• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.342-348
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• 2001

This study was conducted to obtain granular crystalline gypsum that can be used as raw material for plaster boards or cements from waste Plaster board. We could disintegrate preferentially gypsum to gypsum needle in 10${\mu}{\textrm}{m}$ or less size among the contents of waste plaster board (gypsum, paper, fiber, and inorganic material .etc.) by hydration afterwards the dehydration of crushed waste plaster board. In this case, the optimum conditions for minimizing the size of gypsum were dehydration rate of 75%~ 85%, hydration concentration of 10~20%, agitation speed of 250~400rpm, crushing size of 2cm or less. Gypsum of 98.21% grade was recovered with 99.0% yield from under screenings of 325mesh wet screening which followed by the dehydration-hydration process performed in the conditions of dehydration rate of 80%, hydration concentration of 15%, agitation speed of 300rpm, crushing size of 2cm or less. Subsequently, Plate-like Crystalline gypsum of is 151${\mu}{\textrm}{m}$ size and the grade of 99.49% with the Yield of 98.0% from the upper screenings of 270mesh wet screening carried out after the re-crystallization of the recovered gypsum needle slurry.

• Resources Recycling
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• v.10 no.6
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• pp.43-52
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• 2001

This study was conducted to obtain granular crystalline gypsum that can be used as raw material for Plaster boards or cements from waste Plaster board. Gypsum could be Preferentially disintegrated to gypsum needle in $10\mu\textrm{m}$ or less size by hydration after the dehydration of crushed waste Plaster board. The finer the gypsum needle, it is easier to remove coarse impurities and to recover the gypsum needle. The optimum conditions for obtain the finer gypsum size were dehydration rate of 75~85%, solid concentration at hydration of 10~15%, agitation speed of 250~400 rpm, crushing size before dehydration of 2 cm or less. Gypsum of 98.21% grade was recovered with 99.0% yield as the undersize of 325 mesh wet screening followed by the dehydration-hydration process performed at the conditions of dehydration rate of 80%, solid concentration at hydration of 15%, agitation speed of 300 rpm, crushing size before dehydration of 2 cm or less. After the recrystallization of recovered gypsum, Plate-like gypsum of $151\mu\textrm{m}$ size with 99.49% grade was obtained as the oversize of 270 mesh in a wet screening.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.67-71
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• 2008

The study analyzed on fire resistance of high strength concrete followed by thickness of fireproof plaster board and change of adhesive method. In spalling characteristics after fire resistance test, all four-side covering concretes were left out of testing screens. Thus, serious spalling was happened by exposing their internal reinforcing rods. in partial testing screens, spalling was happened till the internal concrete of main reinforcing rod. Only, temperature history didn't have special differences among changes of adhesive method. However, thickness of fireproof plaster board is very important. Namely, mock member reinforcing 25mm general adhesive + Bending was 583℃ in the highest temperature of surface part and 479℃ in the highest temperature of the main reinforcing rod, which was relatively good temperature history.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.40-47
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• 2015

In this study, temperature characteristics and fire damage form were analyzed to investigate flame spreading form and fire probability from ignition sources subject to drivit component materials which is finishing material in architecture. Ignition sources were limited to a gas torch and exterior panel board fire, and the size of the sample was manufacture in 30 cm length ${\times}$ 50 cm height ${\times}$ 5cm thickness size. Marble (inner wall) + 3 mm drivit (outer wall), marble (inner wall) + 4 mm plaster stone (outer wall), sandwich panel + 3 mm driver bit (outer wall), sandwich panel + 3 mm driver bit + insulation (outer wall), and gypsum board (inner wall) + 3 mm drivit (outer wall) were prepared for the sample. As result of the research for temperature characteristics, large temperature difference by each material was shown in $218^{\circ}C{\sim}995^{\circ}C$ at 30 seconds and $501^{\circ}C{\sim}1078^{\circ}C$ at 300 seconds. Especially when the inner wall was a plaster board, lowest temperature of $501^{\circ}C$ was shown at 300 seconds and marble inner wall showed the following lowest temperature of $900^{\circ}C$. Temperature rising over $1000^{\circ}C$ was shown in other materials. Regarding fire damage form, drivit or gypsum board outer wall parts exposed to fire showed combustion and carbonization to show calcination(breaking phenomenon) and influence of heat exposure was higher as calcination became more severe.

• Journal of Korean Society of Steel Construction
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• v.14 no.2
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• pp.357-364
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• 2002

The study performed a series of flexural tests on Closed Cold-Formed Steel Sections for stud, joist, and roof truss. Results were compared with analytical values. Each 2.4-m long and 0.9-m wide specimen consisted of two steel beams set at 0.46 m interval. The steel beams were attached to the specimens using either plaster board or ply wood. Another specimens did not use any attachment material. Positive and negative bending tests were conducted to investigate the composite behavior, including the effects of plaster board or ply wood on the buckling behavior of steel beam. Full-scale roof truss tests were also performed to study the buckling behavior and failure mode of the truss members.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.6
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• pp.692-702
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• 2011

