Vol. 6 Issue 4

Archives Journal Construction Materials and Products 2023

The Influence of High Frequency Plasma Treatment Reduced Pressure Induction Discharge to Improve the Adhesive Characteristics of Fiberglass

The article presents the results of studies confirming the advantages of plasma treatment in the production of glass-filled composite materials based on polyamides, which consist in environmental friendliness, resource saving and no dependence on chemical solutions that plasma treatment offers compared to traditional methods. By optimizing processing parameters, the study also explores how plasma processing can manipulate surface layer characteristics and material structure to improve cer-tain glass fiber characteristics without sacrificing other properties.
As part of the study, experiments were carried out to study the effect of low-energy ions generated by high-frequency plasma on the technological characteristics of glass fibers. Previous studies have shown that plasma treatment in various gaseous media (argon, air, propane-butane mixture) makes it possible to remove the lubricant from the fiberglass surface, activate its surface, and increase adhesion in the polymer-filler system.
Capillarity tests were carried out to evaluate the adhesion characteristics of the plasma-treated glass fibers. The results showed a direct relationship between the increase in the capillarity index, the dura-tion and intensity of the plasma treatment. As a result of the study, the optimal processing parameters were determined to achieve the desired adhesive characteristics, as a result of which the adhesive strength increased by 1.5-1.7 times.
The results of the study confirmed the persistence of the effect of plasma treatment over time, and therefore, it is recommended to use modified glass fibers to reinforce polymer matrices during the first 10-25 days after treatment.
The data obtained make it possible to recommend plasma treatment for the modification of glass fibers in the production of reinforced polymer composites.

Injection mortars based on composite cements for soil fixation

The fixation of subsidence soils is an important practical scientific and technical task, which makes it possible to carry out construction and repair work on weak (subsidence) base soils. Composite cements (CC) have been developed, including aluminosilicates (AS), obtained by enrichment of ash and slag mixture (up to 65 wt.%), Portland cement clinker and gypsum. Based on the developed CC, a wide range of injection solutions with water-binding ratios from 1.0 to 2.0, including screening of crushed granite from 0.7 fineness modules, has been created. The developed injection mortars are capable of effectively fixing the soils of the foundations of underground structures, providing the strength of the soil-concrete mass up to 25.6 MPa with a deformation modulus of 10.1 GPa. According to the sedimentation analysis of solutions, it can be seen that these materials have a percentage of water separation from 22.5% at W/B=1 to 36.5% at W/B=2. At the same time, the viscosity indicators of these materials indicate a high penetrating ability, since the time of the expiration of mortars through a Marsh viscometer for mortars IR5 and IR6 is 39 and 40 seconds at W / B = 1.5 and W/ B = 2, respec-tively. The effect of increasing the density of injection mortars on composite cement at the age of 28 days was maximum at an AS dosage of 45% by weight, then it decreased with an increase in the con-tent of the aluminosilicate component. There are high ratios of the values of strength properties on the second day to similar indicators in the 28-days age: for compressive strength 0.24 (0.20-0.22 for addi-tive-free clinker compositions), for flexural strength 0.16 (0.15 for additive-free clinker compositions; while increasing the AS content above 45%, this ratio decreases to 0.14). High early strength makes it possible to effectively use injection mortars for urgent fixing of soils during the repair of underground structures.

Radar absorbing materials based on sealant “Abris”

The article discusses the creation of elastic self-adhesive radio absorbing materials for the frequency range of 4.5 – 6.0 GHz. In recent decades, technologies related to the emission of electromagnetic energy into the environment have been rapidly developed. In 1996, the World Health Organization first introduced the concept of "Electromagnetic environmental pollution". The electromagnetic field is a biologically active, biotropic factor that, under certain conditions, can cause pathological changes in the functioning of the human body. An effective way to meet the requirements of electromagnetic ecology and safety is to reduce electromagnetic radiation to an acceptable level through the use of protective materials. Analyzing the composition of existing protective materials, it is obvious that the shielding (reflecting) properties dominate over the absorbing ones. Under the conditions of the modern magnetic environment, the need for absorbing materials is great, which is explained by the need to exclude the influence of re-reflections on the complication of the structure of the electromag-netic field, which leads to an increase in the total surface irradiation of the object. In this regard, based on the ethylene-propylene sealant "Abris" produced by LLC "Plant of sealing materials", Dzerzhinsk, Nizhny Novgorod region, a radio-absorbing material was developed. To absorb electromagnetic radia-tion, UFM-4HD carbon fiber and metal scale are introduced into it. It is shown that their introduction into the composition of the composite leads to the absorption of electromagnetic radiation by 75-78%. The material is designed to protect premises and equipment from electromagnetic radiation.

