• 한국강구조학회 논문집
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• 제22권6호
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• pp.523-532
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• 2010

콘크리트가 충전된 각형강관기둥(이하, 각형 CFT기둥)은 높은 내화성능과 하중저항능력을 보유하고 있지만, CFT기둥의 외부에 내화피복을 함으로써 기둥의 내화성능을 향상시킬 필요가 있다. 본 연구는 내화 피복된 각형 CFT기둥의 온도분포에 대한 실험결과이다. 실험을 위하여 특수 제작된 전기로를 이용하여 축소모형 시험체의 재하가열실험을 수행하였다. 축하중을 받는 내화 피복된 각형 CFT기둥의 온도 분포 특성을 파악하기 위하여 내화피복의 종류와 두께, 강관의 두께 및 가열시간 등을 변수로 설정하였다. 실험결과 전기로의 온도에 따른 시험체별 온도분포와 콘크리트와 강재의 온도분포 특성을 파악하였다. 또한 시험체의 온도변화에 따른 축변위와 국부좌굴 등의 거동을 파악하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.481-484
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• 2006

This study investigates the engineering and fire endurance properties of ultra high strength concrete. The mixture proportions with water to binder ratios (W/B) of 0.15 and 0.25 consist of various adding ratios, such as 0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 percent respectively, of polypropylene (PP) fiber. As for the parameters of specimens, fluidity, compressive strength and unloading fire test were carried out. Test showed that an increase of fiber contents had the favorable properties in fire endurance performance; specimens in W/B 15% required 0.3vol% of PP fiber and specimens in W/B 25% needed only 0.1vol% to prevent spalling.

• 한국안전학회지
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• 제26권4호
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• pp.65-68
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• 2011

High strength concrete(HSC) has been mainly used in large SOC structures. HSC have superior property as well as improvement in durability compared with normal strength concrete. In spite of durability of HSC, explosive spalling in concrete front surface near the source of fire occurs serious problem in structural safety. It is reported that spalling is caused by the vapor pressure under fire and polypropylene(PP) fiber has an important role in protecting from spalling. The spalling properties of ultra high strength concrete specimens with various contents of PP fiber were investigated in this study. In results, the content of PP fiber for spalling protection increases over 0.2 vol.% as the concrete strength increases to 120 MPa.

• Computers and Concrete
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• 제12권5호
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• pp.717-737
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• 2013

In this study, experiment and numerical analysis were conducted to identify the heat transfer characteristics and behavior of high-strength concrete upon a fire. The numerical analysis was employed to forecast the characteristics and properties of the high-strength concrete upon a fire, which can not be accomplished through a fire test due to the specific conditions and restrictions associated with the test. The result of the numerical analysis was compared with that of the test to verify the reliability of the analysis. In the numerical analysis of the heat transfer characteristics and behavior of 80 and 100 MPa high-strength concrete upon a fire, the commercial software of ABAQUS(V.6.8) was used. It was observed from the experiment that the contraction of the concrete with fiber-cocktail was mitigated by 25~55 % compared with that without fiber-cocktail because the fiber controlled the heat transfer of the concrete and thus improved the fire-resistance performance of the column.

• 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.

• 한국건축시공학회지
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• 제13권1호
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• pp.58-65
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• 2013

Currently, many high-rise buildings are built in Korea for land-efficient utilization and vista. In high-rise buildings this tall, the use of high-strength concrete is essential to reduce the cross-section of structure members and secure axial load. However, this high strength concrete is vulnerable to spalling by fire, due to the water vapor pressure caused by the very high temperature in fire. To prevent this, the main method used is to reinforce the concrete with fiber. However, there has been little research on the pumpability of fiber reinforced high strength concrete. For this reason, this study features a performance review based on the properties and pumpability of fiber reinforced high strength concrete. In addition, the parameter of rheology was measured by extracting mortar from the concrete, and friction factor was measured through a 400 m horizontal pipe pumping test using the fiber reinforced high strength concrete. The basic information on fiber reinforced high strength concrete that we obtain through the experiments and review will contribute to the field.

