Nanotechnologies in Construction: A Scientific Internet-Journal @nanobuild-en
Статьи журнала - Nanotechnologies in Construction: A Scientific Internet-Journal
Все статьи: 621
Статья научная
Introduction. In the context of sustainable construction, one of the key challenges is the development of effective strategies for the management and recycling of fly ash and slag waste produced by thermal power plants. Recent studies confirm the potential of such waste as a partial substitute for conventional sand in concrete mixtures. However, most research focuses on conventional concrete and does not consider the specific requirements for rheological properties and interlayer adhesion, which are critical for 3D printing technology. Methods and Materials. The study used Portland cement CEM I 42.5N, fly ash and slag waste from the Ust-Kamenogorsk TPP, crushed sand, and the MasterGlenium superplasticizer. The concrete mix design was developed in stages: a base mix, a control mix (with an increased water-to-cement ratio), and experimental mixes with 25% and 50% sand replacement by fly ash and slag waste. Samples were printed using a construction 3D printer (model S-6045) and tested for compressive strength, density, interlayer adhesion, and subjected to micro and nanostructural analysis. Results and Discussion. Experimental mixtures with 25% and 50% sand replacement showed reduced density and strength compared to the control mix. However, the 25% replacement mix maintained satisfactory strength, shape stability, and interlayer bonding. Micro and nanostructural analysis confirmed the relationship between structural compaction and physical-mechanical properties. Despite some limitations, the study demonstrated the potential of TPP-derived ash and slag waste as a viable component in 3D printing, provided the composition and extrusion parameters are optimized. Conclusion. The results indicate that replacing 25% of sand with fly ash and slag waste is optimal for fine-grained concrete mixtures intended for 3D printing. This approach improves resource efficiency and environmental sustainability without compromising the performance of the final products.
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Optimization of fiber-reinforced concrete with polypropylene and basalt fibers using marble fillers
Статья научная
Introduction. One of the most promising materials for dispersed reinforcement of concrete is basalt fiber. It is characterized by high strength, thermal and chemical resistance, as well as environmental safety. The use of reinforcing fibers significantly increases the flexural and tensile strength of concrete and improves its water resistance and resistance to dynamic loads. A number of studies show that the introduction of basalt fiber contributes to an increase in the compressive and flexural strength of composites, as well as their crack resistance. With an optimal fiber content, a spatial reinforcing framework is formed, which increases the energy capacity of material fracture and its resistance to external influences. Methods and materials. Fiber-reinforced concretes were produced using the following technology: marble fillers of different fractions, reinforcing fibers, and Portland cement were first mixed in a dry state for 10 minutes, after which the required amount of water was added. The resulting mixture was stirred for 30 minutes and molded into special forms for physical and technical studies. After 24 hours, the samples were treated with water steam for 30 minutes, after which, after three days, tests for density, water absorption, and strength were carried out. According to the experimental plan of the Ha5 type, 27 compositions of fiber-reinforced concrete were obtained. Based on the experimental results, regression coefficients of models describing the studied properties of fiber-reinforced concrete with marble fillers were determined using the least squares method. Graphical representations of the experimental–statistical models were also constructed in the form of two-dimensional nomograms. Results. It was established that combined reinforcement with basalt fibers (BF) and polypropylene fibers (PF) is possible but requires optimization of their ratio. The most effective scheme is when the main reinforcing role belongs to basalt fibers (2–3%), while polypropylene fibers are introduced in small amounts (up to 1–2%) to control crack formation. The analysis of graphical regions and derivative functions showed the following optimal range of component contents: marble chips – 25–30%, marble powder – 10–15%, marble dust – about 12%, basalt fibers – 2–4%, polypropylene fibers – 0–2%. Conclusion. Basalt fibers are an effective means of increasing the strength characteristics of fiber-reinforced concrete at moderate content (about 2–3%). However, their excessive amount leads to a decrease in density and an increase in water absorption of the material. Polypropylene fibers in most cases reduce density and compressive strength and increase water absorption; therefore, their use should be limited to small doses and mainly applied to improve crack resistance. The best complex of physical and mechanical properties is achieved when marble dust is used in combination with basalt fiber.
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Optimization of properties and structure of lightweight materials using digital methods
Статья научная
Introduction. The solution to problems aimed at improving the efficiency of construction is closely linked to the use of lightweight mineral materials, which include mineral fibres, foam glass, cold-curing cellular glass, cellular concrete, and foam gypsum. Methods and materials. The aim of the research is to study the influence of technological factors on the properties of foam gypsum, as well as on the features of the formation of its structure and optimization of its compositions. The basis of the methodology is digital methods of planning, processing results, and their analytical optimization. Results. Based on the analysis of statistical information, it is established that the optimal composition is the one that includes the consumption of dihydrate gypsum of 76.6 kg/m3, the consumption of the polymerizing component of 9.8 kg/m3, and the consumption of the aqueous solution of the foaming agent of 80 kg/m3. This composition corresponds to a softening coefficient of 0.40–0.42; the compressive strength of foam gypsum is 0.75 MPa, and the average density is 320 kg/m3. Discussion. The properties of foam gypsum are determined by its macro- and microporosity, as well as the structure of the interpore partitions. The presence of connecting pores, as well as the crystalline structure of the interpore partition, makes the material permeable to vapour-air mixtures, which is a positive factor for acoustic materials. Conclusion. This material can be used for the production of individual products, as well as in low-rise construction of houses using frame-sheathing technology.
