Browsing by Author "Shcherban', Evgenii M."

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Highly Effective Injection Composites With Fly Ash and Microsilica for Soil Stabilization
(MDPI, 2025) Ozkilic, Yasin Onuralp; Beskopylny, Alexey N.; Aksoylu, Ceyhun; Stel'makh, Sergey A.; Shcherban', Evgenii M.; Madenci, Emrah; Kosykh, Alexey
Injection composites based on mineral binders are widely used for soil stabilization, using jet grouting technology to solve various geotechnical problems. Cement, which contains toxic components and worsens the ecology of the environment, is typically the main mineral component used to manufacture injection composites. Reducing cement consumption in the production of building materials is currently of great importance. This study developed highly effective, environmentally friendly injection composites for soil stabilization based on three mineral components: Portland cement, fly ash (FA), and microsilica (MS). FA was introduced into the composites as a partial Portland cement substitute, in amounts ranging from 5 to 50% in 5% increments. The properties of fresh and hardened composites, including the density, flow rate, water separation, compressive strength at 7 and 28 days, and the structure and phase composition of the composites, were studied. The inclusion of FA in the composition of composites contributes to a decrease in density by 16.9%, from 1.89 g/cm3 to 1.57 g/cm3, and cone spread by 9%, from 30.1 cm to 27.4 cm, and an increase in water bleeding by 91.4%, from 3.5% to 6.7%, respectively. Based on the results of the experimental studies, the most effective dosage of FA was determined, which amounted to 20%. An increase in compressive strength was recorded for composites at the age of 7 days of 8.3%, from 33.6 MPa to 36.4 MPa, and for compressive strength at the age of 28 days of 9.4%, from 41.3 MPa to 45.2 MPa, respectively. SEM and XRD analysis results show that including FA and MS promotes the formation of additional calcium hydrosilicates (CSH) and the development of a compact and organized composite structure. The developed composites with FA contents of up to 50% exhibit the required properties and can be used for their intended purpose in real-world construction for soil stabilization.
Citation - WoS: 6
Citation - Scopus: 7
Modeling and Calculation of Improved Centrifuged Reinforced Concrete Columns With Variotropic Structure
(MDPI, 2023) Stel'makh, Sergey A.; Shcherban', Evgenii M.; Beskopylny, Alexey N.; Mailyan, Levon R.; Veremeenko, Andrey; Shilov, Aleksandr V.; Ananova, Oxana; Aksoylu, Ceyhun
The use of vibro-centrifugation technology allows the manufacture of variotropic structures that are inhomogeneous in the annular section and have different characteristics along the section thickness. Hardening of the outer layers allows the structure to better resist bending conditions, however, the behavior of the variotropic column under central and eccentric compression remains unexplored. This article considers the problem of compression of hollow columns made of homogeneous concrete that is non-uniform in the annular section (variotropic), and is reinforced with steel reinforcing bars at different values of the load application eccentricity. Variotropic concrete obtained by vibro-centrifugation technology has a stronger outer part and a less durable inner part. The strength of a homogeneous column corresponds to the strength of the middle part of variotropic concrete. The problem was solved numerically in the ANSYS environment for a vertical column rigidly clamped at the bottom edge and loaded with eccentricity at the top edge. Three types of eccentricity are considered; e/r = 0, 0.16 and 0.32 (respectively 0 mm, 0.24 mm and 48 mm). The results of the solution in the form of stress fields, deformations and a pattern of crack development in a spatial setting are obtained. The results showed that for central compression, a homogeneous column has a better bearing capacity of 3.6% than a variotropic one. With the values of eccentricity e/r = 0.16 and 0.32, the variotropic column has a higher bearing capacity (by 5.5% and 6.2%) than the homogeneous one and better resists the development of cracks. The significance of the study lies in the practical application of the proposed approach, developed on a research basis, for non-trivial and complicated operating conditions of columns. This study influences the development of reinforced concrete structures and applies scientific findings to engineering practice.