• 한국해양환경ㆍ에너지학회지
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• 제18권3호
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• pp.207-215
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• 2015

환경문제를 야기시켰던 해상용 FRP재활용에 대해 지난 10여 년간 다양한 국가적 지원이 이루어져서 폐FRP로부터 콘크리트 강화용 섬유 제작이 진행되어 왔다. 이렇게 제작된 강화 콘크리트에 대해 구조적 능력까지 시험한 바 있다. 시험 테스트 결과 재활용 FRP 가루를 사용한 콘크리트는 고강도 콘크리트의 압축강도를 감소시키지 않았을 뿐 만 아니라, 고강도 콘크리트의 내폭 특성을 상당히 증대시켰다. 그러나 폐FRP로부터 매트층의 분리 방법이 안정화되지 않았기 때문에 폐FRP 섬유 가루의 특성에 대한 연구는 종결되지 않았다. 본 연구는 폐FRP로부터 매트층을 분리하는 효과적이며 친환경적인 새로운 방법에 관한 것이며, 이것은 내폭성이 강한 제품이나 구조물에 적합한 FRP섬유가루 생산 공정에 유용한 재활용 공정이라 생각한다.

• 한국강구조학회 논문집
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• 제9권4호통권33호
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• pp.649-658
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• 1997

강관에 콘크리트를 충전하는 경우, 콘크리트 충전강관 기둥은 뛰어난 내력과 변형성능을 발휘한다. 그리고 콘크리트의 축열효과에 의해서 일정시간은 내화피복 없이도 내력을 유지할 수 있다. 화재발생동안 콘크리트 충전강관 기둥의 거동을 알아보고자 강관과 콘크리트의 온도에 따른 특성치 변화를 가정하고 온도 해석 및 축력-모멘트관계에 대한 수치해석을 수행하여 시간변화에 따른 변수별로 비교평가하였다. 온도에 따른 특성치는 기존문헌의 데이터를 이용하였으며 온도해석은 범용 해석프로그램인 ANSYS로 유한요소해석을 하였고 이를 바탕으로 내력에 대한 수치해석을 수행하였다.

• Elastomers and Composites
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• 제45권2호
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• pp.87-93
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• 2010

내화재료는 건축물에서 화재사고로부터 화염을 차단하기 위해 사용된다. 본 연구에서는 실리콘 고무에 무기계 난연제인 aluminium trihydroxide(ATH, $Al(OH)_3$)와 magnesium dihydroxide(MDH, $Mg(OH)_2$)를 첨가한 복합체를 기계적 교반으로 제조한 후 내화성능향상에 관한 연구를 진행하였다. 내화재료의 열 특성분석을 위해 TGA를 사용하였고, rheometer를 이용해 유변학적 분석을 하였다. 내화특성을 분석하기 위해 gas torch를 이용하였다. 본 연구를 통하여 ATH와 MDH가 첨가되면 실리콘 고무의 내화성능이 향상됨을 알 수 있었다.

• 복식
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• 제57권3호
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• pp.53-62
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• 2007

The purpose of this study was to investigate mechanical and comfort performances of the material for the improved working uniform for a volunteer fire brigade member, to get basic data for its evaluation and to help its material and design development. The results were as follows; The material of the newly developed working uniform was thinner and lighter than the material of the current used working uniform. It had better breathability, air permeability and heat transmission rate than the current one. It also had superior anti-flammability In all mechanical properties(tensile, bending, shearing, compression and surface properties), it showed better performances than the current one. It elongated and bended easier and more in both warp and weft directions. The elastic recovery and shape stability after elongation were also higher. The recovery and resistance to shearing and the resiliency and recovery after compression were also better than the current one. It was more flexible, softer and smoother in primary hand value, and was more suitable for the material for winter suit which needs softness and fullness in total hand value. The material of the improved working uniform showed lower thermal insulation value and higher evaporative resistance value compared to the material of the currently used working uniform from the sweating thermal manikin test. It was shown that the physical performances and the hand value of the textile material used in the newly developed working uniform for a volunteer fiber brigade member was improved compared to the one used in the currently used working uniform.