Specifics of information model development for functional conversion of offshore oil platforms

The paper holds that the disposal of offshore oil platforms (OOP) after the expiration of their lifecycle is inexpedient and unjustified from the environmental standpoint, since this process results in a dramatic adverse impact imposed on the hydrosphere, which explains the relevance of OOP conver-sion into objects with other functional purposes. The focus is on the global experience of converting offshore oil platforms into residential and industrial buildings. Special attention is paid to the fact that the conversion of an object leads to a reduced construction timeline, which is possible due to optimiz-ing the timeframe of dismantling works that become unnecessary during the subsequent operation of the OOP structural parts. The point is emphasized that OOP repurposing, and in particular creating so-called floating cities on their basis, is capable of meeting a handful of environmental, socioeconomic and town-planning challenges, which however calls for a rigorous professional approach and a thor-ough study of the OOP lifecycle stages both before and after their functional conversion. This, in turn, may lay the ground for the development of an information model of OOP functional repurposing. The research is aimed to explore the specifics of developing an information model of OOP conversion into other type facilities, and as such identifies the key OOP types (submersion depth and underwater de-sign solutions, principal advantages and disadvantages) required to build individual information blocks to form part of the overarching information model of OOP conversion. Also, a scheme of information environments is provided showing the algorithm of creating an information model of OOP conversion and singling out the stages of various lifecycle phases.
The conclusion is made that the functional repurposing of offshore oil platforms is required to as-sure safety of the natural environment, suggesting that the assessment of the environmental perfor-mance and energy efficiency of the organizational and technological solutions of OOP functional con-version must be made part of the front-end design engineering milestone.

The Exergy Analysis of the Heating Mode of a Trigeneration Energy Complex Based on a New Heat Transformer

The article analyzes from energy and exergy positions the trigeneration power complex, developed by the authors and consisting of two main units: a heat engine and a new heat transformer, additionally having a generator for generating electricity for own needs. The main advantage of this energy complex is the reduction of fuel consumption in the heating mode. The emphasis is on the thermal efficiency of the installation and its thermodynamic parameters.
The energy complex under study operates on organic fuel as well as using renewable energy sources (heat pump on organic fuel) and allows obtaining the value of the coefficient of energy effi-ciency from one and a half to more than three in the heating mode. Based on the analysis of energy efficiency calculated by the method of thermal balances, the authors conducted an exergetic analysis. Different variants of inclusion of mechanical and heat compressors of steam-compression and absorp-tion pumps, such as serial, parallel and mixed, were considered. For each variation, there will be dif-ferent working conditions, efficiency and different use of a source of heat and mechanical energy
As a result of the calculation analysis it was concluded that at a sufficiently high coefficient of en-ergy efficiency in the heating mode, the energy complex also has a large potential for its additional increase. In addition, the energy complex produces cold in the warm season and does not need to be connected to the power supply networks. And insufficiently high values of exergy efficiency indicate the imperfection of the thermodynamic system and its potential for further improvement and increase of the energy efficiency coefficient.

Analysis of International Experience in the Construction of High-Rise Buildings and Justification of Organizational and Technological Solutions for High-Rise Construction

High-rise construction is an urgent way of development of modern megacities in conditions of constant growth of the urban population and the accompanying shortage of land for the construction of residential and civil facilities. At the same time it is necessary to preserve the urban planning herit-age, which forms the individual character of the city. On the one hand it is necessary to orient to his-torical and cultural peculiarities of urban environment and available urban resources, on the other hand it is necessary to strive for individual architectural and urban solutions that would make the high-rise buildings under construction attractive for investors as well as for the urban appearance of the city and attract tourists. However, for the realization of creative ideas in the construction of high-rise buildings is necessary to search for adequate technological solutions, which is often a difficult task, especially in conditions of dense urban development.
The objective of the article is substantiation of organizational and technological solutions for high-rise construction under the conditions of dense urban development.
The analysis of experience in the construction of high-rise buildings has been carried out and substan-tiation of organizational and technological solutions of high-rise construction under the conditions of dense urban building has been provided in the paper.
On the basis of the conducted research there has been shown a possibility of increasing the efficiency of high-rise building management by means of improving the method of substantiation and selection of rational organizational and technological solutions of high-rise building construction, aimed at ef-fective use of resources and reduction of the cost of construction output due to taking into account the urban planning value of territories and the complex influence of energy saving and environmental fac-tors. At the same time the study results showed that during the construction of high-rise buildings with a developed underground part in the conditions of dense urban development it is necessary to solve a number of complex technical problems associated with technological features of construction and en-suring the stability of the existing building. Nevertheless, modern construction technologies and equipment make it possible to carry out a choice of available methods of construction of high-rise buildings with underground structures, for example, the technology "up - down", which makes it pos-sible to carry out work on the underground and aboveground parts of the building almost simultane-ously and thus accelerates construction time of buildings, especially high-rise and high-rise.
The results of the study can be used in the practice of high-rise construction in dense urban develop-ment.