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Статья научная
Introduction. The management of physical and chemical processes of structure formation of high performance cement composites can be provided at several scale levels through the use of modifiers of various nature and mechanism of action, in particular, micro- and nanoscale mineral additives of natural and technogenic origin. It is known that clays and carbonate rocks are promising raw materials to obtain mineral modifiers for cement systems. The purpose of this study was to establish the influence regularities of the prescription and technological parameters (material and granulometric compositions, temperature calcination) to obtain mineral additives based on calcined clays and carbonate rocks on their activity in cement systems. Methods and materials. Polymineral clays and carbonate rocks (dolomite and chalk) from several deposits of the Republic of Mordovia were used as raw materials for obtaining mineral additives. The specific surface area of modifiers was determined on the PSX-12 dispersion analysis device using the Kozeny-Carman method. The study of the granulometric composition of sedimentary rock powders was carried out by laser diffraction method. The research of physical-chemical processes occurring during the heat treatment of polymineral clays and carbonate rocks was carried out using the synchronous thermal analysis method. Optimization of calcination temperature of clay-carbonate mixtures was carried out based on the research results on the effect of their additives on the cement binder activity with the determination of the modifier activity index in accordance with the methodology of the Russian State Standard GOST R 56178-2014. Results and discussion. The optimum calcination temperature, located for polymineral clays in the area of 500–800оC, was established according to the study results of dehydration processes of clay minerals using the synchronous thermal analysis. This temperature range corresponds to the initial restructuring processes in the crystal structure of minerals of the kaolinite and illite groups, associated with their dehydroxylation, which contributes to the transition of these phases to the active form. The study results of influence of additives of calcined clay-carbonate mixtures on the cement binder activity proved the thermal analysis data. It was found that calcination of clays and clay-carbonate mixtures at 700°C contributes to obtaining of the most effective mineral modifiers. Conclusions. On the totality of studies, regularities were revealed in the system “modifier composition – calcination temperature of sedimentary rocks – mixed binder activity”, which allow optimizing the prescription and technological parameters for obtaining mineral additives to achieve the required level of strength characteristics of cement composites.
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Optimization of the composition and properties of a ceramic composite based on barite and bentonite
Статья научная
Introduction. Currently, barium sulfate is actively used in various industries, including paper manufacturing, construction, paints and coatings, rubber, chemical, metallurgical, and electrical engineering industries, as well as in agriculture and medicine. Literature analysis has shown that the composition and properties of barium sulfate depend on its deposit. Different processing technologies have been developed for barium sulfate, including methods for producing materials for a wide range of applications. Particular attention is given to creating radiation-resistant and radiation-shielding materials, including radiation-resistant concretes and ceramics. Methods and materials. In Kyrgyz Republic, there are more than 40 barium sulfate deposits. Among them, the "Arsy" deposit stands out particularly, with sufficient reserves. The chemical composition of barium sulfate from the "Arsy" deposit was analyzed using atomic emission spectrometry, X-ray fluorescence method, and silicate chemical analysis. The analysis results showed that the chemical composition of barium sulfate includes barium sulfate (BaSO₄) at about 89–91%. The remaining components are impurities: calcium (Ca) – 8–8.4%, silicon dioxide (SiO₂) – 1.6–1.8%, aluminum oxide (Al₂O₃) – 0.1–0.13%, and iron oxide (Fe₂O₃) – 0.15–0.25%. Micro-silica is a fine-dispersed powder consisting of silicon dioxide (SiO₂) particles ranging from 0.1 to 0.3 micrometers in size. Its SiO₂ content is approximately 85–98%. It also contains impurities: aluminum oxide (Al₂O₃) – 0.2–0.8%, iron oxide (Fe₂O₃) – 0.1–0.5%, and calcium oxide (CaO) – about 0.5%. The chemical composition of bentonite from the Abshir deposit is characterized by the following component contents: silicon dioxide (SiO₂) – 65.84%, aluminum oxide (Al₂O₃) – 14.8%, iron oxide (Fe₂O₃) – 4.35%, calcium oxide (CaO) – 2.85%, magnesium oxide (MgO) – 1.76%, loss on ignition (LOI) – 2.72%, and other impurities – 7.68%. For processing barium sulfate powder, a hydrocavitator was used, which ensures effective treatment of liquid media through a combination of cavitational and mechanical effects. Results. To develop the technology and optimize the composition and properties of the ceramic composite, bentonite clay, finely ground barium sulfate, and micro-silica were used as raw materials. The experiment was conducted based on a four-factor plan B4. Regression equations describing the dependence of the material’s density, water absorption, strength, and shrinkage on the varying levels of the factors were constructed from the levels of factor variation and the experimental data obtained. Corresponding nomograms reflecting the influence of the studied factors within the experimental plan were developed based on these equations. Optimal parameters ensuring high strength of the ceramic composite were identified: barium sulfate content of about 20–25%, micro-silica content of approximately 5%, firing temperature around 850 °C, and heat treatment duration of 30–45 minutes. Subsequently, the barium sulfate powder was processed using a hydrocavitator, after which the technological modes and physical-technical characteristics of the powder after cavitation treatment were determined. The composition