콘크리트학회논문집 (Journal of the Korea Concrete Institute)

  • 제19권5호
  • /
  • Pages.585-593
  • /
  • 2007
  • /
  • 1229-5515(pISSN)
  • /
  • 2234-2842(eISSN)
한국콘크리트학회 (Korea Concrete Institute)
권호 표지
DOI QR코드

DOI QR Code

해안 환경 하에 있는 콘크리트 구조물의 시간의존적 염화물침투 평가

Time Dependent Chloride Transport Evaluation of Concrete Structures Exposed to Marine Environment

  • 송하원 (연세대학교 사회환경시스템공학부) ;
  • 백승우 (연세대학교 사회환경시스템공학부) ;
  • 안기용 (연세대학교 사회환경시스템공학부)
  • Song, Ha-Won (School of Civil and Environment Engr., Yonsei University) ;
  • Pack, Seung-Woo (School of Civil and Environment Engr., Yonsei University) ;
  • Ann, Ki-Yong (School of Civil and Environment Engr., Yonsei University)
  • 발행 : 2007.10.31
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

본 연구에서는 해안 환경에 노출된 콘크리트 구조물의 내구성 평가에 대한 모델을 표면 염소이온농도 $(C_s)$의 시간에 대한 증가와 염소이온 확산계수 (D) 및 임계염소이온농토 $(C_{lim})$를 고려하여 제안하였다. 또한 콘크리트 구조물의 정밀한 내구수명 예측을 위하여 $C_s$와 D의 시간의존성이 고려되었으며, 시간에 따라 변화하는 $C_s$를 고려한 Fick의 제2법칙의 정밀해를 구하였다. $C_s$의 시간의존성에 대해서는, 기존 실험 결과를 바탕으로 시간에 대한 대수 함수 형태의 $C_s$ 모델을 제안하였으며, D의 시간의존성을 고려하기 위하여 구조물의 전체 노출 기간에 대한 시간의 평균값을 적용하였다. 또한 염해 환경 하에 있는 철도 구조물이 100년의 내구 수명을 보장할 수 있도록 하기 위해, 본 논문에서 제안된 모델과 시방서 기준에 근거하여 내구성 설계를 수행하였다. 제안된 모델은 유럽에서 널리 사용되고 있는 성능 중심의 설계 기법에 의해 검증되었으며, 이로부터 기존의 시방서 설계기준은 해안 환경에 노출된 콘크리트 구조물의 내구 성능을 과소 평가하여 매우 보수적인 설계결과를 유발하고 있음을 알 수 있다. $C_s$와 D의 시간의존성을 고려한 본 모델은 기존 시방기준의 이러한 문제점을 개선하여 염해를 받는 콘크리트 구조물의 내구수명을 정확하고 합리적으로 평가할 수 있을 것이다.

This paper presents a model for durability evaluation of concrete structures exposed to marine environment, considering mainly a build-up of surface chloride $(C_s)$ as well as diffusion coefficient (D) and chloride threshold level $(C_{lim})$. In this study, time dependency of $C_s$ and D were extensively studied for more accurate evaluation of service life of concrete structures. An analytical solution to the Fick's second law was presented for prediction of chloride ingress for time varying $C_s$. For the time varying $C_s$, a refined model using a logarithm function for time dependent $C_s$ was proposed by the regression analysis, and averaging integrated values of the D with time over exposed duration were calculated and then used for prediction of the chloride ingress to consider time dependency of D. Durability design was also carried out for railway concrete structures exposed to marine environment to ensure 100 years of service life by using the proposed models along with the standard specification on durability in Korea. The proposed model was verified by the so-called performance-based durability design, which is widely used in Europe. Results show that the standard specification underestimates durability performances of concrete structures exposed to marine environment, so the cover depth design using current durability evaluation in the standard specifications is very much conservative. Therefore, it is found that utilizing proposed models considering time dependent characteristics of $C_s$ and D can evaluate service lift of concrete structures in marine environment more accurately.

