Ústav technologie stavebních hmot a dílců


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    Vacuum insulation panels: An overview of research literature with an emphasis on environmental and economic studies for building applications
    (ELSEVIER, 2024-01-01) Božiček, David; Peterková, Jitka; Zach, Jiří; Košir, Mitja
    The study provides an overview of the research focus on vacuum insulation panels (VIPs). Scientific literature published between 1960 and 2022 is identified, and a database covering 423 documents is amassed. In the first phase, research documents were categorised into three groups: product, other and buildings. In the second phase, data about the studied building applications and research topics were extracted and quantitatively evaluated. In the last phase, the studies evaluating VIPs' environmental and economic implications in buildings were analysed in detail. The study results show an increasing publication trend on VIPs, with almost 90% of the literature published from 2010 onwards. Building applications are the dominant research subject, representing 56% of identified documents. A detailed analysis of life cycle studies pointed to a consensus that in building applications, fumed silica VIPs exert a higher environmental impact and costs than conventional insulation materials if the comparison is based on an equivalent thermal transmittance value. However, several studies showed reasonable payback and environmental neutrality periods for retrofitting scenarios. Benefits could also be achieved if insulation layer thickness is limited. External wall insulation represents the vast majority of the applications analysed. Studies further showed that VIPs in external wall applications could be economically viable compared to conventional insulation if added useable floor space is considered. The characteristics of life cycle studies were analysed, research gaps and possibilities were identified, and research recommendations for environmental and economic studies of VIPs were provided.
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    Development of a Hydrophobic Polymer Coating in Polyurethane Organic–Mineral Base Containing Waste from Fibreglass Production
    (MDPI, 2023-11-12) Hudec Jakubíková, Karolína; Hodul, Jakub; Hermann, Radek; Drochytka, Rostislav
    In this study, the suitability of waste from glass fibre production as a secondary filler for a polymeric durable hydrophobic coating, based on an innovative polyurethane organic–mineral base, was experimentally verified. The main aim of this work was to develop a basic formulation for a polymeric hydrophobic coating designed primarily for usage in aggressive environments. For this purpose, a total of four formulations were tested with different weight percentages of waste glass fibre, i.e., from 30 to 60%. The basic properties in the fresh state, such as the coating workability and kinematic and dynamic viscosity, were verified, and an application test was performed. The formulations were also verified after the polymerisation of the coating. Adhesion on a concrete substrate and the tensile properties and hardness of the coating were tested. Chemical resistance to liquid aggressive media and the microstructure of the coating after exposure to SO2 were also tested, as these are critical properties. All the formulations showed better workability than the reference coating without a filler, and the formulation with the highest filling (60%) appeared to be optimal. The maximum adhesion on the concrete substrate (11.9 MPa) and tensile strength (21.6 MPa) were recorded for the formulation with 60% waste fibreglass. It can be concluded that with an increase in the waste glass content, there was a significant improvement in the properties of the coatings. Additionally, the waste fibreglass did not have a significant negative impact on chemical resistance.
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    The assessment and treatment of waste from glass fibre production for use as a filler in composites
    (MATEC Web of Conferences, 2023-10-30) Hudec Jakubíková, Karolína; Hermann, Radek; Drochytka, Rostislav
    Waste glass from fibreglass production is waste that is generated at various stages of production. In nature, it is a combination of glass fibres, fine dust, but also larger glass grains, for example also from leakages during production. This material is or may be contaminated by impregnation, lubricants or some impurities that prevent its recovery during production. The main objective of this study is to assess the suitability of glass fibre waste and to optimise the pre-treatment of the raw material for use in the composite. This paper describes the determination of chemical composition, mineralogical composition by X-ray diffraction analysis, determination of bulk density, water absorption and specific surface area. The results obtained are compared with the primary raw material - glass fibre. The results showed that the waste from glass fibre production is primarily composed of silica, calcium, alumina and boron. Minor components include magnesium oxide, sodium oxide, fluorine, iron oxide, strontium oxide, potassium oxide, titanium dioxide, sulphur dioxide and chromium oxide. The specific surface area of treated glass fibre waste correlates with the specific surface area of cement, which is a prerequisite for the use of this waste as a partial substitute for cement in the production of building materials.
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    The effect of cellulose fibres in an epoxy adhesive for bonding wooden load-bearing elements
    (EDP Sciences, 2023-10-30) Laciková, Petra; Vaněrek, Jan; Běťák, Adam
    The work deals with the modification of the properties of epoxy adhesive. The modification consists of reinforcing this adhesive with cellulose fibres. In the field of wood glued elements, the current research focuses on the possibility of increasing the ductile behaviour of the epoxy adhesive, which would significantly increase the ability of the adhesive to transfer the stresses induced by the volumetric changes of the wood adherend. For this purpose, the adhesive was modified with fibres having a reinforcing character, which may include cellulose fibres. Due to the epoxy resin’s non-polar nature and the cellulose fibre's hydrophilic nature, which inhibits the fibre's homogeneous dispersion, the fibres have been modified with silanes. This paper describes the effect of adhesive modification by determination of tensile and shear strength at different amounts of filling and different types of silane pre-treatment of cellulose fibres. The optimum filling amount can be considered as 1.0% filling of nanofibrillated cellulose (NFC) with epoxy-functional silane pre-treatment.
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    Study of the possibility of using vacuum insulation panels in building construction in comparison with conventional insulators
    (2023-08-21) Zach, Jiří; Peterková, Jitka; Novák, Vítězslav; Bubeník, Jan; Košir, Mitja; Božiček, David
    The use of super insulating materials in the construction industry, including vacuum insulation, closely corresponds to the ever-increasing requirements for the construction of low-energy and passive buildings. Their indisputable advantage is their excellent thermal insulation properties at low thickness compared to conventional thermal insulation materials. However, there are also many risks associated with the experience and practice of the personnel involved in the application of these materials to structures. The paper focuses on the overall comparison of the possible use of vacuum insulation panels in modern building structures in terms of possible design solutions and achieved properties. The paper presents the results of selected case studies of the optimal use of vacuum insulation panels (VIP) in the construction industry, which are focused on different areas of building structures, specifically on the detail of the transition of the terrace and the adjacent floor, as well as on the solution of the filling of openings - doors. Based on the results of the studies carried out, it can be concluded that, provided that all procedures for maintaining the VIP properties are followed in the implementation of these materials in structures, vacuum insulations represent a more suitable solution for structural details in selected details (less thickness and comparable thermal insulation properties compared to conventional insulations).