Journal of the Korea institute for structural maintenance and inspection (한국구조물진단유지관리공학회 논문집)

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
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Probabilistic Service Life Analysis of GGBFS Concrete Exposed to Carbonation Cold Joint and Loading Conditions

탄산화에 노출된 GGBFS 콘크리트의 콜드 조인트 및 하중 재하를 고려한 확률론적 내구수명 해석

  • 김태훈 (한남대학교, 건설시스템공학과) ;
  • 권성준 (한남대학교, 건설시스템공학과)
  • Received : 2020.03.20
  • Accepted : 2020.06.24
  • Published : 2020.06.30
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Abstract

Carbonation is a deterioration which degrades structural and material performance by permitting CO2 and corrosion of embedded steel. Service life evaluation through deterministic method is conventional, however the researches with probabilistic approach on service life considering loading and cold joint effect on carbonation have been performed very limitedly. In this study, probabilistic service life evaluation was carried out through MCS (Monte Carlo Simulation) which adopted random variables such as cover depth, CO2 diffusion coefficient, exterior CO2 concentration, and internal carbonatable materials. Probabilistic service life was derived by changing mean value and COV (Coefficient of variation) from 100 % to 300 % and 0.1 ~ 0.2, respectively. From the analysis, maximum reduction ratio (47.7%) and minimum reduction ratio (11.4%) of service life were obtained in cover depth and diffusion coefficient, respectively. In the loading conditions of 30~60% for compressive and tensile stress, GGBFS concrete was effective to reduce cold joint effect on carbonation. In the tensile condition, service life decreased linearly regardless of material types. Additionally service life rapidly decreased due to micro crack propagation in the all cases when 60% loading was considered in compressive condition.

탄산화는 콘크리트 내부로 이산화탄소가 확산되어 매립 철근에 부식을 유발함으로서 콘크리트 구조물의 구조적, 재료적 성능을 저하시키는 열화 현상이다. 결정론적인 방법을 통한 내구수명 평가는 일반적이지만, 하중 및 콜드 조인트 효과를 고려한 확률론적 내구수명 평가에 대한 연구는 매우 제한적이다. 본 연구에서는 확률 변수를 피복 두께, 이산화탄소 확산계수, 외부 이산화탄소 농도, 내부 수화물 반응량으로 정의하고 취약부와 하중 조건을 고려한 확률론적 내구수명 도출을 MCS (Monte Carlo Simulation) 기법을 통해서 진행하였다. 각 확률 변수의 평균을 1.0 ~ 3.0배로 변화시키고, 변동계수를 0.1 ~ 0.2까지 변화시키면서 내구수명을 평가하였다. 분석한 결과 피복 두께에서 47.7%의 내구수명 감소율을, 이산화탄소 확산계수에서 11.4%의 내구수명 감소율을 나타내었다. 파괴 하중에 30% 및 60%의 압축 및 인장 하중을 고려한 결과, 콜드 조인트가 고려된 경우 GGBFS 콘크리트가 OPC 콘크리트보다 탄산화에 대한 높은 저항성을 보였으며, 인장 영역에서는 사용 재료에 상관없이 선형적으로 내구수명 감소가 평가되었다. 또한 압축 하중 60% 조건에는 미세 균열의 진전으로 인해, 모든 조건에서 빠르게 내구수명이 감소하였다.

