English English

Archives

Optimization of concrete composition with polypropylene fiber to improve their crack resistance in road construction conditions

https://doi.org/10.58224/2618-7183-2025-8-2-5
Abstract
The study included a detailed examination of the crack resistance of heavy concrete and foam concrete that were not subjected to autoclave curing. An important aspect of this study was the use of polypropylene fiber as a reinforcing material, which made it possible to identify differences in the characteristics between reinforced and unreinforced samples. The purpose of the work was to evaluate the mechanical properties of the materials under study, as well as their behavior during destruction. For this purpose, the criteria of fracture mechanics were used, which made it possible to establish not only the strength and deformation characteristics, but also the force and energy indicators of crack resistance. The experimental results showed that the addition of polypropylene fiber significantly improves the strength characteristics of both heavy concrete and foam concrete. This improvement was especially noticeable in the case of foam concrete, which, due to reinforcement, demonstrated increased crack resistance. This is due to the fact that polypropylene fiber promotes a more uniform distribution of stress in the material, which in turn reduces the likelihood of cracking and improves resistance to destruction. In addition, the study confirmed that the use of polypropylene fiber not only increases strength, but also improves the durability of concrete, making them more suitable for use in construction, especially in conditions where materials are subject to significant mechanical loads and adverse environmental factors.
PDF

Features of the synthesis of construction geopolymer composites

https://doi.org/10.58224/2618-7183-2025-8-2-6
, , , ,
Abstract
Use of clinker-free binders, such as geopolymers and various equivalents based on mineral additives, can significantly reduce the carbon footprint of the construction sector in the environment. The most promising and appropriate benchmark is the disposal of industrial waste of aluminosilicate oxide composition with subsequent mechanical and alkaline activation. For the first time, the microstructure of geopolymers based on aspiration cement dust and tuff has been comprehensively studied. The theoretical prerequisite for the creation of a binder system of such a concept is the synthesis of sufficiently strong and resistant to external manifestations of alkali metals, including the structures of frame aluminosilicates with a hidden crystalline structure. X-ray diffraction analysis of the obtained samples, as well as the results of scanning electron microscopy, electron dispersion spectrometry, differential-thermal analysis, ad infrared spectrometry confirm the presence in the geopolymer paste of products traditionally necessary for the hydration reaction: aqueous aluminosilicates, aluminates and silicates of sodium and calcium, quartz, calcite, feldspars similar to albite and orthoclase, micas, etc. The results obtained on the key results of the conducted studies confirm the high efficiency of the proposed technology and guarantee increased strength and durability of geopolymer concrete.
PDF

Methods to select structural solutions for wind power generators in low-rise development

https://doi.org/10.58224/2618-7183-2025-8-2-7
, ,
Abstract
The article is devoted to the prospects for the development of renewable energy sources, in particular wind energy, in rural areas of the Rostov region (Russia). The analysis of the state program of the Russian Federation "Integrated Development of Rural Territories" was carried out. The primary measures that contribute to the implementation of directions for the development and improvement of the reliability of power supply through the use of wind energy are considered. The aim and objectives of the study are to create a classification and develop a methodology for selecting design solutions of wind turbines in low-rise residential construction, to develop criteria for evaluating the choice of renewable energy source (RES) technologies, to conduct a multi-criteria analysis of different types of wind turbine designs and to select the most optimal type of wind turbine design by applying multi-criteria analysis methods for selecting optimal wind turbine designs. The possibility of applying the method of multi-criteria analysis for the choice of design solutions for WPPs is substantiated. The assessment of the Rostov region territory and its priority for the placement of wind farms was demonstrated. The classification of wind turbines has been carried out. Design solutions for wing generator are presented. A technique for choosing optimality criteria is formulated. The results of studies by different scientists are summarized and compared with the proposed methods To select the optimal design of the wind turbine, a multi-criteria decision analysis was applied. Methodology for selecting wind energy generation technology elaborated in the course of research by applying multi-criteria analysis, allows us determining with the highest accuracy the most efficient and economically viable design of the wind power plant.
PDF

