Nanotechnologies in Construction: A Scientific Internet-Journal @nanobuild-en
Статьи журнала - Nanotechnologies in Construction: A Scientific Internet-Journal
Все статьи: 591
Статья научная
Introduction. The article discusses the current state of the possibilities to improve the efficiency of construction processes by using fibre-reinforced concrete in the construction of transport and utility tunnels, as well as other critical building structures. The authors present foreign experience with widespread use of fibre-reinforced concrete in transport construction, as well as few such cases for domestic practice. The inconsistency of domestic experience with the modern state of art has been noted. The main blockers in the development of the issue are under consideration, the theoretical approach and practical application are presented. Materials and methods. The principal aspects of the current approach to the quality indicators of fibre-reinforced concrete and the classification principles of fibre-reinforced concrete based on quality criteria, which are the basis for the normalization of material characteristics, are described. The continuity of domestic and European regulatory documents is shown. Results. Illustrated examples of the possibilities of an optimization approach to the selection of structural solutions in the design of transport construction facilities used in international practice are described. Conclusion. The argumentation in favor of technology development is shown. This opens up possibilities for significant cost reduction justified by a scientific approach. In conclusion, the authors provide recommendations on the general application of the promising material in the domestic practice.
Бесплатно
The effects of low curing temperature on the properties of cement mortars containing nanosilica
Статья научная
This study presents the experimental results on the effects of curing temperature and nanosilica, on the compressive strength and absorbing properties of cement mortars. Two groups of mortars were prepared, with the first containing reference samples. The second group was modified with a nanosilica admixture by 3% of the weight of cement. The mortar specimens were cured in 20оC, 10оC and 5оC constant temperature environments. Compressive strength after 12 h, 1, 2, 7 and 28 days, water absorption and capillary porosity were evaluated on a 40×40×40 mm prism. The results confirmed that a low curing temperature delays strength development in the early days of hydration and slows down the strength growth rate of mortars, with an increase in age. The incorporation of nanosilica has a positive effect in improving the mechanical properties of cement mortars cured at low temperatures. Additionally, nanosilica contributes to decreasing the porosity of the cement matrix, so that transport properties, such as open porosity and sorptivity, improve under all curing conditions.
Бесплатно
The electrical conductivity evaluation of nanocoating on intelligent building structure elements
Статья научная
Introduction. Flexible elements made from various materials such as films, papers and geotextiles, coated with an electrically conductive coating containing carbon nanoparticles, have the potential for creating intelligent structures. To rationally choose, design, and apply electrically conducting components, it is necessary to objectively assess their behavior throughout the life cycle of these objects. Currently, there are no objective methods for evaluating such components. Methods and tools are needed that can not only evaluate initial electrical conductivity values of components but also predict dynamics of changes over time. Methods and Materials. The samples were tested under cyclic multi-axial stretching conditions. After each stretch, the strain, thickness, and electrical resistance of the samples were measured. Different materials were selected for the study, including films, nonwoven fabrics, and fabrics which differ in composition, structure, and properties. A composition with carbon nanoparticles was applied to the materials using screen printing. Results and discussion. The tests showed that the irreversible part of deformation of the sample ranged from 8% to 75%, while thickness varied from 6% to 100% depending on the structure of materials. Electrical resistance ranged from 25 Ohms to 5 KOhms, depending on test parameters and composition of coating-substrate composite. Correlation analysis confirmed strong correlation between electrical resistivity and sample deformation with correlation coefficient ranging between 0.6 and 0.78. An approximation was used to derive empirical equations that can be used to predict the reliability of flexible, electrically conductive elements under cyclic stretching conditions, which simulate operating conditions. Conclusion. A comparative analysis of test results under these conditions allowed us to recommend nonwoven fabrics and fabrics with a thickness of 0.5–0.7 mm for use as flexible electrically conducting elements. This method is recommended for objective assessment of changes in the properties of these components in intelligent building structures.
