Nanotechnologies in Construction: A Scientific Internet-Journal @nanobuild-en
Статьи журнала - Nanotechnologies in Construction: A Scientific Internet-Journal
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Automation of monitoring construction works based on laser scanning from unmanned aerial vehicles
Статья научная
Introduction. Current publications and technologies for digital modeling of construction projects often entail considerable expenses and lengthy project timelines. In order to effectively monitor and control a large number of objects, there is a need to develop laser scanning technologies specifically for unmanned aerial vehicles, eliminating the need for ground-based imaging. Materials and methods. The study employed a hexacopter-type unmanned aerial vehicle equipped with a laser scanner, as well as specialized software for processing aerial imagery and laser scanning data, which included tools developed by the authors. The octant method was utilized when developing an algorithm for point cloud comparison. Results and discussion. In the course of the study, a technology for automating the monitoring and control of construction work was developed, in accordance with which aerial photography is performed once and an orthophotomap of the object is built (to accommodate laser scanning data). Then, with a certain frequency, laser surveys are carried out from an unmanned aerial vehicle, dense clouds of points are formed for different dates. To compare them, a linear computational algorithm has been developed, which, using data on two dense point clouds, allows obtaining the resulting cloud, which reflects the progress in the construction work. A feature of the algorithm is that the search for points is not carried out over the entire cloud, but within the boundaries of octants. This speeds up data processing and reduces the load on computing power. The technology received software implementation in the web application “Management system for monitoring construction work at facilities that have passed the state examination.” It allows the user to quickly get a visual representation of the change in the construction object for the selected period, to carry out all the necessary measurements (coordinates, geometric parameters, material consumption, etc.). Conclusions. The developed technology for automating the monitoring of construction work can be used by developers, customers, state and municipal authorities to quickly obtain information in order to control and support managerial decision-making.
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Binder properties for zol-silicate paint
Статья научная
Introduction. The binder for sol-silicate paints is made on the basis of a polysilicate solution obtained on the basis of liquid glass and silicic acid sol. The technological process of creating a polysilicate binder is complex and it is not always possible to achieve the required characteristics. In this regard, the development of a polysilicate binder and the creation of a sol-silicate paint based on it are relevant. Materials and methods. Silicic acid sols Nanosil 20 and Nanosil 30 produced by PK Promsteklotsentr were used in the work. We used sodium liquid glass with a modulus of M = 2.78, potassium liquid glass with a modulus of M = 3.29 (GOST 13078). The conditional viscosity of paints and varnishes was determined using a VZ-4 viscometer according to GOST 8420-74. “Paint materials. Methods for determining the conditional viscosity. Tensile strength (cohesive strength) was determined according to GOST 18299-72* “Paint and varnish materials. Method for determination of tensile strength, elongation at break and modulus of elasticity” on the tensile testing machine IR 5057-50. The silicate modulus of liquid glass was determined according to the method described in GOST 13078-81. The molybdate method was used to study the composition of liquid glasses and polysilicate solutions. Results and discussions. It was revealed that liquid glass and polysilicate solution are typical pseudoplastic bodies. The addition of a sol (an increase in the silicate modulus) promotes an increase in the proportion of high-polymer fractions of siliconoxygen anions (SCA), and with an increase in the sol content, the proportion of the polymeric form of silica increases. It has been established that there is a correlation between the content of silica in the polymer form and the tensile strength of the films, which means that with an increase in the content of silica in the polymer form, an increase in the tensile strength of the films is observed. Conclusions. It has been established that with an increase in the amount of silicic acid sol introduced, a decrease in the pH of solutions is observed at a constant alkali concentration. The introduction of a sol of silicic acid leads to a change in the viscosity of the solutions. The introduction of a sol of silicic acid into liquid glass promotes an increase in the proportion of high-polymer fractions of silicon-oxygen anions. Films based on polysilicate solutions are characterized by faster curing and higher tensile strength compared to films based on liquid glasses.
