Nanotechnologies in Construction: A Scientific Internet-Journal @nanobuild-en
Journal articles - Nanotechnologies in Construction: A Scientific Internet-Journal
All articles: 652
Justification of the criteria requirements for fillers in mixtures for 3D construction printing
Scientific article
Introduction. As part of the task to create new materials for additive technologies, an analysis of the situation was carried out, and a problem was identified with the lack of common approaches to selecting raw material components for mixtures. Theoretical concept. Based on the approaches of fundamental structure rheology, physicochemical mechanics of disperse systems, the theory of packing of granular media, we theoretically justified the criteria requirements for the characteristics of fillers and suggested quantitative criteria for their evaluation. It was proposed to use these quantitative criteria for a preliminary comprehensive assessment of fillers when designing compositions of mixtures for 3D construction printing. Materials and methods. The characteristics of the fillers were evaluated using scanning electron microscopy with a scanning electron microscope Thermo Scientific™ Phenom™ Desktop SEM and processing of images by the ParticleMetric software package as well as using laser granulometry with a laser analyser of particles Analysette 22. Results. We assessed the cement and 5 types of fillers that had different sizes and played different roles in the formation of the mixture properties. We also identified their estimated criterial characteristics, including the average particle diameter, gra-nulometric constant, and particle shape coefficient. Boundary values of these characteristics were determined for particles of different morphology and dispersion degree. Conclusion. Based on the application of the suggested theoretical approaches, we determined the lines of research associated with obtaining experimental patterns of the impact of the criterial characteristics of fillers on the rheological characteristics of mixtures as well as with these characteristics according to their significance and justifying the requirements for the range of quantities of fillers depending on their size, shape, and granulometry.
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Light-transmitting concrete using ash and slag, and glass waste
Scientific article
Introduction. The article discusses the potential for producing “green” light-transmitting concrete products in Vietnam using the available resources of ash and slag and glass waste, which will contribute to the development of a closed-cycle economy and sustainable “green” transformation of industrial production in order to achieve zero carbon dioxide and other greenhouse gases emissions by 2050. The aim of the study is to develop formulations and manufacturing technologies for light-transmitting cement-free concrete products with sufficient strength using high-tonnage waste in the form of ash, slag, glass waste, etc. in combination with an activating solution. To achieve this goal, it was necessary to explore the possibility of using the multi-tonnage waste available in Vietnam, suitable for the production of light-transmitting concretes, in order to select the optimal raw materials, and to assess the potential volumes of suitable secondary resources. Materials and methods. The following raw materials were used in the study: finely ground blast furnace slag, fly ash from incineration power plants, glass waste, ceramic powder “TOTO”, obtained by crushing defective plumbing products, activating alkaline solution, polycarboxylate superplasticizer and water. The research methodology is based upon calculating the compositions of concrete mixtures for the production of light-transmitting cement-free concretes by the absolute volume method and testing the developed concretes to determine their average density, compressive and tensile strength during bending, water absorption and natural moisture of samples in accordance with current Vietnamese standards, as well as in assessing the light transmission capacity of the resulting concrete products. Results and discussion. As a result of the conducted research, compositions of decorative cement-free and light-conducting optical fiber-free concretes has been obtained using multi-tonnage man-made waste with sufficient strength (40÷50 MPa for compression and 11.5÷13 MPa for bending tension), low water absorption (6.5÷10% by weight) and good light transmission ability have been developed. Conclusion. A technology is proposed for the production of decorative thin panels and wall tiles in laboratory conditions that have the ability to transmit light and give architectural expressiveness to outside walls and interiors of residential and public buildings.
