Application of nanomaterials and nanotechnologies in construction. Рубрика в журнале - Nanotechnologies in Construction: A Scientific Internet-Journal
Development of heavy metal-based nanostructured complex technology for use in building mortar
Статья научная
Introduction. Heavy metals (copper, zinc, nickel, lead, chromium, cobalt, cadmium) get into constructional materials with natural and man-made raw materials. The chemical and mineralogical composition of large-tonnage wastes from the petrochemical industry is perfect for constructional materials production. Heavy metals in constructional compositions provide high strength and frost resistance. Currently, nanostructured metal-containing complexes are used in the production of mortars. Therefore, it is necessary to ensure the reliable binding of heavy metals into structurally stable compounds to avoid their emission and secondary environmental pollution. The steadily growing volumes of sludge reservoirs with high concentrations of heavy metals such as chromium (Cr +6), copper (+2), lead (+2), iron (+2), and Fe (+3) cause particular interest to researchers. Qualified extraction of the listed metals and binding them as nanocomponents in the composition of the complexing agent will ensure the creation of a nanostructural composition in the recipe for the preparation of mortar for various purposes. Methods and materials. Sorption methods are the main way to isolate heavy metals. The paper proposes a method for the production of alkyleneaminopolycarboxylic acids and studies its ability to form nanometallic complex compounds for the extraction of heavy metals. Results and discussions. In order to bind metal nanoparticles in oil sludge, the efficiency of the produced compounds, carboxymethyl derivatives of hexamine, was investigated. Optimum synthesis conditions were selected and the structure of the obtained complexing agents was proved by infrared and ultraviolet radiation methods as well as by the method of nuclear magnetic resonance. Conclusion. The resulting nanostructured additions have binding properties that provide high adhesion of the heavy metal to the organic substrate and mortar components, which makes it possible to provide a strong composition that maintains operational properties that meet technical requirements.
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Статья научная
Introduction. At present, the use of polymer coatings in the protection of metallic materials and structures is becoming popular in the construction industry. It is especially important to obtain nanostructured polymer insulating materials with high anticorrosive properties in order to ensure the service life of the equipment of the fuel and energy complex. Technological equipment during the extraction, transportation, processing of petrochemical raw materials is subject to regular exposure to aggressive environments. Damage to production equipment causes annual environmental damage and human health and material burden on the enterprise. The introduction of heteroatoms into the structure of the polymer molecule helps to improve the physico-chemical characteristics of polymer coatings, in particular, to increase the protective properties, since natural and synthetic polymer compounds represent a large cluster of supramolecular structures located in a certain sequence. Methods and materials. A technology has been developed for obtaining new polymeric nanostructured alkenylsuccinimides with anticorrosive properties, which can be used as part of lubricating coatings in various industries, including construction. Alkenylsuccinimides were tested according to TS 38101147-77 for succinimide additives and showed compliance with their standards TS 38101247-77. Results and discussions. In the course of the research a resource-saving non-waste technology of obtaining a nanostructured polymer additive with polyamines as a nanostructuring base to provide an anticorrosive effect has been developed. Conclusion. The obtained compounds based on triethylenetetramine, tetraethylenepentamine, alkenylsuccinic anhydride can be used as effective polymeric anticorrosion additives in the processing of metal materials and structures in the construction industry.