For more effective indoor radon reduction policy and technique, we researched radon data analysis for some buildings in Seoul. Those buildings were categorized as dwelling, underground and office space and the variations of radon concentration and its sources were evaluated. The variations of radon concentrations of indoor space of buildings for a day were patterned specifically by dwelling habits and different environment. As for the new built apartments which were not yet moved in, their indoor radon concentrations were showed more than 3 times after applying interior assembly, and were 5 times higher than ones of rather old residences. As for the subway stations, the radon concentrations during off-run times were about 15% higher than run-times. 10% of radon seemed to be reduced by installation of platform screen doors. As for office space, radon concentrations during working hours were about 2.5 times higher than non-working hours. Plaster board are expected as a main source of radon for them. By radon measurement method for long-term, its data can be over estimated because it covers non-active time in office or public space. Therefore combination of short and long-term measurement method is required for effective and economic reduction. Furthermore importance of ventilation is requested as public information service for all dwelling space. And also standardization for radium content or radiation of radon is necessary.

• Journal of the Korean Institute of Rural Architecture
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• v.23 no.4
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• pp.63-71
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• 2021

The purpose of this study was to investigate whether the standard models for rural housing and wooden housing model have performance for hygrothermal and to propose a way of improvement relevant to hygrothermal performance for those models. All of the models to be analyzed were found to have some parts that were absent of stability in terms of performance for hygrothermal. In the process of analyzing the causes and proposing improvement measures, the following conclusions were derived. Fist, The exterior surface of the structure should be composed of a structure with good moisture permeability, and for the interior surface, a variable vapor retarder paper should be applied in consideration of the reverse condensation phenomenon in summer. Second, in terms of performance for hygrothermal, applications of external insulation plaster finish to the exterior wall or of ventilation method using a rafter vent on the roof should be avoided. Third, a rain screen method with a ventilation layer should be applied to the exterior wall, and a method of constructing ventilation layer separated from the insulation layer with a vapor retarder paper should be applied to the roof. Fourth, the application of insulation materials having capillary action, such as wood fiber insulation board or cellulose insulation board, contributes to more stable performance for hygrothermal.

• KIEAE Journal
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• v.7 no.1
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• pp.33-40
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• 2007

0.4 Million tons of shell powder have been disused as waste in KOREA and caused severe environmental pollution though shell powder can be utilized in real life for many ways. It is impending problem to recycle shell powder as it requires high expense for burying and temporary outside heap and causes severe environmental pollution being a main factor of ocean waste. To suggest the basic data for development of eco-friendly and high-function Wall Coatings Thin Textured Finishes, a wall coating sample was applied to indoor walls of a mock-up and temperature and humidity were measured to assess the thermal performance of it, and a survey of preference for the color sense and feel of the materials with a movie of specimens. The results of the study are following; 1) High insulation performance is shown from the assessment result of the room polystyrene board adhered on the walls then high humidity controlling performance is shown from that of the room polystyrene board coated by shell powder. This point out that shell powder has superiority for humidity controlling. 2) The result of thermal and humidity assessment shows that shell powder makes up for thermal conduction of the polystyrene board and same result can be expected from the assessment with materials which has similar thermal characteristics with polystyrene.3) Ranking of preferred specimens is; 1st Case 13, 2nd Case 17, 3rd Case 16, and 4th Case 12. Preferred shell powder was the ark shell. Preferred powder for plaster was the powder mixed with that sifted by 0.8mm, 100mesh and 40mesh, and for spray was the fine powder mixed with that sifted by 100mesh and 40mesh.

• Journal of Korean Society of Steel Construction
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• v.15 no.2
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• pp.109-116
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• 2003

An investigation on the structural behavior of cold-formed steel lipped C-section stud for interior walls or partitions was carried out. This experimental research was carried out to study the ultimate and service load capacity of stud assemblies that are subjected to lateral loads. Each test specimen consisted of three or four lipped C-section studs and two C-section tracks that restrained both ends. The major factors considered in this experiment were the perforation on the web, the connection of the bridge channel and the special clip. The effect of the plaster board and the ply wood, which were attached to the tension flange on the flexural strength, was also investigated. Thereafter, the test strength capacities were compared with the nominal strength, based on the AISI Specifications (1996).

• Journal of the Korean Home Economics Association
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• v.38 no.11
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• pp.137-149
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• 2000

The Purpose of this study was to investigate actual condition about the modem adaptation of interior elements(floor, wall, ceiling, door & window) in traditional thatched roof house. The examined objects were interior space of 36 restaurants and cafes in Seoul and Kyung-Ki Do area. 1. Floor: Jang-pan was mostly alternated with linoleum which huts Jang-pan pattem. Wumul-maru was adapted from the original and Jang-maru was alternated with wood or linolium which has western state Jang-maru pattern. Mud was adapted from the original or alternated with slate stone or rough finish cement. 2. Wall: Rice proper was alternated with rice paper book witch has chinese character, paper for parcels or modem wall paper. Plaster-white paint or white handy coat. Mud-mud color paint or bamboo stick witch located in the mud wall orginal. Log-half cut log. Wooden board-without cross bar or irregular form. 3. Ceiling: Yondung-Chongang was mostly adapted from the original and Banja-Chonjang was alternated with rice paper book which has Chinese character or modem wall paper. 4. Door and Window: Ttisal-mun and Panjang-mun were adapted from the original. Wan and A’character door and window were simplified character itself.