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Lime-diatomic mortar for finishing the walls of buildings
Scientific article
Introduction. At present, when performing finishing and restoration work, more and more preference is given to dry lime mixes (DBM). Wide opportunities for the production of dry lime-cement mixes are opened up by the use of diatomite, which is both a dry mix filler and an active mineral additive. Previous studies have confirmed the effectiveness of heat treatment of diatomite. After firing at 600–800оC, activity increases when interacting with calcium oxide hydrate. This is explained by the fact that at 600–800оC clay substances are dehydrated to metakaolinite, which is characterized by increased reactivity. The properties of dry mixtures and compositions based on them are affected by the particle size of the components of the dry mixture. In this regard, it is of great importance to study the influence of the dispersion of the components of the dry mixture on the formation of the structure of the finishing compositions. Materials and methods. To study the active centers of the diatomite surface, we used the indicator method for determining the distribution of adsorption centers. Determination of the compressive strength was carried out on a DOSM-3-1 dynamometer on samples 3x3x3 cm in size at the age of 28 days of air-dry hardening of the compositions. The determination of the granulometric composition of the components of the dry mixture was carried out by the method of sedimentation analysis. Adsorption was estimated from the optical density measured with a PEC photoelectrocalorimeter. To study adsorption at the “liquid-solid” interface, the initial components of the dry mixture, lime and diatomite, were used. Results and discussions. Accordingto the data obtained, it was found that a particle size reduction of the dry mixture filler leads to an increase in the strength characteristics of lime-diatomite compositions.It was found that the introduction of C-3 additive into the water favorsincreasing dispersion of hydrated lime, improving plasticity finishing mixture and improving the physical and mechanical characteristics lime-diatomaceous compositions.It is proposed to introduce sulfate additiveinto the formulation of the aluminumdry mixture. Increase in the compressive strength of the finishing composition with addition of aluminum sulfate 1.5–2 times was observed. Conclusion. It has been determined that the developed dry mixture is highly competitive, in terms of technological and operational properties,withprototype. Moreover, the production of the proposed DBM is more economical due to the use of local raw materials and domestic additives.
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Liquid crystaloptical shutter for stained glass and windows
Scientific article
Introduction. Liquid crystal as a nanomaterial has found application in science, engineering and technologies. The unique physical properties of liquid crystals make them sensitive to external influences. The article presents the results of an experimental study of the flexoelectric effect in a liquid crystal, when shear deformations occur, thin layers of which can serve as an optical shutter for the stained glass windows of buildings. Materials and methods. Nematic liquid crystals with a homeotropic orientation of molecules 10÷100 μm thick were used by the birefringence method. Shear frequency 1 kHz. Methods. The experimental cell was assembled from two glass plates in the form of a flat capacitor, spacers were placed between the glasses, which set the sample thickness. A source of shear vibrations was located on the side of the microscope stage, which was connected to the LC cell using a thin waveguide. Results and discussion. According to the geometry of the problem, the director is headed vertically parallel to the Z axis, the velocity vector of the plate vibrations is horizontal along the X axis. The orientation of the liquid crystal molecules in the volume is characterized by the angle θ. An elastic-viscous wave propagates between the moving and stationary substrates of the LC cell, which leads to a perturbation of the initial homeotropic orientation of the director field. The dependences of the first and second harmonics of the shear-induced EMF, as well as the optical signal, on the plate oscillation speed are obtained. They have a threshold nature of occurrence at a critical speed υc~8 mm/s, while the liquid crystal molecules are oriented at an angle θс. The temperature dependences of EMF harmonics far from the nematic – isotropic liquid phase transition showed that when approaching the phase transition, the regression of the signal U1ω stops, and then its value increases up to the temperature transition of the nematic – isotropic state TNI. The magnitude of the optical signal I2ω/Io(T), approaching the phase transition, increases, which is explained by the increase in the amplitude of the director oscillation Θd. Conclusion. The article considers the flexoelectric effect observed in thin layers of nematic liquid crystals with homeotropic orientation of molecules placed between two glass plates. The occurrence of the effect has a threshold character, the critical strain rate is about 8 mm/s. The conditions and parameters of the effect (shear amplitude, sample temperature) on a condenser cell for various liquid crystals are considered. It is proposed to use the results obtained to create an optical shutter (shutter) for stained glass windows or windows of buildings and structures.
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Long-term protection of building structures with sulfur-based nanoscale coatings
Scientific article
The problem of creating reliable protective coatings that increase the mechanical characteristics of concrete building structures (piles, bridges, ceiling arches, tunnels, chutes, culverts, wells, paving slabs and curbs, etc.) operated under the influence of atmospheric factors and groundwater is of great importance. Currently, the most effective way to prevent degradation of materials is the application of various kinds of protective compounds. That protects against various factors of aggressive natural and manmade impact and thus allows increasing the durability of buildings and structures by reducing the amount of water penetrating into the pores. To provide long-term protection of building materials, it is proposed to treat porous surfaces of building materials with a new sulfur-containing compound. The innovative developed impregnating composition is based on sulfur and it provides protection of building materials of different nature from weathering and corrosive media for a long time. Modification of the proposed composition can significantly improve performance and increase the service life of building materials.