Photocatalytic self-cleaning lime coatings

https://doi.org/10.58224/2618-7183-2025-8-2-8
, , , ,
Abstract
The article presents the results of assessing the self-cleaning properties of lime coatings. The use of zinc oxide immobilized on synthesized aluminosilicates as a photocatalyst is considered. The technology of synthesis and properties of aluminosilicates are described. The photocatalytic activity of zinc oxide is analyzed depending on the technology of obtaining the photocatalyst. It was found that the band gap width of the photocatalyst obtained by immobilizing zinc oxide on synthetic zeolite decreased from 3.37 eV to 2.7 eV. Comparison of the self-cleaning ability of lime coating samples, in the formulation of which the photocatalyst was introduced, is carried out using the methods specified in the regulatory documentation- according to the test method in accordance with GOST R 57255-2016, according to the method of the Italian standard UNI 11259. The results of tests according to the methods established in regulatory documents indicate the high photocatalytic activity of the lime coating. It has been established that the lime coating with the use of zinc oxide photocatalyst immobilized on synthetic zeolite exhibits high photocatalytic activity. In accordance with the requirements of the Italian standard UNI 11259, the photocatalytic activity of the surface after 4 hours is R=21.94-55.42%, and after 26 hours – 51.96 - 98.2% depending on the specific surface of zinc oxide.
PDF

Active-adaptive construction project management system based on self-organizing maps for optimization of architectural and structural solutions

https://doi.org/10.58224/2618-7183-2025-8-2-9
, , , ,
Abstract
This research focuses on developing and implementing an active-adaptive construction project management system based on Kohonen Self-Organizing Maps (SOM) technology. The high variability of architectural and structural solutions, complex design dynamics, and multifactorial engineering calculations in modern construction necessitate creating flexible automated management systems capable of self-regulation. The research methodology integrates cluster analysis of design characteristics, multidimensional topological mapping of structural elements, and neural network analysis using SOM algorithms. The empirical base encompasses data from 38 construction projects of various scales during 2019-2023, with a total area exceeding 4.3 million square meters. Results demonstrate a 36.4% reduction in design documentation development time, 21.7% decrease in structural material consumption, and 17.3% improvement in building energy efficiency. A strong correlation (r=0.83) was established between the degree of structural solution optimization and economic efficiency of construction projects. The developed system provides dynamic visualization of multi-parameter design solution structures, enabling real-time identification of critical contradictions and preventive correction of potentially problematic structural nodes. The research significance is confirmed by multifactorial economic implementation efficiency (ROI=2.7) and substantial reduction in construction timeframes (average 14.6%).
PDF

Capabilities of existing frame buildings with shear diaphragms to resist seismic effects of destructive earthquakes

https://doi.org/10.58224/2618-7183-2025-8-2-10
, , , , , , ,
Abstract
In recent times, numerous powerful earthquakes have struck across the globe, with intensities exceeding standard design values by 1 … 2 points, resulting in widespread destruction of buildings and infrastructure. These events underscore the urgent need to revise current regulatory frameworks, particularly by increasing the prescribed seismic design loads. Consequently, it becomes essential to reassess the seismic performance of existing buildings that were originally designed according to outdated codes. This article explores the critical issue of evaluating and enhancing the earthquake resilience of such structures in light of evolving seismic realities.This article presents the results of a seismic resistance assessment for a nine-story reinforced concrete frame building with stiffening diaphragms, subjected to seismic loads exceeding the original design values. To evaluate the seismic performance of the existing structure, a numerical analysis was carried out using a static nonlinear (pushover) method. As a failure criterion, the maximum seismic load corresponding to the complete loss of the building’s load-bearing capacity was selected. The seismic resistance was assessed by considering the maximum values of seismic impact from two horizontal components, applied independently along each principal direction of the building. According to the adopted methodology, the structural model of the building frame, subjected to vertical loads, was incrementally loaded with the horizontal component of seismic action using displacement-controlled nonlinear static analysis. The horizontal load was gradually increased until the structure reached its maximum seismic capacity. The building under study was originally designed in accordance with the outdated seismic code SNiP RK 2.03-30-2006, which specified a seismic load corresponding to a site acceleration of 0.125g. However, under current seismic design standards—SP RK 2.03-30-2017*—the same site is classified for a seismic acceleration of 0.2g. Therefore, the existing structure is now expected to resist a seismic load that is 1.6 times greater than the load considered in its original design (0.2g vs. 0.125g). The study revealed that complete loss of the building's load-bearing capacity occurs under a special load combination when the seismic load is applied in the direction of the Y-axis. It was determined that structural failure takes place at the thirteenth loading stage, corresponding to a horizontal seismic acceleration of 0.163g. This value is lower than the required acceleration of 0.2g as specified by the current seismic code SP RK 2.03-30-2017*. This finding indicates that the building is incapable of withstanding the seismic demands outlined in the updated standards, highlighting its insufficient seismic resistance under the revised design requirements. Based on the results of the conducted research, it was proposed to strengthen the structural system of the building, which was originally designed and constructed in accordance with the outdated standards SNiP RK 2.03-30-2006, in order to enhance its seismic resistance and ensure compliance with current seismic safety requirements.
PDF