키워드

참고문헌

  1. Hausmann, D. A., 'Steel Corrosion in Concrete; How Does It Occur', Materials and Protection, Vol.6, 1967, pp.19-23
  2. Mustafa, M. A. and Yusof, K. M., 'Atmospheric Chloride Penetration into Concrete in Semitropical Marine Environment', Cement and Concrete Research, Vol.24, 1994, pp.661-670 https://doi.org/10.1016/0008-8846(94)90190-2
  3. McGee R., 'Modelling of Durability Performance of ,Tasmanian Bridges', In: Melchers RE, Stewart MG, Editors, ICASP8 Applications of Statistics and Probability in Civil Engineering, Vol.1, 1999, pp.297-306
  4. Collepardi, M., Marcialis, A., and Turriziani, R., 'Penetration of Chloride Ions into Cement Pastes and Concrete', Journal of American Ceramic Society, Vol.55, No.10, 1972, pp.534-535 https://doi.org/10.1111/j.1151-2916.1972.tb13424.x
  5. Thomas, M. D. A. and Bentz, E. C., Life-365 Manual, Released with Program by Master Builders, 2000, pp.6-10
  6. Bamforth, P. B., 'The Derivation of Input Data for Modelling Chloride Ingress from Eight-Years UK Coastal Exposure Trials', Magazine of Concrete Research, Vol.51, 1999, pp.87-96 https://doi.org/10.1680/macr.1999.51.2.87
  7. Weyers, R. E., Fitch, M. G., Larsen, E. P., Al-Qadi, I., Chamberlin, W. P., and Hoffman, P. C., Concrete Bridge Protection and Rehabilitation: Chemical and Physical Techniques, Service Life Estimates, Strategic Highway Research Program, National Research Council, Washington DC, 1994, pp.139-189
  8. Uji, K., Matsuoka, Y., and Maruya, T., 'Formulation of an Equation for Surface Chloride Content of Concrete due to Permeation of Chloride', Corrosion of Reinforcement in Concrete, Elsevier Applied Science, 1990, pp.258-267
  9. Kassir, M. K. and Ghosn, M., 'Chloride-Induced Corrosion of Reinforced Concrete Bridge Decks', Cement and Concrete Research, Vol.32, 2002, pp.139-143 https://doi.org/10.1016/S0008-8846(01)00644-5
  10. 한국콘크리트학회, 콘크리트표준시방서 내구성편, 한국콘크리트학회, 2004, pp.15-18
  11. Buenfeld, N. R., Shurafa-Daoudi, M. T., and McLoughlin, I. M., 'Chloride Tansport due to wick Action in Concrete', In: Chloride Penetration into Concrete, L.O. Nilsson and J. P. Oliver, eds., RILEM Publication, Paris, France, 1997, pp.302-324
  12. Song, H. W., Lee, C. H., and Ahn, K. Y., 'Factors Influencing Chloride Transport in Concrete Structures Exposed to Marine Environments', Cement and Concrete Composite, 2007, Online Available
  13. Crank, J., The Mathematics of Diffusion, The Clarendon Press (2), Oxford, 1975, pp.19-21
  14. Amey, S. L., Johnson, D. A., Miltenberger, M. A., and Farzam, H., 'Predicting the Service Life of Concrete Marine Structures: An Environment Methodology', ACI Structural Journal, Vol.95, No.2, 1998, pp.205-214
  15. Carslaw, H.S. and Jaeger, J.C., Conduction of Heat in Solids, The Clarendon Press (2), Oxford, 1959, pp.50-92
  16. Song, H. W., Pack, S. W., and Moon, J. S., 'Durability Evaluation of Concrete Structures Exposed to Marine Environment Focusing on a Chloride Build-up on Concrete Surface', Proceedings of the International Workshop on Life Cycle Management of Coastal Concrete Structures, Nagaoka, Japan, 2006, pp.1-9
  17. 日本土木學會, コンクリ-ト標準示方書 (構造性能照査編), 2002, pp.94-114
  18. Kawamura, C., Tanimura, Y., Sogabe, M., Tottori, S., Hasegawa, M., and Higashigawa, K., 'Study on the Penetration of Chloride Ions into Concrete Based on Investigation of Railway Structures', Journal of the Japan Society of Civil Engineering, No.781, Vol.66, 2005, pp.193-204
  19. Poulsen, E., 'On a Model of Chloride Ingress into Concrete, Nordic Miniseminar-Chloride Transport', Department of Building Materials, Chalmers University of Technology, Gothenburg, 1993, pp.1-12
  20. 한국콘크리트학회, 해양 환경에서 염해를 받는 철근콘크리트 조 구조물의 유지관리 지침(안), 특수환경콘크리트위원회, 2004, pp.26-51
  21. Schiessl, P. and Raupach, M., 'Influence of Concrete Ccomposition and Mmicroclimate on the Ccritical Cchloride Ccontent in Cconcrete', In: Corrosion of Reinforcement in Concrete, Page, C. L., Treadaway, K. W. J. & Bamforth, P. B., eds., Elsevier Applied Science, London UK, 1990, pp.49-58
  22. Vassie, P., 'Reinforcement Corrosion and the Durability of Concrete Bridges', Proceeding of Institution of Civil Engineers, Vol.76, 1984, pp.713-723
  23. British Standard (BS) 8110, Part 1, Structural Use of Concrete - Code of Practice for Design and Construction, British Standards Institute, London UK, 1985, pp.3-8
  24. Hooton, R. D., Geiker, M. R., and Bentz, E. C., 'Effects of Curing on Chloride Ingress and Implications on Service Life', ACI Material Journal, Vol.99, 2002, pp.201-206
  25. Liu, Y. and Weyer, R. E., 'Time to Cracking for Chloride-Induced Corrosion in Reinforced Concrete', In: Corrosion of Reinforcement in Concrete Construction, Page, C.L., Bamforth, P.B. and Figg, J.W., eds., Cambridge UK, 1996, pp.88-104
  26. Ann, K. Y. and Song, H. W., 'Chloride threshold level for corrosion of steel in concrete', Corrosion Science, 2007, Online Available
  27. 한국콘크리트학회, 콘크리트 구조설계기준, 한국콘크리트학회, 2003, pp.95-115
  28. ISO/TC98, General Principles on the Design of Structures for Durability, ISO/CD 13823, 2005, pp.1-8
  29. DuraCrete, Final Technical Report, Probabilistic Performance Based Durability Design of Concrete Structures, Document BE95-1347/R17, European Brite-Euram Programme, 2000, pp.27-51
  30. CEB-FIP, Model Code for Service Life Design, the International Federation for Structural Concrete (fib), Task Group 5.6, 2006, pp.38-39

피인용 문헌

  1. Influence of Temperature on Chloride Ion Diffusion of Concrete vol.26, pp.1, 2014, https://doi.org/10.4334/JKCI.2014.26.1.071
  2. Development of Three Dimensional Chloride Ion Penetration Model Based on Finite Element Method vol.57, pp.5, 2015, https://doi.org/10.5389/KSAE.2015.57.5.043
  3. Development of Two Dimensional Chloride Ion Penetration Model Using Moving Mesh Technique vol.57, pp.6, 2015, https://doi.org/10.5389/KSAE.2015.57.6.001