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Low carbon footprint building materials using industrial waste
Scientific article
Introduction. The possibility of producing construction materials in Vietnam based on man-made waste with a low carbon footprint and capable of absorbing carbon dioxide is being considered in order to achieve zero greenhouse gas emissions by 2050. To date, insufficient attention has been paid to the search for a solution to this problem. Methods and materials. Studies were conducted to assess the possibility of obtaining a ”green“ cement-free concrete material using local industrial and agricultural waste in the form of fly ash and bottom slag from the Green Star incineration plant, alumina sludge, ceramic waste, lime powder and coconut fiber combined with a special activating agent. an alkaline solution. The average density, compressive strength, and water absorption of the developed cement-free concrete were determined on cube samples measuring 100×100×100 mm in accordance with the requirements of current Vietnamese standards. The ability of the resulting concrete to absorb carbon dioxide was evaluated using the developed method by measuring the mass of carbon dioxide absorbed by concrete samples. Results and discussion. The average density of the developed concrete is 1950 kg/m3; compressive strength at the age of 28 days is 7.5–11.5 MPa; water absorption is 8–10% by weight. The main advantages of using cement-free concrete of the developed composition include reducing the carbon footprint due to the abandonment of the use of Portland cement, the ability of concrete to absorb carbon dioxide and the possibility of recycling high-tonnage man-made waste during its manufacture. Conclusion. The results of the conducted research show that the use of the developed cement-free ”green“ concrete for the manufacture of building products and structures in Vietnam will allow to recycle about 1.1 tons. high-tonnage industrial waste per 1 cubic meter and absorb 10–13 kg of carbon dioxide during operation. This will contribute to the implementation of the planned course for the ”green“ transformation of Vietnam's economy into a sustainable closed-loop economy.
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Low-energy binding agent for stone wool-based products
Scientific article
Introduction. The primary objective of this study is to reduce the energy consumption involved in manufacturing mineral wool products by developing an innovative binder based on modified epoxy compounds. To achieve this objective, the potential use of epoxy compounds as binders and their modification methods were thoroughly investigated. Materials and Methods. The materials used included an epoxy binder, a modifier, and a plasticizer. The mineral wool featured an acidity modulus ranging from 1.8 to 2.1 and fiber diameters approximately 4–5 μm. Adhesion strength and tensile strength tests were conducted using an INSTRON 3382 testing machine. A methodology was developed and implemented to study the formulation and technological parameters for producing the modified epoxy binder. Results. The optimal composition of the modified epoxy binder was identified, comprising 6% modifier (latent component) and 3% plasticizer. The recommended thermal curing temperature was established at 150–154 °C, which is significantly lower than the 240–320 °C typically required for conventional binders. This work helps by creating a digital method to study the technology and showing that, obtained using a latent component and plasticizer, modified epoxy compounds can be used as binders for mineral wool products. Following curing, the adhesion strength to mineral surfaces reached 58.4 MPa, the tensile strength of the binder was 77.4 MPa, and the adhesion strength after climatic testing was 29.1 MPa. Conclusion. Assessment of the properties of mineral wool products demonstrated that their operational durability is comparable to that of products manufactured with traditional binders. Mineral fiber products – including basalt, glass, and stone wool – are among the most commonly used and effective thermal and sound insulation materials. Their application significantly reduces energy consumption for cooling during hot periods and heating during cold seasons. Using the modified epoxy binder cuts energy costs for heating by 50% and lowers overall heat use by 20–30%, which improves the energy efficiency of the products.
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Lyophobic sols «БЕТОПРЕСС»® as additives to chemical admixtures into concrete
Scientific article
The article presents an innovative approach to enhancing cement concrete, bordering on a scientific breakthrough, and explains it in a way that is easy to understand. The core concept is the integration of a reactive agent with a chemical fluid to augment the material and endow it with novel characteristics. The technique, as suggested by the author, involves utilizing lyophobic sols that they have formulated as admixtures, combined with aqueous solutions of chemical additives produced by Russian companies. Due to the inclusion of these Nanostructured sols in the chemical additives, heavy cement concrete treated in this manner shows remarkable resilience. It remains unaffected by repeated freeze-thaw cycles, even when immersed in saline or mineral-rich waters. Furthermore, this advanced concrete does not demand any special measures for protection, maintenance, or repair, nor does it require additional waterproofing.
