75504
2712-8172
Magazine of Civil Engineering
2
118
2023
RAR
RUS
11801-11801
0000-0002-4966-9894
Singh
Jagdeep
Chitkara University
jagdeep.singh71717@gmail.com
Rajpura, India
6701385641
0000-0003-0128-6306
Siddique
Rafat
siddique_66@yahoo.com
Patiala, India
Performance of waste foundry sand concrete in sulfate environment
Waste foundry sand is generated by the metal casting industry and has great potential to be used as a construction material. Nearly 70 % of the waste foundry generated is disposed of as a landfill which poses a threat to the surrounding environment. The negative impact of landfill disposal of waste foundry sand on the environment has invited the intentions of research faculty. In this research work, the impact of waste foundry sand as sand replacement on the properties of concrete cured in water as well as sulfate solution were explored. Test results indicate that the compressive strength of concrete cured in sulfate solution decreases with the use of waste foundry sand as partial substitution of natural sand. However, a chloride ion penetration resistance of concrete hikes on the accumulation of waste foundry sand. Up to 56 days, a concrete mixture made up of 15 % waste foundry sand showed optimum strength properties. Ultrasonic pulse velocities through concrete mixtures cured either in water or sulfate solution were almost identical. Energy dispersive spectroscopy analysis showed traces of sulfur in concrete mixtures cured in a sulfate solution.
10.34910/MCE.118.1
691.5
concrete
curing
compressive strength
durability
microstructure
scanning electron microscopy
x-ray diffraction
https://engstroy.spbstu.ru/article/2023.118.1/
RAR
RUS
11802-11802
57218421564
0000-0003-2238-196X
Nguyen
Ngoc Lam
Hanoi University of Civil Engineering
lamnn@huce.edu.vn
Hanoi, Vietnam
15749118200
0000-0002-3561-9781
Georgin
Jean Francois
National Institute of Applied Sciences of Lyon
jean-francois.georgin@insa-lyon.fr
Villeurbanne, France
35737585800
0000-0001-9637-7125
Prud'Homme
Elodie
National Institute of Applied Sciences of Lyon
elodie.prudhomme@insa-lyon.fr
Villeurbanne, France
Long-term strength and porosity of mortars based on ettringite binder
Ettringite binder is widely used in mortars for technical applications such as patching mortars, self-leveling screeds, repair mortars thanks to their fast hardening ability and high early strength. However, depending on the amount and types of raw materials used in the composition, the properties of these types of binder have different behaviors at early-age and at long term. In this work, the influence of the nature and dosage of calcium sulfate in ettringite binder on the long-term strength of mortar in different curing conditions was determined. The results showed that the increase of calcium sulfate content in ettringite binder from 10–25 % improves the strength of mortars regardless of the calcium sulfate nature. In all curing conditions (endogenous, drying, outdoor), the strength of ettringite mortars with anhydrite is smaller than that of mortars containing hemihydrate. There is no major difference in the porosity of the mortars in different types of curing conditions before 28 days. However, after 28 days the porosity of mortar in drying condition is about 2–3 % higher than that of the mortars in endogenous and outdoor conditions.
10.34910/MCE.118.2
691.31
ettringite
durability
long-term
porosity
strength
https://engstroy.spbstu.ru/article/2023.118.2/
RAR
RUS
11803-11803
0000-0002-0934-549X
Dudynov
Sergey
National Research Mordovia State University
dsergey@mail.ru
Saransk, Russia
Influence of biological additives on the properties of cement systems
The object of the research is cement systems, the materials most commonly used in the construction industry. Since people interact with construction materials all the time, they should only contain harmless components; this requirement applies to modifiers as well. The existing liquefiers are obsolete; there is a need for an alternative composition and production technology. The purpose of the research is, first, to theoretically design the structure of an environmentally friendly plasticizing additive for cement systems based on fragments of natural compounds – lipids and carbohydrates. Secondly, to select a non-pathogenic microbial culture capable of synthesizing this product and the conditions for its fermentation. And finally, to study the properties of cement systems containing the synthesized biomodifier. This paper proposes novel modifiers based on fragments of natural compounds. The production process should be based on biological synthesis running through the cellular structures of microorganisms growing in a synthetic nutrient medium. A non-pathogenic microbial culture was ‘tamed’ to synthesize this product. The authors further designed a synthetic nutrient medium and optimized the fermentation parameters. Ten hours after the onset of fermentation, a fat-like substrate is added to the nutrient medium so that Leuconostoc mesenteroides would be able to synthesize the hypothesized modifier. The output is an efficient glycolipid plasticizer. X-ray diffraction analysis, a plastometer, a flow table, a cone, a viscometer, a versatile press, and an ionometer were used in this research to find the parameters of the synthesized bioadditives and cement systems based on them. The bioplasticizer injection was noted to increase the fluidity of cement mixtures by a factor of 3 to 5. The novel modifiers greatly inhibit early cement hydration when dosed at >0.8 wt.%. However, while inhibiting early structuring, these liquefiers strengthen the material in the long term (3+ months). Injecting these biological additives in the mixture at up to 0.8 wt.% produces a material that is 20÷30 % stronger than the additive-free alternative and absorbs less water while being as resistant to frost. As per our hypothesis, the microbial synthesis did in fact produce efficient cement system modifiers for industrial and residential construction that would be subject to no environmental restrictions.