and properties of the barium sulfate powder were analyzed using X-ray diffractometry, performed on an AL-27MINI diffractometer within the 2θ range of 10° to 70°. Fourier-IR spectra were recorded on an IRSpirit-T spectrometer equipped with a QATR-S accessory, within the range of 400–4000 cm–1. Conclusion. Optimization of the composition and properties of the ceramic composite based on the analysis of mathematical models indicates that it is advisable to use barium sulfate powder in an amount of about 20–30% and micro-silica up to 10%, at a firing temperature of 850–900 °C and a heat treatment duration of 30–45 minutes. Such a composition allows achieving high strength and water resistance of the material. After cavitation treatment, barium sulfate powder changes its chemical activity and can be used in the composite in an amount up to 20% by mass relative to the bentonite. Adding more than 20% of barium sulfate powder causes intense chemical reactions due to the presence of sulfur, leading to the destruction of the material’s structure. Therefore, it is recommended to limit the barium sulfate content to a maximum of 20% to avoid undesirable effects, including explosive or destructive processes within the ceramic composite structure.
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Optimization of the properties of lightweight ceramic products using statistical methods
Статья научная
Introduction. Improving the efficiency of ceramic bricks and blocks involves reducing their average density and corresponding thermal conductivity. One possible approach is to introduce porosity into the ceramic structure using burnable additives or specialized foams during the preparation of the ceramic mixture. Another option is incorporating ultra-lightweight aggregates, particularly crushed foam glass. The aim of this study was to develop a method for determining and optimizing the formulations of lightweight ceramic bricks based on regulatory requirements for strength characteristics, density, and thermal conductivity. Methods and materials. The raw materials used included medium-plasticity loam, a fluxing component (finely ground glass waste), and crushed foam glass gravel. The properties of the samples were assessed using standardized methods, while statistical and digital techniques were employed for experimental planning and data processing. Results. It was found that the optimal conditions include drying at 80 °C and 55% air humidity, followed by firing at 900–950 °C with the introduction of a fluxing component. The optimal values of the factors were determined as follows: foam glass density: 150 kg/m³; foam glass consumption: 30 kg/m³; optimal particle size of crushed foam glass: 0.68–0.69 mm; fluxing additive content: 8.3–8.4% of the clay mass. These parameters correspond to the following material properties: Average density: 1320–1360 kg/m³; Compressive strength: 15–16 MPa; Thermal conductivity: 0.15–0.16 W/(m•°C); Frost resistance grade: F35. Discussion. The use of digital methods revealed the influence of variable factors on the material's properties (strength, density, and thermal conductivity), which was confirmed through model validation in active experiment series and structural analysis of the material. Conclusion. This research has established a methodological framework for predicting the properties of ceramic products and optimizing their composition using digital methods. Requirements for optimizing the properties of foam glass based products were determined, including guidelines for the consumption of foam glass and fluxing agents. The resulting materials fully comply with the relevant standards for such products. The lightweight brick exhibits both structural and thermal insulation properties, making it suitable for use as a wall material.
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Overview of the instrumentation base for monitoring greenhouse gases
Статья научная
Introduction. The article describes the results of a comparative analysis of three large companies presenting on the market close control equipment for the control of climatically important parameters: LI-COR, Picarro and Gasera, and using nanotechnologies; the urgency of the ecological problem of finding a technical solution for the control of climatically active gases, including CO2 in the atmospheric air, was studied. The aim of the work is to analyze the world leaders in the production of precision equipment for monitoring greenhouse gases in the manufacture of nanomaterials and in scientific centers for the study of climate change. Methods and materials. The study is based on the information from open information sources, materials and reviews of various fields of knowledge made by scientific researchers, who describe the features of the activities of these companies or are directly involved in product development, and then compile a report on their work. The article contains information from true sources, namely from the official websites of companies, which describes their history of creation and development process. Research methods are benchmarking and SWOT analysis. Results and discussion. The study carried out a comparative analysis of companies in terms of the duration of work in world markets and its impact on the quality and technical features of products. The article provides information about companies that have achieved very good results from the beginning of their foundation to the present. The species diversity of old and new generation quality control devices sold in markets around the world by the companies in question is the same, which leads to very high competition. A description of the companies’ operations, their location, coverage of consumers is given, as well as the annual income from the sale of products, the amount of work that they do in the course of their activities. Conclusion. It was revealed that the companies LI-COR, Picarro, Gasera carry out the production of quality control devices that reproduce the required measurement parameters. Gas-analyzers of the companies are in demand in the market of precision control devices used to capture greenhouse gases in order to develop building nanomaterials, scientific research on the climate problems of modern society.