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Main routes of the porous composite materials creation
Scientific article
This paper is devoted to an overview of the main ways of creating porous composite materials. Porous materials are solids containing free space in the form of cavities, channels, or pores, which determine the presence of an internal interfacial surface. The analysis of the general methods of obtaining porous materials. A deposition is one of the most common methods for producing porous materials. Thermal decomposition, as a method used to obtain porous oxide materials by thermal decomposition of various compounds. Hydrothermal synthesis is widely used to produce zeolites. Selective dissolution of individual components of a substance using chemical reactions is also one of the effective methods for creating or increasing porosity. The paper discusses the methods of forming highly porous refractory materials. There are two main ways of forming refractory ceramic products. The first way is the direct sintering of dispersions of ceramic fibers. The second method is the use of a binder, which can significantly reduce the temperature of obtaining a porous product. The possibilities of obtaining porous nanocomposites based on aerogels are shown. Composite materials are usually obtained by combining two different materials. In general, the creation of composites is used to take advantage of each type of material and to minimize their disadvantages. Aerogels are fragile substances. But with the introduction of another component into their structure, it is possible to increase the strength of the material. Such materials have the desired optical properties, high surface area, and low density like silica aerogel. A review of methods for obtaining porous materials using the phenomenon of spinodal decomposition has been carried out. Materials whose structure is formed in microphase separation during polymerization or polycondensation have high permeability and a sufficiently large specific surface. A significant advantage of such materials is high porosity, which can reach 80% or more.
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Management Analytics: A Bibliometric Analysis
Scientific article
Introduction. As nanotechnology continues to evolve and its industrial applications expand, the need for effective data management, analysis, and dissemination is becoming more urgent. Management analytics has emerged as a critical new interdisciplinary field in current business environments, enabling organizations to leverage data-driven insights for informed decision-making and strategic planning. Methods and materials. This study reviews and analyzes research in the interdisciplinary field of management analytics for the period from 2021 to 2023. To conduct bibliometric analysis, data from various sources were used, including academic publications, monographs, reviews, reports, etc. Through a systematic review of the relevant literature, this study aims to provide insight into key topics, methodologies and outcomes in the field of management analytics, as well as to identify directions for future research directions. Results: according to the results of the analysis, it was found that the main source of articles in this area is the Journal of Management Analytics. The total number of publications on this topic for the period amounted to 83 units, the total number of citations for a certain time period has been increasing. The leading countries in terms of the number of citations of academic articles on the topic under study are the United States, India and China. Discussion. So far, the interdisciplinary field of management analytics has not been widely discussed in academic circles. However, leading countries in the world in terms of the number of academic articles and citations are at the forefront of this emerging field. This should be taken into account especially in the development of the nanosystems and nanomaterials industry, which is one of the priority areas for the development of science and technology, where management analytics technologies will be in demand and can provide competitive advantages to companies. Conclusion. The importance of the new interdisciplinary field of management analytics will continue to grow. In the course of the study, it was found that this emerging field has been increasing its popularity and it could be an effective tool for organizations in the nearest fu-ture.
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Scientific article
Introduction. Existing automated construction inspection technologies do not allow the user to select the level of detail. At the same time, in the context of the use of nanotechnology, there is a growing need to expand the capabilities of monitoring and control of construction projects. The aim of the research is to develop, implement software, and validate a technology for controlling the speed and accuracy of constructing three-dimensional models from dense point clouds for automated monitoring of construction works. Materials and methods. The research is based on the methodology of non-binary data trees, including the method of constructing octant trees. An unmanned aerial vehicle with an aerial laser scanner, a ground-based scanning total station, and specialized software were used, including the web application “Management System for Monitoring Construction Works on Objects that have undergone state expertise” developed with the participation of the authors. Results and discussion. In the course of the study, a technology was developed and implemented in software that allows the user to select the required balance between accuracy, degree of detail of monitoring and control data for construction work and time costs and computing power requirements. The comparison is made between a construction project, presented in the form of a building information model, and a three-dimensional model of a real object, obtained from a dense point cloud. The degree of comparison accuracy is set by choosing the level of octrees used. By default, the web application uses level eight. However, in the early stages of construction, when the geometric parameters of a dense point cloud deviate significantly from the design boundaries, the ninth, tenth and other levels can be used. In this case, the accuracy and degree of detail increases. Positive and negative deviations are visualized in red and blue colors, respectively, which allows the user to monitor and control the progress of work at the site. Conclusions. The developed technology can be used by customers and other decision makers to control and monitor work.
