Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Variation of Bilinear Stress-Crack Opening Relation for Tensile Cracking of Concrete at Early Ages

초기재령에서 콘크리트 인장균열에 대한 쌍선형 응력-균열 개구 관계의 변화

  • Kwon, Seung-Hee (Dept. of Civil and Environmental Engineering, Myongji University) ;
  • Choi, Kang (Dept. of Civil and Environmental Engineering, Myongji University) ;
  • Lee, Yun (Dept. of Architectural tural Engineering, Ewha Womans University) ;
  • Park, Hong-Yong (Dept. of Civil and Environmental Engineering, Myongji University)
  • 권승희 (명지대학교 토목환경공학과) ;
  • 최강 (명지대학교 토목환경공학과) ;
  • 이윤 (이화여자대학교 건축공학과) ;
  • 박홍용 (명지대학교 토목환경공학과)
  • Received : 2010.02.03
  • Accepted : 2010.04.07
  • Published : 2010.06.30
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Abstract

One of the most vulnerable properties in concrete is tensile cracking, which usually happens at early ages due to hydration heat and shrinkage. In order to accurately predict the early age cracking, it needs to find out how stress-crack opening relation is varying over time. In this study, inverse analyses were performed with the existing experimental data for wedge-splitting tests, and the parameters of the softening curve for the stress-crack opening relation were determined from the best fits of the measured load-CMOD curves. Based on the optimized softening curve, variation of fracture energy over time was first examined, and a model for the stress-crack opening relation at early ages was suggested considering the found feature of the fracture energy. The model was verified by comparisons of the peak loads, CMODs at peak loads, and fracture energies obtained from the experiments and the inverse analysis.

인장 균열은 콘크리트의 가장 취약한 특성으로 수화열 및 건조수축 등으로 인해 초기재령에서 발생되는 경우가 많다. 초기의 균열을 정확히 예측하기 위해서는 응력-균열 개구 관계가 시간에 따라 어떻게 변화하는 지를 파악해야 한다. 이 연구에서는 기존에 수행되었던 쐐기형 쪼갬 실험결과에 대한 역해석을 수행하였으며, 측정된 하중-균열 개구 변위를 최적으로 모사하는 응력-균열 개구 관계에 대한 쌍선형 연화곡선을 구하였다. 파괴에너지의 시간에 따른 변화에 관한 분석이 이루어졌으며, 분석 결과를 바탕으로 초기재령에서의 응력-균열 개구 관계에 대한 모델을 제안하였다. 최대 하중, 최대 하중에서의 균열 개구 변위, 파괴에너지에 대하여 실험 측정값, 역해석 결과, 모델로부터 계산된 결과들을 비교해 보았으며, 이를 통해 제안된 모델을 검증하였다.

Keywords

References

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  1. Variation of stress – crack opening relationships for tensile cracking of self-consolidating concrete at early ages vol.39, pp.2, 2012, https://doi.org/10.1139/l11-125