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

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
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Chloride Diffusion Coefficients in Cold Joint Concrete with GGBFS

고로슬래그 미분말을 혼입한 콜드조인트 콘크리트의 염화물 확산계수

  • 오경석 (한남대학교 건설시스템 공학과) ;
  • 문진만 (한남대학교 건설시스템 공학과) ;
  • 권성준 (한남대학교 건설시스템 공학과)
  • Received : 2016.04.07
  • Accepted : 2016.05.12
  • Published : 2016.09.01
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Abstract

Among the deteriorating agents, chloride ion is reported to be one of the most harmful ions due to its rapid diffusion and direct effect on steel corrosion. Cold joint which occurs in mass concrete placing is vulnerable to shear resistance and more severe deterioration. The paper presents an quantitative evaluation of chloride diffusion coefficient in OPC(Ordinary Portland Cement) and GGBFS(Ground Granulated Blast Furnace Slag) concrete containing cold joint. GGBFS concrete shows $6.6{\times}10^{-12}m^2/sec$ which is almost 30% level of OPC concrete results and the trend is repeated in the case of cold joint concrete. Compared with OPC concrete, GGBFS concrete is evaluated to have better resistance to chloride penetration, showing 0.30 times of chloride diffusion coefficient in concrete without cold joint 0.39 times with cold joint, respectively.

철근 콘크리트 구조물의 철근에 대한 부식을 발생시키는 다양한 유해 열화인자 중 염화물 이온(Cl-)은 침투로 인한 확산속도가 빠르고, 철근에 직접적으로 관여하여 부식을 야기시켜 매우 중요한 열화원인이다. 대형 콘크리트 구조물의 타설에서 불가피하게 발생하는 콜드 조인트는 전단력에 취약하여, 이는 내구적 열화에 대한 피해를 증가시키는 경향을 보인다. 본 연구에서는 콜드조인트를 가진 OPC(Ordinary Portland Cement) 콘크리트와 GGBFS(Ground Granulated Blast Furnace Slag) 염화물 촉진 실험으로 염화물 확산계수를 정량적으로 평가하였다. GGBFS 콘크리트에서는 $6.6{\times}10^{-12}m^2/sec$의 확산계수가 측정되었는데. 이는 OPC 콘크리트에 비하여 약 30% 수준의 낮은 확산계수값을 나타내었으며, 콜드조인트를 가진 콘크리트에서도 비슷한 경향이 관측되었다. OPC 건전부 콘크리트에 비하여 GGBFS 콘크리트의 염화물 확산계수는 건전부에서 0.30배, 콜드조인트부에서 0.39배 정도의 우수한 염해 저항성을 나타내었다.

