Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Analysis of Air Voids System Using Image Analysis Technique in Hardened Concrete

화상분석법을 통한 경화 콘크리트의 미세 공극 구조 분석

  • Yun Kyong-Ku (Dept. of Civil Engineering, Kangwon National University) ;
  • Jeong Won-Kyong (Dept. of Civil Engineering, Kangwon National University) ;
  • Jun In-Koo (Korea Agricultural & Rural Infrastructure Corporation) ;
  • Lee Bong-Hak (Dept. of Civil Engineering, Kangwon National University)
  • Published : 2004.12.01
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Abstract

Air voids in hardened concrete have an important influence on concrete durability such as freeze-thaw resistance, surface scaling resistance, and water permeability, and they have been characterized by spacing factor Linear traverse and point count methods in ASTM standard have been used in estimating an air void system in hardened concrete. However, these methods require lots of time and efforts, further they are not repeatable. Image analysis method could be utilized In estimating an air void systems in hardened concrete with a developments of microscope, digital camera and computer program. The purpose of this study was to develope image analysis method and provide a guideline by comparing the results from ASTM method and image analysis method. The concerns were at air void content and diameter distribution, air voids system as well as spacing factors. The experimental variables included air content by air entrained agent (0, 0.01, $0.03\%$) and depth of specimen (top, middle, bottom). The result showed that it was possible to calculate spacing factor using image analysis technique, as well as air content, air diameter distribution, and air structure. This study also contributed in developing an reasonable and repeatable image analysis method.

경화 후 콘크리트 내부 공극은 간격계수로 특정지어질 수 있으며 이는 동결융해 저항성, 표면박리 저항성 그리고 투수성과 같은 콘크리트의 내구성에 매우 중요한 영향을 주게 된다. ASTM에 규정되어 있는 리니어트래버스방법과 수정포인트카운트 방법은 이러한 콘크리트의 공극 구조를 분석하기 위하여 사용되어져 왔다. 그러나, 이들 방법은 많은 시간과 노력을 필요로 하며 반복측정성 또한 신뢰성이 높지 못한 단점을 가지고 있다. 화상분석방법은 미세현미경, 디지털카메라 그리고 컴퓨터 프로그램을 이용하여 경화 후 콘크리트의 내부 공극 구조에 활용되어 질 수 있는 방법이다. 본 연구의 목적은 화상분석법의 개발과 기존의 ASTM방법에 의한 결과를 비교 분석하여 사용성을 확인하고자 하였다. 이를 위해 공기량과 공극분포, 공극 구조 및 간격계수와 연관성을 분석하였다. 실험적 변수는 공기연행제의 첨가률에 따른 공기량 변화와 시편 깊이에 따른 공극 구조를 비교 분석하였다. 실험결과 화상분석기법을 사용할 경우에도 간격계수의 산출이 가능하였으며 또한, 공기량, 공극 크기분포, 공극 구조 등을 분석할 수 있었다.

Keywords

References

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