"Вестник МГСУ"

In the article, the author describes the technological peculiarities of erection of frame buildings at negative temperatures. The author also demonstrates structural and technological peculiarities of prefabricated frame elements. The author also speaks about the technology of prefabricated production of stacked columns, pre-stressed girders, beams and hollow core slabs.
It is proven that the frame system is applicable for the construction of industrial, residential and office buildings that may have different numbers of storeys and that are flexible in terms of design concepts. Besides, the author describes the technological peculiarities of the assembly of structural elements, their temporary and permanent fixing.
The author also provides basic requirements applicable to the technology of grouting of column-to-girder joints and hollow slabs designated for a cased frame. The article also contains an analytical solution of the heat conductivity equation that describes the period of heating of connected elements. The solution makes it possible to use numerical methods to identify the depth of heating of girders and columns, depending on the ambient temperature and the duration of exposure to the heat.
The author has also analyzed the technology of grouting of precast structure joints at negative temperatures in the event of pre-heating of structural elements to be connected and the heating of the concrete mix with heating wires. The author has identified the range of rational heating modes for structural joints on the basis of the parameters of negative temperatures.

Subject: multi-layer building envelope is the subject of the paper. Recently, in the context of energy conservation policies, the heat engineering requirements for enveloping structures of buildings and structures have significantly increased. At the same time, their moisture condition has a significant impact on the operational properties of materials of structures and on microclimate of rooms constrained by these structures. Research objectives: emphasize importance of the task of predicting the temperature and moisture condition of the walling at the stage of design and construction of building envelopes. In this paper, the temperature distributions in layered walls are analyzed. Materials and methods: to achieve the objectives, computational and experimental studies are conducted. By alternating (rearranging) layers and preserving the thermal resistance of the wall on the whole, we find the optimal alternation of layers that minimizes deviation of the maximum wall temperature from the average temperature. Results: for the optimal location of layers in the wall’s structure, the moisture penetration into the wall is minimal or absent altogether. This is possible if the heat-insulating layer is mounted on the outer surface of the structure. Conclusions: the obtained results of computational and experimental studies allow us to verify appropriateness of accounting for alternation of layers in multilayer structures. These calculations proved that the higher the average temperature level, the more energy-efficient the structure will be.

Subject: the treatment of External Thermal Insulation Composite Systems (ETICS) surfaces affected by bio-corrosion takes place as a part of planned or operational maintenance. As part of this process, ambient environments are loaded with running water and detergents that contain heavy metals. The article presents the results of research on reducing the impact of environmental contamination by cleaning and preventive coating of ETICS surfaces with biocides. The paper gives an overview of the problem and new approaches to the treatment of new and renovated buildings. Purposes: at the present time, the maintenance of existing ETICS lacks system solutions, instead using chemical methods for the treatment of contamination by microorganisms. While complete information on environmental impacts is lacking it is necessary to take this into consideration. The cost of renovation, which should include investment for future treatment of ETICS surfaces, is often underestimated. Film preservation biocides contain both algaecides and fungicides. Consequently, ETICS preservation agents in exterior paints and renders represent a potential risk for humans, animals and the wider biological environment and new concepts underlying more sustainable approaches are required. Materials and methods: the research was based on an evaluation of existing technologies for eliminating microorganisms from the ETICS surfaces and an analysis of their environmental effects. The aim was to find optimal operational and planned ETICS maintenance approaches that minimise negative environmental effects. Results: environmentally-friendly approaches were identified and a new leaching system for safe dewatering was designed. These approaches differ according to their suitability for periodic or operational maintenance. Conclusions: there is a wide range of materials used for ETICS finishes. It is important to consider the reliability and maintainability of the construction across the entire life cycle of a building. Operation and maintenance should be a significant element of the life-cycle cost of a building. The removal of bio corrosion coatings from ETICS structures by means of chemical and preservative substances (biocides) is currently the most-used and only effective technology. The uncontrolled release of applied chemicals is unacceptable. A system designed for collecting wastewater from the cleaned surface is considered an effective means of reducing the deleterious effects of biocidal substances on the environment. The safe dewatering of chemicals leached from the surface of the facade is presented by a drain system designed in accordance with the building type, use and age.

Heat-protective qualities of building structures are determined by the qualities of the used materials, adequate design solutions and construction and installation work of high quality. This rule refers both to the structures made of materials similar in their structure and nature and mixed, combined by a construction system. The necessity to ecaluate thermal conductivity is important for a product and for a construction. Methods for evaluating the thermal protection of walls are based on the methods of calculation, on full-scale tests in a laboratory or on objects. At the same time there is a reason to believe that even deep and detailed calculation may cause deviation of the values from real data. Using finite difference method can improve accuracy of the results, but it doesn’t solve all problems. The article discusses new approaches to evaluating thermal insulation properties of walls. The authors propose technique of accurate measurement of thermal insulation properties in single blocks and fragments of walls and structures.

Effectiveness of thermal insulation products is determined by a set of criteria that can be expressed in terms of energy costs: reduction of the cost of heating (the main criterion), energy consumption in the course of construction, energy consumption in the course of production of materials having pre-set properties, and service durability of the material.On the one hand, service durability (as a property) is generated in the course of material production, and on the other hand, it depends on the conditions that the material is exposed to in the course of any construction process. The same parameter affects energy-related criteria. Insulation replacement or unplanned repairs add supplementary energy costs.The manufacturing process of thermal insulation materials contemplates processing of a significant amount of non-renewable natural resources, namely, fuel combustion. Optimization of these costs is necessary and possible through appropriate organization of processes, including the process of heat treatment of products.Layered materials can improve the product performance and durability. Production and heat treatment of mineral fibers are the most energy-consuming steps of the mineral wool production. Optimization of these processes can involve significant economic effects.

Creating an effective insulation envelope of the building is possible only using high-quality materials, preserving their characteristics both in the early stages of operation, and for the whole billing period. It is an important opportunity to assess the thermal insulation properties and predict its changes over time directly in the conditions of the construction site. The products based on mineral fibers (rock and glass wool, basalt fiber) are the most widely used type of insulating materials in the domestic construction. Therefore, the operational stability valuation methods must be primarily created for this group of products. The methodology for assessing the thermal insulation properties includes two main components: testing equipment and methodology for assessing the operational stability. The authors tested the methodology of the accelerated testing and prediction of durability for mineral wool products of laminated, corrugated and volume-oriented structures. The test results give good convergence with the methods recommended by the building regulations. Application of thermal insulation materials are an effective way to form the thermal envelope of the building, reducing energy costs and increasing the durability of building structures. The material properties are determined by their structure, which is formed during the technological impacts.

The use of thermal insulation materials is an effective method to create an insulating envelope of a building, as well as to reduce energy costs and increase the durability of building structures. The properties of stone wool products and their operational durability is largely determined by the conditions of formation of the mineral wool carpet, uniform distribution of binder and its curing and the heat treatment conditions. Most domestic technologies are aimed at the production of mineral wool products with volume-oriented structure, which is formed using special units: spreader and corrugator placed in a production line. The next step to obtain the optimum structures is the production of dual density slabs. The denser upper layer receives mechanical loads caused by the operating conditions; the lower, less dense, but more thick layer performs the main function - insulation. The dual density slabs are produced on standard lines supplemented with a special unit, which is located in front of the heat treatment camera. Optimization of heat treatment parameters and prediction of the properties of materials is performed using software package.