English English

Archives

Coarse-grained soils compaction at the experimental site during the safe construction of the earthen dam

https://doi.org/10.58224/2618-7183-2026-9-5-1
, , , , , , ,
Abstract
Achieving a high degree of compaction in coarse-grained soils is a critical requirement for ensuring the stability, safety, and long-term performance of earth dams. This study presents the results of comprehensive laboratory and field investigations aimed at identifying the optimal technological parameters for compaction of coarse-grained soils used in hydraulic embankment construction. The influence of grain-size distribution, fine fraction content, and compacted layer thickness on the achieved dry density was systematically investigated. Laboratory experiments were performed using the standard Soyuzdornii compaction apparatus and a vibration compaction device with a cylindrical mold of 300 mm in diameter. Field investigations were conducted at an experimental test site using a 27-ton SANY vibratory roller with compacted layer thicknesses of 50, 70, and 80 cm. The experimental results demonstrated that the highest dry density was achieved for a compacted layer thickness of 50 cm, whereas increasing the layer thickness reduced compaction efficiency due to the limited transmission of vibratory energy throughout the embankment. Furthermore, the proposed grain-size modelling approach was validated by comparing laboratory and field test results, confirming its applicability for reproducing the mechanical behaviour of natural coarse-grained soils under controlled laboratory conditions. The findings provide practical recommendations for selecting rational compaction parameters and can be applied in the design and construction of earth-filled hydraulic structures to improve embankment quality, structural reliability, and long-term operational performance.
PDF

Structure formation of a polychelate composite based on waste mining for hydro- and thermal insulation of tailings in the cryolithozone

https://doi.org/10.58224/2618-7183-2026-9-5-3
, , , , ,
Abstract
This paper presents a scientifically substantiated and experimentally validated study of the structure formation patterns of a polychelate composite based on a polymer matrix and enrichment waste used as a filler. It was established that cyclic cryogenic exposure ensures the formation of a heterogeneous, highly filled system with developed interphase zones. Using powder X-ray diffraction, basal reflections of layered hydrosilicates (muscovite-2M1 and kaolinite-2M) were recorded against a pronounced amorphous halo of the polymer matrix, demonstrating the chemisorption process without disrupting the crystalline structure of the filler. The observed polymorphic transformation of feldspars, with the transition of sanidine and microcline to orthoclase, indicates deep relaxation of internal microstresses in defective near-surface layers at the phase boundary. This process occurs due to the formation of coordination bonds between the functional groups of the matrix and the metal cations of the filler, which is confirmed by the high-frequency shift of the stretching vibrations of carboxylate anions in the infrared spectrum. The method of computed X-ray microtomography revealed the formation of a continuous spatial framework, the dominance of pores with sizes of 15-45 μm and the presence of a large number of isolated micropores with an average size of 13 μm. The spatial organomineral structure formed during cryogenic treatment is characterized by a low thermal conductivity coefficient (0.18 W/(m⋅K)) and the maximum water resistance grade (W20). The method of biotesting on test objects of two trophic levels proved the environmental safety of the developed material: the mortality rates of Daphnia magna Straus were 3.8–7.0%, deviations in the number of Chlorella vulgaris Beijer cells were 1.6-17.4%. The high efficiency of chemisorption immobilization of toxic components in the composite structure eliminates the risks of their desorption and leaching, which allows it to be recommended for reliable hydro- and thermal insulation of tailings storage facilities in cryolithozone conditions.
PDF

Experimental determination of heat losses through cracks in building walls

https://doi.org/10.58224/2618-7183-2026-9-5-5
, , , , ,
Abstract
This study investigates how a repaired crack affects heat losses through a building envelope. An experimental setup was designed and assembled to test wall specimens containing a crack repaired by injection grout. A calculation procedure was developed to determine the specific heat loss through the repaired crack under the conditions of the proposed experimental apparatus. The experimental data were statistically processed using the Shapiro-Wilk test to assess normality. Differences in the specific heat loss before and after crack formation were evaluated with the paired Student's t-test. Statistical significance was accepted at p < 0.05. All statistical analyses were carried out in IBM SPSS Statistics. Tests were carried out on foam-concrete, clay brick, and reinforced concrete specimens. Ten speci-mens were prepared for each material under investigation. During the first stage, intact specimens without cracks were tested. Afterwards, an artificial crack was introduced into each specimen, repaired by injection grouting, and the specimens were tested again under identical conditions. The measured results showed a statistically significant increase in heat loss after crack repair. On average, the specific heat loss increased by 12.1%. The experimental findings were compared with numerical simulations. The temperature field around the repaired crack was calculated by solving the two-dimensional steady-state heat conduction equation. Robin (third-kind) boundary conditions were assigned to the external surfaces exposed to air, Neumann (second-kind) boundary conditions were specified at the truncated boundaries of the computational domain, and fourth-kind boundary conditions were applied at material interfaces. Numerical simulations were performed in ANSYS Workbench 2024. The difference between the numerical predictions and the experimental measurements did not exceed 2.1% for foam concrete, 3.8% for clay brick, and 2.4% for reinforced concrete. The results demonstrate that even after repair, wall cracks noticeably affect the thermal performance of building envelopes. The proposed mathematical model can therefore be used for numerical assessment of heat transfer in walls containing cracks repaired with injection grout.
PDF

