The Experts below are selected from a list of 50217 Experts worldwide ranked by ideXlab platform

Robert Cerný - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of thermal performance of window lintel construction detail
    IOP Conference Series: Materials Science and Engineering, 2018
    Co-Authors: Jan Fořt, Milos Jerman, Zbyšek Pavlík, Robert Cerný
    Abstract:

    Ceramic bricks belong to the oldest and most used building material since the ancient ages. Notwithstanding, this favorable building material passed through many improvements and currently used ceramic brick is substantially improved compared to bricks from ancient production. The contemporary demands are paid especially on the mechanical resistance, high vapor permeability, outstanding thermal insulation properties, thermal accumulation function and noise insulation. On this account, the hygrothermal properties of construction detail composed by a contemporary lightweight hollow brick together with window lintel is investigated within this paper. Compared to laboratory methods aimed at the measurement of small samples, the semi-scale analysis represents a valuable approach for building materials testing. For this purpose, a system composed of two climatic chambers separated by the connecting tunnel with desired building construction detail is used. The brick block and window lintel is placed in a chamber connection tunnel, thermally insulated by Mineral Wool to ensure one dimensional transport and studied in sense of loading by real climatic data from Czech Republic. This valuable analysis allows long-term monitoring of the wall cross-section temperature and relative humidity profiles of particular elements in real scale. The obtained results represent valuable information for the practical application of the studied brick block in building practice. Such comparison allows optimization of building envelopes in order to improve their energy efficiency.

  • computer aided design of interior thermal insulation system suitable for autoclaved aerated concrete structures
    Applied Thermal Engineering, 2013
    Co-Authors: Vaclav Koci, Jiři Maděra, Robert Cerný
    Abstract:

    Abstract The idea of using interior thermal insulation systems for autoclaved aerated concrete (AAC) structures is introduced. In the computer aided design, the hygric properties of the thermal insulation layer and the connecting layer between the AAC block and the thermal insulation board are investigated. The computational analysis shows that the moisture diffusivity, κ, of the thermal insulation layer should be very high (≈1 × 10−6 m2/s), its water vapor diffusion resistance factor, μ, very low (≈3–5), and hygroscopic moisture content, whyg, moderate (≈0.01 m3/m3). This combination of properties can potentially be met by modifications of some not commonly used thermal insulation materials, such as are hydrophilic Mineral Wool or calcium silicate. On the other hand, the hygric properties of the connecting layer are not found very restrictive. Common lime–cement or lime–pozzolan mortars can meet the required criteria of κ ≈ 1 × 10−9 m2/s–1 × 10−8 m2/s, μ ≈ 10–20, and whyg ≈ 0.05 m3/m3. The application of an interior thermal insulation system with the properties given above for an AAC envelope can reduce the hygrothermal straining of exterior plaster, which is typical for the exterior thermal insulation systems, in a very significant way, thus increase the service life of the whole envelope.

  • effect of moisture content on heat and moisture transport and storage properties of thermal insulation materials
    Energy and Buildings, 2012
    Co-Authors: Milos Jerman, Robert Cerný
    Abstract:

    Abstract Computational models of heat and moisture transport are frequently used in calculating energy gains and losses in buildings. However, any model can provide reliable information only in the case that the quality of input data is adequate. This is not always true because the standard lists of thermal and hygric parameters given by the producers as well as the material databases included in the simulation tools are usually far from complete. In this paper, we present the measurements of complete sets of heat and moisture transport and storage parameters of selected thermal insulation materials in dependence on moisture content. Two common thermal insulation materials, namely hydrophobic Mineral Wool and expanded polystyrene, are selected as reference materials. Two types of hydrophilic Mineral Wool and an autoclaved-aerated-concrete thermal insulation board are the representatives of prospective materials which appeared on the market within the last couple of years. The studied material parameters include bulk density, matrix density, porosity, saturation moisture content, thermal conductivity, specific heat capacity, moisture diffusivity, water vapor diffusion coefficient, sorption isotherm, and water retention curve.

