Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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An Analytical Method for the Evaluation of Micro-cracking in Concrete Shrinkage Induced

콘크리트의 수축으로 인한 미세균열 발생 평가를 위한 해석적 기법

  • Song, Young-Chul (Korea Electric Power Research Institute, Green Growth Laboratory) ;
  • Kim, Do-Gyeum (Korea Institute of Construction Technology, Structural Engineering and Bridges Research Division) ;
  • Moon, Jae-Heum (Korea Institute of Construction Materials, Construction Material Research Center)
  • 송영철 (한국전력공사 전력연구원 녹색성장 연구소) ;
  • 김도겸 (한국건설기술연구원 구조교량연구실) ;
  • 문재흠 (한국건자재시험연구원 건설기반기술센터)
  • Published : 2010.02.28
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Abstract

The majority of research that has been performed on cracking potential of concrete by shrinkage has assumed that concrete acts as a homogeneous material. However, with this approach, it is not able to evaluate the micro-cracking behavior in concrete due to autogenous shrinkage under unrestrained boundary condition (free boundary condition) nor to understand the cracking behavior properly because of the heterogeneous nature of concrete. To better understand the micro-cracking behavior of concrete induced by autogenous shrinkage, series of experiments were performed measuring the length change and acoustic emission energy. As an analytical approach, this research uses an object oriented finite element analysis code (OOF code) to simulate the behavior of the concrete on a meso-scale. The concrete images used in the simulations were directly obtained from mortar samples. From the experiments and simulation results, it was able to better understand the micro-cracking behaviour of concrete due to shrinking of paste phase and internal restraint by aggregates.

콘크리트의 수축으로 인한 균열가능성 평가에 있어서 대부분의 경우 콘크리트를 균질한 물질로 가정하는 방식으로 접근하고 있다. 그러나 이러한 방식으로 접근할 경우 불구속조건 하의 콘크리트에서 자기수축으로 인한 미세균열(micro-cracking) 현상을 평가하는 것이 불가능함과 동시에 콘크리트 내부의 균열 발생 현상을 이해하는데 한계가 있다. 이에 이 연구에서는 시멘트 모르타르 시험체를 가지고 실험적으로는 음향방출(acoustic emission) 장비를 사용하여 내부 균열 발생량을 측정 및 평가하였으며, 이론적인 접근방식의 일환으로 실제 모르타르 시험체로부터 구하여진 이차원 이미지를 사용하여 NIST에서 개발한 OOF code로 유한요소해석을 수행하였다. 실험 및 해석 결과, 모르타르의 내부에서 시멘트 페이스트상의 수축 및 골재의 내부구속으로 인하여 발생하는 미세균열 발생 현상을 보다 현실적으로 이해할 수 있었다.

Keywords

References

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