• 한국건축시공학회지
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• 제11권4호
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• pp.353-362
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• 2011

High Strength Concrete (HSC) has weakness that in a fire, it is spalled and brittles. The phenomenon of spalling is made by water vapor's being confined in watertight concrete. This study is aimed to evaluate explosive spalling properties of high strength concrete with ${\square}100{\times}100{\times}200$ mm specimen and ${\square}400{\times}400{\times}1500$ mm column. To prevent spalling of concrete, fireproof coating and PP fiber are used. As a result, ${\square}400{\times}400{\times}1500$ mm column was prevented spalling likes ${\times}100{\times}100{\times}200$ mm specimen. When concrete protected failure to explosive spalling, quantity heat ratio (which fireproof coating specimen to pp fiber mixed specimen) between ${\square}100{\times}100{\times}200$ mm and ${\square}400{\times}400{\times}1500$ mm was maximum value at 20 minute, but difference of quantity heat ratio decreased and quantity heat ratio of each specimen is almost same at 30 minute.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.517-520
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• 2006

The waterproofing of Building on the roof has been exposed more underground or the other part of waterproofing than environmental factor(solar heat, UV, salt, acid rain, wind, temperature, snow, rain, etc.) or physical factor. So it must be have a waterproofing performance and it has a special technique for the maintaining of concrete durability. Therefore, exposed waterproof layer has to protected from UV, solar heat, rain and the outside environment also, to endurance durability methods spread face plate topcoat material on the waterproof layer. But, actuality faceplate waterproof layer of topcoat materials are unbearable to UV, solar heat and moisture etc. and it doesn't have adhesion with waterproof layer in the middle. So it happens to crack, separating and heaving etc. Therefore, in the study, we will suggest that using of the exposed roof waterproof layer topcoat materials test method manage rooftop waterproof layer for the durability and the stability.

• Journal of Advanced Marine Engineering and Technology
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• 제38권10호
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• pp.1206-1211
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• 2014

This study has been conducted to confirm the effect of sacrificial anode cathodic protection system for 90 days to protect corrosion on pier that is located in Korea. The cathodically protected structure was a slab and a pile cap. Before the construction of cathodic protection system, the macrography was carried out. As a result of the macrography, many corrosion traces were confirmed in this structure. The trace was mainly focused on joint and zones that concrete cover was eliminated. To apply the cathodic protection system, many onsite techniques have been adopted. In addition, to confirm the inner state of steel in concrete properly, a corrosion monitoring sensor (DMS-100, Conclinic Co. Ltd) has been applied. Test factors were corrosion & cathodic protection potential, 4 hour depolarization potential, resistivity and current density. After 90 days from the installation of cathodic protection system, it could confirm that proper corrosion protection effect was obtained by considering the result of tests.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.61-62
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• 2017

In this study, the initiation of steel corrosion was monitored due to chloride attack using embedded sensor. In general, Steel bars embedded in concrete are protected from corrosion by being forming a passive film on the surface. However, the passive film is destroyed by chemical erosion such as concrete carbonation and chloride penetration, and the rebar is exposed to the deteriorating factor and corrosion proceeds. In order to realize the initiation of steel corrosion, OCP and change of Impedance parameter were observed by using Half-cell and EIS method depending on cover depth. As result, 10mm cover showed the impedence increased in 6weeks.

• 한국태양에너지학회 논문집
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• 제30권3호
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• pp.71-80
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• 2010

This study carried out to understand the thermal characteristics of various surface material which compose the city through the observation in the summer. To examine passive cooling effect of planting of building, it is arranged four different materials that is natural grass, grass block, concrete slab and artificial grass. The results of this study are as follows; (1) Natural grass and grass block show the lower surface temperature because of the structures of leaf can do more thermal dissipation effectively. (2) There is little surface temperature between artificial grass and concrete. But there is little high surface temperature difference between natural grass and concrete because of latent heat effect. (3) The concrete can play a role of the tropical nights phenomenon as high heat capacity of concrete compare with other materials. (4) It is nearly same color in artificial grass and natural grass but there is large difference between natural grass and artificial grass at albedo. There is different albedo in near infrared ray range. (5) A short wave radiation gives more effect at the globe temperature than long wave radiation. (6) The artificial turf protected the slab surface temperature increase in spite of thin and low albedo materials.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.83-85
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• 2011

This study investigated the results of insulation heat curing method using double layer bubble sheet in concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that concrete was protected from early freezing by remaining between 7℃ and 3℃ even in case outside temperature drops -7℃ below zero until the 3d day from piling. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.25-28
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• 2009

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 5 and $l0^{\circ}C$ even in case outside temperature drops $-11^{\circ}C$ below zero until the 4nd day from piling. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• 한국전통조경학회지
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• 제30권1호
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• pp.125-134
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• 2012

