• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.18-25
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• 2019

The cracks occurred during service life of concrete structure should be considered in durability design, because of the concrete's material property which is weak in tensile strength. In this study, the fly ash concrete mixtures considering 2 levels of strength is designed and outdoor exposure tests are conducted for those concrete specimens. The exposure environment is set to a splash zone, and in order to evaluate the effect of crack width on the behavior of chloride diffusion, the crack width of up to 1.0 mm is generated at intervals of 0.1 mm at each concrete mixture. After that, apparent chloride diffusion coefficient and surface chloride contents are deducted considering 3 levels of exposure periods(180 days, 365 days, 730 days). The diffusion coefficients of two types of mixture increase with the increase of crack width, and the diffusion coefficients decrease with the increase of exposure periods. In addition, the effect of the crack width on the diffusion coefficient is reduced as the exposure periods increase, which is attributed to the extra hydrate by chloride ion reducing the diffusivity of concrete. The behavior of the surface chloride contents does not significantly change by the increase in crack width, compared to the behavior of apparent chloride diffusion coefficient. Also, In the high strength FA concrete mixture, the surface chloride contents are 78.9 % ~ 90.7 % than the normal FA strength concrete mixture. Thus, Surface chloride contents have correlation with the strength of concrete.

• Journal of Conservation Science
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• v.32 no.4
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• pp.491-500
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• 2016

Fog is atmospheric in which tiny drops of water vapor are suspended in the air near the ground. Its form, occurrence, etc., change according to the temperature, relative humidity, wind and geographical features of the space around it. In particular, fog tends to occur near a source of water because of temperature and relative humidity difference. These days, climate change is increasingly affecting the occurrence of fog. Therefore the purpose of this study was to investigate how fog affects materials that are part of our cultural properties through outdoor exposure tests and artificial degradation. The degradation evaluation of materials as a function of fog occurrence frequency, showed that the color of metals changed noticeably, whereas dyed silk and Dancheong showed degradation on the surface and color differences but no particular tendencies. Therefore, damage prediction by color differences as a function of fog occurrence frequency was based on metal samples, which showed constant color differences. Through a comparison of the predictive value and color difference by outdoor exposure, the accuracy and applicability of the damage prediction formula was confirmed. If a more complex damage prediction formula is created, it is expected that prediction of the degree of material damage in the field would be possible.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.176-177
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• 2022

In this study, surface performance evaluation was conducted according to the fiber and surface finishing technique of the exterior material using Ultra High Performance Concrete(UHPC), whitch is spotlighted as a highly durable exterior material. As a result of outdoor exposure, the initial performance of the UHPC Panel using organic fibers was maintained without being affected by the surface finishing technique. In the specimen using steel fiber, the surface performance was maintained when the water repellent treatment was performed in the plain specimen, but fiber corrosion occurred in the specimen to which the surface finishing technique was applied.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.44-50
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• 2007

The objective of this study was to investigate the influence of the vehicle resin on the coating performance of Dan-Chung. The starch glue (F), fish glue (G), and aqueous acrylic resin emulsion (E) were used as vehicle resins. Panels coated with Dan-Chung were tested at accelerated weathering and outdoor conditions. Aqueous acrylic resin was proved as an excellent vehicle resin for Dan-Chung, because there was no flaking in Dan-Chung film after accelerated weathering and outdoor exposure. Discoloration of Dan-Chung using E was the smallest among the acceleratedly weathered panels. Adhesive property of Dan-Chung film using G was. remarkably improved by G-undercoating. On the contrary, G-undercoating lowered adhesive property of Dan-Chung film using E.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.47-54
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• 2008

To make up original defects of the wooden materials for decks, and to supply the wooden material for outdoor, we fabricated preservative treated plywood(PTP). Copper azole (CUAZ-1) preservative was treated with a normal full-cell process. Bond Strength of PTP was not affected after the preservative treatment. The anti-fungal efficiency and dimensional stability were obtained from PTP. A little discoloration of the surface was detected, but the dimensional change or peel bonded area off were not observed after accelerated weathering test. Although some strength of PTP was reduced after 17 months of field exposure, the PTP should be applicable for outdoor applications.

