One of the most important priorities for all countries with property beyond the Arctic Circle and territories located in permafrost areas is the development of special construction technologies and systems. The required conditions are met by insulation systems based on seamless insulation shells made of polyethylene foam. The study of the strength and performance properties of polyethylene foam and its combinability was carried out according to standard methods and using the methods of experimental design and the analytical processing of the results. The change in material properties at negative temperatures was determined based on the results of climatic tests, followed by an evaluation of creep under load. The evaluation of the effectiveness of the design solutions was carried out using special computer programs. It was found that the performance characteristics of products made of polyethylene foam (rolls, mats) meet the requirements for insulation materials used at temperatures down to −60 °C. The resulting material is moderately combustible, which must be taken into account when developing recommendations for its use in insulation systems. A nomogram has been developed that makes it possible to predict the properties of a material and solve formulation problems. Insulation systems were developed, and a visualisation of the thermal fields of the insulation systems of the external walls and ceilings of a building was carried out.
In the areas of construction materials science, the most promising solution is a set of issues related to the study of the influence of conditions for the formation of the material structure, including the possibilities of its self-organization, on its properties. The chemical and physical aspects of this influence are studied at the micro level, using the entire complex of “subtle” studies. At the same time, there are methods that allow us to assess the possibility of nanoeffects in experiments carried out at the macro level: in production or in the laboratory. One of these methods is the method described in the article. The main provisions of the methodology have been formed on the basis of statistical methods for conducting experiments and studying technological processes. This technique can significantly reduce the number of experiments performed while maintaining the adequacy of the results obtained and makes it possible to perform further analytical optimization of the results and their engineering interpretation. In particular, application of this technique allows evaluating joint influence of various factors on the result, that makes it possible to identify synergistic and antagonistic effects and then test them at the micro level by studying the nanostructure of materials. The article, as an example, considers the technology of concrete, focused on the utilization of concrete scrap as a filler or filler in building materials for various purposes. The results of research on the development of composite binder compositions based on fine-ground concrete scrap waste, mineral binder, synthetic fibers and polymers cured as a result of chemical interaction with the components of the concrete mixture are presented. This binder can be used for making various wall elements of buildings.
The article discusses the results of studying the thermotechnical properties and energy saving factors of insulation systems based on mineral wool products and products based on extruded polystyrene foam under conditions close to natural ones. The studies were carried out on the basis of the hypothesis according to which the heat-saving characteristics of the facade insulation systems are most dependent on the thermal resistance along the surface of the wall, on the thermotechnical uniformity of the insulating sheath and on the stability of the properties of the heat-insulating materials under real operating conditions. The implemented complex made it possible to establish that the smallest difference between the air temperature in the room and the surface temperature in the lower zone was achieved on a fragment of the building envelope with a mounted facade system with XPS as insulation. For the same type of facade system, the maximum heat transfer resistance in the lower zone of the building envelope was reached - 2.72 m2 ° C / W for the cold period of the year, which significantly exceeds the characteristics of the system of mounted ventilated facades with mineral wool thermal insulation in the corresponding zones. The factor of “additional warming” from the soil, which is used to justify the rejection of warming in the buried part of the structure, does not work in the cold season. Flooding at thezone with the junction of the wall with the soil significantly affects the values and nature of the distribution of operating humidity inside the insulation layers.
The article presents studies of the exploitation characteristics of the material, the results of a full-scale survey of a residential private house insulated with expanded polyethylene, as well as the main design solutions for the insulation of a frame cottage. The features of insulation systems of low-rise buildings, including those with a frame-bearing carrier system, are considered. It has been substantiated that the use as thermal insulation of mineral-wool plates used on non-loaded structures assumes the mandatory placement of vapor barrier (usually plastic film) from the inside of the insulated surface and the windproof membrane outside. The use of a rolled foamed polyethylene as an insulating material makes it possible to realize an insulating sheath without additional layers. Experimental determinations of diffusion moisture absorption, water absorption upon partial immersion in water, water absorption upon full immersion in water, tensile strength in the longitudinal direction, and adhesion strength of the adhesive layer to metal were performed. It was established that the diffusion moisture absorption of samples of expanded polyethylene is 0.51-0.75%, and taking into account the weld it is 0.70-0.75%. Water absorption of samples when fully immersed in water does not exceed 0.96% by volume. The tensile strength in the longitudinal direction for products with a metallized coating is 80-92 kPa, without a metallized coating - 80-87 kPa, and for a weld - 29-32 kPa. A field survey showed that the humidity of the pine timber is within the normative. The expediency of warming only the outer coating of expanded polyethylene of the calculated thickness without filling the frame is justified, which, with standard air exchange and observance of the conditioning conditions, will be sufficient to maintain the microclimate in the room.
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