KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Development of Plane Spacing Factor of Concrete Air Voids by Image Analysis Method

화상분석법에 의한 콘크리트 공극의 평면간격계수 제안 및 평가

Jeong, Won-Kyong;Hong, Chang-Woo;Yun, Kyong-Ku
정원경;홍창우;윤경구

  • Published : 2005.11.30

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Abstract

Entrained air in concrete is the most widely used method for assuring freeze-thaw resistance. The adequacy of air entrainment in a given hardened concrete can be estimated by a spacing factor. However, has demerit: the spacing factor is based on the assumption of air voids arranged in three-dimension but calculated from the measurement obtained in two-dimension. This study is proposed a new approach for spacing of air voids by simple and easy concept for analyzed two-dimension. The method for analysis air void system was used image analysis method. Because estimated factors were reduced, the developed errors were as possible as decreased. The proposed plane spacing factor equation was estimated with main experimental variables such as cement types and admixtures. Also, air void systems of concretes were compared with plane spacing factor and ASTM spacing factor. The results are as follows; It was showed that plane spacing equation has similar air-void system than standard spacing equation with air voids even at same air contents by image analysis method. They showed very good relationship, indicating the accuracy of the proposed plane spacing factor.

콘크리트의 내동결성을 향상시키기 위해 연행공기를 가장 널리 이용한다. 적정한 공기의 연행을 평가하는 방법은 경화 후 콘크리트의 간격계수를 측정하는 것이다. 그러나 간격계수는 3차원 가정임에도 불구하고 선 또는 점에 의해 평가되고 있다. 본 연구에서는 콘크리트 공극구조를 정의하고 평가함에 있어서 기존의 방식에서 다루지 않았던 단위공극개수를 이용하여 2차원 평면에서 동일 공극으로 환산한 후 행렬개념을 이용한 평면간격계수를 제안하였다. 제안된 평면간격계수와 ASTM 간격계수와의 상관성을 분석하기 위하여 시멘트분말도 차이에 따른 콘크리트 4종류와 AE제 및 소포제를 사용한 67개의 시편을 제작하였다. 시편은 화상분석법을 이용하여 공극정보를 추출하였다. 본 연구에서 제안된 평면간격계수에 대한 비교분석결과, 공기량 변화에 따른 평면간격계수와 ASTM 간격계수의 변화는 동일하게 평가되었다. 또한, 두 계수간의 상관성 분석결과, 0.948로 매우 높게 평가되어 제안된 평면간격계수를 이용한 콘크리트 내부 공극 특성 분석이 가능한 것으로 판단되었다.

Keywords

References

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