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Oxyalkylated alcohols phthalates
Статья научная
Polyvinyl chloride (PVC) is used to obtain a wide range of materials for various purposes. High demand of PVC is explained by possibility to modify polyvinyl chloride and produce broad range of materials with improved properties as well as to have cost efficient ratio: productivity, available raw materials, saving of natural resources. However, under normal temperature polyvinyl chloride is brittle and inelastic, that limits the fields of PVC application. The production of basic PVC compositions is impossible without plasticizers – low-molecular compounds that allow direct regulating physical and mechanical properties of polymer. Production of plasticizers became one of the most important branch of petrochemical industry. Recently, however, the range and production of plasticizers have drastically decreased due to the increased cost, which reduced the competitiveness of plasticized PVC products. Therefore, the expansion of plasticizer variety for PVC is a strategic task of great practical significance. The present work describes synthesis methods of esters on the basis of oxyalkylated alcohols suggested as polyvinyl chloride plasticizers. Physico-chemical properties of synthesized compounds were studied. Conditions for their production with maximum outcome were selected. The results of experiments in which obtained compounds were tested as additives in the plasticization of PVC showed that the obtained samples of cable plastic, adhesive PVC tapes and multi-layered polyvinyl chloride linoleum satisfy all the technical requirements by the main indicators: cable plastic compound – GOST 5960-72 with amendment 1-9; a PVC adhesive tape – Technical Conditions – 2245-001-00203312-2003; multilayered linoleum – GOST 7251-77. According to the experimental results, phthalates of oxyalkylated alcohols possess rather high efficiency as plasticizers of polyvinyl chloride and are recommended for use in the above-mentioned industrial PVC recipes.
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Ozonation of woodworking enterprises using a heterogeneous nanocatalyst
Статья научная
Despite the variety of existing methods of wastewater treatment, this problem can not be considered solved for the woodworking industry. Taking into account that the waste water of plywood-board plants includes phenols, formaldehyde and many other toxic substances, the development of a method for their treatment is an extremely important and actual task. In this regard, we studied the effectiveness of wastewater treatment of the Ufa plywood-board factory (UPBF) by ozonation in the presence of the available and most studied heterogeneous catalysts: Fe2O3, applied in the form of nanofilms of 0.5–1.0 mm particles γ-Al2O3; Al2O3, applied in the form of nanofilms 2.5–3.0 mm particles of TiO2; MnO2, applied in the form of nanofilms 2.5–3.0 mm particles of TiO2. Optimal cleaning conditions were determined by the kinetic curves of phenol decomposition. The results of the conducted experiments on catalytic ozonation of wastewater showed a high purification effect. COD decreased 1.7 (Al2O3, MnO2) and 3 times (Fe2O3) compared to non-catalyst ozonation. The obtained results allow us to confidently assert that in order to improve the efficiency of treatment of UPBF’s wastewater needs ozonation to be carried out in the presence of a heterogeneous nanocatalyst Fe2O3, which is used in a small amount, so there is no need to purify water from iron (III) ions as in homogeneous catalysis. The concentration of iron ion (III) did not exceed the maximum permissible concentration in drinking water (0.3 mg/dm3). The effect of treatment of COD is up to 96%. The paper presents physical and chemical parameters of the quality of the original wastewater and after ozonation in the presence of the catalyst Fe2O3. The studied method of purification makes it possible to reduce the content of phenol to the standard quality index (0.01 mg/dm3). Preliminary ozonation of wastewater increases the efficiency of further biological treatment.
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Patterns of structure formation in lime composites with additive based on amorphous aluminosilicates
Статья научная
Introduction. One of the reasons for coating destruction enclosing structures is the formation of condensate at the boundary of the fence and the finishing layer. As a result of external impact and freezing of moisture in the pores of the plaster coating, a network of small cracks is formed, and it is also possible to peel off the finishing layer. To test this hypothesis, the facades of three different buildings were examined. It is established that all the studied plaster coatings are made on the basis of cement mortar. It is also known that lime mixture is used less often due to the lack of sufficient resistance to moisture. Therefore, there is a need to increase the resistance of coatings based on lime compositions. This can be achieved by introducing an alumosilicate-based modifying additive into it. Materials and methods. Liquid sodium glass, aluminum powder PAP-1 and distilled water were used for the synthesis of the additive. Slaked lime (pushonka) with an activity of 84% was used to prepare test samples. Fritsch particle sizer Analysette 22 was used to analyze the granulometric composition of the additive. Compressive strength was determined on the samples measuring 20×20×20 mm. A testing machine of the type “IR 5057-50” was used for the study of compressive strength of samples. The analysis of rheological properties was determined by the Shvedov-Bingham equation. To study the plastic strength (ultimate shear stress) of the finishing mixture, a conical plastometer KP-3 was used. The plastic viscosity of the composition was determined with a rotary viscometer BCH – 3. Results and discussions. The synthesized additive is a light powder of light gray color with a bulk density of 0.55 ± 0.05 g/cm3. The synthesized additive revealed a high content of oxides Al2O3, SiO2, Na2O respectively, amounting to 51.03%, 36.36%, 11.89%. The additive consists of particles of 100.0–200.0 microns, which make up more than 20% of the total composition. The influence of an aluminosilicate additive on a lime binder on rheological properties was investigated, a slight increase in static shear stress was revealed, respectively, an increase in the percentage of the additive. The value of the dynamic shear stress increases significantly with an additive content of more than 10%. Conclusions. The regularities of hardening of a lime binder with a nanostructured additive based on amorphous aluminosilicates are established, and the optimal content of an aluminosilicate additive in the amount of 10% by weight of lime is determined.
