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

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
권호 표지
DOI QR코드

DOI QR Code

Temperature-dependent Diffusion Coefficient of Chloride Ion in UAE Concrete

UAE 콘크리트에 대한 염화물 확산의 온도의존성

  • Ji-Won Hwang ;
  • Seung-Jun Kwon (Department of Civil and Environmental Engineering, Hannam University)
  • 황지원 (경기대학교 건축공학과) ;
  • 권성준 (한남대학교 토목환경공학과)
  • Received : 2024.07.15
  • Accepted : 2024.07.31
  • Published : 2024.08.31
Download PDF
⟨ Previous Next ⟩

Abstract

NPP (Nuclear power plant) structures have been constructed near to the sea shore line for cooling water and exposed to steel corrosion due to chloride attack. Regarding NPP structures built in the UAE, chloride transport may be more rapid than those in the other regions since the temperature near to the coast is high. In this study, concrete samples with 5,000psi (35MPa) design strength grade were manufactured with the materials and mix proportions, which were the same as used in the UAE NPP structures, then chloride diffusion coefficients were evaluated considering temperature and curing age. The compressive strength and the diffusion coefficient were evaluated and analyzed for the samples with 28 and 91 curing days. In addition, chloride diffusion tests for 91-day-cured condition were carried out in the range of 20℃ to 50℃. The activation energy was obtained through converting the temperature slope to a logarithmic function and it was compared with the previous studies. The proposed activation energy can be useful for a reasonable durability design by using actual temperature-dependent chloride diffusion coefficient.

원전 구조물은 냉각수를 사용하기 위해 해안가에 위치하고 있으며, 염해에 의한 철근부식에 노출되어 있다. UAE에 지어지는 원전 구조물의 경우, 해안가의 온도가 높으므로 염화물 이동이 다른 지역에 비하여 빠르게 평가된다. 본 연구에서는 원전 구조물에 사용되어지는 재료와 배합을 이용하여 5,000 psi (35 MPa)설계강도 등급의 시편을 제작하였으며, 온도와 재령을 고려하여 염화물 확산계수를 평가하였다. 재령 28일 및 91일에 강도 평가 및 온도에 따른 확산계수를 평가하여 특성을 분석하였다. 또한 91일 재령 콘크리트에 대하여 20℃~50℃의 범위에서 염화물 확산실험을 수행하였다. 또한 온도에 따른 기울기를 로그함수로 변환하여 활성화에너지를 도출하였으며, 기존의 제안값들과 비교하였다. 제안된 활성화에너지는 온도의존형 염화물 확산계수에 사용하여 합리적인 내구성 설계를 수행할 것으로 평가된다.

Keywords

Acknowledgement

본 연구는 정부의 지원으로 한국연구재단 원자력 연구개발사업(원자력 연구개발사업 NRF-2022M2E9A3091898)에 의해 수행되었으며, 저자들은 이에 감사드립니다.