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Materials based on modified gypsum for facade systems
Scientific article
Introduction. The use of gypsum in construction systems exposed to atmospheric influences involves the introduction of modifying additives of various types: polymer compositions, mineral fine and nanodisperse components, which can also be products of other industries. Methods and materials. To increase the weather resistance of gypsum stone, its strength characteristics and water resistance, the research considered a complex method of modifying gypsum binder by introducing aqueous solutions of polycondensation resins that harden in the material and nanocomponents. The experiment to assess the effect of the composition of complexly modified gypsum on its properties was carried out on the basis of the matrix of a complete quadratic three-factor experiment. Results. The strength of a complex modified gypsum stone during compression and bending increases by 30% and 25%, respectively, during 80 days of storage in the air. The compressive strength is 60 MPa, and the bending strength is 12 MPa. The samples can withstand 150 cycles of alternating freezing and thawing. Discussion. The introduction of polymer additives into the composition of the gypsum mixture leads to the fact that the gypsum during hydration creates a framework of crystalline aggregates of dehydrate, and the resin, when cured, forms a continuous polymer matrix. The polymer gypsum has the property of increasing the strength over time due to the ongoing polymerization of the resin. Conclusion. A weather-resistant gypsum-containing material was obtained. The use of man-made waste makes it possible to solve the problem of their disposal, which determines the reduction of the negative load on the environment. The methodology for assessing the weather resistance of gypsum stone, and, first, frost resistance, was tested.
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Scientific article
Introduction. The complexity and laboriousness of system studies of physical and chemical processes in the volume and at the interface of the porous medium determines the need to apply mathematical modeling. This allows not only to identify and study the determining physical and chemical processes in a porous medium, but also to solve the problems of optimization and optimal control of processes and regimes by selecting the most favorable conditions. Methods and Materials. The method of mathematical modeling is used to study the processes, including the creation of composite and nanocomposite materials, as well as the moistening and moisture absorption in porous materials. In this context, the porous material is treated as a pseudohomogeneous medium with averaged physical and technological parameters. Results. The mathematical models of physical and chemical processes in the porous medium have been developed, the boundary conditions have been formulated, physical and effective constants have been determined. The processes in porous medium during metallization of carbon-graphite fibrous material, moistening of compacted textile material by an air flow, and moisture absorption by porous construction materials have been studied. Discussion. The adequacy of mathematical models to real physical and chemical processes is discussed. The results of calculations obtained by modeling equations implemented in the form of computer computational algorithms and experiments are compared. Conclusions. The effectiveness of the method for studying physical-chemical processes in a porous medium and for calculating optimal values of technological parameters has been established. ACKNOWLEDGEMENTS. The research was carried out with the financial support of Moscow State University of Civil Engineering. (Contract No. PSUAC/K-23 dated 05.06.2023) within the 2023 competition for basic and applied research (R&D) by scientific teams of organizations – members and strategic partners of the Industry Consortium “Construction and Architecture” in order to implement the Development Program of Moscow State University of Civil Engineering and Architecture for 2021–2030 as part of the Strategic Academic Leadership the “Priority-2030”.