Keywords

References

  1. ACI 224. 3R - 95. (2001), Joints in Concrete Construction, American Concrete Institute.
  2. Ang, A. H. S., Tang, W. H. (2007), Probability Concepts in Engineering Planning and Design : Emphasis on Application to Civil and Environmental Engineering, Wiley, 199-231.
  3. Amey, S. L., Johnson, D. A., Miltenberger, M. A., Farzam, H. (1998), Predicting the service life of concrete marine structures : an environmental methodology, ACI Structural Journal, 95(2), 205-214.
  4. Ann, K. Y., Park, S. W., Hwang, J. P., Song, H. W., Kim, S. H. (2010), Service life prediction of a concrete bridge structure subjected to carbonation, Construction and Building Materials, 24(8), 1494-1501. https://doi.org/10.1016/j.conbuildmat.2010.01.023
  5. Badaoui, A., Badaoui, M. H., Kharchi, F. (2013), Probabilistic analysis of reinforced concrete carbonation depth, Materials Sciences and Applications, 4(3A), 205-215. https://doi.org/10.4236/msa.2013.43A025
  6. Banthia, N., Biparva, A., Mindess, S. (2005), Permeaility of concrete under stress, Cement and Concrete Research, 35(9), 1651-1655. https://doi.org/10.1016/j.cemconres.2004.10.044
  7. CEB. (1997), New Approach to Durability Design, 96-102.
  8. Clifton, J. R. (1993), Predicting the service life of concrete, ACI Materials Journal, 90(6), 611-617.
  9. Cho, S. J., Yoon, Y. S., Kwon, S. J. (2018), Carbonation brhavior of GGBFS - based concrete with cold joint considering curing period, Journal of the Korean Recycled Construction Resources Institute, 6(4), 259-266. https://doi.org/10.14190/JRCR.2018.6.4.259
  10. Choi, S. J., Kang, S. P., Kim, S. C., Kwon, S. J. (2015), Analysis technique on water permeability in concrete with cold joint considering micro pore structure and mineral admixture, Advances in Materials Science and Engineering, 2015, 1-10.
  11. Defaux, G., Pendola, M., Sudret, B. (2006), Using spatial reliability in the probabilistic study of concrete structures : The exemple of a RC beam subjected to carbonation inducing corrosion, Journal de Physique IV(Proceedings), 136, 243-253. https://doi.org/10.1051/jp4:2006136025
  12. EN - 1991. (2000), Eurocode 1 : Basic of Design and Actions on Structures, European Committee for Standardization.
  13. Ecoseoul. (2013), Map of CO2 concentrations in seoul. Available at: http://www.ecoseoul.or.kr/xe/?document_srl=1893070.
  14. Hwang, S. H., Yoon, Y. S., Kwon, S. J. (2019), Carbonation behavoir of GGBFS concrete considering loading conditions and cold joint, Journal of the Korea Concrete Institute, 31(4), 365-373. https://doi.org/10.4334/jkci.2019.31.4.365
  15. Hwang, S. H., Yoon, Y. S., Kwon, S. J. (2019), Carbonation Behavior Evaluation of OPC Concrete Considering Effect of Aging and Loading Conditions, Journal of the Korea Institute for structural maintance and inspection, 23(1), 122-129.
  16. Izumi, I. Kita, D., Maeda, H. (1986), Carbonation, Kibodang Publication, 35-88.
  17. JSCE. (2000), Concrete Cold Joint Problems and Countermeasures, Concrete Library Japan 387 Society of Civil Engineering, 103.
  18. Kown, S. J. (2017), Simulation on Optimum Repairing Number of Carbonated RC Structure Based on Probabilistic Approach, Journal of the Korean Recycled Construction Resources Institute, 5(3), 230-238. https://doi.org/10.14190/JRCR.2017.5.3.230
  19. Kown, S. J. (2019), Probabilistic Service Life Evaluation for OPC Concrete under Carbonation Considering Cold Joint and Induced Stress Level, Journal of the Korea Institute for structural maintance and inspection, 23(6), 45-52.
  20. KDS 14 20 40. (2016), Concrete Structure durability design standard, Korea Design Standard, 13-14.
  21. KMA. (2019), Report of Global Atmosphere Watch 2018, National Institute of Meteorlogical Science, Jeju, 26-27.
  22. Kim, G. Y., Choe, G. C., Nam, J. S., Choi, H. G. (2015), Durability design of concrete structure based on carbonation, Journal of the Korea Concrete Institute, 27(5), 21-24. https://doi.org/10.4334/JKCI.2015.27.1.021
  23. Koh, T. H., Kim, M. K., Yang, K. H., Yoon, Y. S., Kwon, S. J. (2019), Service life evaluation of RC T - girder under carbonation considering cold joint and loading effects, Construction and Building Materials, 226, 106-116. https://doi.org/10.1016/j.conbuildmat.2019.07.106
  24. Lee, Y., Kwon, S. J., Park, K. T. (2015), Simplified A carbonation model considering Ca(OH)2 solubility and porosity reduction, Journal of the Korea Institute for structural maintance and inspection, 19(1), 128-138. https://doi.org/10.11112/jksmi.2015.19.1.128
  25. Lounis, Z. (2003), Probabilistic modeling of chloride contamination and corrosion of concrete bridge structures, Proceeding of Fourth International Symposium on Uncertainty Modeling and Analysis, IEEE, Washington, 447-451.
  26. Maekawa, K., Ishida, T., Kishi, T. (2003), Multi-scale modeling of concrete performance - integrated material and structural mechanics, Advanced Concrete Technology, 1(1), 91-119. https://doi.org/10.3151/jact.1.91
  27. Maekawa, K., Ishida, T., Kishi, T. (2009), Multi-Scale Modeling of Structural Concrete, Taylor & Francis, 86-105.
  28. Na, U. J., Kwon, S. J., Chaudhuri, S. R., Shinozuka, M. (2012), Stochastic model for service life prediction of RC structures exposed to carbonation using random field simulation, Journal of the Korea Society of Civil Engineers, 16(1), 133-143.
  29. Nath, P., Sarker, P. K. (2014), Effect of GGBFS on setting, workability and early strength properties of fly ash geopolymer concrete cured in ambient condition, Construction and Building Materials, 66, 163-171. https://doi.org/10.1016/j.conbuildmat.2014.05.080
  30. Papadakis, V. G., Vayenas, C. G., Fardis, M. N. (1991), Physical and chemical characteristics affecting the durability of concrete, ACI Materials Journal, 88(2), 186-196.
  31. Song, H. W., Kwon, S. J., Lee, S. W., Byun, K. J. (2003), A study on resistance of chloride ion penetration in ground granulated blast furnace slag concrete. Journal of the Korea Concrete Institute, 15(3), 400-408. https://doi.org/10.4334/JKCI.2003.15.3.400
  32. Tasaka, S., Shinozuka, M., Chaudhuri, S., Na, U. J. (2009), Bayesian inference for prediction of carbonation depth of concrete using MCMC, Memoirs of Akashi National College of Technology, 52, 45-50.
  33. Vesikari, E. (1988), Service Life of Concrete Structures with regard to Corrosion of Reinforcement, Technical Reports 533, VTT Technical Report Center of Finland, 29-128.
  34. Yoon, Y. S., Cheon, J. H., Kwon, S. J. (2019), Quantification of chloride diffusivity in steady state condition in concrete with fly ash considering curing and crack effect, Journal of the Korean Recycled Construction Resources Institute, 7(2), 109-115. https://doi.org/10.14190/JRCR.2019.7.2.109
  35. Yoo, S. W., Kwon, S. J. (2016), Effects of cold joint and loading conditions on chloride diffusion in concrete containing GGBFS, Construction and Building Materials, 115, 247-255. https://doi.org/10.1016/j.conbuildmat.2016.04.010
  36. Yoo, S. W., Bang, G. S. Jung, S. H., Chang, S. P. (2007), Study on the carbonation properties of fly ash concrete by the new rapid carbonation experimental system, Journal of the Korean Society of Civil Engineers, 27(4A), 601-607.

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