• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.117-123
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• 2016

Glass wool is a material that has been used as a heat insulator in various fields including construction industry. Since it is a nonflammable material, it does not generate toxic gases on fire, and thus public agencies recommend using glass wool as a heat insulator instead of other organic materials. However, repeated drying and wetting cycles can deteriorate thermal property of glass wool due to the shrinkage and reduction in pore size. For this reason, it needs to be replaced periodically, and waste materials are generated. This research aims to utilize waste glass wool as additives for increasing mechanical properties of concrete. According to the experimental results, it was found that glass wool has weak pozzolanic activity, and beneficial effect on both compressive and flexural strength. The optimum amount found in this experimental work was 0.5% volumetric addition to the concrete.

• Elastomers and Composites
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• v.46 no.1
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• pp.29-36
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• 2011

The term 'thermal insulating materials' describes a class of materials which can improve the thermal efficiency by reducing the thermal conduction, convention and radiation between the inside and outside of the system. As a thermal insulating material, numerous industrial applications are possible including the automobile, aerospace, aviation, and petrochemical. Especially, the silica aerogel, with their superior thermal insulating behavior, has been widely used as thermal insulating materials. Because the mechanical properties of the silica aerogel cannot meet the industrial demand, use of the silica aerogel is limited. This article aims to review the thermal insulating materials and silica aerogel, and to introduce the silica aerogel/polymer composites.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.531-541
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• 2009

The research analyzes and investigates conventional concrete, hydration heat, set, and mechanical properties by making high flowing self-compacting concretes of binary blend and ternary blend as one of evaluations about the properties of the hydration heat of high flowing self-compacting concrete with a strength of 30, 50, and 70 MPa. In addition, it estimates concrete adiabatic temperatures by calculating a thermal property value of powder obtained by measuring a heat evolution amount for powder used in concrete, a thermal property value of concrete obtained by conducting a simple adiabatic temperature test, and a normal thermal property value of material used in concrete, using a simple equation. Moreover, it analyzes and investigates the hydration heat property of high flowing self-compacting concrete and the thermal stress caused by hydration heat by conducting a 3D temperature stress analysis for the hydration heat and the adiabatic temperature obtained by temperature analysis, using MIDAS CIVIL 06 program.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.488-496
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• 2003

To establish nondestructive test method for rocket motor assembly with rubber and aerospace composite materials, practicable quality control acoustic emission test method is presented. Structural analysis for motor assembly is performed by ABAQUS code and analysis output result is confirmed by strain gage and AE data. Various specimens were tested and analyzed using strain gage and acoustic emission data. The hit rate of acoustic emission was closely related with case/rubber debonding. This report also describes practicable acoustic emission nondestructive method for evaluating motor case assembly quality assurance in the industrial field.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.6
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• pp.18-25
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• 2007

In a plastic metal forming of thermally rate-sensitive material, the localized shear band stems from evolution of a narrow region in which intensive plastic flow occurs. And it give rise to fatal fracture with plastic instability. The objectives of this study are to investigate the localization behavior by using numerical method and predict the failure for WHA(Tungsten Heavy Alloy). In this work, the implicit finite difference scheme is used because of the advantage about convergence and the numerical stability. This study is based on an analysed material with hardening as well as thermally softening behavior which includes isotropic strain hardening and observed the extension of localization within shear band according to material properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.85-88
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• 2012

Lately, the scale of the primary energy consumption in Korea is ranked 10th in the world, and it takes up about 1.9% of the entire energy consumption in the world. And among total energy consumption in Korea, the ratio of the part corresponding to the residence or commercial buildings is about 30.5%. Also, with the increased interest in eco-friendly buildings, the production of eco-friendly building materials consisting of them also increases as well. However, since the process of their production generates much energy consumption, so this is being raised as a social problem. Therefore, this study suggests a method to improve thermal performance by using eco-friendly earth plastering materials and natural materials in order to reduce energy consumption in buildings. The experiment evaluated thermal performance by measuring the external and internal temperature of the curing after the plastering of 1cm in the wooden box of 30cm * 30cm * 30cm. As a result, there was difference in the order of powdered coal, pealite, chaff, and rice straw. Among them, powdered coal indicated excellent thermal performance. This will be the foundational research used to improve interior environment and reduce heating bills.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.2
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• pp.103-114
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• 2012