본 연구는 보호수 입지지반별로 각 개체의 생육실태를 분석하여 수세종합판단을 하였고 이 결과와 수관면적 내 지장물 면적비율을 교차분석하여 보호수 수세에 미치는 영향인 인위적 지장물에 대한 관리 방안을 제시하고자 하였다. 대상지는 김포시 보호수 대장에 등재된 68개소를 대상으로 생육실태분석은 자연성, 수목활력도, 수세종합판단을 실시하였으며, 수관면적은 가지가 뻗고 있는 동서남북 방향을 중심으로 실측하여 면적을 산출하였고, 수관면적 내 지장물은 인공지장물인 포장(아스콘, 콘크리트, 블록 등), 건물, 옹벽과 자연지장물인 토사(복토), 석축, 자갈 등으로 구분하여 분석하였으며, 본 연구에서 도출된 결론은 다음과 같다. 자연성 분석에 있어 보호수가 위치한 입지지반은 인공과 인공+준 자연지반이 전체의 72.05%로 나타났으며, 수관면적은 심우경과 신세균(1992)이 보호수 생육에 필요한 수관면적을 제시한 것에 비해 대부분 부족한 것이 많았으며, 수관면적 내 지장물 면적이 차지하는 비율은 김포시 보호수 주변이 도시화 되어감에 따라 높아지고, 수형변형과 수세쇠약으로 이어지고 있어 보호수의 생육 공간 확보와 지장물관리가 절실히 필요한 상태로 분석되었다. 이번 연구에서 수관면적에 지장물이 차지하는 면적이 20% 이하인 것이 수세판단 1-2등급, 21-50% 이하는 2-3등급, 50% 이상은 3-5등급으로 나타났다. 지장물이 많이 차지할수록 생육에 지장을 초래하고 있어, 보호수의 근계관리에 있어서 그 면적비율이 20% 이하를 유지하도록 관리하여야 함을 입증하였다. 보호수 수세에 미치는 영향인 인위적 지장물의 관리방안에 대한 기준에 대하여 다음 사항을 제안하고자 한다. 첫째, 수관면적 내 지장물은 20% 이하로 제한하되 수관면적 밖이 인공지장물이 아닌 경우에는 지장물면적이 차지하는 비율을 다소 상향할 수 있을 것으로 사료된다. 둘째, 보호수 생육 공간 확보를 수관면적만큼 유지 확보하고, 지장물은 수관면적 밖으로 설치되어야 한다. 셋째, 보호수 이식에 있어 생육 공간 확보 시 입지지반 여건을 반드시 고려해야 한다. 넷째, 택지개발 시 보호수 주변을 공원으로 활용하고, 수관면적 내 지장물의 설치 면적은 제한하여야 한다. 다섯째, 선행연구들에서 많이 제시된 노거수, 보호수 주변의 생육환경 개선을 위해, 토지소유자의 세제해택과 보호수 주변 토지매입 등이 필요하며, 보다 효율적인 관리를 위해 지자체의 예산 확보와 전문가의 조언이 필요하다고 사료된다. 또한, 보호수 주변의 지장물 종류별, 두께 등이 수목에 미치는 영향 등에 대한 후속 연구는 계속되어져야 할 것으로 사료된다.

• Structural Engineering and Mechanics
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• 제77권5호
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• pp.673-689
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• 2021

This paper addresses the efficiency of thermal insulation layers applied to protect structural elements strengthened by fiber-reinforced polymers (FRP) in the case of fire event. The paper presents numerical modeling and nonlinear analysis of reinforced concrete (RC) columns externally strengthened by FRP and protected by thermal insulation layers when subjected to elevated temperature specified by standard fire tests, in order to predict their residual capacity and fire endurance. The adopted numerical approach uses commercial software includes heat transfer, variation of thermal and mechanical properties of concrete, steel reinforcement, FRP and insulation material with elevated temperature. The numerical results show good agreement with published results of full-scale fire tests. A parametric study was conducted to investigate the influence of several variables on the structural response and residual capacity of insulated FRP-confined columns loaded by service loads when exposed to fire. The residual capacity of FRP-confined RC column was affected by concrete grade and insulation material and was shown to improve substantially by increasing the concrete cover and insulation layer thickness. By increasing the VG insulation layer thickness 15, 32, 44, 57 mm, the loss in column capacity after 5 hours of fire was 30%, 13%, 7% and 5%, respectively. The obtained results demonstrate the validity of the presented approach for estimation of fire endurance and residual strength, as an alternative for fire testing, and for design of fire protection layers for FRP-confined RC columns.

• 콘크리트학회논문집
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• 제20권1호
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• pp.89-97
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• 2008

메타카올린을 시멘트 치환재로, 잔골재를 폐타이어 잔입자로 일부 치환시킴으로써 건축물 화재시 고강도콘크리트를 폭렬로부터 보호하는 한편, 내부에 배근된 철근의 온도 상승을 억제하는 방법의 검토 및 이들 재료를 혼입한 고강도콘크리트의 기초적 성상에 대하여 검토하였다. 검토 결과 메타카올린은 콘크리트 자체의 내화성을 향상시키며, 고강도콘크리트의 내부 팽창압의 상쇄 기능을 폐타이어 잔입자가 분담할 수 있는 것으로 확인되었다. 세부적으로는 메타카올린을 시멘트에 대해 4$\sim$8%의 중량비로, 폐타이어 잔입자를 0.6$\sim$3 mm의 입도 범위를 사용하며, 잔골재인 모래에 대해 5$\sim$10%의 중량비로 치환하는 것이 고강도콘크리트의 폭렬 방지를 위해 유효한 배합 수준인 것으로 분석되었다.