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Статья научная
The authors developed a notion of the three-dimensional matrix of chemical elements, which made it possible to eliminate the main disadvantages of tabular forms of the structure of chemical elements developed by D.I. Mendeleev and the international community of IUPAC chemists. The three-dimensional structure is represented as an expanding conic matrix. At the same time, all known chemical elements up to number 118 are combined into four blocks. The block-structure made it possible to substantiate an electron-level formula, even for the proposed new chemical elements of the 5th block E with numbers 119 through 218. This allows for the development of a digital model for calculating interactions of chemical elements and obtaining new types of compounds and materials.
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Peculiarities of the formation of silicon oxide films modified with metal nanoparticles
Статья научная
Introduction. Silicon oxide film coatings have unique properties and are widely used in various industries, including construction. This paper presents the results on the preparation of polyalkylhydroxysiloxane liquid film in the presence of nanoscale particles of metallic bismuth. Methods and materials. Laser ablation method of metallic bismuth in aqueous medium was used to obtain bismuth nanoparticles. The surface of the target was treated with a laser beam at the workstation of an ytterbium pulsed fiber laser are discussed. The particle size and electrokinetic properties of colloidal bismuth sols were determined method by dynamic light scattering. After drying, Bi powder was added to polyalkylhydroxysiloxane liquid. Thin films cured under different heat treatment modes are applied to glass substrates by dipping. The resulting films were characterized by SEM, X-ray phase analysis, and FTIR spectroscopy. Results. In this work, the electrokinetic properties of colloidal bismuth sols are discussed. Laser ablation of a bismuth substrate leads to an increase in electrical conductivity and the appearance of a double electric layer in colloidal sols. The effect of the curing temperature on the properties of the coating is shown. It was found that the content of bismuth nanoparticles in the polyalkylhydroxysiloxane coating (3 wt.%) does not lead to the formation of crystalline phases. At the same time, the composition of the film and the mode of heat treatment affect the short-range order of molecular bonds. Increasing the content of bismuth nanoparticles in the coating of more than 10 wt.% leads to the appearance of microcrystalline phases of bismuth silicates in the system. Conclusion. The results obtained in the course of the study supplement the information about the production of bismuth nanoparticles by laser ablation and are of great importance in the practice of creating composite films.
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Статья научная
Introduction. Studies have shown that current science and technology development is closely related to the growth of intellectualization of industrial relations, the emergence of new technologies, which, in turn, leads to the actualization of understanding and countering threats in the field of digital, energy, climate, and mental security. The convergent basis in the development of nanotechnology is revealed. The aim of this research is to establish the prerequisites and opportunities for the promising rapid development of nanotechnology on a global scale, as well as to identify potential risks associated with it. Methods and materials. An interdisciplinary approach, based on the convergent nature of modern technology foundation, is significant in studying the prerequisites and patterns for the cross-cutting edge development of nanotechnology on a global scale. Results and discussion. On the basis of the existing research in the field of nanotechnology application in strategically important industries, the postulates of a new worldview concept мировоззренческой концепции for studying the future path of nanotechnologies are proposed. The postulates are based on an integral concept of interlinking such major components: the prerequisites for of threats emergence; threats and their identification; factors forming the emergence and manifestation of threats; problems; risks affecting the aggravation of negative factors. Socio-cultural, technocratic and institutional prerequisites for studying the opportunities and risks of the further development of nanotechnologies are identified and substantiated. Conclusion. The interdependence of socio-cultural, technocratic and institutional prerequisites and opportunities for the emergence of threats and risks for the future development of nanotechnologies is presented. The need for institutional regulation of the long-term development of nanotechnologies is justified, highlighting several emerging institutional challenges that could hinder their industrial application. Recommendations for how to regulate the development of nanotechnologies through institutions are also proposed.