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Scientific article
Introduction. The task of uniformly coating carbon-graphite fibers with metal as a base for composite materials is a pressing issue. Galvanic metallization is preferred due to the ability to control the parameters of the electrochemical system. Materials and methods. To determine the effective values of specific electrical conductivity and reactive surface area of a carbon flow three-dimensional electrode (FTE), as well as to identify rational metal electrodeposition modes, mathematical modeling and a combination of calculated and experimental data regarding the feasibility of producing carbon fiber materials (CFM) and FTEs with desired properties are useful. Proper selection of electrolyzer operating modes and parameters allows for intensification of the metallization process and facilitates the production of the desired composites. Results. Mathematical models of electrolysis using a CFM were developed in the form of systems of differential equations for the potential distribution functions, polarizing current density, and deposited metal concentration across the electrode thickness. Boundary value problems were formulated. An optimal control problem was posed with control actions in the form of distributed values of the resistivity and specific surface area of the electrode and an optimization criterion – an indicator of the uniformity of metal distribution across the electrode thickness. The solution was based on S.L. Pontryagin's maximum principle and direct selection of control parameters using the equations of the mathematical model. Discussion. The proposed mathematical models and methods are consistent with the modern electrochemical theory of metal electrodeposition in FTEs. Accounting for dynamic changes in electrode properties and the metallization process of the carbongraphite filaments that comprise it expands the applicability of mathematical models to describe real-world electrolysis processes in FTEs and improves the adequacy of the models for real-world physicochemical processes. Conclusion. The presented mathematical modeling methods and computational algorithms 1) are used both to study the theoretical principles of electrolysis processes in FTEs and to analyze the properties of actual carbon-graphite material metallization processes; 2) allow one to determine the effective values of the distributed specific electrical conductivity and the reactive surface area of the carbon-graphite material to improve the uniformity of electrodeposition across the TFE thickness and to produce carbon-graphite fibers with desired properties.
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Method of obtaining calcium silicate for construction
Scientific article
Introduction. Calcium silicate is one of the well-known building materials. Its structure determines the ability of such nanostructured additives to form a secondary structure – a fractal (volumetrical) network with which cement grains interact. The addition of nanomodifying additives to improve the technology of cement production will reduce the space dimension in which molecules are sorbed on the cement grain, and, accordingly, increase the rate and efficiency of its blocking. Methods and materials. The paper proposes a method for obtaining calcium silicate from soda ash production waste. The sol-gel method for the synthesis of individual nanomodifiers in the silicate form will improve the technology for producing concretes by forming a solid phase state of the modified structure of a cement stone. In the production of soda ash, the land plots (sludge accumulators) are allocated for the collection of production waste (distiller liquid). In this regard, the acute problem is a disposition of industry waste, because the area allocated for sludge accumulators is limited. Results and discussions. The study revealed that the addition of certain components allows us not only to reduce the required firing temperature, but also to affect the nanostructure of the resulting product. The range of values of the content of additives per 5 g of calcium silicate: С – 0.2÷0.4; S – 0.3÷0.5; ZnO – 0.1÷0.3; P2O5 – 0.3÷0.5; NH2CONH2 – 0.3÷0.3. According to the obtained matrix of conditions, 16 samples of substances were prepared. Nanomodification of cement stone leads to its hardening in the early stages of structure formation. Conclusion. The addition of hydroperite to calcium silicate significantly increases the hardness of the final product; when coal, sulfur, zinc oxide and phosphorus pentoxide are added as components, the hardness and structure of the compound changes. Thus, the use of a nanostructured cement additive based on calcium silicate obtained by qualified processing of the main waste that is part of the distiller liquid - calcium oxide, will improve the quality of concrete by improving the technology of cement production
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Scientific article
Introduction. The current stage of the construction industry and building materials science development involves the introduction and widespread application of nano- and fine particles capable of improving the properties of traditional materials. However, it is necessary to provide stabilization of nano- and fine-dispersed components in the cement system. Plasticizing additives can be used as stabilizers. It is important to set their concentration. Therefore, the purpose of this study is outlined, which lays in the methodological substantiation the stabilizing effect of various types of plasticizers on the suspension of fine synthetic bismuth titanate used in the modification of cement systems, and the establishment of the limits of their optimal concentrations. Materials and methods. The research is aimed at establishing the limits of optimal concentrations of polycarboxylate and sulfonaphthalene formaldehyde plasticizers. The limits of plasticizers optimal concentrationsis determined withdye solubilization method, surface tension and conductometric methods, and studies on establishing the stabilizing effect of plasticizers on a bismuth titanate fine particles suspension. Results and discussion. To establish the limits of the optimal concentration capable of stabilizing fine particles of bismuth titanate in suspension, CMC is determined by the dye solubilization method, surface tension and conductometric methods. It is found that a polycarboxylate plasticizer is characterized by one CMC point, and a sulfonaphthalinformaldehyde plasticizer is characterized by two CMC points: CMC1 and CMC2. At CMC1 point unstable spherical micelles are formed, which turn into stable ones at the CMC2 point. At concentrations exceeding the CMC2 value, polymorphic transformations of spherical micelles into nonspherical asymmetric micelles occur. The same can be traced for the polycarboxylate plasticizer CMC only in one stage. It can also be concluded that it is not reasonable to increase the plasticizer concentration above CMC for polycarboxylate plasticizer and above CMC2 for sulfonaphthalinformaldehyde plasticizer, which is due to structural changes in the micelles of plasticizers. It is assumed that in order to stabilize bismuth titanate fine particles, it is necessary to choose the plasticizers concentration within the limits not exceeding the values of CMC for polycarboxylate plasticizer and CMC2 for sulfonaphthalinformaldehyde plasticizer. Conclusion. Concluding results demonstrate the limits of optimal plasticizers concentrations for the stabilization of bismuth titanate fine particles suspension. For polycarboxylate plasticizer this range of concentrations is 1.1 – 1.5 g/l; for sulfonaphthalinformaldehyde plasticizer its 2.2 – 4.0 g/l.