Бесплатно
The electronic edition «NANOTECHNOLOGIES IN CONSTRUCTION: A Scientific Internet-Journal»
Другой
Бесплатно
Другой
Бесплатно
The electronic edition «Nanotechnologies in construction: A Scientific Internet-Journal»
Другой
Бесплатно
The electronic edition «Nanotechnologies in construction: A Scientific Internet-Journal»
Другой
Бесплатно
The electronic edition «Nanotechnologies in construction: A Scientific Internet-Journal»
Другой
Бесплатно
The electronic edition «Nanotechnologies in construction: A Scientific Internet-Journal»
Другой
Бесплатно
The electronic edition «Nanotechnologies in construction: A Scientific Internet-Journal»
Другой
Бесплатно
Статья научная
Introduction. A primary geotechnical challenge pertains to the stabilization of unstable soils due to their inadequate deformation, physical, mechanical, and filtration characteristics, which, in turn, can result in abnormal settlements, the destabilization of the soil mass under external loads, or even its own weight. The advent of chemical technologies on a global scale, along with their development within the Russian Federation, has precipitated the utilization of advanced equipment in conjunction with novel, innovative technologies. This confluence has given rise to novel methodologies and the fabrication of new materials, which have been instrumental in addressing a myriad of geotechnical challenges. The predominant methods of soil stabilization with mineral compounds (predominantly based on Portland cement) possess clear advantages; however, they do not always permit work to be conducted in soils with high water saturation, under conditions of high filtration, or in soils with low deformation indices. Consequently, issues pertaining to cementation stabilization periodically emerge. These issues manifest, for instance, in water-saturated rock soils under high hydrostatic pressures, in various fractured soils complicated by the presence of karst depressions, and in silty and organomineral soils with structural instability. Materials and methods. The employment of innovative polymer materials, such as polyurethane-based materials, facilitates the injection of mixtures with optimized strength gain, thereby addressing the issue of soil reinforcement within this process or enhancing the criteria for constraining the propagation of injection mixtures for subsequent cement grouting. Results and conclusion. Laboratory tests and analysis of a number of completed projects allow us to consider this technology effective and practical in complex engineering and geological conditions and beyond design-basis parameters for underground construction projects. This research was carried out using the facilities of the Head Regional Shared Research Facilities of the Moscow State University of Civil Engineering, with support from the Ministry of Science and Higher Education of the Russian Federation (Agreement No. 075- 15-2025-549)
Бесплатно
Статья научная
Introduction. A primary geotechnical challenge pertains to the stabilization of unstable soils due to their inadequate deformation, physical, mechanical, and filtration characteristics, which, in turn, can result in abnormal settlements, the destabilization of the soil mass under external loads, or even its own weight. The advent of chemical technologies on a global scale, along with their development within the Russian Federation, has precipitated the utilization of advanced equipment in conjunction with novel, innovative technologies. This confluence has given rise to novel methodologies and the fabrication of new materials, which have been instrumental in addressing a myriad of geotechnical challenges. The predominant methods of soil stabilization with mineral compounds (predominantly based on Portland cement) possess clear advantages; however, they do not always permit work to be conducted in soils with high water saturation, under conditions of high filtration, or in soils with low deformation indices. Consequently, issues pertaining to cementation stabilization periodically emerge. These issues manifest, for instance, in water-saturated rock soils under high hydrostatic pressures, in various fractured soils complicated by the presence of karst depressions, in dispersed, silty, and organo-mineral structurally unstable soils. Materials and methods. The employment of innovative polymer materials, such as polyurethane-based materials, facilitates the injection of mixtures with optimized strength gain, thereby addressing the issue of soil reinforcement within this process or enhancing the criteria for constraining the propagation of injection mixtures for subsequent cement grouting. Results and conclusion. Laboratory tests and analysis of a number of completed projects allow us to consider this technology effective and practical in complex engineering and geological conditions and beyond design-basis parameters for underground construction projects. The present study was carried out using the material and technical resources of the Main Regional Center for Collective Use of Scientific Equipment and Installations of the Moscow State University of Civil Engineering, with the support of the Ministry of Science and Higher Education of the Russian Federation (agreement No. 075-15-2025-549).
Бесплатно
The formation of the sol-gel nanostructures of road bitumen by selecting chemical group composition
Статья научная
The studies of paving bitumen chemical composition and physicochemical properties produced by compounding deeply oxidized bitumen, tar and vacuum gas-oil of different hydrocarbon composition are carried out. The bitumen is marked to have the optimal complex of properties if the best chemical group composition of three main elements bitumen binding agents – oils, resins and asphaltenes - is formed. That provides the best structure of bitumen oildisperse system. The object of the research is the selection of compounded paving bitumen chemical group composition that provides the formation of bitumen nanodisperse system as «sol-gel» which quality metrics match the requirements of the new State Standard 33133-2014 «Petroleum paving viscous bitumen». The analysis of the research results makes it possible to determine the optimal chemical group composition of compounded bitumen that meets standard requirements by physicochemical properties. It has been determined that the higher the bitumen dispersion is, the more plastic properties it has. In addition, the bitumen ability to thermal-oxidative processes of deterioration decreases. The value range of bitumen dispersion and the most optimal values of asphaltenes ratio to the amount of oils and resins for bitumen grade BND 100/130 and for bitumen grade BND 70/100 were found. This amount of oils and resins for referred bitumen grades provide production of nanostructured bitumen as «sol-gel». It is shown that when processing tar of different chemical composition the optimal chemical group composition of finished product can be formed by compounding. That rises probability that the end product will fit to the new State Standard 33133-2014. The represented results of the research can be used in fabrication as the modern laboratories of the oil-refining enterprises can determine quite efficiently the chemical composition of oil products used in compounding processes in bitumen binding agents production.
