실태조사를 통한 간만대 콘크리트 교각의 염화물 확산계수 특성 = Characteristics of Chloride Diffusion Coefficient in RC Column at Tidal Zone through Field Investigation

다국어 초록 (Multilingual Abstract)

Concrete is a durable construction material but chloride attack is considered as a critical deterioration phenomena due to corrosion in embedded steel. This paper presents evaluation of apparent diffusion coefficient and surface chloride content in 13 concrete cores with 4.8∼48.4m height location from RC (Reinforced Concrete) column exposed to tidal and atmospheric zone through field investigation. Concrete cores under high water level of 6.0m show very high surface chloride content but they show very reduced values over high water level, so that chloride effect on corrosion is expected to be insignificant over 9.0m. The measured diffusion coefficient has a range of 1.05∼7.24×10-12m2/sec, which is relatively low for previous investigation. The apparent diffusion coefficient and surface chloride contents are quantitatively investigated in the paper.

국문 초록 (Abstract)

콘크리트는 내구적인 건설재료이지만, 매립된 철근 부식으로 인해 염해는 매우 중요한 열화인자로 고려되고 있다. 본 연구에서는 실태조사를 수행하여, 간만대 및 비말대에 노출되고 3.7∼4.7년 경과된 RC 교각에 대해 4.8∼48.4m 위치의 코어를 13개 채취하여 겉보기 확산계수 및 표면염화물량을 분석하였다. 해수면이 닿는 6.0m까지는 매우 높은 표면염화물량이 도출되었으나 그 이후는 매우 낮은 표면염화물량이 측정되어 9.0m 이상의 부재에서는 내구성에 큰 영향이 없을 것으로 평가되었다. 평가된 겉보기 확산계수는 1.05∼7.24×10-12m2/sec의 범위를 가졌으며 기존의 연구에 비하여 낮은 확산계수를 보이고 있었다. 본 연구에서는 해수면 위치에 따른 표면염화물량 및 겉보기 확산계수의 변화가 정량적으로 분석되었다.

참고문헌 (Reference)

1 박상순, "콘크리트의 투수 및 확산에 미치는 균열효과" 건설환경연구소 9 (9): 1-9, 2014

2 삼성기술연구소, "고내구성 콘크리트의 염소이온확산특성 평가" 15-28, 2003

3 나웅진, "Stochastic Model for Service Life Prediction of RC Structures Exposed to Carbonation using Random Field Simulation" 대한토목학회 16 (16): 133-143, 2012

4 "Standard specification for concrete structures"

5 "Standard Method of Test for Sampling and Testing for Chloride Ion in Concrete and Concrete Raw Materials"

6 Kwon, S.-J., "Service Life Prediction of Concrete Wharves with Early-Aged Crack : Probabilistic Approach for Chloride Diffusion" 31 (31): 75-83, 2009

7 권성준, "Prediction of Repairing Time for RC Columns with Crack and Joint under Carbonation based on Probabilistic Approach" 한국콘크리트학회 5 (5): 11-18, 2011

8 Biparva, A., "Permeability and durability of high volume flyash concrete under an applied compressive stress" University of British Colombia 2005

9 Wang, K., "Permeability Study of Cracked Concrete" 27 (27): 381-393, 1997

10 Park, S.-S., "Modeling of Water Permeability in Early Aged Concrete with Cracks Based on Micro Pore Structure" 27 (27): 597-604, 2012

11 Thomas M. D. A., "Modeling Chloride Diffusion in Concrete : Effect of Fly Ash and Slag" 29 (29): 487-495, 1999

12 Kim, Y. Y., "Effect of Cover Depth, w/c Ratio, and Crack Width on Half Cell Potential in Cracked Concrete Exposed to Salt Sprayed Condition" 54 (54): 636-645, 2014

13 Korea Highway Corporation, "Effect of Cement Types on the Durability of Concrete Structures, Technical Report" 129-133, 1999

14 RILEM., "Durability Design of Concrete Structures" E&FN 28-52, 1994

15 Broomfield J. P., "Corrosion of Steel in Concrete:Understanding, Investigation and Repair" E&FN 1-15, 1997

16 "Concrete standard specification–Durability Part"

17 Thomas MDA, "Computer program for predicting the service life and life-cycle costs of reinforced concrete exposed to chlorides. Life365Manual"

18 Park, S. S., "Analysis Technique for Chloride Penetration in Cracked Concrete using Equivalent Diffusion and Permeation" 29 (29): 183-192, 2012