콘크리트학회논문집 (Journal of the Korea Concrete Institute)

  • 제24권5호
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  • Pages.605-612
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  • 2012
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  • 1229-5515(pISSN)
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  • 2234-2842(eISSN)
한국콘크리트학회 (Korea Concrete Institute)
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가열 속도에 따른 콘크리트의 폭렬 특성 및 내부 수증기압력 평가

Evaluation of Spalling Property and Water Vapor Pressure of Concrete with Heating Rate

  • Choe, Gyeong-Cheol (Dept. of Architectural Engineering, Chungnam National University) ;
  • Lee, Tae-Gyu (Dept. of Architectural Engineering, Chungnam National University) ;
  • Nam, Jeong-Soo (Dept. of Architectural Engineering, Chungnam National University) ;
  • Park, Byung-Keun (SAMSUNG C&T Corporation) ;
  • Kim, Gyu-Yong (Dept. of Architectural Engineering, Chungnam National University)
  • 투고 : 2012.05.29
  • 심사 : 2012.08.13
  • 발행 : 2012.10.31
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초록

콘크리트의 폭렬 발생 메커니즘에 대해서는 수증기압력에 의한 파괴, 내 외부의 온도 차이에 의해 발생하는 표면 압축력에 의한 파괴, 앞선 두 가지 요인의 복합작용에 의한 파괴가 있다. 이러한 폭렬에 영향을 주는 요인은 콘크리트 자체의 재료적 특성과 관계된 내부 요인과 환경에 의한 외부 요인으로 나눌 수 있으며 폭렬 현상을 이해하기 위해서는 두 가지 요인에 대한 충분한 고려가 필요하다. 외부 환경의 요소로써 가열 속도가 다른 경우 콘크리트 내부의 수분응집 및 수증기압력의 거동이 달라질 것으로 판단된다. 따라서 이 연구에서는 30, 50, 70, 90, 110 MPa의 다양한 강도 영역의 콘크리트를 대상으로 ISO-834 표준가열곡선과 $1^{\circ}C/min$의 가열 속도를 적용하여 가열 속도에 따른 콘크리트의 폭렬 성상 및 수증기압력, 열팽창 변형을 평가하였다. 실험 결과 콘크리트의 폭렬은 급속 가열조건에서 발생하며, 콘크리트가 고강도화될수록 폭렬에 의한 단면손실량이 증가하였다. 또한, 가열 초기에 콘크리트 표면부의 수증기압력 상승 속도 및 가열 속도에 따른 열팽창에 의한 초기압력 상쇄효과가 콘크리트의 폭렬 발생에 중요한 영향을 미치는 것으로 나타났다.

Spalling of concrete occurs due to vapor pressure ignited explosion, temperature difference across a section, and combination of these factors. Factors affecting spalling can be classified into internal and external factors such as material property and environmental condition, respectively, have to be considered to precisely understand spalling behavior. An external environmental factor such as differences in heating rate cause internal humidity cohesion and different vapor pressure behavior. Therefore, spalling property, vapor pressure and thermal strain property were measured from concrete with compressive strengths of 30 MPa, 50 MPa, 70 MPa, 90 MPa, and 110 MPa, applied with ISO-834 standard heating curve of $1^{\circ}C/min$ heating rate. The experimental results showed that spalling occurred when rapid heating condition was applied. Also, when concrete strength was higher, the more cross section loss from spalling occurred. Also, spalling property is influenced by first pressure cancellation effect of thermal expansion caused by vapor pressure and heating rates.

키워드

참고문헌

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피인용 문헌

  1. Study on the High Temperature Properties of Fireproof Mortar Using Various Types of Fine Aggregate vol.2, pp.2, 2014, https://doi.org/10.14190/JRCR.2014.2.2.100