Бесплатно
Статья научная
Introduction. The article discusses how artificial wood aging affects the retention of its fireproofing efficiency to evaluate the ability of a fire-bio-moisture-resistant impregnating agent to protect facing timber materials of facade systems exposed to weathering, such as varying temperature and humidity, if standardized levels of fire hazard and integrity are maintained and the impregnating agent has water-soluble phosphorus and nitrogen compounds of the nanoscale range. Research focus and methods. A specimen of pine wood was subjected to artificial aging for 120 days, which is equivalent to 15 years of outdoor operation. The method of pressurized impregnation was applied to pre-treat the specimen with the fireproofing agent. Climate testing was followed by a comparative evaluation of combustibility parameters according to a standard experimental method used to distribute combustible and hardly combustible materials between combustibility groups. Besides, before and after aging, all surfaces of fireproof wood specimens were subjected to thermo-analytical studies and visual inspection. Results and discussion. Results of combustibility group identification and principal thermal decomposition parameters of fireproof pine timber remained nearly the same before and after climate testing. Further comparative visual examination of surfaces of timber specimens identified no external changes. Conclusion. Research on the stability of fireproofing properties in pressure-impregnated timber shows that it can retain its effectiveness for up to 15 years under natural weathering conditions.
Бесплатно
The influence of nano-additives in the synthesis of eco-friendly polyester plasticizers
Статья научная
Plasticized polymer materials are widely used in all spheres of human life. The most common plasticizers are aromatic compounds-esters of o-phthalic acid. However, their use was limited in accordance with the EU Directive REACH (2009) due to possible toxicity, which contributed to the development of new non-toxic alternatives, which include polyester plasticizers. Polyester plasticizers are classified as special purpose plasticizers. Due to the wide variety of starting materials and the ability to vary the size of the molecule, a wide range of plasticizers can be synthesized. These are mainly polyesters of polyatomic alcohols esterified with dibasic acids and modified with monocarboxylic acid or aliphatic alcohol. Polyesters-based plasticizers contribute to the production of PVC compositions with improved properties such as low volatility, resistance to extraction, excellent flexibility, wear resistance, UV resistance and heat resistance. Also, such plasticizers exhibit an excellent non-sweating property of plastics. This paper describes a method for preparing a polyester compound propylene glycol adipate modified with cyclohexanecarboxylic acid, proposed as a plasticizer of polyvinyl chloride. Conditions of its production with maximum output are given. Physical and chemical properties of the resulting compound were studied. The formulation of PVC-composition on the basis of the received polyester plasticizer is offered. The results of tests of PVC plastic according to state standard 5960-72 are presented. It is shown that the use of propylene adipate modified with cyclohexanecarboxylic acid provides a plasticizing efficiency as high as DOP, while having a reduced migration. This fact allows us to use the developed polyester plasticizer as a non-toxic alternative to industrial PVC plasticizers. It has been found that the use of calcium adipate nano quantities in the production of propylene glycol adipate increases the yield of the desired ester and improves the physical and mechanical properties of PVC plastic.
Бесплатно
Статья научная
Introduction. Drilling and reconstruction of oil and gas wells are key stages in the development of hydrocarbon fields. One of the most significant technological elements that greatly influences the efficiency of the process is the drilling fluid (DF). It performs many functions, including cooling and lubrication of rock-cutting and special tools, bottomhole cleaning from drilled rock, maintaining well wall stability and many others. In recent years, special attention has been paid to the use of nanomaterials in the DF drilling fluid composition. Nanoscale additives can significantly improve technological properties of water-based muds, increase their efficiency and reduce drilling costs. Methods and Materials. The influence of additives on general technological parameters of Clay-Free Drilling Mud (CFDM) was evaluated. Special attention was paid to revealing the influence of the developed experimental additives on the friction coefficient and antifriction properties of (CFDM), which were determined using modified friction machine AI5018. Results and discussion. This study focuses on the investigation of the impact of nano-additives on the technical properties of water-based mud (WBs) and their effectiveness for drilling and well reconstruction. In the course of the work, comprehensive laboratory studies have been carried out to evaluate the effect of nano-additives of different nature, such as nano-graphite and nano-carbon materials, on the lubricating properties of water-based mud (WBs), which helps to reduce the wear of drilling equipment, increase the mechanical speed of drilling and, as a consequence, reduce the time and financial costs of well construction and re-construction. Conclusion. The introduction of nano-additives allowed significantly in improving the technological properties of drilling fluid DF. The obtained results can be used to improve the compositions of solutions based on the use of nanomaterials, which will increase the efficiency and reliability of well drilling processes.