10.34910/MCE.118.3
691.32:579.66
сoncrete
cements
mixtures
additives
microbiological synthesis
proteins
lipids
mechanical properties
hydration
environmental safety
https://engstroy.spbstu.ru/article/2023.118.3/
RAR
RUS
11804-11804
57196438866
0000-0002-1035-887X
Erofeev
Alexander
Tambov State Technical University
AV.Erofeev@yandex.ru
Tambov, Russia
57194260987
0000-0002-1410-9520
Gorokhov
Timofey
Tambov State Technical University
gorohowt@yandex.ru
Tambov, Russia
Method for determining the thermal fluctuation constants of the generalized Zhurkov equation
Reliable forecasting of the service life of building materials and products allows you to lay down the costs of repair work in a timely manner, which in modern economic realities is undoubtedly an urgent task. This paper presents the results of a study on the development and comparison with existing methods for determining the thermal fluctuation constants of the generalized Zhurkov equation. A new method is proposed for determining the thermal fluctuation constants of the generalized Zhurkov equation. Practical application of the methodology will make it possible to reliably predict the service life of building materials. The main goal is to develop a method for determining the thermal fluctuation constants of the generalized Zhurkov equation, characterized by higher reliability by reducing the number of operations entailing errors, while increasing the number of experiments conducted under identical conditions (increasing the sample when determining durability under constant operating conditions). To achieve this goal, it is necessary to solve a number of tasks: 1) analyze the main provisions of the thermal fluctuation concept; 2) develop a method for determining the thermal fluctuation constants; 3) to conduct a comparative analysis of the obtained results of determining the thermal fluctuation constants. The object of the study is the constants of thermal fluctuation. The subject of the study is a new method for determining thermal fluctuation constants. The main methods of scientific knowledge used in the development of the methodology are hypothetical (the hypothesis of a linear dependence of the change slope of direct temperatures in the coordinates of the logarithm of durability - stress) and experiment (determination of durability of samples under transverse bending under specified operating conditions). A new method was developed for determining the thermal fluctuation constants of the generalized Zhurkov equation. It allows you to determine constants by plotting only one straight line temperature and one control point at a different temperature. Application of the proposed technique allows increasing the number of samples tested in identical conditions while reducing labor costs for experimental research. An increase in the sample leads to an increase in the accuracy and reliability of predicting the service life of building materials.
10.34910/MCE.118.4
691
construction
experimental research
forecasting
performance
durability
temperature
thermal fluctuation
https://engstroy.spbstu.ru/article/2023.118.4/
RAR
RUS
11805-11805
55644946900
0000-0002-4508-4733
Almerich-Chulia
Ana
Universitat Politecnica de Valencia
analchu@mes.upv.es
Valencia, Spain
55644567800
0000-0001-8857-3249
Martin-Concepcion
Pedro
Universitat Politecnica de Valencia
pmartin@mes.upv.es
Valencia, Spain
54994161700
0000-0002-3721-5369
Molines-Cano
Jose M
Universitat Jaume I
molines@uji.es
Castelló, Spain
57195312827
0000-0001-9262-7916
Moreno-Puchalt
Jesica
Universitat Politecnica de Valencia
jemopuc@mes.upv.es
Valencia, Spain
Experimental behavior of novel GFRP reinforcing bars under compressive loads
Glass fiber-reinforced polymer (GFRP) bars have been used in RC structures due to their high tensile strength capacity and resistance to corrosion in comparison with steel. However, international standards do not recommend their use in RC structure elements subjected to compressive loads. Currently, there is no standard method to determine the compressive characteristics of FRP bars. This article presents a new type of GFRP bars designed specially to support compressive loads: they have additional winding GFRP layers around the longitudinal fibers. An exhaustive experimental study was carried out to obtain compressive properties of the bars: compressive strength, Young’s modulus and stress-strain relation. After post-processing the experimental results of the study, this paper showed compressive strength between 50% and 60% of tensile strength, which allows employing the bars as internal reinforcement in RC structures. Their obtained Young’s modulus is the same in both tensile and compression, which enables the linear stress-strain relation to be extended to the entire range of deformations. This is most advantageous for structural analysis procedures in the linear elastic regime. Finally, based on the experimental results of failure modes, some limitations about the cross-sectional area or the slenderness were proposed for the use as internal reinforcing in RC structures, which helps the researchers in the design procedure for members reinforced with FRP bars.