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Статья научная
Introduction. The elaboration of foamed eco-friendly gypsum nanocomposites with low specific gravity, high thermal insulation, operational and technical and economic characteristics remains an urgent task. Controlled hardening of gypsum foam nanoassemblers using dry foaming agents is a promising direction in the technology of production of heat-insulating building materials. Methods and materials. The production of a foam gypsum composition was carried out in an ejector-turbulent mixer by mixing a gypsum nanobinder with functional foaming nanoadditives. Building gypsum G5 BII was used as a binder in the work; porization of gypsum compositions was carried out using an adsorbed foaming agent PBNS. Results. The transformation of liquid-phase foaming agents into solid-phase ones by binding water allows the production of gypsum foam compositions from dry mixtures, which gives high dosing accuracy, a good degree of homogenization of components and stable characteristics of foamed gypsum nanocompositions. In production conditions, a one-storey small-sized pavilion was built using a pilot 3D printer AMT S1160, in which vertical enclosing structures are filled with foamed heat-insulating nanostructured foam gypsum. Monolithic foam gypsum nanomaterial with a density of 300–400 kg/m3 was used for insulation and sound insulation of attic floors during the overhaul of the historic building of the Veterans Hospital in Ufa. Discussion. The elaboration of technology for obtaining foam gypsum from dry mixtures is based on the advantage of manufacturing and using thermal insulation nanocompositions, which allows for significant punctuality of dosing and stable characteristics of foam gypsum building materials. Surfactants have a significant effect on the kinetics of the structure formation of the foam gypsum nanocomposition and slow down the coalescence of air bubbles. Conclusions. Nanoporous foam gypsum concrete, obtained as a result of controlled hardening, with a density of 400 kg/m3 has a thermal conductivity of 0.12 W/(m•ºС) and a compressive strength of 1.4 MPa. The compressive strength of foamed foam gypsum using a dry foaming agent on sorbents is 17% higher than the strength of a heat-insulating nanomaterial prepared using traditional technology.
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Статья научная
Introduction. Mineral wool is one of the widely used materials in the construction industry. A wide range of technologies and structures with integrated mineral wool is also connected with the following: ventilated facades of buildings, facades made using FICS (facade insulation composite system) technology, insulation of roofs and attics, and much more. Methods and materials. Under different conditions, the nanostructure durability for mineral wool fibers will vary significantly. Currently, there are no scientifically based methods for assessing the durability of the nanostructure. Results. The article proposes to evaluate the nanostructure durability for the of mineral wool fibers based on the developed method of chemical destruction of building ceramics. The methods of laboratory analysis of the building ceramics material and their modernization for the nanostructure of mineral wool fibers are given. Discussion. According to the results of experimental studies, it was found that the corrosion process in the mineral wool material occurs by the mechanism of reaction of alkali metal hydroxides with silicon and aluminum oxides in the mineral wool material, removing them into solution and leading to chemical destruction of the material, which is generally similar to the studied process of destruction of the wall ceramics material. The results obtained allow us to conclude that the process of chemical destruction of mineral wool has a greater dependence on temperature and less dependence on the concentration of hydroxides than the process of destruction of brick material. Conclusions. The results of the conducted studies allow us to calculate the temperature coefficient of the destruction process rate in the Van't-Hoff formula, the coefficients in the Arrhenius equation and the value of the activation energy of the destruction process. Examples of field studies are given.
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High-performance nano-modified concrete of increased strength and durability
Статья научная
Introduction. To create concrete with a set of physical and mechanical characteristics, a rational selection of the components of the concrete mix is required, including the use of finely dispersed fillers, including those based on recyclable materials, and a highly effective chemical additive of a certain nature and reactive action, which has a complex effect on concrete system. Methods and materials. The effectiveness of the components in used additive was assessed by changing the indicators of compressive strength, tensile strength in bending, the assessment of which was carried out according to GOST 10180-2012 “Concrete. Methods for determining the strength of control samples. For carrying out scientific and experimental studies, the following materials were used: Portland cement CEM I 42.5N; natural sand; fine microsilica; complex chemical additive with increased plasticizing and reactive effects. Results. The combination of polycarboxylate polymers and nanodispersions of silicon hydroxide enhances the effectiveness of each component, which is reflected in a significant increase in the coefficient of crack resistance of concrete at high compressive strength. It has been established that when using a complex nanopolymer chemical additive, the increase in tensile strength in bending is 67% and it exceeds the increase in compressive strength by more than 30%. Discussion. An increase in hydration activity in the presence of a nanopolymer additive has a positive effect on the compaction of the emerging concrete structure. Confirmation of the formation of a dense and strong structure during the hardening of nanomodified concrete is an increase in the water resistance of concrete by 2.5 times and its frost resistance by more than 2.5 times. Conclusion. The advantage of nanomodified concrete is its increased chemical resistance to carbon dioxide and magnesia corrosion and, in accordance with the index of chemical resistance coefficient, CCSт> 0.8, and GOST R 58895-2020, the developed nanomodified concrete belongs to chemically highly resistant concretes. It is advisable to recommend nanopolymer concrete with high physical and mechanical properties for the manufacture of structures for overhead power transmission lines (OPL).