Citation - WoS: 4
Citation - Scopus: 3
Performance Assessment of a Novel Green Concrete Using Coffee Grounds Biochar Waste
(Mdpi, 2024) Beskopylny, Alexey N.; Stel'makh, Sergey A.; Shcherban', Evgenii M.; Ananova, Oxana; Chernil'nik, Andrei; El'shaeva, Diana; Pogrebnyak, Anastasia
An actual scientific problem in current concrete science is poor knowledge of the problem of modifying concrete with plant waste. At the same time, plant waste benefits from other types of waste because it is a recycled raw material. A promising technological approach to modifying concrete with plant waste is the introduction of components based on the processing of coffee production waste into concrete. This study aims to investigate the use of biochar additives from spent coffee grounds (biochar spent coffee grounds-BSCG) in the technology of cement composites and to identify rational formulations. A biochar-modifying additive was produced from waste coffee grounds by heat treatment of these wastes and additional mechanical grinding after pyrolysis. The phase composition of the manufactured BSCG additive was determined, which is characterized by the presence of phases such as quartz, cristobalite, and amorphous carbon. The results showed that the use of BSCG increases the water demand for cement pastes and reduces the cone slump of concrete mixtures. Rational dosages of BSCG have been determined to improve the properties of cement pastes and concrete. As a result of the tests, it was determined that the ideal situation is for the BSCG ratio to be at a maximum of 8% in the concrete and not to exceed this rate. For cement pastes, the most effective BSCG content was 3% for concrete (3%-4%). The compressive and flexural strengths of the cement pastes were 6.06% and 6.32%, respectively. Concrete's compressive strength increased by 5.85%, and water absorption decreased by 6.58%. The obtained results prove the feasibility of using BSCG in cement composite technology to reduce cement consumption and solve the environmental problem of recycling plant waste.
Citation - WoS: 14
Citation - Scopus: 18
Physical, Mechanical and Structural Characteristics of Sulfur Concrete With Bitumen Modified Sulfur and Fly Ash
(MDPI, 2023) Stel'makh, Sergey A.; Shcherban', Evgenii M.; Beskopylny, Alexey N.; Mailyan, Levon R.; Meskhi, Besarion; Shilov, Alexandr A.; Evtushenko, Alexandr; Aksoylu, Ceyhun
Industrial waste usage in the technology of construction materials is currently in a relevant and promising direction. Materials made of industrial waste have a lower cost and are highly environmentally friendly. The objective of this study is to develop effective compositions of sulfur concrete based on the maximum possible number of various wastes of the local industry for this and to investigate the characteristics of this composite. Test samples of sulfur concrete were made from sulfur, fly ash, mineral aggregates and bitumen additive. The dosages of fly ash, sand and bitumen varied, while the content of sulfur and crushed stone remained constant. The following main characteristics of sulfur concrete were determined: density; compressive strength; and water absorption. Tests of sulfur concrete were carried out after 1 day and 28 days of hardening. The best values of compressive strength (24.8 MPa) and water absorption (0.9%) were recorded for the composition of sulfur concrete at the age of 28 days with the following content of components: sulfur-25%, modified with 4% bitumen of its mass; fly ash-10%; crushed stone-40%; and sand-25%. The optimal composition of modified sulfur concrete showed compressive strength up to 78% more and water absorption up to 53% less than the control composition. The characteristics of the sulfur concrete samples after 28 days of hardening differ slightly from the values after 1 day of hardening (up to 1.8%). An analysis of the structure confirmed the effectiveness of the developed composition of sulfur concrete in comparison with the control.