Keywords

References

  1. ACI 224.3R-95 (2001), Joints in Concrete Construction, American Concrete Institute, USA, Reapproved.
  2. ASTM C1202 (1993), Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration, Annual Book of American Society for Testing Materials Standards.
  3. Broomfield, J. P. (1997), Corrosion of Steel in Concrete: Understanding, Investigation and Repair, E&FN, London.
  4. Hyun, T.-Y., Kim, C.-Y., and Kim, J.-K. (2008), Permeability of Cracked Concrete as a Function of Hydraulic Pressure and Crack Width, Journal of The Korea Concrete institute, 20(3), 291-298. https://doi.org/10.4334/JKCI.2008.20.3.291
  5. JSCE (2000), Concrete Cold Joint Problems and Countermeasures, Concrete Library, 103.
  6. Kwon, S.-J., and Na, U.-J. (2011), Prediction of Durability for RC Columns with Crack and Joint under Carbonation Based on Probabilistic Approach, International Journal of Concrete Structures and Materials, 5(1), 11-18. https://doi.org/10.4334/IJCSM.2011.5.1.011
  7. Kwon, S.-J., Park, S.-S., Nam, S. H., and Cho, H. J. (2007), Study on Survey of Carbonation for Sound, Cracked, and Joint Concrete in RC Column in Metropolitan City, Journal of the Korea Structure Maintenance Institute, 11(3), 116-122.
  8. Lee, S. S., and Song, H. Y. (2007), An Experimental Study on the Durability and Mechanical Properties of High Performance Concrete Using Blast-Furnace Slag Powder, Architectural institute of Korea, 23(11), 119-126.
  9. Leng, F., Feng, N., and Lu, X. (2000), An Experiment Study on the Properties of Resistance to Diffusion of Chloride Ions of Fly Ash and Blast Furnace Slag Concrete, Cement and Concrete Research, 30(6), 989-992. https://doi.org/10.1016/S0008-8846(00)00250-7
  10. Maekawa, K., Ishida, T., and Kishi, T. (2003a), Multi-Scale Modeling of Concrete Performance, Journal of Advanced Concrete Technology, 1(2), 91-126. https://doi.org/10.3151/jact.1.91
  11. Maekawa, K., Ishida, T., and Kishi, T. (2003b), Multi-Scale Modeling of Structural Concrete, Tylor&Francis, London and Newyork, 1st Edition, 291-352.
  12. Otsuki, N., Nagtataki, S., and Nakashita, K. (1992), Evaluation of $AgNO_3$ Solution Spray Method for Measurement of Chloride Penetration into Hardened Cementitious Matrix Materials, Construction and Building Materials, 7(4), 195-201. https://doi.org/10.1016/0950-0618(93)90002-T
  13. Park, M. S. (2001), Study on Control of Carbonation at Cold Joint of Reinforced Concrete Structures, Master's Thesis, Yonsei University.
  14. Park, S. S., Kwon, S.-J., and Jung, S. H. (2012), Analysis Technique for Chloride Penetration in Cracked Concrete Using Equivalent Diffusion and Permeation, Construction and Building Materials, 29(2), 183-192. https://doi.org/10.1016/j.conbuildmat.2011.09.019
  15. RILEM (1994), Durability Design of Concrete Structures, Report of RILEM Technical Committee 130-CSL, E&FN, 28-52.
  16. Ryu, D. W., Kim, W. J., Yang, W.H., Yu, J. H., and Ko, J. W. (2012), An Experimental Study on the Freezing-Thawing and Chloride Resistance of Concrete Using High Volumes of GGBS, The Korea Institute of Building Construction, 12(3), 315-322. https://doi.org/10.5345/JKIBC.2012.12.3.315
  17. Song, H. W., Lee, C. H., and Lee, K. C. (2009), A Study on Corrosion Potential of Cracked Concrete Beam According to Corrosion Resistance Assessment, Journal of the Korea Institute for Structural Maintenance and Inspection, 13(1), 97-105 (in Korean).
  18. Song, H.-W., and Kwon, S.-J. (2009), Evaluation of Chloride Penetration in High Performance Concrete Using Neural Network Algorithm and Micro Pore Structure, Cement and Concrete Research, 39(9), 814-824. https://doi.org/10.1016/j.cemconres.2009.05.013
  19. Song, H.-W., Pack, S. W., Lee, C. H., and Kwon, S.-J. (2006), Service Life Prediction of Concrete Structures under Marine Environment Considering Coupled Deterioration, Journal of Restoration Buildings and Monuments, 1(2), 265-284.
  20. Tang, L. (1996), Electrically Accelerated Methods for Determining Chloride Diffusivity in Concrete-Current Development, Magazine of Concrete Research, 48(176), 173-179. https://doi.org/10.1680/macr.1996.48.176.173
  21. Thomas, M. D. A., and Bamforth, P. B. (1999), Modeling Chloride Diffusion in Concrete: Effect of Fly Ash and Slag, Cement and Concrete Research, 29(4), 487-495. https://doi.org/10.1016/S0008-8846(98)00192-6
  22. Yokozeki, K., Okada, K., Tsutsumi, T., and Watanabe, K. (1998), Prediction of the Service Life of RC with Crack Exposed to Chloride Attack, Journal of Symposium: Rehabilitation of Concrete Structure, 10, 1-6.