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High-strength wall ceramics based on phosphorus slag and bentonite clay
Статья научная
Introduction. One of the promising ways to get high-strength ceramics is the method of semi-dry pressing of the "coarsely dispersed component – finely ground binder" formula. This method suggests using crushed industrial waste as the core, and finely ground nanostructured fusible clay as the binder material. Methods and materials. In the research, bentonite clay of the Darbazinsky deposit of the Turkestan region was used as plastic material, and dense crystallized phosphorus slag which is a waste of phosphorus production was used as a non-plastic coarse material. The study of the prescription factors’ influence on the basic physical and mechanical properties of ceramic wall materials was carried out by the simplex method characterized as lattice planning of experiments. The nanostructure of the phosphorus slag and bentonite clay formula was studied by the electron microscopic analysis method. Results. The binder content in the amount of 25% guarantees the density of the packages, while the sintering effect becomes sufficient and the strength of the samples is 27.1 MPa. If the amount of binder increases from 25% to 40%, the sintering effect continues to grow and the strength of the samples reaches 54.3 MPa. Discussion. The results show that the most active sintering effect and the dense structures forming in coarse-grained formulas with high-calcium phosphorus slag occur at 40–60% binder content. The presence of flux around slag grains in an amount of less than 30% contributes to obtaining less dense samples, with a binder content of 40%, a density increase is observed, which corresponds to the mixed ceramic structures modeling. Conclusion. To get high-strength ceramic bricks, the content of coarsely dispersed components in the form of phosphorus slag with a fraction of less than 1.25 mm should amount to 60–70%, finely ground phosphorus slag should be 5–10%, and bentonite clay is to be 20–30%. Optimum technological indicators are: calcination temperature 1050–1100oC, pressing pressure 20–25 MPa, press powder moisture content 7–8%.
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Статья научная
Introduction. We studied the effect of nanosized silicon dioxide (SiO2) on the structural and technological characteristics of nanomodified cement compositions introduced together with activated mixing water. Materials and research methods. Activation of mixing water was carried out by means of magnetic field and ultrasonic action. For investigation the capability to maintain their properties for a long time, the stability of silica suspensions in activated water was studied. For finding out the effect of activated silica suspensions on the structure and properties of composite materials based on cement, the physical and mechanical properties of the studied compositions were explored. X-ray and differential thermal analysis of the hardened activated nanomodified cement paste were also carried out. Results and discussion. The positive role of the suspension of silicon dioxide in activated water was associated with a decrease in the microheterogeneity of the hardened cement paste, ensuring the stability of its physical and mechanical characteristics. Based on the above mentioned observations, a mechanism was proposed for more efficient incorporation of nanosized silicon dioxide into cement hydration processes both due to chemisorption with Ca(OH)2 in the hardening cement paste and due to the topological effect of nanoparticle localization in defects and ultramicrovoids of a crystallizing disperse system. Conclusion. The results show that suspensions of silica in activated water can maintain their properties for a long time. Graphical dependencies are shown, indicating the effectiveness of the use of activated silica suspensions in the production of cement composites. This quality makes it possible to obtain repair compounds with the required properties during construction work for various purposes.
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Influence of high-dispersive powder mixture of WC and TiC on the composite materials properties
Статья научная
Introduction. The purpose of the research is to study the effect of a high-dispersive powder mixture of WC, TiC, obtained from recycling of hard-alloy manufactured articles from TK group (titanium-tungsten alloys), on the change in the structural and physical and mechanical properties of cement materials. Materials and research methods. WC, TiC Powder (particle size 20–150 nm, agglomerates 300 nm – 1.5 μm) was added to the cement mortar by partial replacement of cement in various concentrations of 0%, 1%, 2%, 3%, 4%, 5% by mass. The basic physical and mechanical properties of the cement paste and obtained cement materials were studied in accordance with standard methods, taking into account regulatory documents of Russian and foreign standards. Thermokinetic, X-ray phase analysis, scanning electron microscope investigation with an integrated system of energy-dispersive analysis were also applied. Results and discussion. It has been proved that highly dispersed WC, TiC powder additive to cement materials leads to increase in density, paste fluidity, reduction in setting time, decrease in water absorption, porosity, and increase in strength characteristics both in early and later periods of hardening. A highly dispersed additive promotes earlier hydration. The structure of the cement sample with powder additive is denser throughout the considered periods of hardening compared to the control sample. Conclusion. The obtained results are of great importance for understanding the action mechanism on cement materials of highly-dispersed particles of WC, TiC, which can later be used to improve the properties of composite cement-based materials in various fields of application.