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Biodegradable polymer materials and modifying additives: state of the art. Part I
Статья научная
One of the most demanded materials on the planet is plastic, the excellent performance of which contributes to the accumulation of a significant amount of waste on its basis. In this regard, a new approach to the development of these materials has been formed in scientific circles: the production of polymer composites with constant performance characteristics for a certain period and then capable of destruction under the influence of environmental factors. Analysis of the current state of the industry of polymeric materials shows that the most urgent is the use of such classical polymers as polyolefins and polyvinyl chloride. First of all, the optimal solution to this problem due to the lack of a suitable replacement for traditional polymers is the development of composites based on them with the use of biodegradable additives. In this case, a set of problems associated with waste disposal is solved: the decomposition period of the recycled waste is significantly reduced, the territories required for plastic waste are reduced. The paper outlines the preconditions for the emergence and further development of the field of biodegradable polymers. The main quantitative characteristics of the production capacities of manufactured bioplastics by types, regions and industries of application are given. Modern methods of reducing and regulating the degradation time of polymer materials are presented. The main global and domestic manufacturers of biodegradable polymers and their products are listed, as well as a list of the main manufacturers of biodegradable additives for polymeric materials. Modern types of bioplastics based on renewable raw materials, composites with their use, as well as modified materials from natural and synthetic polymers are listed. The main methods for determining the biodegradability of existing bioplastics are described.
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Biodegradable polymer materials and modifying additives: state of the art. Part II
Статья научная
One of the most demanded materials on the planet is plastic, the excellent performance of which contributes to the accumulationof a significant amount of waste on its basis. In this regard, a new approach to the development of these materials hasbeen formed in scientific circles: the production of polymer composites with constant performance characteristics for a certainperiod and then capable of destruction under the influence of environmental factors. Analysis of the current state of the industry of polymeric materials shows that the most urgent is the use of such classical polymers as polyolefins and polyvinyl chloride. First of all, the optimal solution to this problem due to the lack of a suitable replacement for traditional polymers is the development of composites based on them with the use of biodegradable additives. In this case, a set of problems associated with waste disposal issolved: the decomposition period of the recycled waste is significantly reduced, the territories required for plastic waste are reduced. The paper outlines the preconditions for the emergence and further development of the field of biodegradable polymers. The mainquantitative characteristics of the production capacities of manufactured bioplastics by types, regions and industries of applicationare given. Modern methods of reducing and regulating the degradation time of polymer materials are presented. The main global and domestic manufacturers of biodegradable polymers and their products are listed, as well as a list of the main manufacturers of biodegradable additives for polymeric materials. Modern types of bioplastics based on renewable raw materials, composites with their use, aswell as modified materials from natural and synthetic polymers are listed. The main methods for determining the biodegradability of existing bioplastics are described.
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Biodegradable polymer materials and modifying additives: state of the art. Part III
Статья научная
One of the most demanded materials on the planet is plastic, the excellent performance of which contributes to the accumulationof a significant amount of waste on its basis. In this regard, a new approach to the development of these materials hasbeen formed in scientific circles: the production of polymer composites with constant performance characteristics for a certainperiod and then capable of destruction under the influence of environmental factors. Analysis of the current state of the industry of polymeric materials shows that the most urgent is the use of such classical polymers as polyolefins and polyvinyl chloride. First of all, the optimal solution to this problem due to the lack of a suitable replacement for traditional polymers is the development of composites based on them with the use of biodegradable additives. In this case, a set of problems associated with waste disposal issolved: the decomposition period of the recycled waste is significantly reduced, the territories required for plastic waste are reduced. The paper outlines the preconditions for the emergence and further development of the field of biodegradable polymers. The mainquantitative characteristics of the production capacities of manufactured bioplastics by types, regions and industries of applicationare given. Modern methods of reducing and regulating the degradation time of polymer materials are presented. The main global and domestic manufacturers of biodegradable polymers and their products are listed, as well as a list of the main manufacturers of biodegradable additives for polymeric materials. Modern types of bioplastics based on renewable raw materials, composites with their use, aswell as modified materials from natural and synthetic polymers are listed. The main methods for determining the biodegradability of existing bioplastics are described.