Eco-Friendly Foam Concrete with Improved Physical and Mechanical Properties, Modified with Fly Ash and Reinforced with Coconut Fibers

https://doi.org/10.58224/2618-7183-2025-8-1-1
, , , , , ,
Abstract
The development of new types of environmentally friendly and cost-effective building materials is currently a relevant topic and is actively developing throughout the world. In modern construction materials science, the most popular direction is the development of new concrete compositions using waste of various origins. The objective of this study is to develop new compositions of foam concrete using local waste from the fuel and energy complex and plant natural fibers. To determine the optimal amount of the modifying additive fly ash (FA), 7 experimental concrete compositions with different percentages of cement replacement by FA were made. The content was established as optimal. Foam concrete with 15% FA has the lowest density of 1075 kg/m3 and a minimum thermal conductivity coefficient of 0.248 W/m × °C, as well as increases in compressive and bending strength of 23.3% and 21.7%, respectively. The effect of coconut fiber (CF) was assessed on the composition of foam concrete modified with the optimal amount of FA 15%. The optimal dosage of CF was 0.6%. As a result of FA modification and CF dispersed reinforcement, a complex effect was obtained. The increase in compressive and bending strength was 30.14% and 72.83%, respectively, compared to conventional foam concrete. The density and thermal conductivity coefficient decreased by 9.8% and 8.34%, respectively. The results obtained during the experimental studies prove the effectiveness of the proposed formulation solutions and allow obtaining an energy-efficient foam concrete composite with improved characteristics.
PDF

Photocatalysts based on Zn-Ti layered double hydroxide and its calcination products for self-cleaning concretes: Structure formation and photocatalytic activity

https://doi.org/10.58224/2618-7183-2025-8-1-2
, , , ,
Abstract
Currently, the development of highly active photocatalytic additives for self-cleaning cement materials is a topical direction of building materials science. Mixed transition metal oxides are one of the effective types of photocatalysts, because they have improved functional characteristics compared to monometallic compounds. The purpose of this study was to establish the effects of synthesis conditions on the structure parameters and photocatalytic activity of zinc-titanium layered double hydroxide (Zn-Ti LDH) with Zn2+/Ti4+ molar ratio of 2/1, as well as its calcination products in the form of zinc-titanium mixed metal oxides (Zn-Ti MMOs). It was found that the mixing temperature of solutions of precursor salts and precipitators, as well as the temperature of sediment aging, were the main synthesis parameters that had the greatest impact on the phase composition and crystallite size of layered double hydroxide.
The research results showed differences in the kinetics of photodestruction of methylene blue (MB) in solution under UV radiation in the presence of Zn-Ti layered double hydroxide and Zn-Ti mixed metal oxides. The photocatalytic process involving Zn-Ti MMOs, corresponding to a pseudo-first order reaction kinetic, proceeded in a diffusion mode with limiting step in the form of dye adsorption on the surface of photocatalyst. The photodegradation of MB in the presence of Zn-Ti LDH, which was more accurately described by a pseudo-second order model, occurred in a kinetic regime, where the photocatalytic reaction was the limiting stage.
Mixed metal oxides of zinc and titanium had significantly higher functional characteristics compared to their Zn-Ti LDH precursor. The calcination of Zn-Ti layered double hydroxide at 200–500 °C allowed to achieve the highest photocatalytic activity of Zn-Ti MMO, which was due to phase transformations occurring during thermal treatment. The decomposition of Zn-Ti LDH at 200–250 °C resulted in the formation of a crystalline phase of zinc oxide (ZnO), which had a hexagonal wurtzite crystal structure with the ability to effectively absorb radiation from almost the entire UV spectral region. The rise of the Zn-Ti LDH calcination temperature to 500 °C led to an increase in the crystallinity degree of ZnO.
PDF