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Method of obtaining calcium silicate for construction
Статья научная
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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Статья научная
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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Modification of portland cement with nanoadditives
Статья научная
Introduction. Portland cement slurries (suspensions) used for well cementing have high water-cement ratios (0.45–0.6). They also contain a minimum amount of inert fillers, must have zero water separation and controlled hardening with a minimum time between the start and end of setting. Literature review. Most of the scientific work on the use of nano-additives in binder systems relates to the construction industry. Nanosilicon, nanotitanium, nanocarbonate, nanoclays, carbon nanofibers, etc. were widely used as modifiers of cement systems, which showed an increase in the strength characteristics of the resulting concretes. Literature review showed that there is a very wide range of concentrations of nanoadditives in cement systems from 0.001 to 10.0%. An increase in the strength of cement with high concentrations of additives in a number of publications is explained by a decrease in its capillary porosity due to clogging of the pore space. However, nanoadditives should not play the role of microfillers in the hardened stone. They should work in cement slurry at the stage of cement hydration and cement structure formation at concentrations less than 1.0%. Results and Discussion. The paper presents the results of experimental studies of the rheological properties and early strength of stone based on Portland cement with additives (0.01%) of nanocarbonate and nanoiron. The role of nanoadditives is to increase the rate of cement hydration by reducing the activation energy, and accelerating the dissolution of the solid phase in the liquid. Nanoadditives can be a “substrate” on which two-dimensional nuclei of a new phase are formed. The probability of the appearance of two-dimensional nuclei on the substrate is much higher than for the formation of three-dimensional nuclei of a new phase in the bulk of the solution. Conclusion. The results show an ambiguous effect of additives on the tested parameters, which indicates the need to optimize the amount of additives. One of the reasons for the ambiguity of the results may be high water-cement ratios, which reduce the likelihood of the formation of “constrained” conditions in cement slurries. At the same time, the effects of accelerated cement hydration are “levelled” and the number of contacts between hydration products is reduced.
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Nanocoatings in modern construction
Статья научная
The review analyzes the state of the nanocoating market, shows main types of nanocoatings, as well as drivers and barriers to their development and application. Modern progress in the field of nanotechnology allows us to attribute nanocoating to high performance materials, the structure and properties of which can be “designed” according to specific functional criteria and the level of environmental impact. They present unique remarkable characteristics compared to conventional coating materials in construction industry. The government’s grandiose plans to commission new housing and road infrastructure, as well as ambitious projects to develop the Arctic and ensure national security, should lead to the growth of the industry as a whole, as well as to an increase in demand for more efficient, innovative building materials, including nanocoatings and nanopaints.