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Performance evaluation of foamed materials based on cold-cured liquid glass
Статья научная
Introduction. The current trend of transition to non-combustible and environmentally friendly thermal insulation and sound-absorbing materials involves development of research to obtain foamed silicate compositions, particularly those based on cold-cured liquid glass. The primary advantage of this material is its eco-friendliness throughout both its operational and production stages, facilitated by the employment of energy-efficient manufacturing technology. Materials and methods. Cold-cured liquid sodium glass and cullet-based foam glass were used as main raw materials. To determine optimal curing additive of liquid glass, Portland cement, slaked lime and sodium ethylsilicate were selected. The thermal conductivity of materials was evaluated with by means of appropriate coefficient, value of which depended on volume content of pores in material, nature of porosity and distribution of pores by size. The decrease in water absorption capacity was estimated by value of wetting edge angle. Sorption humidity was determined in accordance with GOST 24816-2014, and sound absorption coefficient was determined according to GOST 16297-80. Results and discussion. The prime objective of this study was to examine trends and provide explanations for the formation of specified performance indicators of thermal insulation and sound-absorbing materials, particularly those based on cold-cured foamed liquid glass. The issue of increasing water resistance of material by selecting effective additive-hardener was also investigated. Conclusion. The developed thermal insulation material based on cold-cured liquid glass is eco-friendly, with presence of large number of small and mainly open pores, giving it good sound-absorbing properties. The problem of high-water absorption of material was solved by introducing Portland cement as a curing additive.
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Phase-structural heterogeneity and activity of the surface of polymineral sand powders
Статья научная
Introduction. The value of the specific surface (Ssp), the degree of crystallinity (С, %) and surface activity (ks) plays an important role in creating various compositions. The increase in the size of Ssp is associated with a change in the “С” of rock powders, the value of which characterizes the properties of fillers. The reactivity of the finely dispersed material can be determined by the value of ks, which allows quantifying transition of the potential energy into free surface energy by activating the surface of the raw material. Therefore, determining the functional relationship between the parameters characterizing the reactivity of rock powders is an urgent task. Methods and Materials. Four deposits of polymineral construction sands are selected as raw materials. To obtain fine powders, the samples were ground by dry dispersion. The specific surface area of rock systems was determined by gas sorption. Crystallinity was calculated from the X-ray diffractogram of the samples. Results and Discussion. The certain sizes of specific surfaces for highly dispersed rocks have shown, that deposits “Kenica” and “Nekhtskoye” possess the greatest values Ssp. The study of the phase-structural heterogeneity of the samples, showed a significant increase of the content of the amorphous phase. At the same time, the degree of crystallinity for the sands “Kenica” and “Nekhtskoye” deposits decreases 25%. The functional relationship between the surface activity and the shares of the amorphous component (c) for highly dispersed sands was characterized by mathematical expression ks = 21•10–6•c+0,58•10–6. The identified dependence demonstrates the relationship between the parameters of the phase-structural heterogeneity and ks of fine-dispersed samples. Conclusion. The results obtained showed that mechanical dispersion contributes to the activation of raw materials. This is due to the breakability of the crystal structure of minerals and the texture of the raw materials. These characteristics are reflected in the value of the activity of the surface of finedispersed systems of the rocky rocks.
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Plastic Drainage Slabs with low-temperature nanosintering of granules
Статья научная
Introduction. Currently, the construction industry is developing rapidly. New residential and industrial buildings and structures appear both in megalopolises and small towns. In this regard, an active development of the underground space continually gains in scope: basements and buried facilities, multistorey structures, underpasses and parking lots, shopping malls and many other structures are being built. In order to create reliable and durable structures much attention should be paid to the protection of underground parts of buildings from the destructive effects of groundwater. Waterproofing and drainage materials currently used do not always meet the necessary requirements. The paper discusses the development of a new material for wall drainage in order to provide reliable protection for underground buildings against the damaging influence of groundwater. Methods and materials. The article presents a detailed analysis of existing methods and materials that are used in the installation of wall drainage systems. Plastic slabs made of filtration expanded polystyrene have been proposed as an effective drainage material. The technology of filtration material with high water transmission capacity is presented. This methodology is based on the low-temperature nanosintering of polystyrene granules. The main structural characteristics of filtration polystyrene, including characteristic pore diameter and intergranular porosity, and its physical and mechanical properties were determined. Results and discussion. The results of research on the structure of filtration expanded polystyrene with different grain-size compositions are given. It is shown that due to the process of nanosintering of granules it is possible to form varies types of drainage slab structures, which are necessary to obtain required characteristics. In addition, the experimental results of the water transmission capacity of drainage slabs, depending on the structural characteristics of the material, are also presented. Based on the tests conducted, an empirical formula has been developed to calculate the filtration coefficient of the plastic drainage slabs. Recommendations have been developed for selecting the grain composition of material when working on cohesive and non-cohesive soils. Conclusion. The results of our study show that filtration expanded polystyrene slabs have a high-water transmission capacity and sufficient compressive strength and can be used to protect the underground parts of buildings based on different soil types.