References

  1. ACI Committee 304 (1996), Heavyweight concrete: Measuring, mixing, transporting, and placing (ACI 304.3R-96), American Concrete Institute (ACI), USA, 1-8.
  2. Broomfield, J. P. (1997), Corrosion of Steel in Concrete: Understanding, Investigation and Repair, E&FN, London 1-15.
  3. Bruck, P. M., Esselman, T. C., Elaidi, B. M., Wall, J. J., and Wong, E. L. (2019), Structural assessment of radiation damage in light water power reactor concrete biological shield walls, Nuclear Engineering and Design, 350, 9-20.
  4. CEB-FIP (2006), Model code for service life design, The International Federation for Structural Concrete, Switzerland, 1-116.
  5. Dhir, R. K., Jones, M. R., and Elghaly, A. E. (1993), PFA Concrete: exposure temperature effects on chloride diffusion, Cement and Concrete Research, 23(5), 1105-1114.
  6. Field, K. G., Remec, I., and Le Pape, Y. (2015), Radiation effects in concrete for nuclear power plants-Part I: Quantification of radiation exposure and radiation effects, Nuclear Engineering and Design, 282, 126-143.
  7. Goto, S., and Roy, D. M. (1981), Diffusion of ions through hardened cement pastes, Cement and Concrete Research, 11(5-6), 751-757.
  8. Jang, S. Y., Karthick, S., and Kwon, S. J. (2017), Investigation on Durability Performance in Early Aged High-Performance Concrete Containing GGBFS and FA, Advances in Materials Science and Engineering, 2017, 3214696.
  9. Julio-Betancourt, G. A., and Hooton, R. D. (2004), Study of the Joule effect on rapid chloride permeability values and evaluation of related electrical properties of concretes, Cement and Concrete Research, 34(6), 1007-1015.
  10. Jung, S. H., Rye, H. S., Karthick, S., and Kwon, S. J. (2018), Time and crack effect on chloride diffusion for concrete with fly ash, International Journal of Concrete Structures and Materials, 12(1), 1-10.
  11. KDI. (2010), Become one of the top 3 nuclear export powerhouses by 2030, https://eiec.kdi.re.kr/publish/naraView.do?cidx=6998. (in Korean).
  12. Lee, K. M., Yoon, Y. S., Yang, K. H., Yoo, B. Y., and Kwon, S. J. (2022), Corrosion Behavior in RC Member with Different Cover Depth under Cyclic Chloride Ingress Conditions for 2 Years, Applied Sciences, 12(24), 13002.
  13. Matsumura, T., Shirai, K., and Saegusa, T. (2008). Verification method for durability of reinforced concrete structures subjected to salt attack under high temperature conditions, Nuclear Engineering and Design, 238(5), 1181-1188.
  14. Page, C. L., Short, N. R., and Tarras, A. E. (1981), Diffusion of chloride ions in hardened cement pastes, Cement and Concrete Research, 11(3), 395-406.
  15. Pomaro, B. (2016), A review on radiation damage in concrete for nuclear facilities: from experiments to modeling, Modelling and Simulation in Engineering, 2016, 4165746.
  16. Popova, A. (2007), Temperature effect on mild steel corrosion in acid media in presence of azoles, Corrosion Science, 49(5), 2144-2158.
  17. So, H. S., Choi, S. H., Seo, J. S., So, S. Y., and Seo, K. S. (2014), Influence of temperature on chloride ion diffusion of concrete, Journal of Korea Concrete Institute, 26(1), 71-78 (in Korean).
  18. Thomas, M. D. A., and Bentz, E. C. (2002), Computer program for predicting the service life and life-cycle costs of reinforced concrete exposed to chlorides, Life365 Manual, Silica Fume Association, Lovettsville, USA.
  19. Weatherspark. (2022), https://ko.weatherspark.com.
  20. Yang, K. H., and Kwon, S. J. (2023), Evaluation of Strength and Chloride Diffusion in Concrete with FA Considering Temperature Effect, Journal of the Korean Recycled Construction Resources Institute, 11(1), 62-69 (in Korean).
  21. Yang, K. H., Kwon, S. J., Hwang, J. W., and Yoon, Y. S. (2023), Temperature effect on strength and chloride migration in nuclear power plant concrete, Construction and Building Materials, 405, 133345.
  22. Yoon, Y. S., Lim, H. S., and Kwon, S. J. (2019), Evaluation of Apparent Chloride Diffusion Coefficient of Fly Ash Concrete by Marine Environment Exposure Tests, Journal of the Korea Institute for Structural Maintenance and Inspection, 23(3), 1-8 (in Korean).
  23. Yuan, F. L., and Li, C. Q. (2011), Corrosion propagation of prestressing steel strands in concrete subject to chloride attack, Construction and Building Materials, 25(10), 3878-3885.
  24. Yuan, Q., Shi, C., Schutter, G. D., and Audenaert. K. (2008), Effect of temperature on transport of chloride ions in concrete, Concrete Repair, Rehabilitation and Retrofitting II, 345-351.