hazards in many countries, where many structures and infrastructure are damaged by the impact of falling rocks. This research aims to study the efficiency of shear reinforcement as rehabilitation techniques for PT “post-tensioned” slabs damaged by falling rocks. Two simply supported PT slabs were considered in this study. Each has a dimension of (6.6 m×3 m×0.25 m) and was subjected to an impact from a 605 Kg reinforced concrete falling block at a height of 20 m. The first slab (PT-1) was hit at its center of gravity, while the second one (PT-2) was hit at the mid-span of its free edge. After impact, both slabs were repaired by replacing the damaged parts and adding shear ties in order to prevent any future collapse when new impact occurred. The impact test was repeated again after repairing, and both punching shear capacity and normal stresses were recorded. Results showed that the repaired slabs were able to resist the repeated impact successfully. Both punching shear and normal stress capacities were higher than the applied stresses. Moreover, using shear reinforcement helped in changing the crack pattern from shear to flexure. At the end of this study, some recommendations were suggested for further studies. 10.18720/MCE.93.11 rockfall impact load post-tension shear reinforcement energy repair https://engstroy.spbstu.ru/article/2020.93.11/
RAR RUS 147-155 Kazan State University of Architecture and Engineering Vdovin Yevgeniy vdovin007@mail.ru https://orcid.org/0000-0001-9680-6698 Kazan State University of Architecture and Engineering Stroganov Victor svf08@mail.ru
Kazan, Russia
 Properties of cement-bound mixes depending on technological factors The influence of technological factors on the properties of cement-bound mixes, hardening at positive and negative temperatures in the construction of pavements, is studied. The relationships between density and strength of cement-bound mixes and the content of cement and water are established. The optimal moisture contents of mixes (10.5–11.5 %) were determined, which ensure the maximum material density from 2000 to 2300 kg/m3 with a cement content of 6 to 12 % by weight of the crushed stone mix. The influence of complex antifreeze additives on the mix technological properties (density, workability, constructability time) was studied. It was shown that sodium formate additives contribute to increasing the mix density and reducing the mix technological hardness (workability) under positive and negative temperatures. The influence of temperature and the amount of functional additives on the constructability time of cement-bound mixes is considered. It was established that additives contribute to preservation of the required workability of mixes at negative temperatures (down to -15 °C) for 1–2 hours and provide the necessary conditions for efficient work performance without reducing their quality and reducing the technological cycle period. 10.18720/MCE.93.12 cement-bound mixes sodium formate technological factors workability density humidity mixture manufacturability time https://engstroy.spbstu.ru/article/2020.93.12/