Heat dissipation of cement and design the composition of concrete for massive structures

https://doi.org/10.58224/2618-7183-2025-8-1-3
, ,
Abstract
Introduction. When designing a concrete composition depending on the type of structure, cement content is determined taking into account regulatory requirements for the minimum cement content depending on the operating environment. The maximum cement content is limited by economic indicators and technical conditions depending on the methods and conditions of work; the limitation on the amount of heat dissipation is not considered. Research objective: to develop a methodology for accounting for the heat dissipation of cement when assigning its consumption in concrete compositions for massive structures depending on their parameters and construction conditions. Methods. Experimental studies and analysis of regulatory documents and literary data on heat dissipation of cements and concretes. Modeling the parameters of temperature fields and stress fields depending on the class of concrete and its specific heat dissipation using the example of a foundation slab with specified dimensions and parameters of heat exchange with the environment. Results: An approach is proposed to standardizing the value of the maximum heat dissipation of concrete when designing a concrete composition for massive reinforced concrete structures. The article substantiates the position that the value of the level of tensile temperature stresses is less significantly affected by the concrete class than by its specific heat dissipation, since it is the heat dissipation of concrete that forms the temperature field and the temperature difference "center – top". Prevention of the risk of early cracking is associated not with slowing down heat dissipation, but with the value of specific heat dissipation, which determines the parameters of temperature fields, temperature gradients and stresses. The example shows that for a massive flat foundation slab with an accepted permissible level of tensile stresses of 0.67, the value of specific heat dissipation of concrete should not exceed 140 mJ / m3. A principle is proposed for determining the maximum class of concrete for compressive strength depending on the properties of cement. A dependence between the level of tensile temperature-shrinkage stresses and the criterion of thermal crack resistance of Zaporozhets I.D., independent of the concrete class, is revealed.
PDF

Investigation of structure and properties of expanded clay waste with the purpose of their use in the construction industry

https://doi.org/10.58224/2618-7183-2025-8-1-4
, , , ,
Abstract
This paper describes the structure and properties of large-tonnage expanded clay gravel waste, which is generated as dust from the cyclone, or clay dust (when drying granules), and expanded clay dust from filters (when leaving the kiln, from the cooler and screen). The mineralogical and phase composition of expanded clay dust and its hydraulic activity were determined. Clay dust from cyclones corresponds to the specific surface of 2500 cm2/g, and expanded clay dust from filters - 6800 cm2/g, which allows us to recommend it for use as a fine mineral additive to cement mortars and concretes. Due to the fact that the bulk density of clay dust is about 1000 kg/m3, and expanded clay dust - 6300 kg/m3, it allows to recommend it in the form of facilitating raw material additives in the production of wall and partition products. The results of X-ray phase analysis of clay dust from cyclones showed the presence of significant residues of unburnt clay (more than 80%), and the analysis of expanded clay dust from filters showed the presence of solid high-temperature phases consisting of: Quartz (SiO2) – 50.28%, Albite C-1 (NaAlSi3O8) – 14.82%, Microcline maximum (KAlSi3O8) – 15.73%, Lime (CaO) – 2.77%, Calcite (CaCO3) – 5.11%, Alunogen (Al2(SO4)2(H2O)22) – 11.29%. Hydraulic activity of clay and expanded clay dust according to the methods of GOST R 56593 and GOST 30744 showed that it is extremely low, especially for clay dust (0.3 MPa). On the contrary, the characteristics of samples of clay-alkali compositions showed sufficient strength (for clay dust up to 6.8 MPa, and expanded clay dust up to 3.6 MPa), which allows them to be recommended as a component of slag-alkali binder for cement-soil bases of highways.
PDF