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Scientific article
Introduction. The development of methodological monitoring tools to implement building nanomaterials into production is an integral element of designing a mechanism for effective management of the development of business structures. University entrepreneurship and research and educational centers in the ecosystem trend are considered as central actors in the process of creating tools for university transfer of nanobinders for construction purposes. Methods and materials. The process of forming digital competencies among students and teachers in the process of commercialization of scientific developments of a construction university (institute, faculty, department) should be considered as the result of fractal interactions. The development of the innovative ecosystem of the university is achieved by the effective implementation of the process of transferring the results of intellectual activity for the creation of gypsum and ceramic nanocomposites, which are in demand by the regional construction industry. Results. The intellectual and technological potential of universities that train bachelor’s and master’s students for the construction industry determines the prospects for the successful development of the industry in an innovative society. Accelerated promotion of investment developments, requested nanotechnologies of universities, provides universities with additional extrabudgetary funding. On the example of the development of technology for producing small-piece wall and partition products based on nanostructured gypsum binders, they were tested in experimental industrial conditions. Discussion. Effective methodological tools for the transfer of nanotechnological university engineering to the construction industry are: the creation of basic departments at enterprises and the successful functioning of research and educational centers, the participation of employers in educational and industrial practice, etc. From the point of view of laborious commercialization and transfer of scientific developments, the effective way from the idea to the widespread introduction of high-tech products is the real application of the intellectual potential of the teaching staff of the university, institute, departments. Conclusions. The engineering of methodological tools for reliable monitoring of the attractiveness of the regional business ecosystem for the generation and development of transfer processes of popular nanomaterials is an integral element of designing a mechanism for effective management of business structures in construction. Due to the formation of the innovative ecosystem of the university, an effective implementation of the process of commercialization of the results of intellectual activity in the field of nanotechnology, which are in demand by the construction industry of the region, is achieved.
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Scientific article
Introduction. Modification of traditional materials based on mineral binders with fine-dispersed and nano-additives is an essential way to create new functional construction materials with a set of unique characteristics. However, the main difficulty in this process is the method of introducing a finely dispersed component into the cement matrix and the uniformity of its distribution. The homogeneous distribution of the additive particles in the cement composite improves the physical and mechanical characteristics, intensifies the hydration of cement clinker minerals, and is leading to a more durable and dense cement stone structure. The main methods of introducing additives into the cement composition include joint grinding, dry mixing and the introduction of a stabilized suspension of the additive instead of mixing water. Thus, the purpose of this research is to compare the options for the introduction of additives based on the TiO2–Bi2O3 oxide system, which can provide the cement composite with improved physical, mechanical and structural characteristics and the ability to resist mold fouling. The object of this research is the cement compositions modified with an additive based on the TiO2–Bi2O3 system. Materials and methods. The studies were carried out to establish the optimal method of introducing a fine-dispersed additive based on the TiO2–Bi2O3 system. At the first stage, the phase and granulometric composition of the additive was studied, then the additive was introduced into the cement composition in four different ways. The cement stone samples were obtained by dry mixing of the components then mixed with water, by mixing cement powder with water suspension of the additive after ultrasound processing, by mixing a dry mixture of cement and an additive with water-plasticizer solution, and cement powder mixed with water-polymer suspension of the additive after ultrasound processing. After that, the strength characteristics, porosity and ability of the samples to resist fungi fouling were investigated. Results. As a result of the study, the authors concluded that the highest physical and mechanical characteristics of cement stone can be provided by introducing an additive in the form of a stabilized water-polymer suspension. This method contributes to the formation of a more durable and dense structure of cement stone, with an increase in strength of 31; 38 and 44.8% at first day age, 28; 30 and 32% at third day age and 2.4; 9.0 and 14% at 28 days age relative to the control sample containing cement, water and plasticizer. It was found that the highest strength results were shown by a sample containing a stabilized suspension of an additive with a concentration of 50 g/l. The study of the cement stone porosity showed its decrease by 13% at first day age in relation to the control sample with a plasticizer, and by 10% after 28 days of hardening. It was also shown that samples modified with 50 g/l (1.7 wt.