10.34910/MCE.118.5
624.07
fiber-reinforced polymer
glass fiber-reinforced polymer
GFRP bars
compression test
compressive strength
slenderness
reinforced concrete
mechanical properties
https://engstroy.spbstu.ru/article/2023.118.5/
05.pdf
RAR
RUS
11806-11806
57212348775
0000-0002-7168-5786
Gebre
Tesfaldet
Peoples’ Friendship University of Russia
tesfaldethg@gmail.com
Moscow, Russia
https://orcid.org/0000-0003-2493-7255
Galishnikova
Vera
Peoples' Friendship University of Russia (RUDN University)
galishnikova-vv@rudn.ru
Moscow, Russia
57197822677
0000-0003-3926-8701
Lebed
Evgeny
Moscow State University of Civil Engineering (National Research University)
evglebed@mail.ru
Moscow, Russia
Tupikova
Evgeniya
Peoples' Friendship University of Russia
emelian-off@yandex.ru
Moscow, Russia
Modelling of thin-walled members with restrained torsion considering the section properties
Various engineering structures include lightweight or thin-walled beam structures that are used in a complex loading situation which includes restrained torsion of closed or open section. The importance of restrained torsion of thin-walled cross-sections is significant as the deformations and stresses caused by torsion affect the behaviour of the structures with open as well as closed section. The aim of this study is to demonstrate and compare different methods used to develop stiffness matrix for the finite element beam calculation of open and closed thin-walled sections with restrained torsion. The beam stiffness matrices are presented and graphically compared in order to choose the most convenient method for advanced structural analysis of thin-walled 3D beams with restrained torsion. The interpolation functions containing hyperbolic and approximate functions are considered, which satisfy the governing differential equation for torsion, with different value of characteristic number of torsion (θ). Comparing both methods, we can conclude that both are similar for small value of θ and this is commonly considered for open thin-walled section as their value of θ is small. The percentage of error between the results obtained by two methods of element stiffness matrix development for torsion with restrained warping is given graphically. Based on this study, numerical examples are considered and compared with results obtained by different finite element software. The examples include restrained and free torsion which are nonuniform and uniform torsion, respectively.
10.34910/MCE.118.6
69.04
thin-walled structures
stiffness matrix
open section
closed section
angle of twist
uniformed torsion
nonuniform warping
https://engstroy.spbstu.ru/article/2023.118.6/
RAR
RUS
11807-11807
0000-0002-0317-7296
Vartanyan
Moscow Aviation Institute
arevshadvartanyan@mail.ru
Moscow, Russia
0000-0003-4928-9960
Sarukhanyan
Arestak
National University of Architecture and Construction of Armenia
sarukhanyan.arestak@mail.ru
Yerevan, Republic of Armenia
0000-0001-9093-2271
Veranyan
Gevorg
National University of Architecture and Construction of Armenia
g.g.veranyan@mail.ru
Yerevan, Republic of Armenia
0000-0002-2315-7233
Tokmajyan
Hovhannes
Shushi University of Technology
tokmadzhyan_hv@mail.ru
Yerevan, Republic of Armenia
Regularity of natural oscillations characteristics change of tall earth dams
A preliminary assessment of the strength of earth dams under dynamic loads is one of the most important tasks associated with the design of such massive hydraulic structures. The present study is devoted to predicting the deformation of earth dams under the influence of strong earthquakes, which are possible in the immediate vicinity of the dam location. Recently, a number of large earthquakes have occurred in the world, which led to severe destruction and indicate high seismic risks associated with the potential instability of existing large earth dams. Under intense seismic impacts, the response of the dam depends on various factors, including its geometric dimensions, as well as the type of structure. A number of existing dams, which were designed and built according to the normative rules of their time, do not take into account modern real operating conditions, in particular, potential seismic loads. This article examines the influence of these factors on the stability and strength of earth dams, taking into account the real properties of the soils of the dam body and the base of the bottom of the hydraulic structure in accordance with the new regulatory requirements. On the basis of the proposed mathematical model, verification calculations for the strength and stability of such earth dams located in the seismic zone were carried out. To assess seismic safety of high earth dams built and operating in regions of complex climatic conditions, including frequent earthquakes, the proof of the method choice capable of reliable and valid results in terms of adopted assessment criteria is required. Correct mathematical model choice ensures, on the basis of computations, strength indices of the hydraulic structure under study. In particular, comparison and analysis of calculated date obtained in case of the plane calculation model and spatial model with the field measurements results and spectral analyses of the Sarsang dam accelerograms showed the suggested calculation models provided reliable strength indices results for the earth dams in the operating reservoirs. The use of more complex models of the physical and mechanical properties of the dams’ soil leads to reliable results that are in good agreement with real field tests.