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Статья научная
Introduction. Research of polymer concrete properties show that it differs favorably from conventional concrete by such indicators as mechanical strength, resistance to aggressive impact of various environments, water resistance, abrasion resistance, water-repellency and frost resistance. Currently, it is possible to obtain polymer concrete with characteristic and chemical properties –specified density, strength, deformability, ductility, and corrosion resistance. Methods and materials. The research is carried out by comparing laboratory tests of polymer concrete based on furfural binder. Furfural has a high reactivity and can form resin compounds with many chemicals. Diphenylamine was added to furfural in different proportions. Benzenesulfonic acid, sulfuric acid and their mixture at a ratio – 1:1 by weight were used as hardeners. Crushed sand or ground andesite based on nanostructured microfiller served as aggregate for various compositions of polymer solutions. The polymer concrete strength, chemical resistance, lasting properties, water resistance, abrasion resistance, metal adhesion were tested during the research. Structural changes in properties were studied by the electron microscopic analysis method. Results and discussion. It is established that the diphenylamine solution in furfural, provided that it is solidified by sulfuric acid, benzolsulfoacid or mixture of these acids, is a polymer binder capable to form a high-strength material under normal hardening conditions by acid-resistant aggregates. It is also determined that to prepare resin, the ratio of furfural and diphenylamine should be within 1:0.5–0.3 by weight. The resin containing 1 weight part (w.p.) of furfural and 0.5 weight part of diphenylamine is conventionally named FD-1; containing 1 weight part of furfural and 0.4 weight part of diphenylamine – FD-2 and resin with 0.3 weight part of diphenylamine – FD-3. Conclusion. The introduction of nanostructured microfiller into the polymer concrete composition could save expensive resin. Comparison of the technologies for producing FD resin and polymer concrete, as well as preliminary test data of the studied materials, can determine the possible technical and economic advantages of polymer concrete based on FD resin over the polymer concrete based on FA (furfurolacetone) monomer which is currently used in construction of hydro-engineering structures. Polymer concrete based on FD resin has high strength and exceeds the strength of polymer concrete based on FA monomer by 20–25%.
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Potentiometric method for assessing the pozzolatic activity of highly dispersed materials
Статья научная
Introduction. Pozzolatic activity is an important indicator for highly dispersed materials, particularly clay soils. It determines their effective use and characterizes the ability of the active components in their composition to interact with calcium hydroxide. Various methods are employed to assess this pozzolatic activity. Potentiometric methods are effective. They are based on measuring the electrode potential, which is functionally related to the change in the concentration (activity) of calcium ions in the analyzed solutions as the main information parameter of the pozzolatic reaction. The purpose of the research is to test the potentiometric method to assess the pozzolatic activity of highly dispersed materials, as well as the application of suggested approach to determine the rational amount of an active mineral lime-containing additive as a binder component for producing soil-concrete. Materials and Methods. We have chosen clay soil models with different plasticity index and sandy loam of the Arkhangelsk region as the objects. The potentiometric analysis method involved sequentially adding 0.015 mol/l calcium hydroxide solution, in amounts ranging from 0.2 to 0.8 ml, to a suspension containing 0.5 g of soil in 80 ml of distilled water. The potential of the system was measured while continuously stirring at a fixed speed. Results and Discussion. All studied objects are characterized by the pozzolatic activity, which increases in the series sandy loam sandy → clay loam light silty → clay light silty ≈ sandy loam silty and has the order of absolute values coinciding with the literature data. The rational amount of the active mineral lime-containing additive was 1–2% for clay soil models, depending on the plasticity index, and more than 2 % for the sandy loam of the Arkhangelsk region (from the soil mass on dried basis). Conclusion. We have shown the applicability of the potentiometric method of analysis using a calcium-selective electrode to assess the pozzolatic activity of highly dispersed materials on the example of models of clay soils with different plasticity index and sandy loam of the Arkhangelsk region.
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Potentiometric method for determination of hydraulic activity of quartzcontaining powders
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Introduction. An important aspect of concrete mixture preparation technology is the exploration of methods to effectively utilize the properties of aggregates (fillers) in hardening multi-component systems. The most common binder composition is a mixture of a binder system with crushed quartz-containing polymineral sand. It is known that micro silica is classified as an active mineral additive (filler), the properties of which are characterized by the amount of Ca2+ ions absorbed from a saturated lime solution. Literature sources describe two types of analytical methods for determining pozzolanic activity. The first type that trace the change in the content of Ca(OH)2 over time during the pozzolanic reaction. The second type that aim to determine the physical and mechanical characteristics of the material under study. These characteristics reflect its ability to bind free calcium oxide into stable hydrate compounds. Previously applicability of the potentiometric method of analysis using an ion-selective electrode with pCa-function was demonstrated for the assessment of pozzolanic activity of highly dispersed materials. It should be noted to note that this electrochemical method of analysis which is functionally related to the concentration of the determined component in the tested solution, is very efficient in terms of expressiveness and labour intensity. The objective of the research is to validate the method for micro silica systems obtained by mechanical grinding of raw materials of polymineral sands from different deposits. The experiments were conducted using sands from the Arkhangelsk region deposits. The quartz sand (QS) was chosen as