• KIEAE Journal
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• v.7 no.3
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• pp.57-62
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• 2007

Most of current building materials are made of organic compounds or at least made with chemical treatments. Though easy to use and comparatively pay less, those materials are generally not enviornmentally sound. VOC is one of harmful effects. On contrary, natural materials such as soil are usually eco-friendly, and environmentally sustainable as well if not treated in autoclaves. Acoustica materials made of such environmentally sound and sustainable could be widely used. It is aimed to prove that soil based materials could be effectively used in acoustical fields rather than the other usual materials. Experiments with various types of soil blocks and soil plaster were performed. It is proved that the soil plaster has better apsorption features than cement plaster. Soil blocks have higher absorption cofficients than soil plaster, due to the thickness, and the absorption characteristics can be controlled by the design of the blocks.

• Journal of architectural history
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• v.19 no.3
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• pp.89-106
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• 2010

Since the 1970's, UNESCO and ICOMOS have adopted or emphasized on the principles of historic preservation. One of them is what to require a repair should not be repaired beyond the limits of the features and techniques which had been adopted in those days of establishment. On the premise, this paper is to examine the materials and technique of wall plaster work in the government building constructions in the Joseon dynasty. The result of this examination shall come up with a basic conformity in the case of repairing the building established in the late of Joseon dynasty. This paper is carried out for the proper repair and restoration of architectural cultural properties. Construction reports and other documents in those days are examined for the study. Following conclusions have been reached through the study. The materials and technique which applied to wall plaster work in those days were quite different from the present. The technique that was used to wall plaster of government buildings in those days was not a lime wall plaster, but sand coat one. The kinds of material for setting of the sand coat wall plaster had been revised with the change of the times or constructions. The main kinds of material were composed of sand, white clay, paper fiber, and cereal starch. However, the present materials were composed of sand, white clay. Therefore, the present materials and technique which applied to wall plaster work for the repair and restoration of architectural cultural properties have to be revised and corrected.

• Journal of architectural history
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• v.18 no.4
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• pp.63-79
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• 2009

Since the 1970's, UNESCO and ICOMOS have adopted or emphasized on the principles of historic preservation. One of them is what to require a repair have not to be repaired beyond the limits of the features and techniques to have been born in those days of establishment. On the premise, this paper is to examine the materials and technique of lime plaster work in order for roof ridge, and for bond paste of stones and bricks in government constructions in the late of Joseon dynasty(17~19c). The result of this examination will come up with a basic conformity in the case of repairing the building established in the late of Joseon dynasty. This paper is carried out for the proper repair and restoration of architectural cultural properties. Construction reports and other documents in those days are examined for the study. Following conclusions have been reached through the study. The components of old plaster mixtures which agglutinate stones each other were quicklime, perilla oil, and paper fiber. The components of old plaster mixtures which point joint of black bricks consisted of slaked lime, perilla oil, paper fiber, and cereal starch. These components were the same as coat surface of roof ridges. In the case of times, one of the following sand, white clay, sap of boiled elm bark was added to these components for the purpose of high efficiency. These materials and techniques which applied to plaster work of those buildings had developed in the process of making royal tombs. But these materials and techniques were quite different from the present.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.493-505
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• 1999

Purpose: This study was to evaluate the effects of Aloe. Gelfoam. and Plaster of Paris on bone healing. Materials and Methods: Four experimental defects were created for placement of the three materials in the right femur of dogs. One defect served as an empty control site. The evaluation was performed at 1-. 6-. and 12-weeks by light microscopy and radiographs. Results: Radiographic and histologic examinations showed new bone formation in the presence of Aloe, Gelfoam. and Plaster of Paris and similar bone healing reactions. Conclusion: On the basis of these findings, it was concluded that Aloe, Gelfoam. and Plaster of Paris may be adequate agents for use in bone procurement.

• Journal of the Korea Institute of Building Construction
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• v.12 no.2
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• pp.152-160
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• 2012

The development of building must be accompanied with construction technology and performance of materials. In particular, wet processes have a high level of dependence on manpower and a low level of diversification of materials used. This study aimed to determine the applicability of various materials for wet process, mechanized construction and eco-friendly building materials through a comparison with dry premixed mortar. As a result, it was found that resin plaster and gypsum plaster's strength is lower than that of dry cement mortar, but their mechanization application, construction simplification, smoothness and bond strength are higher than that of dry cement mortar. And estimate that is valid as workability, bonding strength, eco-friendly building material in occasion of gypsum plaster.

• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.4
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• pp.53-60
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• 1985

The plaster mixed to loam and sandy soil from 4 to 12 percent by dry soil weight, and the compaction, permeability, CBR, unconfined compressive strength and freezingthawing test were performed The results obtained are summarized as follows; 1.The coefficient of permeability reduced sharply at the plaster content of 4 percent, and in the CBR test, the swelling ratio reduced by the increment of plaster content. 2.The addition of plaster increased the unconfined compressive strength by the cementing effect, and it was found that the optimum plaster content, existed with the soil type, which showed the maximum strength 3.It was possible to enhance the unconfined compressive strength of the gypsum-lime-soil mixtures when the optimum content of plaster was mixed to the hydrated lime. 4.In case of sandy soil, the relative frost heave decreased with the mixture of plaster, however in loam soil, the relative frost heave began to increase at the plaster content of 12 percent than non-treated soil. Therefore the optimum plaster content existed for protecting frost heave by the different soil type. 5.The above summarized results make it possible to expect the effects such as improvement of soil properties, decrement of permeability, increment of unconfined compressive strength, and protection of frost heave, etc, therefore, it is considered that it is possible to it is plaster as sub-base materials of road.

• Korean Journal of Materials Research
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• v.25 no.11
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• pp.590-597
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• 2015

In this article, poly methyl triethoxy silane was compounded with an inorganic waterproof admixture at a certain ratio to improve the performance of gypsum products; a new type of high-efficiency compound water-proofing additive was also investigated. Furthermore, the waterproof mechanism and the various properties on the hardened gypsum plaster were investigated in detail by XRD and SEM. The results show that the intenerate coefficient of gypsum plaster increased to more than 0.9; the water absorbing rate decreased to less than 10 %. Both the bending strength and the compressive strength of gypsum plaster increased by various degrees. The intenerate coefficient reached a maximum value of 0.73 and the strength of the samples showed almost no change when 5% cement alone was added. In this new type of the high-efficiency compound with waterproof additive, the optimal technological parameters for formulas were obtained to be: 5% cement, 18 % mineral powder, and 0.8% poly methyl triethoxy silane, to compound gypsum plaster. Meanwhile, the production of high performance gypsum as a building material has become possible.

• Journal of the Korean Ceramic Society
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• v.52 no.1
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• pp.28-32
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• 2015

In this article, the influence of a hydrolyzed wheat protein retarder on the hydration process, ion concentration in liquid phase, degree of supersaturation, and crystal morphology of plaster was investigated. Furthermore, the retarding mechanism and the strength loss of gypsum were also studied by scanning electron microscopy (SEM). The results indicate that the use of the hydrolyzed wheat protein retarder for plaster achieved a better retarding effect and lower strength loss. The combination of gypsum plaster with the retarder not only decreased the plaster's early hydration rate and prolonged its setting time efficiently, but also militated against the crystal morphology of dihydrate gypsum. For example, the crystal dimensions changed little, but the proportion of needle-shaped crystals decreased. Combination with calcium ions on the surface of dihydrate gypsum crystal nuclei may form a chemisorbed layer, reduce the surface energy of the crystal nuclei, and inhibit the growth of the crystal nuclei of dihydrate gypsum. Consequently, the hydration process of building gypsum becomes greatly extended and is slowed down significantly.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.1
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• pp.26-32
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• 1996

This study was performed to determine the ideal mixing ratio of toothash and plaster of Paris. The histopathologic and histomorphometric study of bone response of five implant materials, toothash(Group A), tooth and plaster mixture, mixing ratio due to weight 2 : 1(Group B), 3 : 1(Group C), 4 : 1(Group D), and plaster Paris(Group E), were performed in rat calvarial defect. No sign of extensive inflammatory reaction was defected. Newly-formed bony ingrowth occurred in all experimental groups except for group E at 12 weeks after operation. Bone was deposited directly on the surface of implant materials. The highest rate of direct bony union between implant material and newly-formed bone occurred with the group B, followed group C, D, and A.

• Journal of Korea Foundry Society
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• v.4 no.4
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• pp.5-13
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• 1984

This paper is presented for showing the effect of cooling rate on dendrite arm spacing, correlated with the chilling power of molding materials (conventional plaster, foamed plaster, silica sand) and section thickness, and also showing relationship between dendrite arm spacing and mechanical properties for an aluminum - 8.6 percent silicon - 3.6 percent copper alloy. Local solidification time $(t_f)$ and secondary dendrite arm spacing (d) could be varied widely in accordance with the molding materials and casting thickness, and the following relationship is obtained: $d=9.4t_f\;^{0.31}$ A good correlation between dendrite arm spacing and mechanical properties such as ultimate tensile strength, yield strength, hardness was found, that is, mechanical properties decreased in a linear manner with increase in log of secondary dendrite arm spacing. Ultimate tensile strength in conventional plaster mold casting decreased by 15 percent comparing with the sand casting, where as in foamed plaster mold casting, it decreased by 30 percent comparing with the sand casting. From those results, it has been verified that DAS might be the most representative parameter for predicting mechanical properties varing with the different cooling condition.