10.34910/MCE.118.7
627.8
dam
oscillation
period
accelerogram
strength characteristics of earth dams
hydraulic structure
https://engstroy.spbstu.ru/article/2023.118.7/
RAR
RUS
11808-11808
0000-0003-3715-5180
Moradi
Hamidreza
Department of Civil Engineering, Qazvin Branch, Islamic Azad University
hamidrezamoradi1360@yahoo.com
Qazvin, Iran
0000-0001-8385-9272
Hashemi
Seyed Amir Hossein
Department of Civil Engineering, Qazvin Branch, Islamic Azad University
hashemi@qiau.ac.ir
Qazvin, Iran
Neural prediction of mechanical properties of fiber-reinforced lightweight concrete containing silica fume and nano-silica
Experimenting to acquire the optimum result for producing a product in a real environment takes a long time and has various costs. Numerical simulations help save time and improve accuracy in implementing numerous complex tests. The present study exploits neural networks in MATLAB to calculate the mechanical properties of fiber-reinforced lightweight concrete under different fractions of silica fume and Nano silica, steel and polypropylene fibers, cement, and scoria. Concrete specimens were constructed under different mix designs and subjected to 7- and 28-day compressive, tensile, flexural, and initial and ultimate water absorption tests. Then, a multilayer perceptron (MLP) was used as the neural network. Furthermore, 70 % of the specimens were utilized as the training data samples, 15 % were exploited as the validation data samples, and the remaining 15 % were employed as the testing data samples. The MLP was trained for seven inputs, one hidden layer, and 20 neurons. The model training, testing, and overall accuracy were 100 %, 97.3 %, and 99.5 %, respectively, indicating the model is efficient and effective.
10.34910/MCE.118.8
624
artificial neural network
lightweight concrete
mechanical properties
steel fibers
polypropylene fibers
silica fume
nanosilica
fiber-reinforced concrete
https://engstroy.spbstu.ru/article/2023.118.8/
RAR
RUS
11809-11809
Pimenov
Sergey
Kazan State University of Architecture and Engineering
3.14manon@mail.ru
Kazan, Russia
0000-0001-9999-6925
Galautdinov
Albert
Kazan State University of Architecture and Engineering
galautdinov89@mail.ru
Kazan, Russia
Heavy-weight concrete with increased early strength
Production process rate is the most important thing in industrial engineering of concrete and reinforced concrete products, which heavily depends on duration of concrete handling strength development. One of the methods of processes’ intensification of concrete structure formation is steam treatment. However, destructive processes developing in concrete in some instances during its long steam treatment at the temperatures above 40°C necessitate reducing its duration. This is achieved through the use of methods of further intensification of concrete structure formation processes, one of which is hydromechanical activation of binder. Research results of joint effect of hydromechanical activation of cement binder and following steam treatment on kinetics of heavy-weight concrete strength development are presented in the paper; special aspects of hydration and structure formation of cement stone are studied. We found an increase in strength development rate of heavy-weight concrete during isothermal warming temperature increment. Technological parameters of steam treatment of concrete based on cement binder under hydromechanical activation are determined for preparing В30–В60 grade concretes using components for В25 heavy-weight concrete. Received results are of substantial interest to construction industry and can be used in prefabricated concrete and reinforced concrete technology, which gives the opportunity to reduce energy intensity of production and end product cost.