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Obtaining the retainer for waterproofing road bitumens
Статья научная
Bitumen is a mixture of hydrocarbons and hetero-organic compounds. It is one of the most popular building materials today. Due to the growing consumption of bitumen for various purposes, the requirements for its quality characteristics are increasing, which prompts a comprehensive study of the physical and mechanical properties and methods of its modification. Currently, various additives are used, from inorganic materials to organic binders, including waste chemical, petrochemical and household industries. These additives create a nanodispersed structure inside the bitumen, which provides a change in the physical and mechanical properties in the required direction. Methods and materials. The work proposes a method for obtaining a fixer for waterproofing road bitumen based on nitrogen-containing organic compounds. The goal of research is to study the effect of the additive-derivative of triethylenediaminedicyan, which leads to the formation of a nanodispersed structure of bitumen of the “sol-gel” type, the quality indicators of which will meet the requirements of the new standard GOST 33133-2014 “Viscous road oil bitumen”. The object of the study is the bitumen production unit of workshop No. 14 of Gazprom neftekhimSalavat LLC, designed to produce commercial bitumen: oil road grades CB 90/130 in accordance with GOST 22245-90, used in road, civil and industrial construction as a binder and waterproofing material. Results and discussion. In the course of the study, the nature of the interaction and the effect of the modifier on the properties of bitumen, which ensure the production of nanostructured bitumen of the “sol-gel” type, were revealed. As a result of the study, a comparative assessment of the effect of the fixer on the properties of waterproofing bitumen revealed a significant improvement in physical and mechanical properties in comparison with bitumen grade CB 90/130. Conclusion. The obtained compound based on triethylenediaminedicyancan can be used as a fixing additive to road bitumen
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Production of a nanostructured bitumen modifier in the reprocessing of automobile tires
Статья научная
Introduction. Polymer-bitumen binders are innovative nano-binders for asphalt concrete pavement. Introduction of a polymer modifier improves the characteristics of bitumen and asphalt concrete. The use of waste tires rubber for bitumen modification is considered to be an environmentally friendly solution, but it is limited due to the poor cosite of rubber with bitumen. Various methods based on activation of the rubber surface, dispersion of rubber to nanosized particles, and thermochemical transformations of rubber into individual organic compounds are known to overcome this limitation. Methods and materials. The method of joint pyrolysis of rubber with oxygen-containing oil under pressure is proposed to be used for converting it into a nanostructural bitumen modifier. The resulting product is studied by the methods of thermogravimetry, NMR-spectroscopy, chromatomasspectrometry, scanning electron microscopy and solubility in toluene. Results and discussion. It has been established that during joint pyrolysis rubber undergoes devulcanization, cracking and dispersion to nanosized particles, and as a result the product becomes compatible with bitumen. Thermochemical reprocessing of waste automobile tires can be considered to be a promising method for the production of a nanostructured bitumen modifier. Conclusion. The use of thermochemical pressure treatment of waste tire rubber in the presence of oxygen-containing oil makes it possible to obtain a nanostructured product compatible with bitumen for further use of the resulting modifier in the production of asphalt concrete.
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X-ray spectral methods for measuring the degree of ordering of carbon nanoparticles
Статья научная
Methods for the quantitative assessment of the content of ordered structures in the products of synthesis of fulleroid materials based on the spectra of characteristic X-ray radiation and X-ray diffraction are considered. The introduction shows that the use of carbon fulleroid materials (fullerenes, fullerenols and their compounds, fulleroid nanoparticles) as modifiers of the properties of various structural materials and plasticizers of concrete mixes is currently one of the most rapidly developing areas in the field of nanotechnology in construction. Methods and materials. In this work, the following analytical control methods were used: scanning microscopy, local X-ray spectral analysis and X-ray diffractometry. The products of synthesis of fulleroid materials were studied: samples of fullerene-containing soot collected at different distances from the arc synthesis zone. Results. Raster images of the synthesis products with various magnifications are shown, as well as the X-ray fluorescence spectra and the elemental composition of the synthesis products. The X-ray phase analysis of the synthesis products was carried out. It is shown that the analysis of the amorphous component of the composition, which is one of the products of the yield, will make it possible to control the synthesis at each stage and under various conditions of its implementation. Analysis of a nonlinear dynamic system. To construct an attractor of a dynamic system, the correlation dimension, the dimension of the phase space and the fractal dimension of the process under study were calculated. The correlation dimension and the dimension of the phase space were calculated using the Takens’ method. The fractal dimension is calculated using the Hurst exponent. Conclusions. To study the dynamics of chemical reactions occurring during arc synthesis, the system of differential Rössler attractor is used. A solution to this system is obtained – Rössler attractor – an attracting set of trajectories in the phase space, which is identical in appearance to the process under study, which makes it possible to estimate, relying on attractors characteristic of each sample (synthesis material), at what stage the synthesis process occurs, and by making differential model, to organize the control to improve the quality of output products. Thus, the possibility of evaluating the efficiency of the synthesis of fulleroids used for the modification of building materials is demonstrated.
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