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Carbon-containing modifier for fluoranhydrite binder
Статья научная
Introduction. In order to widen the functionality of construction and building materials and widespread electrically conductive building constructions, it is highly recommended to reduce cost of the solutions. This can be achieved by replacing binders with the industrial by-products. At the same time, there are a few articles about adjustment of electrically conductive properties of materials based on by-product binders and this field is of a great importance. Also, highly dispersed particles in modifiers and their role might be considered as important to find out, especially when such additives are used to improve structure and properties of composites. Methods and materials. To study the possibility of controlling the electrical properties of the matrix, compositions based on fluoroanhydrite, sodium sulfate as a hardening activator, and UPC-MIX-1 suspension as an electrically conductive additive, were made. The effect of UPC-MIX-1 suspension on the electrical performance and structure formation of a mineral matrix containing dispersed carbon black particles was studied. The polydisperse nature of the modifying additive and the ratio of the nanodispersed and microdispersed parts of the solid phase were determined. Indicators for calculating the specific volumetric electrical resistance were determined by the probe method. The influence of the dispersed additive on the characteristics of the fluoroanhydrite composite was evaluated by standard laboratory methods. Features of structure formation were evaluated using the methods of physicochemical analysis. Results and discussion. It was confirmed that a fluoranhydrite-based mineral binder with sodium sulfate has moderate physical mechanical properties and might be used as a substitute for gypsum binder. The usage of an electrically conductive additive as a modifier enhances such mechanical properties as flexural compressive strength and compressive strength which increase by 51% and 65% correspondingly. Also, hydro physical properties have been improved, for instance the coefficient of softening for the FD-4 sample has increased by 39%, and the water absorption by mass for the same sample has decreased by 36%. Specific volume electrical resistance has decreased by 49–52% and equals13,6 kOm • cm, 8% of electrically conductive additive being added. The physical and technical properties of the presented composite are due to significant changes of the physical and chemical properties including the features of structure formation. Conclusions. The obtained compositions require extra optimization in order to be used as a heating component. At the same time, the achieved electrical conductivity is sufficient to level the electrostatic effect of self-leveling floors. Regularities in the formation of the structure of the fluoroanhydrite composite have been established, which manifest themselves in the formation of a larger number of contacts for the intergrowth of crystalline hydrate new formations ensured by the presence of a nanodispersed part in the modifying additive.
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Cement stone on the basis of quartz-ash-cement binder
Статья научная
Introduction. One of the promising areas related to formation of concrete structure on the basis of a mineral binder with specified performance properties employs the addition of ultradispersed fillers (nanomodifiers) to the binder composition. Wastes of quartz and hydro-removal ash are used as nanomodifiers. The presence of nanoparticles in the binder can significantly change the processes of hydration and hardening of the concrete mix. Materials and methods. Hydro-removal ash from Omsk combined heat and power plant 5 (CHPP-5), cement and quartz waste obtained from the production of highly pure quartz concentrate which acted as an enhancer of pozzolanic activity to hydro-removal ash were used as materials for cement stone on the basis of a quartzash- cement binder. Nanomodifier was obtained as a result of mechanical, mechanohydraulic (water) and mechanohydrochemical (water + Megalit S-3ML additive) activations. Activation of the quartz-ash mixture was carried out in a continuous-action rotary mill. The mechanical method provides only mechanical activation, and the mechanohydraulic method provides mechanical, hydraulic, turbulent and acoustic activations. The mechanohydrochemical method provides all actions of hydraulic activation including chemical one. Results. The article investigated cement stone on the basis of quartz-ash-cement binder (activated quartz waste and hydraulic ash from Omsk CHPP-5, cement). The technologies of activation of the quartz-ash mixture by increasing the specific surface of the dispersed phase for the production of quartz-ash-cement binder are considered. The obtained results of the weight distribution of particles of hydro-removal ash and quartz before and after activation show that the average size of the nanoparticle diameter is from 25 μm to 1.5 μm and specific surface is 967–7729 cm2/g. Conclusions. The use of nanoparticles in a quartz-ash mixture allows increasing the strength characteristics of cement stone from 23 to 59%. The use of quartz waste from the production of high-purity quartz concentrate and ash hydraulic removal from Omsk CHPP-5 power plant with the introduction of the proposed technologies for their activation allows increasing the formation of cement stone on a quartz-ash-cement binder by increasing the package density and chemical activity of nanoparticles in the processes of phase formation of hydrate compounds, which will reduce intergranular space between non-hydrated cement grains and will improve physical and mechanical characteristics of cement stone.
