AlfaBuild

RAR RUS 3201-3201 0009-0009-9559-748X Panarin Igor Ivanovich N-6730-2017 57199850188 0000-0002-2279-1240 Far Eastern Federal University Fediuk Roman Sergeevich roman44@yandex.ru

Vladivostok, Russian Federation

0000-0002-7395-6557 Nagruzova Lyubov Petrovna L_nag@bk.ru Composite cements and shotcrete activated with enriched ash and slag mixtures The construction industry requires the use of effective materials that meet the growing needs in the design, construction, operation and repair of buildings and structures for various purposes. The object of research is the construction industry that requires the use of effective materials that meet the increasing needs in the design, construction, operation and repair of buildings and structures for various purposes. This work aims to develop a scientifically based technological solution aimed at creating effective composite cements activated with enriched ash and slag mixtures, and shotcrete based on them. Methods. A systematic study of the structure and properties of raw materials and cement composites was carried out. To create repair compositions, the theoretical provisions of the law of structure affinity were used. The physical and mechanical properties of the raw material and materials developed on its basis were determined using standard research methods: physical and chemical methods of analysis, laser granulometry, X-ray phase and differential thermal analysis, scanning electron microscopy, etc. Results. A scientifically based technological solution for producing shotcrete using composite cement has been proposed, which consists in the use of technogenic resources based on industrial waste (ash and slag mixtures) and construction (concrete scrap from dismantling buildings and structures), activated and homogenized in a vibration mill, which allows you to control the processes of structure formation due to the affinity of structures and the formation of high-strength new formations. The developed low rebound shotcrete mixture ( 10.57728/ALF.32.1 69 Concrete Composite Binder Superplasticizer Cement Ash and slag mixture Strength https://alfabuild.spbstu.ru/article/2024.32.1/ 3201.pdf

RAR RUS 3202-3202 0000-0003-4283-0400 Korolev Alexander Sergeevich 0000-0002-4879-6699 Zadorin Alexander Alexandrovich 0000-0003-4021-003X Mishnev Maxim Vladimirovich The modeling of a thermosetted polymer’s deformations using the finite element method The object of research is a cured thermoset polymer on the example of cured epoxy polymer. This work aims to improve the methods of finite element (FE) modeling of the structure of cured thermoset polymers to predict their mechanical, deformative and thermal properties. Method. The structural mathematical modeling method with subsequent computer FE modeling was used. The structure of the FE model was based on the cured polymer's tetrahedral supramolecular structure. Using the structural density as structure model's parameter, the relative size and disposition of the finite elements were determined. The shift from elastic to viscoelastic behavior was controlled by modifying the structural density and compressive/tensile properties of joints. The long-term plastic deformation and stress relaxation were determined as the result of supramolecular structure's inner shearing with the decrease of its structural density. The FE modeling of stress and deformation was realized by LIRA SAPR computer design program. Results. The FE models of the cured epoxy polymer were developed, making it possible to predict short-term and long-term deformations under load with high accuracy considering the temperature factor. 10.57728/ALF.32.2 69 Glassed polymer Thermosetting polymer Modulus of elasticity Supramolecular structure model Finite element model https://alfabuild.spbstu.ru/article/2024.32.2/ 3202.pdf

RAR RUS 3203-3203 0000-0003-3177-0959 Borovkov Aleksey Ivanovich borovkov@spbstu.ru 0000-0002-7422-5494 Peter the Great St. Petersburg Polytechnic University Vafaeva KHristina Maksudovna vafaeva.khm@gmail.com

St. Petersburg, Russian Federation

O-6995-2019 6508103761 0000-0002-1196-8004 Peter the Great St. Petersburg Polytechnic University Vatin Nikolai Ivanovich vatin@mail.ru

Saint-Petersburg, Russian Federation

Microstructure and physicomechanical properties of glass-basalt fiber reinforced polymer pipes: 3D fractal modeling The object of research is the microstructure of glass-basalt plastic composite pipes and the relationship between its fractal dimensionality and the physical-mechanical properties. Method. The study involves conducting physical experiments to measure and analyze the properties of glass-fiber-reinforced and glass-basalt-fiber-reinforced composite pipes. The experiments include testing for strength, modulus of elasticity, fracture, bending, and other mechanical characteristics. Results. The paper explores the potential for modeling the microstructure of glass-basalt plastic composite pipes using 3D fractal analysis. The material composition of the pipes by mass was 70% roving and 30% binder. An evaluation of the fractal dimensionality of the microstructure was carried out at a scale representation of 300 µm, focusing on the boundary interfaces between the structural elements (fiber matrix and epoxy component of the pipes). A one-to-one correspondence was established between the fractal dimensionality of glass-basalt fibers in 3D space, the interfacial boundaries in 2D space, and the tensile strength, compressive strength, and Young’s modulus. An increase in the physical-mechanical properties of the pipes was observed with the rise in the fractal dimensionality of the glass-basalt fibers from 2.055 to 2.245 and the interfacial boundaries from 1.228 to 1.415. The increase in the length and fractal dimensionality of the interfacial boundaries indicates higher energy expenditure during pipe fracture, thus leading to improved strength properties. The calculated mathematical models allow for the prediction of the physical-mechanical properties of glass-basalt plastic composite pipes with satisfactory practical accuracy based on the fractal analysis of the microstructure. 10.57728/ALF.32.3 69 Fractal Modeling Microstructure Physicomechanical properties Materials development Glass-Basalt Fiber Polymer Pipes Forecast Interphase boundaries https://alfabuild.spbstu.ru/article/2024.32.3/ 3203.pdf

RAR RUS 3204-3204 0000-0003-3177-0959 Borovkov Aleksey Ivanovich borovkov@spbstu.ru 0000-0002-7422-5494 Peter the Great St. Petersburg Polytechnic University Vafaeva KHristina Maksudovna vafaeva.khm@gmail.com

St. Petersburg, Russian Federation

O-6995-2019 6508103761 0000-0002-1196-8004 Peter the Great St. Petersburg Polytechnic University Vatin Nikolai Ivanovich vatin@mail.ru

Saint-Petersburg, Russian Federation

Compressive strength of hybrid glass-basalt fiber reinforced polymer composite tube: Multifractal microstructure characteristics The object of research is the microstructure of glass-basalt fiber-reinforced polymer (GFRP/BFRP) composite tubes and the relationship between its multifractal dimensions and their physical and mechanical properties. The structure of many materials exhibits heterogeneity across various length scales, which is often assessed through the geometrical characteristics of its elements. However, the complexity of these structural elements poses challenges for quantitative analysis. Method. The study utilized fractal formalism to evaluate the heterogeneous microstructure of GFRP/BFRP composite tubes. The multifractal dimensions of the matrix fibers and epoxy component were analyzed to assess structural heterogeneity. Results. The heterogeneity values were determined using the multifractal spectrum function f(α) for both the matrix fibers and the epoxy component. The sensitivity of the compressive strength of hybrid GFRP/BFRP composite tubes to these heterogeneity indicators ranged from 0.06 to 0.63 for the matrix fibers and from 0.17 to 0.44 for the epoxy component. The correlation coefficients of the fractal models were between 0.75 and 0.81, providing a sufficient level of accuracy for estimating the compressive strength of the tubes. This accuracy supports the interpretation of the proposed method as a non-destructive approach for evaluating the quality of GFRP/BFRP composite tubes. 10.57728/ALF.32.4 69 Hybrid GFRP/BFRP Composites Compressive strength Multifractal analysis Microstructure Scanning electron microscopy Fractal analysis Non-destructive testing https://alfabuild.spbstu.ru/article/2024.32.4/ 3204.pdf