a reference object to establish the nature of change in the functional relationship of the measured potential of the electrode system from the volume of added Ca(OH)2 solution. Methods and Materials. The polymineral sand of the Krasnoflotsky-West deposit is categorised as alluvialmarine modern Quaternary sediments (am IV). The sand of the Kholmogorskoye deposit is quartz-feldspathic sand, which belongs to alluvial modern Quaternary sediments (a IV). The mineralogical composition of polymineral sands was determined by means of the semi-quantitative method, utilising the binocular microscope MBS-1. Fine sand powders were obtained by dry mechanical grinding in a Retsch PM100 planetary. The specific surface area of the obtained fine powders was measured by the Kozeny-Karman gas permeability method on a PSKh-10a apparatus. The potentiometric analysis was conducted using an apparatus comprising an electrode pair, consisting of a measuring electrode with pCa-function and a reference electrode connected to an Expert-001-3.0.1 ionometer. The reaction system was stirred using a magnetic stirrer. In order to ascertain the sorption capacity of silica-containing raw materials, a lime solution with a concentration and a suspension of fine sand powders were prepared in advance. Concurrently, the EMF (potential) of the system was measured, with constant stirring. The concentration of calcium ions, Cact, was then calculated based on the previously established calibration dependence, using the potential values (mV) obtained. In order to determine the activity of fine mineral powders of silica, the dependence between the values of the given concentration of calcium ions in lime solution when adding a certain volume of lime to the suspension of the studied sands and the concentration values obtained by potentiometric measurements was plotted. Results and Discussion. The obtained powders of quartz-containing polymineral sands, which had been finely dispersed, had the following specific surface values: quartz sand – 1020±31 m2/kg, Krasnoflotsky West – 465±14 m2/kg and Kholmogorskoye – 450±14 m2/kg. The given data on the specific surface of powders of natural origin allow for a comparative analysis of experimental potentiometric measurements. Concurrently, the dependence of the measured potential on the concentration of calcium ions in the solution for quartz sand suspension can be utilised as a reference, given the significantly high specific surface of the powder, thereby resulting in a more pronounced dependence E = f(Vadd). Relationship obtained the dependence of the measured potential of the electrode system on the volume of added Ca(OH)2 solution in a suspension of quartz sand (as a reference sample) and distilled water (as an idle experiment) shows that the nature of the change in the functional relationship of the analysed two samples (QS and H2O) is different. Concurrently, it can be observed that the incorporation of a lime solution into water (in accordance with the anticipated outcome) results in a nearly constant augmentation in the measured potential values, the magnitude of which is proportional to –lgCCa. Change of potential of electrode pair in suspension of quartz sand powder has character different from that mentioned above for water.
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Introduction. The production of plasticizing additives using nanoparticles for the construction industry represents a promising sector in the development of advanced building materials. By incorporating nanoparticles, such as silicon dioxide, into complex additives, it is possible to significantly enhance the structural and mechanical characteristics of cement-based systems, resulting in increased strength, durability, and resistance to external forces. This study aims to investigate the process of synthesizing silicon dioxide nanoparticles in aqueous media and creating a complex organic-mineral additive comprising phloroglucinol- furfural oligomers with silicon dioxide nanoparticles. Materials and methods of research. A modifier based on phloroglucinol-furfural oligomers was used as an organic component of the complex additive. To synthesize silicon dioxide nanoparticles, which are the mineral component of the additive, liquid glass (sodium silicate solution) was used. Additionally, Aerosil, with a specific surface area of 2,000 m3/kg, was used as the dispersed phase in the organic mineral additive to study the compatibility of the components and the mechanism of their interaction. The particle and size distribution were determined using laser light diffraction on the Malvern Mastersizer 3000 device and dynamic light scattering on the Microtrac S3500 device. Microscopic analysis of the complex additive was performed on a TESCAN MIRA 3 LMU scanning electron microscope. The chemical structure and composition of the obtained additive were monitored by UV and IR spectrophotometry on Specord 200 Plus and Alpha Bruker Optics devices, respectively. Results and discussion. The article presents the results of the development of a method for the synthesis of silicon dioxide nanoparticles and creating an organic-mineral additive based on phloroglucinol-furfural oligomers containing these nanoparticles. The additive is designed for use in mineral suspensions in construction additive technologies. It has been shown that it is possible to obtain nanoscale particles of silicon dioxide through the hydrolysis of sodium silicate. It has been demonstrated that as the concentration of sodium silicate increases, the number of silica particles increases significantly, the number of silicon dioxide particles increases significantly. This leads to faster coagulation of the particles, resulting in the formation of larger aggregates. It has been shown that silicon dioxide particles smaller than 10 nm can be obtained through acid titration. During the maturation period, particles increase in size by about 7 times over a period of 1 to 7 days. The optimal ratio for particle synthesis should be considered to be a 2:1 ratio of reagent solutions (sodium silicate to hydrochloric acid) by volume. It is shown that the introduction of the specific additive at the stage of particle formation can help to stabilize their growth. Conclusion. The complex organic-mineral additive based on a phloroglucinol-furfural oligomer and silicon dioxide nanoparticles has been developed. It has been established that the introduction of the specific additive in the process of synthesis of silicon dioxide particles contributes to an increase in the aggregate stability of the dispersed system of the complex additive, reduces the tendency of particles to enlargement and sedimentation.
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