%) of the additive demonstrate resistance to bio-fouling. Conclusion. As a result of the research, the authors concluded that the optimal way to introduce a finely dispersed additive based on the TiO2–Bi2O3 system is to mix cement powder with a stabilized water-polymer suspension of the additive, resulting in a more durable and dense structure of cement stone, especially at an early stage of hydration, which can also resist fungi bio-fouling. Thus, the authors came to the conclusion that the cement compositions obtained by this method can be applied as repair compounds and tile grout in damp shaded rooms with favorable conditions for fungi colonization.
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Microstructural analysis of strain-resistant cement designed for well construction
Scientific article
Introduction. The efficiency of oil and gas well construction depends largely on the stage of casing cementing and is completed by checking the quality of its fixing by various methods, most often by geophysical methods. The necessity of highquality cementing and ensuring the quality of technical conditions in the subsequent years of oil and gas well operation is the main task. Materials and methods. Microstructural features of cement slurries and cement stone were analyzed with advance methods. The essential technological properties were developed according to the requirements of GOST 1581-96 and API standards (API spec.10B). Class G cement (PCT-I-G) was used for all formulations. Polypropylene fiber and expanding additive СMA were used to increase impact resistance and to ensure tight contact with the confining surfaces of the obtained plugging stone. Microstructural analysis of the obtained cement stones and developed plugging mortars was carried out by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results and discussion. The results of the study showed that the expanding additive in tandem with polypropylene fiber works effectively to ensure the integrity of the cement ring. Conclusion. Microstructural analysis of plugging stones showed a tight bond between polypropylene fiber and cement stone at a concentration of – 0.25%. The expanding additive is fully hydrated and the obtained cement stone has no expansion cracks at 7 days. The developed grouts with a water-cement ratio of 0.44 showed high compressive strength.
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Microstructural and micro-mechanical characteristics of cement paste incorporating cuttlebone powder
Scientific article
Introduction. Marine bio-waste provides a sustainable calcium-rich resource for cementitious materials, but its role in hydration control remains limited. Cuttlebone powder (CBP) is a marine bio-calcium with a porous hierarchical structure, and it forms a nanostructured calcium carbonate system. This system influences phase evolution and structure–property relationships in cement paste. This study evaluates its effects on phase composition, Ca/Si balance, microstructure, and structure–property relationships. Materials and Methods. The study prepares plain and CBP-modified cement paste. CBP replaces cement at 10–50% by weight. All mixtures use a constant w/b ratio of 0.5 and cure for 28 days. TGA evaluates phase composition, EDS determines Ca/Si ratio, SEM and mapping examine microstructure, and Vickers hardness measures micro-mechanical properties. Results. CBP modifies the phase composition of cement paste. Calcium hydroxide decreases from 18.68% to 13.13%, while calcium carbonate increases from 2.80% to 15.05%. The Ca/Si ratio increases and indicates a Ca-rich system. The microstructure becomes heterogeneous, and Ca distribution becomes more localized, while Si remains relatively stable. Micro-mechanical properties increase up to CBP40 and decrease at higher replacement levels. Discussion. CBP influences hydration through its porous hierarchical structure and calcium carbonate composition. This structure controls ion distribution and phase development and governs Ca/Si balance and microstructural evolution. The results establish a structure–property relationship and define the micro-mechanical response. Conclusion. CBP acts as a nanostructured calcium carbonate and alters phase composition, Ca/Si balance, and microstructure. This modification improves micro-mechanical performance at moderate replacement levels but reduces matrix continuity at higher levels.
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