Passportization and digitalization as a tool for preserving endangered cultural heritage (using the example of the Arsk barracks and the Alexander Nevsky сhurch in the village of Bol’shiye Memi)

https://doi.org/10.58224/2618-7183-2026-9-5-9
, , , , ,
Abstract
Architectural heritage is the material memory of humanity, recording the history, culture and identity of eras. Today, thousands of unique architectural monuments around the world are threatened with extinction due to wars, climate change, urbanization, and lack of funding for restoration. In circumstances where the physical preservation of a building is impossible or delayed, the complete recording of data about the object through photography, measurements, and 3D-scanning becomes a critical task. This article presents research materials on two historical sites (the Arsk Barracks Complex in Kazan, the Church of St. Alexander Nevsky, and the village of Bol'shiye Memi), which were under threat of complete disappearance and the only chance of preserving them was to record them and subsequently passportization.
For the first site of the former military town of Arsk Barracks a comprehensive analysis of the large-scale urban development project for the comprehensive reconstruction of the territory, implemented between 2019 and 2025, is presented. The above-mentioned facility is located in the Sovietsky district of Kazan and is bounded by key city thoroughfares – Nikolay Ershov, Patrice Lumumby, and Iskra streets. The transformation of this vast area from a closed, restricted-access facility into the modern, multifunctional residential complex «Art-City» is viewed not simply as a construction process, but as a complex socio-urban development phenomenon, where what were once suburban military barracks first found themselves within the urban structure, and later were absorbed by that structure. Only the timely preservation of these structures has allowed their appearance to be preserved to this day.
For the second site, the Church of St. Alexander Nevsky in the village of Bol'shiye Memi, a comprehensive study of the building is presented, with documentation of various periods of its existence, as well as a preliminary reconstruction project. The mentioned object is located in the Republic of Tatarstan, № 1, Molodezhnaya street, Bolshiye Memi village, Verkhneuslonsky municipal district. The church was built in 1892 in the eclectic style according to a prescribed project, which was later used to build several similar churches in the Kazan Governorate. At the time of the site inspection, the building was in an extremely dilapidated condition; part of the church had collapsed, and the remaining structures were in a pre-stressed state. All the structural elements were measured and recorded at the site, and two years later, after the site was inspected, the building finally collapsed. The surviving research materials allowed for a high-quality restoration project to be completed.
The relevance of the study is due to the growing interest in preserving the heritage of Tatarstan. The work provides a detailed analysis of the chronology and sequence of management decisions, investment agreements, and urban development approvals that formed the basis of the passportization projects. The relevance of the certification and prompt recording of deteriorating cultural heritage sites (CHS) is very high and important due to the irreversible nature of the loss of historical data and material culture objects. Timely registration and monitoring serve as the only legal and practical foundation for saving the monuments.
The main goal of this study is to develop conservation processes for endangered cultural heritage sites. This goal’s relevance is underscored by the importance of listing a monument in official registers to obtain state-protected status. Key objectives of the study include: capturing an accurate «cast» of the site at the current time to track the rate of its deterioration; compiling historical, architectural, and archival data into a single standardized document; performing precise measurements and drawings for future work on the possible reconstruction of the site; determining the scale of destruction to calculate the cost of emergency and/or restoration work; creating a transparent database for potential patrons, investors, or government programs; using the recorded data as evidence when holding owners accountable for improper maintenance; and developing new design solutions for the site, taking into account the site's history.
PDF