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Статья научная
Introduction. The use of nanomaterials and nanotechnology represents one of the most important areas in global scientific and technological development. Nanotechnology involves the controlled regulation of the properties of objects at the molecular and supramolecular level, which determine most of the fundamental parameters and properties of physical objects, based on the targeted manipulation of their atoms and molecules. In hydraulic engineering, this involves the use of nanomaterials and technologies that improve the properties of building materials and structures, increasing their durability and resistance to external influences. Methods and materials. The Novosibirsk Reservoir is a unique multi-purpose water facility. For more than 60 years, it has been intensively used for national economic purposes – it is a source of water supply, the main recreation area for residents of Novosibirsk, the Novosibirsk Region, and the Altai Territory, and is used for navigation and fisheries. There are 41 settlements located within a two-kilometer zone of the reservoir's coastal strip, including the cities of Kamen-na-Obi, Berdsk, Iskitim, and Ordynskoe. The forested coastal area is home to health resorts, cottage and dacha settlements, and gardening communities, as well as a place for short-term recreation for the population. In this regard, the recreational load on the coastal zone of the reservoir is very high, partly due to the steepness of the banks. Various methods are used to calculate the design of shore protection hydraulic structures on water bodies, which take into account, first of all, the natural conditions and characteristics of the water body's shoreline. The results of the calculations are verified and refined on the basis of field studies and, if necessary, laboratory tests and experiments. Results. The paper presents calculations for determining the design parameters of the structure, such as: wind surge height, wave run-up height, top elevation of the structure, scour in front of the stone bank, design composition of the stone bank, and parameters of the stone bank. Discussion. Currently, there are many varieties of nanoscale additives and nanomodified materials. The possibilities for implementing modification mechanisms are determined by the type, characteristics, and dosage of nanoscale particles. As a suggestion, the authors propose to pay attention to the use of geogrids with different cell sizes and nanomodified concretes. However, it should be noted that at present, even with a low required content of nanomodifying additives (2–3% of the total mass of concrete), the addition of such additives will significantly increase the cost of the material. A comparison of technical and economic indicators in this case will clearly indicate this disadvantage and, as a result, the impossibility of using this option for economic reasons. Conclusion. One of the most important criteria for assessing the prospects for the introduction of nanotechnological innovations in the construction industry is their final cost. Nanomodifiers for concrete and building mortars at a price of $100 per gram, even though their strength properties increase by 30%, are unlikely to be in demand. Most of the experts agree that nanostructuring should be applied to widely used materials, including concrete, metals, and fiber-based composites. These breakthrough technologies can be applied in many areas, including hydraulic engineering, strengthening concrete foundations of gas transmission systems, creating flexible plastic geogrids, selecting and creating new high-quality fillers for them, etc. Also, thanks to new nanomaterials, it is possible to produce metal that will last an order of magnitude longer than modern samples. There are sufficient scientific developments in this area. Now it is necessary to find practical applications for them. However, this vector of development entails the need for production reequipment, staff training, and so on.
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Changes in permeability and microstructure of sand during reinforcement with polyurethane resin
Статья научная
Introduction. In complex geotechnical conditions during construction and operation of engineering structures, polyurethane compositions are used to strengthen loose soils. Analysis of current research has shown that the effect of polymers on sandy soil filtration properties is poorly studied. The purpose of this study is to determine the dependence of permeability and microstructure of chemically strengthened sand on the treatment method, polyurethane resin consumption and external compressive loads. Methods and Materials. Experiments are carried out with fine and medium-grained sands. Two-component highly elastic and one-component polyurethane resins are used for strengthening. Their main purposes are soil stabilization, waterproofing, and formation of cutoff curtains. The effect of the resins on rock permeability and microstructure is assessed based on the experimental results. The experiments include formation of the polymer-sand mixtures using one-solution and two-solution resin treatments with resin/rock volume ratios of 0.05–0.25, microstructure study and filtration tests under various sample loading conditions. Results and discussion. The dependence of the sand permeability on the method of strengthening with polyurethanes has been determined. In the case of one-solution treatment with highly elastic resin with composition/rock volume ratio of 0.2, the permeability of the samples is 7–13 ·10–3 μm2. A two-fold decrease of the resin content causes an increase in permeability by 1–2 orders of magnitude. Such behavior is explained by the structure in which open intergranular pores predominate and form connected pore channels. The addition of a small volume of a one-component rigid polyurethane composition reduces sand permeability by 1.5–3.2 times and improves the stability of samples under compressive loads. Conclusion. The practical significance of the results consists in the increasing efficiency of sand filtration properties reduction with polyurethane resins strengthening. The proper choice of a chemical treatment method with consider of the geotechnical problem provides both effective rock permeability reduction and decrease in the consumption of expensive polymer compositions for the construction of cutoff curtains and screens in the rock mass.
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