Бесплатно
The inventions in nanotechnologies as practical solutions. Part I
Статья научная
A brief review of patents is given. The research performed by scientists, engineers and specialists in the area of nanotechnologies and nanomaterials result in increased efficiency of construction, housing sector and adjacent fields of economy. The invention «A method of introduction of single-shell and/or double-shell and/or multi-shell carbon nanotubes in adhesive additive composition for asphalt coating and application of single-shell and/or double-shell and/or multi-shell carbon nanotubes as a part of adhesive additive composition» refers to construction, in particular, to the materials used in road, airdrome and civil construction. Concentration (content) of single-shell and/or double-shell and/or multi-shell carbon nanotubes varies from 0,01% to 15% of volume of asphalt covering. The invention «A method to produce nanocomposite material» based on aluminium refers to powder metallurgy, in particular to production of metal and carbon composite materials and articles of them in different shapes and can be used in auto industry, shipbuilding, aircraft engineering and instrument manufacture and other areas. The invention «A method of low temperature application of nanocrystal coating of alpha-oxide aluminium» refers to method of production nanocrystal coating of alpha-oxide aluminium with high rate under low temperature. Coatings of aluminium oxide are characterized by high thermal resistance, chemical inaction, hardness, compression resistance, heat-insulation capacity and is widely used for protection the products exposed to high temperatures and aggressive environments. The specialists can also be interested in the following inventions in the area of nanotechnologies: device and method for production of powder materials based on nano- and microparticles through electric explosion of wire; vacuum machine for application of nanostructured coating made of material with shape memory effect on the detail surface; hierarchically reinforced heteromodular extrudable solid lubricant nanocomposite based on UHMW PE and a method to produce it; hydrogen-accumulating materials and a method to produce them et al.
Бесплатно
The inventions in nanotechnologies as practical solutions. Part II
Статья научная
A brief review of patents is given. The research performed by scientists, engineers and specialists in the area of nanotechnologies and nanomaterials result in increased efficiency of construction, housing sector and adjacent fields of economy. For example, invention «Elastic conductive film on the basis of silver nanoparticles», according to experts, is of great interest for science and industry. This new type of electronics potentially can be applied in many fields, such as elastic sensor skin for robot devices, portable electronics for functional clothes, elastic sensors and flexible electronic displays. Elasticity of materials is highly needed in electronic devices that contact the human body or curved surfaces. Elastic conductive film contains many annealed nanoparticles of conductive metal, in particular silver, applied on substrate. Adhesion of silver film is of great quality: when abrasion test was finished, there were no defects or there were slight defects. The specialists can also be interested in the following inventions in the area of nanotechnologies: a method to introduce single-wall and/or two-wall and/or multi-wall carbon nanotubes in composition of adhesive additives for asphalt coating and application of single-wall and/or two-wall and/or multi-wall carbon nanotubes in composition of adhesive additives; welding wire with nanocomposite coating for welding of high-tensile steel; A method to produce nanocomposite material based on aluminium; sewage treatment system with nanomodified natural sorbents et al.
Бесплатно
The inventions in nanotechnologies as practical solutions. Part III
Статья научная
A brief review of patents is given. The research performed by scientists, engineers and specialists in the area of nanotechnologies and nanomaterials resulted in increased efficiency of construction, housing sector and adjacent fields of economy. For example, the invention «Construction structural element» refers to the field of construction. The building element is made of a cured mixture containing the following components, wt. %: dispersed foamglass – 60–85; 25–30% alumina solution in phosphoric acid – 13–34; basalt microfiber – 2–6; fulleroid type carbon toroid-like nanoparticles (fractions from 15 to 150 nm) – 0.009–0005. The dispersed foamglass is made in the form of foamed glass beads, on the surface of which a layer of polyparaxilylene 2–5 microns thick is applied. The mixture is cured at a temperature of 160–180оC. The technical result is increased strength, toughness, crack resistance and durability at low density, that is important when building objects, for example, to create internal walls and cellular partitions in rooms. The specialists can also be interested in the following inventions in the area of nanotechnologies: composite reinforcement, a method of manufacturing composite powder material from alumina carbon nanotubes; the method of plasma deposition of nanostructured heat-shielding coating; the method of degassing tungsten nanopowder; method to produce mixtures of highly dispersed heterophase powders based on boron carbide, etc.
Бесплатно