  • hygrothermal performance study of an innovative interior thermal insulation system
    Applied Thermal Engineering, 2009
    Co-Authors: Zbyšek Pavlík, Robert Cerný
    Abstract:

    An innovative interior thermal insulation system on the basis of hydrophilic Mineral Wool which can serve as an alternative solution to the commonly used systems with water vapor barrier is presented in the paper. At first, the process of materials design is described. Then, the hygrothermal performance of the designed insulation system is tested in the difference climate conditions that correspond to the winter climate in Middle Europe. In the experiment, the profiles of temperature, relative humidity and liquid moisture content are monitored. Measured temperature profiles demonstrate the proper thermal insulation function of the system. The hygric function can also be considered very good as no water condensation during the whole testing period of five months appears in the insulation layer. Therefore, the basic requirements for the successful application of the system in building practice are met.

  • thermal conductivity of Mineral Wool materials partially saturated by water
    International Journal of Thermophysics, 2006
    Co-Authors: M Jiřickova, Zbyšek Pavlík, Lukas Fiala, Robert Cerný
    Abstract:

    The thermal conductivity of several types of Mineral Wool-based materials, namely, materials with hydrophobic admixtures, hydrophilic admixtures, and without any admixtures are measured as a function of moisture content from the dry state to the partially water saturated state. An impulse technique is employed for the measurements using both surface and needle probes. The data are analyzed using the Bruggeman effective media concept for different shapes of inclusions and Wiener’s basic formulas. It is found that for most materials, the experimental data for thermal conductivity in the range of low moisture content are close to the lower Wiener’s bound but in the range of higher moisture content the data are close to the upper Wiener’s bound.

Timo Karki - One of the best experts on this subject based on the ideXlab platform.

  • Environmental assessment of recycled Mineral Wool and polypropylene utilized in wood polymer composites
    Resources Conservation and Recycling, 2015
    Co-Authors: Olli Väntsi, Timo Karki
    Abstract:

    Abstract Environmental performance is an important promotive factor in the future use of wood polymer composites. In this study, the environmental effects of replacing virgin glass fibers with recycled Mineral Wool fibers, as well as replacing virgin polypropylene with recycled polypropylene are investigated. Furthermore, the environmental performance of two different end-of-life options for composite waste, incineration for energy use and landfill deposition is evaluated. The recycled Mineral Wool was found to have better environmental performance compared to glass fiber in every impact category assessed. The utilization of recycled polypropylene proved to be advantageous in global warming potential and abiotic depletion categories. It was found that the end-of-life management of composite waste has an important role in the environmental performance of composites. Incineration of composite waste for energy use had better performance compared to landfill deposition in all the categories assessed, except for global warming potential. It is concluded that while the environmentally optimal recycling method for polypropylene waste must be evaluated case by case, recycled Mineral Wool seems to provide an environmentally superior option to glass fiber in wood polymer composite applications where properties obtainable by the use of a Mineral filler are required.

  • utilization of recycled Mineral Wool as filler in wood polypropylene composites
    Construction and Building Materials, 2014
    Co-Authors: Olli Väntsi, Timo Karki
    Abstract:

    Abstract The construction and demolition (C&D) industry is a major source of waste. Environmental regulations and laws have been implemented in many countries to improve and encourage the recycling of C&D waste. To meet tightened regulations, new C&D waste recycling methods must be developed. Mineral Wool is a waste fraction that is currently considered un-recyclable. In this study, the mechanical and moisture resistance properties of wood plastic composites utilizing recycled Mineral Wool as filler are presented. According to the findings, the addition of recycled Mineral Wool improved the moisture resistance properties of the composites noticeably, but a decrease in some mechanical properties was observed.