Nowadays membrane material is widely used for large indoor spaces and long spaces such as traditional market. Thermal insulation and sound field control performance is considered as a main properties for design of such buildings. In this paper sound absorption and thermal insulation properties of membrane material was investigated. Firstly, normal incidence sound absorption coefficient of 10 kinds of glass wool textiles showed that sound absorption coefficient was increased in proportion of thickness and surface density of textile. Sound absorption coefficient of 4 kinds of sound absorptive inner membrane with outer membrane was tested in the reverberation chamber. Sound absorption coefficient of mid frequency range was about 0.4 ~ 0.6. Also, sound absorption coefficient was changed by the air space behind the membrane material. Secondly, sound field control performance was investigated using mock-up space. By the installation of sound absorption membrane material, reverberation time was decreased and speech intelligibility was increased. Finally, thermal resistance and room temperature in two kinds of mock-up rooms were tested, simultaneously. Results of thermal properties showed thermal insulation properties ware increased by adding inner membrane material underneath the outer membrane.

• Journal of Navigation and Port Research
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• v.40 no.1
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• pp.7-14
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• 2016

Although the life jacket can provide the buoyance with the drowner, heat loss can make the drowned individual be subject to the hypothermia. In this study, The thermal insulation of two types life jacket including inflatable and foam type were evaluate by both experiments and numerical analysis. To estimate the thermal resistance of the jackets, experiments on the heat flux were conducted by the thermal manikin exposed to cold water. Heat flux loss on the surface of thermal manikin were measured for both foam and inflatable type life jacket. Also, finite element method is applied to a body section in order to understand the level of hypothermia of each life jacket. The segmental of human thigh is represented by a multi-layered section which considers the heat conduction within tissue, bone and fat. As a result, the thermal resistance and hypothermia time of each jackets have been compared based on the finite element analysis. It was found that the insulation ability of suggested life jackets is better than that of conventional type.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.3
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• pp.132-139
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• 2019

EPS (expanded polystyrene) is one of the most used building materials for insulation that is favored by its excellent heat insulation, economical efficiency and lightweight characteristics. However, EPS is vulnerable to the fire and producing large amount of toxic gases in case of fire. Therefore, ultra-lightweight geopolymer which can replace EPS is fabricated by using IGCC (integrated gasification combined cycle) fused slag and Si sludge as raw materials and the possibility of replacement on ultra-lightweight geopolymer for EPS as an insulation building material was evaluated in this study. Ultra-lightweight geopolymer can be fabricated with the pulverized IGCC fused slag having low carbon content and density, compressive strength, thermal conductivity were $0.064g/cm^3$, 0.04 MPa, and 0.072 W/mK, respectively. The thermal conductivity of ultra-lightweight geopolymer is 1.5~2.0 times higher than that of EPS suggested in the KS M 3808; however, the thermal conductivity value of geopolymer is meaningful and competitive to that of EPS in the market. Therefore, ultralightweight geopolymer can be applicable to the building material for thermal insulation purpose and have an enough possibility to replace EPS in the future because it is not only much safer than EPS in case of fire but also it can be fabricate by using waste materials from the industry.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.474-480
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• 2017

In this study, the evolution of electrical impedance of electric nodes was investigated to determine the setting time of cement paste using the electrical impedance spectroscopy method. The electric nodes were embedded in fresh cement paste and the electrical impedance signatures were continuously monitored. Vicat needle test and semi-adiabatic calorimetry test were also conducted to validate the electrical impedance spectroscopy method. During hydration period of cement paste, the magnitude of conductance gradually increased, and then started to decrease rapidly at a first certain time. After that, the magnitude of conductance gradually decreased at a second certain time. The times of turning point in the curves of magnitude of conductance seem to be related with the setting time by Vicat needle test. Also, the setting times by the electrical impedance spectroscopy method are well posed within the setting period estimated by the semi-adiabatic calorimetry test. Based on the results, it can be concluded that the setting time of cement paste can be effectively monitored through the electrical impedance spectroscopy method.