Citation - WoS: 2
Citation - Scopus: 2
Porosity Analysis and Thermal Conductivity Prediction of Non-Autoclaved Aerated Concrete Using Convolutional Neural Network and Numerical Modeling
(MDPI, 2025) Beskopylny, Alexey N.; Shcherban', Evgenii M.; Stel'makh, Sergey A.; Elshaeva, Diana; Chernil'nik, Andrei; Razveeva, Irina; Ozkilic, Yasin Onuralp
Currently, the visual study of the structure of building materials and products is gradually supplemented by intelligent algorithms based on computer vision technologies. These algorithms are powerful tools for the visual diagnostic analysis of materials and are of great importance in analyzing the quality of production processes and predicting their mechanical properties. This paper considers the process of analyzing the visual structure of non-autoclaved aerated concrete products, namely their porosity, using the YOLOv11 convolutional neural network, with a subsequent prediction of one of the most important properties-thermal conductivity. The object of this study is a database of images of aerated concrete samples obtained under laboratory conditions and under the same photography conditions, supplemented by using the author's augmentation algorithm (up to 100 photographs). The results of the porosity analysis, obtained in the form of a log-normal distribution of pore sizes, show that the developed computer vision model has a high accuracy of analyzing the porous structure of the material under study: Precision = 0.86 and Recall = 0.88 for detection; precision = 0.86 and recall = 0.91 for segmentation. The Hellinger and Kolmogorov-Smirnov statistical criteria, for determining the belonging of the real distribution and the one obtained using the intelligent algorithm to the same general population show high significance. Subsequent modeling of the material using the ANSYS 2024 R2 Material Designer module, taking into account the stochastic nature of the pore size, allowed us to predict the main characteristics-thermal conductivity and density. Comparison of the predicted results with real data showed an error less than 7%.
Sustainable Concrete with Waste Tire Rubber and Recycled Steel Fibers: Experimental Insights and Hybrid PINN-CatBoost Prediction
(MDPI, 2025) Ecemis, Ali Serdar; Yildizel, Sadik Alper; Beskopylny, Alexey N.; Stel'makh, Sergey A.; Shcherban', Evgenii M.; Aksoylu, Ceyhun; Ozkilic, Yasin Onuralp
The growing environmental concern over waste tire accumulation necessitates innovative recycling strategies in construction materials. Therefore, this study aims to develop and evaluate sustainable concrete by integrating waste tire rubber (WTR) aggregates of different sizes and recycled waste tire steel fibers (WTSFs), assessing their combined effects on the mechanical and microstructural performance of concrete through experimental and analytical approaches. WTR aggregates, consisting of fine (0-4 mm), small coarse (5-8 mm), and large coarse (11-22 mm) particles, were used at substitution rates of 0-20%; WTSF was used at volumetric dosages of 0-2%, resulting in a total of 40 mixtures. Mechanical performance was evaluated using density and pressure resistance tests, while microstructural properties were assessed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The findings indicate systematic decreases in density and compressive strength with increasing WTR ratio; the average strength losses were approximately 12%, 20%, and 31% at 5%, 10%, and 20% for WTR substitution, respectively. Among the WTR types, the most negative effect occurred in fine particles (FWTR), while the least negative effect occurred in coarse particles (LCWTR). The addition of WTSF compensated for losses at low/medium dosages (0.5-1.0%) and increased strength by 2-10%. However, high dosages (2.0%) reduced strength by 20-40% due to workability issues, fiber clumping, and void formation. The highest strength was achieved in the 5LCWTR-1WTSF mixture at 36.98 MPa (approximate to 6% increase compared to the reference/control concrete), while the lowest strength was measured at 16.72 MPa in the 20FWTR-2WTSF mixture (approximate to 52% decrease compared to the reference/control). A strong positive correlation was found between density and strength (r, Pearson correlation coefficient, approximate to 0.77). SEM and EDX analyses confirmed the weak matrix-rubber interface and the crack-bridging effect of steel fibers in mixtures containing fine WTR. Additionally, a hybrid prediction model combining physics-informed neural networks (PINNs) and CatBoost, supported by data augmentation strategies, accurately estimated compressive strength. Overall, the results highlight that optimized integration of WTR and WTSF enables sustainable concrete production with acceptable mechanical and microstructural performance.