  • Mineral Wool waste in Europe: a review of Mineral Wool waste quantity, quality, and current recycling methods
    Journal of Material Cycles and Waste Management, 2014
    Co-Authors: Olli Väntsi, Timo Karki
    Abstract:

    The construction and demolition (C&D) industry has been identified as a major source of waste. European Union legislation states that, by 2020, 70 % of C&D waste must be prepared for reuse, recycled or recovered. European Union member states must increase their C&D waste recycling percentages in order to meet this binding target. Utilization of Mineral Wool waste, often considered unrecyclable, could improve the recycling percentage of C&D waste. In this article, Mineral Wool production and waste volumes are estimated based on information from the Eurostat database. A literature survey is conducted to collect information about Mineral Wool material properties, current recycling methods, and barriers to recycling of Mineral Wool, and suitable methods for separating Mineral Wool from C&D waste streams and the economic viability of Mineral Wool recycling are discussed. It is noted that accurate estimation of Mineral Wool waste volumes is problematic due to the fragmented nature of available data. Based on the literature review, current methods for recycling Mineral Wool waste include utilization of Mineral Wool waste as a raw material in various products. Barriers to recycling include economic questions and issues related to the purity and health effects of Mineral Wool waste. Material properties of Mineral Wool waste, such as fire resistance, could provide improved properties in products utilizing Mineral Wool waste as a raw material.

Saulius Vaitkus - One of the best experts on this subject based on the ideXlab platform.

  • analysis of structure and deformation mechanisms of Mineral Wool slabs under compression
    Materials Science, 2012
    Co-Authors: Laimutis Steponaitis, Sigitas Vėjelis, Saulius Vaitkus
    Abstract:

    The products of Mineral Wool are widely used for thermal insulation of buildings, both at construction of new buildings and at renovation of old ones. The mechanical resistance and stability of them, as well as their energy saving and heat saving requirements are in most cases related to the essential specifications of the building. The mechanical characteristics of these products are subject to structure of material, density, content of binder in the product and to technology of production. Subject to the latter, Mineral Wool products with different fibrous structure are received, therefore, for the structure of each type, the individual structural models are developed attempting to describe the properties of fibrous systems. The deformability of Mineral Wool products is conditioned by mobility of fibrous structure, which shows up best under compression by short term loads. This study established the impact of various thicknesses and deformations on changes in structure of rock Wool products. It also established that the thickness of Mineral Wool products conditions and influences considerable changes in their structure. DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1926

  • Long-term prediction of creep strains of Mineral Wool slabs under constant compressive stress
    Mechanics of Time-Dependent Materials, 2012
    Co-Authors: Ivan Gnip, Saulius Vaitkus, Vladislovas Keršulis, Sigitas Vėjelis
    Abstract:

    The results obtained in determining the creep strain of Mineral Wool slabs under compressive stress, used for insulating flat roofs and facades, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. The creep strain tests were conducted under a compressive stress of σ _ c =0.35 σ _10%. Interval forecasting of creep strain was made by extrapolating the creep behaviour and approximated in accordance with EN 1606 by a power equation and reduced to a linear form using logarithms. This was performed for a lead time of 10 years. The extension of the range of the confidence interval due to discount of the prediction data, i.e. a decrease in their informativity was allowed for by an additional coefficient. Analysis of the experimental data obtained from the tests having 65 and 122 days duration showed that the prediction of creep strains for 10 years can be made based on data obtained in experiments with durations shorter than the 122 days as specified by EN 13162. Interval prediction of creep strains (with a confidence probability of 90%) was based on using the mean square deviation of the actual direct observations of creep strains in logarithmic form to have the linear trend in a retrospective area.

  • strength and deformability of Mineral Wool slabs under short term compressive tensile and shear loads
    Construction and Building Materials, 2010
    Co-Authors: Iva Gnip, Sigitas Vėjelis, V Kersulis, Saulius Vaitkus
    Abstract:

    Abstract The results obtained in the experimental study of Mineral Wool slabs under short-term compressive, tensile and shear loads, used for insulating flat roofs, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. To describe the experimental data of strength and deformability of Mineral Wool slabs, the regression equations of the linear form, provided with one-sided confidence intervals for predicting the resultant characteristic with probability Р  = 0.90, are used. The interrelationship between strength and deformability characteristics of Mineral Wool slabs under tension and shear, and their strength and deformability under short-term compression are determined. Based on the experimental data, differences in deformability and strength characteristics of Mineral Wool slabs under shear load in mutually perpendicular planes (in the direction of slab forming and perpendicular to it) are demonstrated.

