외부온도에 따른 황산염 침식 단면을 고려한 콘크리트의 압축강도 모델링
Modeling on Compressive Strength of Concrete Exposed to Temperature-Dependent Sulfate Attack
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초록
황산염 확산계수는 열화깊이를 평가하는데 있어 매우 중요한 내구성 설계인자이며, 이 값은 온도에 따라 변하게 된다. 본 연구에서는 UAE 원전 콘크리트의 사용재료를 입수하여, 콘크리트를 제조하였으며, 온도변화에 따른 황산염 확산계수를 도출하였다. 자연확산실험을통하여 20℃ ∼ 50℃ 까지 10℃ 간격으로 황산염 확산계수를 도출하였으며, 3개의 시편을 통하여 평균과 표준편차를 도출하여 확산성에 대한확률분포를 도출하였다. 또한 비선형 회귀분석을 통하여 확산계수를 온도에 대한 함수로 정량화하였다. 확산실험 후 1면 열화단면에 대하여 3 개의 변수를 도입하여 온도증가에 따른 열화깊이증가를 고려한 강도평가식을 제안하였는데, 온도에 대한 확산성 증가와 콘크리트 압축강도감소를 잘 구현하고 있다.
Abstract
The sulfate diffusion coefficient is an important durability design factor for evaluating sulfate-deterioration depth, and it varies with exterior temperature. In this study, the materials used for UAE nuclear power plant were delivered and concrete was prepared with the materials, and the sulfate diffusion coefficient was evaluated. The diffusion coefficients were obtained from 20°C to 50°C with 10°C intervals through natural diffusion test, and the probabilistic information for the diffusivity was derived through average and standard deviation from 3 samples. In addition, the diffusion coefficients were quantified as a function of temperature through nonlinear regression analysis. For the 1-D deteriorated section due to sulfate ingress, compressive strength evaluation technique was proposed with three parameters which can handle the increasing deterioration depth due to raised temperature. The proposed technique effectively showed the increasing diffusivity and the reduced compressive strength with increasing temperature.
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