Transformation of the architectural and structural paradigm in the integration of renewable energy sources in high-rise construction

https://doi.org/10.58224/2618-7183-2026-9-5-10
, ,
Abstract
The article examines the evolutionary transition in the design of modern buildings and structures driven by the integration of renewable energy sources (RES). It analyzes the paradigm shift from static, additive placement of energy equipment to systematic design with adaptive RES. The study investigates modern classes of energy systems: mobile photovoltaic complexes, reconfigurable BIPV facades, adaptive wind turbines, as well as autonomous robotic and aerostatic platforms as a promising direction. The principles of architectural shaping, structural solutions, and material requirements for unique and high rise buildings acting as adaptive platforms are described. Based on an analysis of more than 70 implemented projects and concepts worldwide, including facilities in China, Europe, the USA, and the Middle East, it is concluded that a new architectural and structural philosophy is emerging, in which the building becomes an active, «living» organism, and its structural scheme becomes a programmable skeleton for future energy technologies. The author proposes a classification of RES integration types and formulates recommendations for the design of new generation structural systems.
PDF

PM2.5 and PM10 fine dust pollution of construction waste transloading at dwelling zone

https://doi.org/10.58224/2618-7183-2026-9-4-1
, , , , ,
Abstract
In many cities, the problem of dust pollution from construction waste caused by fine dust particles PM2,5 and PM10 is particularly acute. In the context of the rapidly developing construction industry in cities, issues of environmental safety of the urban air environment are becoming critically important for many states. The main source of urban waste in the context of growing urbanization has become construction waste, which accounts for more than 80% of the total urban waste in the Russian Federation. These areas of accumulation of construction debris not only take up space but also contribute to the deterioration of the urban environment due to dust that rises into the air during transportation and storage of waste. The purpose of this study is to determine the degree of impact of dust emissions of PM2.5 and PM10 particles on the air environment in the dwelling zone, to obtain empirically parameterized «distance–concentration» relationship for PM10 and PM2.5 particles during the loading of solid waste into an open container, and to present the results both in absolute units and in a standardized form using the concentration excess index I. Dust pollution monitoring was carried out at an active construction site located in a dense residential area in St. Petersburg, Russia. Concentration measurements were carried out during periods of dumping garbage into a container and transportation outside the construction site. The PM10 concentration decreased from 30.6 mg/m3 at the dust source to 1.2 mg/m3 at a distance of 50 m. The MPC limits of PM10 concentration (0.06 mg/m3) were determined at a distance of 37.5 m from the dust source. The PM2.5 concentration at a distance of 0-50 m remained below the MPC limits (0.035 mg/m3). From a practical point of view, the data obtained make it possible to organize an effective multi-level dust management system and can be integrated into summary calculations of emissions and an inventory of sources of pollutants.
PDF

Patterns of formation of the pore matrix structure and thermophysical properties of calcareous-ash mortars modified with opoka and recycled basalt fiber

https://doi.org/10.58224/2618-7183-2026-9-4-2
, , , , , ,
Abstract
The study investigates patterns in the formation of the structure and properties of calcareous-ash mortars modified with silica rock opoka and recycled basalt fiber. The research goal was to establish the relationship between the composition, pore structure, and thermophysical and physico-mechanical characteristics of the material.
The raw components used included lime, fly ash, granulated blast furnace slag, opoka, quartz sand, and recycled basalt fiber obtained from spent mineral wool substrate after heat treatment. The conducted studies involved the determination of density, compressive and bending strength, thermal conductivity, shrinkage strain, and microstructure.
The introduction of opoka was found to contribute to the formation of a microporous structure, providing a 20-35% reduction in average density and a decrease in thermal conductivity to 40-55%. Recycled basalt fiber reduced shrinkage strain and improved crack resistance by stabilizing the pore matrix structure. The study showed that synergetic interaction of components leads to the formation of a hierarchical structure providing the optimal combination of strength and thermophysical characteristics.
The optimal density range achieving the best balance of properties has been determined (1,400–1,600 kg/m³).
PDF

Methodological aspects of training dataset construction for predicting the mechanical strength of filled polymer coatings during natural climatic aging