10.34910/MCE.118.9
691.32
heavy-weight concrete
steam treatment
hydromechanical activation
isothermal warming
https://engstroy.spbstu.ru/article/2023.118.9/
RAR
RUS
11810-11810
Jurayev
Doniyor
Tashkent Institute of Irrigation and Agricultural Mechanization Engineers
tohir-zs@mail.ru
M-6585-2013
6508103761
0000-0002-1196-8004
Vatin
Nikolai
Peter the Great Saint Petersburg Polytechnic University
vatin@mail.ru
Polytechnicheskay, 29
55586710000
0000-0002-6498-5043
Sultanov
Takhirjon
Tashkent Institute of Irrigation and Agricultural Mechanization Engineers
tz-sultanov@mail.ru
Tashkent, Republic of Uzbekistan
S-1676-2017
6507460407
0000-0002-8907-7869
Mirsaidov
Mirziyod
Tashkent Institute of Irrigation and Agricultural Mechanization Engineers
theormir@mail.ru
39, Kori Niyoziy St., Tashkent, Uzbekistan, 100000
Spatial stress-strain state of earth dams
The study is devoted to the stress-strain state (SSS) of various earth dams analyzed using a spatial model. The article provides a detailed review of well-known scientific publications on the SSS assessment of dams. In this article, a mathematical model was developed to assess the SSS of earth dams using a spatial model based on the Lagrange variational equation, considering real geometry, properties of the material, and non-homogeneous design features of structures. A technique was developed for solving spatial problems to assess the SSS of earth dams by the finite element method using the program developed by the authors and the ABAQUS software. The adequacy of the mathematical model and the accuracy of the results obtained were verified by solving test problems. The SSS of the Ghissarak (H = 138.5 m), Sokh (H = 87.3 m), and Pachkamar (H = 70.0 m) earth dams under the action of body forces and hydrostatic water pressure was studied. It was established that the greatest displacements were observed on the crest and in the zone of the dam core; an account for nonhomogeneous design features significantly affects the resulting displacement field in the core zone; a spatial deformed state of the structure occurs near the banks; positive stress (not considered in a plane model) arises in a small area in the upper part of the core near the crest, caused by the crest indentation by the lateral surcharge.
10.34910/MCE.118.10
539.3
earth dam
plane and spatial models
body forces
hydrostatic pressure
stress-strain state
variational equation
core indentation
https://engstroy.spbstu.ru/article/2023.118.10/
RAR
RUS
11811-11811
0000-0003-0198-6679
Eshmatov
Bakhtiyor
Almalik Branch, National University of Science and Technology MISiS
ebkh@mail.ru
Almalik, Uzbekistan
6506522453
0000-0001-8114-1187
Abdikarimov
Rustamkhan
Tashkent Financial Institute
rabdikarimov@mail.ru
60A, A.Temur street, Tashkent city, 100000
0000-0001-9340-4474
Amabili
Marco
McGill University
marco.amabili@mcgill.ca
Montreal, Canada
M-6585-2013
6508103761
0000-0002-1196-8004
Vatin
Nikolai
Peter the Great Saint Petersburg Polytechnic University
vatin@mail.ru
Polytechnicheskay, 29
Nonlinear vibrations and dynamic stability of viscoelastic anisotropic fiber reinforced plates
Fiber-reinforced plastic composites are one of the most widely used composite materials because they balance well between properties and cost. Despite their widespread use in the aviation and automotive industries, there is currently a lack of effective mathematical models for their calculation under various dynamic loads. The research object of this work is an anisotropic viscoelastic fiber-reinforced simply supported rectangular plate. Two dynamic problems are considered: vibrations of the plate under the influence of a uniformly distributed static load; stability of the plate compressed in one direction. Within the Kirchhoff-Love hypothesis framework, a mathematical model was built in a geometrically nonlinear formulation, taking into account the tangential forces of inertia. By the Bubnov-Galerkin method, based on a polynomial approximation of the deflection and displacement, the problem was reduced to solving systems of nonlinear ordinary integro-differential equations. With a weakly singular Koltunov-Rzhanitsyn kernel with variable coefficients, the resulting system was solved by a numerical method based on quadrature formulas. By using experimental studies, considering the directions of the fibers, the values of the rheological parameters of some plastic materials (KAST-V and EDF) were obtained. The plate's dynamical behavior was investigated depending on the plate's geometric parameters, viscoelastic and inhomogeneous material properties. Results show the importance of taking into account the viscoelastic properties of the material when solving dynamic problems of anisotropic reinforced plates made of composite materials. In particular, when studying the problem of dynamic stability of an anisotropic reinforced plate made of KAST-V, the results obtained in elastic and viscoelastic formulations in some cases differ from each other by more than 20 %.
10.34910/MCE.118.11
69.04
nonlinear vibrations
dynamic stability
viscoelastic anisotropic fiber-reinforced plate
integro-differential equations
weakly-singular Koltunov-Rzhanitsyn kernel
https://engstroy.spbstu.ru/article/2023.118.11/