  • predicting the deformability of Mineral Wool slabs under constant compressive stress
    Construction and Building Materials, 2009
    Co-Authors: Iva Gnip, Saulius Vaitkus, V Kersulis, Sigitas Vėjelis
    Abstract:

    Abstract The results of investigating the creep strain Mineral Wool slabs used for thermal insulation of flat roofs, cast-in-place floors and external walls of basements subjected to long-term compressive stress σ c = 0.35 σ 10 % are presented. Slabs under short-term compressive stress are tested and regressive equations for calculating the stress σ 10 % , ultimate stress σcr, which slabs can endure without changing their structure, and the respective relative ultimate strain ecr, as well as the initial modulus of elasticity E, are offered. For the approximation of the creep curves an exponential equation is used according to EN 1606. It has been shown that the prediction of the creep strains for the lead time of 10 years may be made based on the data obtained in the direct experiment with the duration shorter than 122 days as specified in EN13162. A possibility of estimating the expected creep strains of Mineral Wool slabs for the lead time of 10 years, based on the stress σ c = 0.35 σ 10 % and relative ultimate strain ecr of slabs under short-term compressive stress, has been considered.

Sigitas Vėjelis - One of the best experts on this subject based on the ideXlab platform.

  • analysis of structure and deformation mechanisms of Mineral Wool slabs under compression
    Materials Science, 2012
    Co-Authors: Laimutis Steponaitis, Sigitas Vėjelis, Saulius Vaitkus
    Abstract:

    The products of Mineral Wool are widely used for thermal insulation of buildings, both at construction of new buildings and at renovation of old ones. The mechanical resistance and stability of them, as well as their energy saving and heat saving requirements are in most cases related to the essential specifications of the building. The mechanical characteristics of these products are subject to structure of material, density, content of binder in the product and to technology of production. Subject to the latter, Mineral Wool products with different fibrous structure are received, therefore, for the structure of each type, the individual structural models are developed attempting to describe the properties of fibrous systems. The deformability of Mineral Wool products is conditioned by mobility of fibrous structure, which shows up best under compression by short term loads. This study established the impact of various thicknesses and deformations on changes in structure of rock Wool products. It also established that the thickness of Mineral Wool products conditions and influences considerable changes in their structure. DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1926

  • strength and deformability of Mineral Wool slabs under short term compressive tensile and shear loads
    Construction and Building Materials, 2010
    Co-Authors: Iva Gnip, Sigitas Vėjelis, V Kersulis, Saulius Vaitkus
    Abstract:

    Abstract The results obtained in the experimental study of Mineral Wool slabs under short-term compressive, tensile and shear loads, used for insulating flat roofs, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. To describe the experimental data of strength and deformability of Mineral Wool slabs, the regression equations of the linear form, provided with one-sided confidence intervals for predicting the resultant characteristic with probability Р  = 0.90, are used. The interrelationship between strength and deformability characteristics of Mineral Wool slabs under tension and shear, and their strength and deformability under short-term compression are determined. Based on the experimental data, differences in deformability and strength characteristics of Mineral Wool slabs under shear load in mutually perpendicular planes (in the direction of slab forming and perpendicular to it) are demonstrated.

