혼화재 혼입에 따른 콘크리트에 매립된 철근의 부식 임계 염화물량의 변화 = Variation of Critical Chloride Content of Rebar Embedded in Concrete with Admixture

다국어 초록 (Multilingual Abstract)

The critical chloride content of rebar embedded in concrete was experimentally evaluated according to the admixturereplacement ratio and admixture type. Four types of reinforced concrete were mixed OPC 100%, OPC 70% + GGBFS30%, OPC 40% + GGBFS 60%, and OPC 40% + GGBFS 40% + FA 20%. NaCl solution was supplied to the specimens,and the open circuit potential of the embedded rebar was monitored. The specimens determined to initiate corrosionwere cut at intervals of 5㎜ from the NaCl solution supply surface and conducted to chlorine ion profile. Corrosioninitiation time of rebar embedded in concrete was delayed as the admixture replacement ratio increased. Looking at thecritical chloride content of the types of reinforced concrete, it was highest in OPC 1.46kg/㎥, followed in order by S300.98kg/㎥, TBC 0.74kg/㎥, and S60 0.71kg/㎥.

국문 초록 (Abstract)

혼화재 혼입에 따른 콘크리트의 철근부식 임계염화물량의 변화를 실험적으로 평가하였다. 콘크리트 배합조건은 OPC 100%, OPC 70% + GGBFS 30%, OPC 40% +GGBFS 60%, OPC 40% + GGBFS 40% + FA 20% 로구분하여 4가지 배합의 철근 콘크리트 시험체를 제작하였다. 시험체에 NaCl 수용액을 공급하며, 매립된 철근의 자연전위를 모니터링 하였다. 부식이 발생한 것으로 판단된시험체는 NaCl 수용액 공급면으로부터 5㎜간격으로 절단하여 염소이온량 프로파일을 실시하였다. 콘크리트에 매립된 철근의 부식 개시시기는 시멘트를 혼화재로 치환하여사용하는 경우 지연되는 것을 확인하였다. 하지만 콘크리트에 매립된 철근의 부식임계염화물량은 혼화재 혼입율 증가에 따라 감소하여, OPC 1.46kg/㎥, S30 0.98kg/㎥, TBC 0.74kg/㎥, S60 0.71kg/㎥ 순으로 높게 나타났다.

참고문헌 (Reference)

1 정연백, "플라이애쉬가 콘크리트의 전과정 환경영향에 미치는 효과" 한국건축시공학회 14 (14): 515-522, 2014

2 진충국, "철근 콘크리트 구조물용 다기능 멀티센서의 부식 모니터링에 관한 연구: Part 1" 한국부식방식학회 11 (11): 270-274, 2012

3 양승규, "단위시멘트량이 다른 콘크리트 중에서의 철근부식 임계염화물량에 관한 연구" 한국콘크리트학회 20 (20): 415-421, 2008

4 J. S. Ryou, "Variation in the chloride threshold level for steel corrosion in concrete arising from different chloride sources" Thomas Telford Ltd. 60 (60): 177-187, 2008

5 Wallbank EJ, "The performance of concrete in bridges. A survey of 200 highway bridges" HMSO 96-, 1989

6 Berke NS, "Resistance of microsilica concrete to steel corrosion erosion and chemical attack" 114 : 861-886, 1989

7 Thirumalai Parthiban, "Potential monitoring system for corrosion of steel in concrete" Elsevier BV 37 (37): 375-381, 2006

8 Hussain SE, "Mechanisms of high durability performance of plain and blended cements" King Fahd University of Petroleum and Minerals 1991

9 Skalny J, "Materials science of concrete" American Ceramic Society 285-313, 1999

10 "KS L 5405. Fly ash"

11 "KS L 5201. Portland Cement"

12 "KS F 2713. Standard test method for analysis of chloride in concrete and concrete raw materials"

13 "KS F 2563. Groung granulated blast-furnace slag for use in concrete"

14 "KS F 2421. Standard test method for air content of fresh concrete bt the pressure method : air receiver method"

15 "KS F 2405. Standard test method for compressive strength of concrete"

16 "KS F 2403. Standard test method for making and curing concrete specimens"

17 "KS F 2402. Standard test method for concrete slump"

18 David J. M. Flower, "Green house gas emissions due to concrete manufacture" Springer Science and Business Media LLC 12 (12): 282-288, 2007

19 S. Muralidharan, "Evaluation of embeddable potential sensor for corrosion monitoring in concrete structures" Elsevier BV 53 (53): 7248-7254, 2008

20 Hussain SE, "Corrosion resistance performance of fly ash blended cement concrete" 91 (91): 264-272, 1994

21 Bertolini L, "Corrosion of steel in concrete: Prevention, Diagnosis, Repair" WILEY-VCH 392-, 2003

22 Malhotra VM, "Concrete technology for a sustainable development in the 21st century" CRC Press 226-235, 1999

23 Ministry of Land, Infrastructure and Transport (KOREA), "Concrete Standard specification"

24 Michael Thomas, "Chloride thresholds in marine concrete" Elsevier BV 26 (26): 513-519, 1996

25 "ASTM Standard C876. Standard test method for half-cell potentials of uncoated reinforcing steel in concrete"