• Archives of design research
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• v.20 no.3 s.71
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• pp.191-202
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• 2007

In these days, open signboard system is controlled by administrative policy and law, but there is no consideration for different types of building. As such, this study aims to propose planning criteria for streetside commercial buildings, such as elevation and mass design of buildings, layout of signboard attached to the building elevation with consideration for streetscape. In mass planning for streetside commercial buildings, the building type with front open space keeps lower open signboard density than the building type directly leading to the street. It is desirable that open signboard of lower floor part is attached by a horizontal type, open signboard of low medium floor part by a projected vertical type, open signboard of high medium floor part and roof part with a minumum attachment of open signboard. As for elevation planning relative to open signboard, it is desirable that an irregular wall type is more useful than a regular wall type to control open signboard. And in all cases, horizontal element facade has a handicap to control the quantity of signboard. If the building has a corner, the piloti should be used in the corner of lower story for smooth circulation of pedestrians and emphasizing the transparency of elevation. Specially, in the case of a round corner, the corner should be emphasized by the composition of high transparent mass.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.27-32
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• 2002

We investigated the effect of polyethylene glycol(PEG) treatment of preservative treated green japanese cedar(Cryptomeria japonica) round posts on their preservative penetration and check formation during the air drying. The round rods were dip-treated in 10% preservative solution of Basilit CFK for 1 day, followed by application(3, 5, and 10 times) with 50% PEG-400 solution, and then dried for 30 days under natural conditions. The rate of preservative penetration into sapwood was a low by 23.2% without PEG treatment, whereas that was a high by about 51.2~64.5% with PEG treatment. From these results, it was assumed that PEG played an affirmative role in the penetration of preservative components loaded onto the surface of round rods by dipping. During the air drying, the formation of drying checks decreased significantly with increasing application times of PEG. Even though some drying checks in PEG treated rods were developed, the number and size of checks was reduced remarkably by PEG treatment. After 2 months of outdoor exposure, PEG treatment failed to reduce checking in preservative-treated rods whereas finishing of polyurethane resin lacquer after PEG treatment was significantly effective in preventing check development.

• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.85-93
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• 2011

The width of sidewalk is one of the important factors constructing a pleasant pedestrian environment. The procedure for sidewalk width design based on the Level of Service is suggested in Korea Highway Capacity Manual. However, this manual does not give a difference between the sidewalk on the street with the passage of the subway, therefore, the different flow characteristic of these places is not appropriately reflected. Though the pedestrian flow in the subway encounters a frequent stop and go situation as like the platoon of vehicles, the similar condition is rarely observed at the urban streets. The new measure of LOS for sidewalk is in need. The study reviewed the prominent measure of LOS and carried out the outdoor experiment to evaluate the new measure. Particularity, GPS was used to collect the pedestrian foot path trajectory for the quantitative evaluation and the results from quantitative and qualitative are compared.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.427-428
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• 2006

최근 대기환경 악화로 송전용 철탑 도장의 열화가 촉진되어 내후성이 강한 신도료를 송전철탑에 적용이 필요하게 되었다. 도료 제조업체의 신도료로 도장시편을 제작하여 옥외에 폭로후 전문기관에서 성능을 확인하였으며, 이를 토대로 도료의 재질을 실리콘 아크릴우레탄계로 변경하였으며, 철탑용 도료 성능시험 기준을 강화하여 철탑 재도장에 따른 유지보수 비용 절감이 될 수 있도록 개선하였다.

• Proceedings of the Korean Reliability Society Conference
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• 2002.06a
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• pp.115-115
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• 2002

최근 중장비용 도료의 외관 즉 색상 및 광택의 변화는 상품가치를 결정하는 중요한 요소의 하나로 대두되고 있다. 이와 관련 도장 품질향상을 위해서 각종의 신도료가 개발되고 있고 물성 확인은 필수적이다. 특히 검사 항목중 내후성 확인은 Field에서 2년 이상 장시간의 시험기간이 필요하나 검증기간 단축을 위해 시험실에서 Weathering test를 시행하고 있다. 그러나 이러한 Lab. test 결과와 실제 Field data와의 상관관계를 알 수 없어 추정에 그치는 것이 현실이었다. 본 연구에서는 중장비용 우레탄도료의 내후성에 영향을 미치는 인자를 고려, 물성을 대폭 향상시킨 도료에 대해 시험실 Weathering test 결과와 옥외폭로시험 결과, 실제 장비에 적용한 Data를 토대로 중장비용 우레탄 도료의 내후성시험 가속계수를 도출하여 개발도료의 내후성 검증기간을 단축하고자 하였다.