Topical Problems of Green Architecture, Civil and Environmental Engineering 2019 (TPACEE 2019)
Using the example of pipeline insulation systems, the basics of the concept of environmentally sustainable construction are outlined, including requirements for materials, construction systems that use these materials, engineering systems and working technologies. Insulation based on polyethylene foam technology of its installation meets the requirements of EcoMaterial Basic or EcoMaterial Green. The article presents the main provisions of the methods for calculating insulation systems based on polyethylene in terms of energy efficiency, which is decisive, including the environmental assessment of insulation systems. The optimal thickness of the polyethylene foam is determined, as well as the recommended insulation thickness to ensure a given (safe for humans) temperature; to prevent moisture condensation on the surface of the insulation layer. The estimated period during which the thermal insulation prevents freezing of cold water in case of an emergency stop of its movement in pipelines in the winter period is established.
The factors affecting the durability of insulation systems and products based on mineral fibers are analyzed. It is emphasized that the ratio of acid oxides contained in the charge to the main oxides is the main factor affecting the stability of mineral fibers, as well as the energy intensity of their production. Hypotheses have been put forward and confirmed that the operational resistance of fibers depends on the content of heavy metals (their oxides) in the charge. The determination of the elementary composition of the stone wool samples was carried out using X-ray fluorescence. The conducted studies show that the fibers are safe in terms of radiation indicators, and their operational stability may be due to heavy metal oxides. It is confirmed that the durability of construction systems in which mineral wool products are used as thermal insulation is determined by the properties of mineral wool products, design competence and installation quality.
Methods of dispersed reinforcement of the concrete matrix with the help of fibers make it possible to manufacture structures of complex configuration and solve the problems of frost resistance of products. Fiber replaces secondary reinforcement, reducing the amount of use of structural steel reinforcement. Cellular fiber concrete is characterized by increased flexural and tensile strength, impact strength and crack resistance. One of the promising types of dispersed reinforcement of light concrete is the use of expanded vermiculite. Expanded vermiculite can be simultaneously considered as a strengthening component of the lamellar structure, as a component that reduces the density of the material and its thermal conductivity, as well as improves fire-fighting properties. The foamed vermiculite can be used both in facing piece products, and as a part of dry warm and fire-resistant gypsum mixes".
The criteria for the effectiveness of the thermal insulation system are its technical properties, strength and cost of production. Modern thermal insulation products made of mineral stone fiber with high chemical resistance. The structure of the products is such that the fiber is firmly intertwined and has a volume-oriented state structure. The complex bonded structure provides additional strength characteristics of the product, and is secured by curing the binder. Reduced costs caused by the use of a binder with a curing temperature of up to 150 ° C. The possibility of justifying the use of an epoxy-modified binder with a hidden hardener is justified in the article, as well as the method of selecting the parameters of the heat treatment mode of mineral wool cylinders with this type of binder.
The basic requirements for the insulation systems of pitched roofs are given. The properties of thermal insulation materials used in insulation systems are analyzed. It is confirmed that the heat resistance of such structures on the roof surface is formed taking into account the thermal conductivity of thermal insulation, the thermal conductivity of wooden rafters and heat loss as a result of temperature bridges and loose contact of insulation to the rafters. The impact of various types of loads on the thermal insulation layer is evaluated, namely: the influence of the air flow in the ventilated gap; the movement of the vapor-air mixture in the material; condensation of water vapor and penetration of liquid droplets. The expediency of using products based on reinforced foamed plastics in the construction of pitched roofs with a wooden roof system is justified, taking into account the advantages and features of these materials.
The results of thermal imaging monitoring of building structures with and without insulation are discussed. Studies and thermal and physical calculations have shown that the loss of heat from the premises is determined by two groups of factors: the loss of surface depending on the thermal conductivity, as well as the permeability of steam and air from the enclosing elements and the loss of heat in all types of structures. Thermal insulation with plate materials significantly reduces heat loss, but at the same time, heat leaks through the joints between the heat - insulating plates and in the area of their contact with other structural elements, which requires the use of steam-and waterproof windproof roll materials. The use of elastic and thermoplastic materials in the insulation system minimizes heat loss at the joints between the thermal insulation elements and along the smooth surface of the wall. In the systems of frame cottages, when using rolled polyethylene foam as a thermal insulation, it becomes possible to form a seamless insulation shell of the building.
The results of the study of the state of production of foam glass and the nomenclature of its products are presented. It is shown that it is advisable to use recycled glass obtained from bottle packaging, waste glass and double-glazed windows as raw materials for the production of foam glass. The features of the production technology of foam glass on specialized lines are described. The features of the technology are the composition of the charge and the temperature conditions of heat treatment. Currently, about 70% of the foam glass aggregate is used for roofs and stylobates; the rest is used in landscaping, road construction, foundations, and major repairs. The areas of application of foam glass can be significantly expanded in the direction of building systems, light aggregates, etc., which implies an in-depth study of the properties of this material.
Insulation systems of buildings and structures involve the use of effective thermal insulation materials based on mineral wool, expanded polystyrene, polyurethane foam, etc. For a long time, products made of unstitched polyethylene foam were used as pipeline insulation, retroreflective insulation. Protection against air penetration, etc. Modern technologies and engineering solutions have made it possible to expand the scope of application of unstitched foamed polyethylene as a building insulation material. The article discusses a number of insulation systems based on the use of products made of foamed polyethylene. In particular, these are systems for insulation of walls of frame buildings, insulation of floors, as well as insulation of logistics facilities and hangars.
Insulation systems of building structures involve solving the following group of tasks: creating favorable conditions for the operation of structural elements and construction in general; optimizing heat loss through insulation shells; creating comfortable conditions in the room. Such a system will function normally if effective thermal insulation, including polyethylene, is used. The article presents the results of experimental studies, the purpose of which is to optimize the composition of polyethylene foam with the addition of secondary polyethylene, the formation of methods for selecting its composition and the development of systems for the use of products. The main provisions of the analytical optimization method are presented, which allows to significantly reduce the material and processing time of the experimental results. The article discusses the aspects of the implementation of building systems using products based on polyethylene foam from the point of view of minimizing heat loss through contact zones.