  • predicting the deformability of Mineral Wool slabs under constant compressive stress
    Construction and Building Materials, 2009
    Co-Authors: Iva Gnip, Saulius Vaitkus, V Kersulis, Sigitas Vėjelis
    Abstract:

    Abstract The results of investigating the creep strain Mineral Wool slabs used for thermal insulation of flat roofs, cast-in-place floors and external walls of basements subjected to long-term compressive stress σ c = 0.35 σ 10 % are presented. Slabs under short-term compressive stress are tested and regressive equations for calculating the stress σ 10 % , ultimate stress σcr, which slabs can endure without changing their structure, and the respective relative ultimate strain ecr, as well as the initial modulus of elasticity E, are offered. For the approximation of the creep curves an exponential equation is used according to EN 1606. It has been shown that the prediction of the creep strains for the lead time of 10 years may be made based on the data obtained in the direct experiment with the duration shorter than 122 days as specified in EN13162. A possibility of estimating the expected creep strains of Mineral Wool slabs for the lead time of 10 years, based on the stress σ c = 0.35 σ 10 % and relative ultimate strain ecr of slabs under short-term compressive stress, has been considered.

Olli Väntsi - One of the best experts on this subject based on the ideXlab platform.

  • Environmental assessment of recycled Mineral Wool and polypropylene utilized in wood polymer composites
    Resources Conservation and Recycling, 2015
    Co-Authors: Olli Väntsi, Timo Karki
    Abstract:

    Abstract Environmental performance is an important promotive factor in the future use of wood polymer composites. In this study, the environmental effects of replacing virgin glass fibers with recycled Mineral Wool fibers, as well as replacing virgin polypropylene with recycled polypropylene are investigated. Furthermore, the environmental performance of two different end-of-life options for composite waste, incineration for energy use and landfill deposition is evaluated. The recycled Mineral Wool was found to have better environmental performance compared to glass fiber in every impact category assessed. The utilization of recycled polypropylene proved to be advantageous in global warming potential and abiotic depletion categories. It was found that the end-of-life management of composite waste has an important role in the environmental performance of composites. Incineration of composite waste for energy use had better performance compared to landfill deposition in all the categories assessed, except for global warming potential. It is concluded that while the environmentally optimal recycling method for polypropylene waste must be evaluated case by case, recycled Mineral Wool seems to provide an environmentally superior option to glass fiber in wood polymer composite applications where properties obtainable by the use of a Mineral filler are required.

  • utilization of recycled Mineral Wool as filler in wood polypropylene composites
    Construction and Building Materials, 2014
    Co-Authors: Olli Väntsi, Timo Karki
    Abstract:

    Abstract The construction and demolition (C&D) industry is a major source of waste. Environmental regulations and laws have been implemented in many countries to improve and encourage the recycling of C&D waste. To meet tightened regulations, new C&D waste recycling methods must be developed. Mineral Wool is a waste fraction that is currently considered un-recyclable. In this study, the mechanical and moisture resistance properties of wood plastic composites utilizing recycled Mineral Wool as filler are presented. According to the findings, the addition of recycled Mineral Wool improved the moisture resistance properties of the composites noticeably, but a decrease in some mechanical properties was observed.

  • Mineral Wool waste in Europe: a review of Mineral Wool waste quantity, quality, and current recycling methods
    Journal of Material Cycles and Waste Management, 2014
    Co-Authors: Olli Väntsi, Timo Karki
    Abstract:

    The construction and demolition (C&D) industry has been identified as a major source of waste. European Union legislation states that, by 2020, 70 % of C&D waste must be prepared for reuse, recycled or recovered. European Union member states must increase their C&D waste recycling percentages in order to meet this binding target. Utilization of Mineral Wool waste, often considered unrecyclable, could improve the recycling percentage of C&D waste. In this article, Mineral Wool production and waste volumes are estimated based on information from the Eurostat database. A literature survey is conducted to collect information about Mineral Wool material properties, current recycling methods, and barriers to recycling of Mineral Wool, and suitable methods for separating Mineral Wool from C&D waste streams and the economic viability of Mineral Wool recycling are discussed. It is noted that accurate estimation of Mineral Wool waste volumes is problematic due to the fragmented nature of available data. Based on the literature review, current methods for recycling Mineral Wool waste include utilization of Mineral Wool waste as a raw material in various products. Barriers to recycling include economic questions and issues related to the purity and health effects of Mineral Wool waste. Material properties of Mineral Wool waste, such as fire resistance, could provide improved properties in products utilizing Mineral Wool waste as a raw material.