https://doi.org/10.58224/2618-7183-2026-9-4-3
, ,
Abstract
The paper presents the results of investigating the strength characteristics of eleven compositions of protective and decorative epoxy polymer coatings with mineral fillers and an unfilled polymer under natural climatic aging in a temperate climate (Saransk). The work formalises the methodological approach to the formation of a training dataset for predicting changes in the strength characteristics of polymer composites with mineral fillers using machine learning methods. It is shown that with the introduction of a mineral filler, the failure mode of the epoxy matrix under bending changes from viscous-fluid to brittle, which allows the bending strength to be unambiguously determined. Under uniaxial compression, the classical strength value is reached in the region of relative strains of 50 % and higher, which corresponds to the densification phase of the already failed material and does not physically reflect the actual strength response. As a methodologically correct alternative, the yield strength is proposed, identified as the first local maximum on the smoothed σ–ε curve and unambiguously determined for all studied compositions at all natural climatic aging points. The relative difference Δσ between the strength value (in bending) or the yield strength (in compression) of the filled composition and the corresponding stress value on the deformation curve of the unfilled polymer, taken at the same point of relative strains for each time point of climatic aging, is proposed as the target feature of the prediction model. This approach automatically eliminates from the target variable the components associated with the post-curing effects and the degradation of the polymer matrix itself, leaving the model with the task of predicting the contribution of the filler and the state of the polymer–filler interface. Based on the analysis of the reinforcing effect of the eleven filled compositions in the reference state without post-curing, three groups of fillers are identified according to the level of the relative strength gain under bending («low» 3÷10 %, «moderate» 24÷53 %, «high» 70÷120 %), which are consistent with the physical picture of the filler–polymer matrix interaction. Recommendations are formulated on the composition of the model's input feature space, including the type and shape of the filler particles, the mass fraction, the characteristic particle size, the specific surface area, and the characteristic relative strain of the composition in the reference state. It is noted that the bending tests possess substantially greater informativeness in the assessment of the climatic resistance of the investigated class of materials in comparison with uniaxial compression.
PDF

Mathematical modeling of heat transfer through building envelopes with cracks

https://doi.org/10.58224/2618-7183-2026-9-4-4
, , , , ,
Abstract
Cracks formed in building walls are frequently restored by injecting specially formulated repair grouts into the damaged areas. This study examines the effect of such repaired cracks on the thermal performance of building envelopes. Heat transfer within cracked wall sections was modeled by solving the two-dimensional steady-state heat conduction equation. Convective boundary conditions of the third kind were specified on the exterior surfaces to account for heat exchange between the wall and the surrounding environment. The truncated edges of the computational domain were assigned insulated (second-kind) boundary conditions, corresponding to zero normal heat flux. At the interfaces between adjacent materials, continuity of both temperature and heat flux was enforced through fourth-kind boundary conditions. The numerical analysis was carried out using the finite element method implemented in ANSYS Workbench 2024. Based on the obtained numerical results, a procedure was developed for constructing nomograms that characterize the specific heat losses associated with wall cracks repaired by injection grouting. The temperature fields of aerated concrete, clay brick, and reinforced concrete wall assemblies were investigated. The results indicate that injecting a repair grout into a crack increases the heat flux through the examined section in brick and aerated concrete walls, whereas the opposite effect is observed for reinforced concrete walls, where the heat flux decreases after crack injection. The simulations demonstrated that replacing the air-filled crack with injection grout increases the heat flux across the repaired region of the wall. Graphical nomograms were therefore established to estimate the heat flow through repaired cracks directly from two governing parameters – the crack depth and the crack opening width – without the need for a complete numerical solution of the temperature field. In addition, the paper presents a practical algorithm describing the application of these nomograms in engineering calculations. The developed graphical tools can be employed to evaluate the overall thermal resistance of building envelopes during reconstruction, rehabilitation, and major renovation of existing buildings.
PDF

Improving the efficiency of steam condensation from combined-cycle gas mixtures in shell-and-tube condensers during CO₂ capture in cement plants

https://doi.org/10.58224/2618-7183-2026-9-4-5
, , , , , , ,
Abstract
The article discusses the processes of heat exchange during the condensation of vapors from combined-cycle gas mixtures containing a significant amount of non-condensing gases and solid impurities. The original design of a horizontal shell-and-tube condenser with profiled fins providing rupture and dispersion of the condensate film is presented. A quantitative assessment of the effectiveness of the proposed apparatus was carried out in relation to the conditions of a cement plant (capacity of 1.0 million tons of cement per year). It is shown that the introduction of oxygen combustion of fuel with subsequent condensation of water vapor makes it possible to reduce the volume of exhaust gases by 54.6%, increase the mass fraction of co₂ in the stream to 94.8% and reduce carbon dioxide emissions by 0.83 tons of co₂ per ton of cement produced. The optimal angle of inclination of the fins distribution strips is 5°, at which the degree of condensation reaches 95.1%, and the heat transfer coefficient is 260 W/(m2•K). The proposed design makes it possible to reduce the metal consumption of the condenser by 12-15% compared to smooth-tube analogues without increasing hydraulic resistance.
PDF