Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Assessment of Bond Characteristics between New and Old Concrete in Various Mixtures and Joint Conditions

배합 및 접합면 처리에 따른 신·구 콘크리트의 부착특성 평가

  • Cho, Byeong-Du (Railway & Metro Division, Dohwa Engineering) ;
  • Kim, Sang-Hyun (Dept. of Civil Systems Engineering, Ajou University) ;
  • Jeon, Se-Jin (Dept. of Civil Systems Engineering, Ajou University)
  • 조병두 (도화엔지니어링 철도부문) ;
  • 김상현 (아주대학교 건설시스템공학과) ;
  • 전세진 (아주대학교 건설시스템공학과)
  • Received : 2014.03.24
  • Accepted : 2014.04.29
  • Published : 2014.08.30
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Abstract

Although the construction joints of a concrete structure are properly treated with some measures, leakage has frequently occurred. A series of tests on the bond characteristics between new and old concrete were carried out in this study, assuming that the leakage at the construction joints has certain relationship with the bond of concrete. To assess the bond characteristics under various conditions, a number of specimens were made that have an interface between new and old concrete and bond strength, flexural strength and splitting tensile strength were measured. Main test variables are type and amount of mineral admixtures, treatment method of the interface and type of waterstops. In addition, the effects of placing interval between the concrete and of the age of the strength tests were investigated. The test results showed a slightly increased bond strength when applying mineral admixtures, which can be attributed to the interface filled with the calcium silicate hydrate that is formed by pozzolanic reaction. On the other hand, the bond strength was higher when the interface was treated rough and dry, and the roughness of a waterstop affected the bond capacity of the waterstop. Also, an assessment is required that considers the type of strength test because the bond strength varied according to the test methods.

콘크리트 구조물의 시공이음부는 적절한 처리에도 불구하고 누수되는 사례가 빈번히 발생되고 있다. 이 연구에서는 이러한 누수 현상이 신 구 콘크리트 간의 부착특성과도 관련이 있을 것으로 보고 이에 대한 실험을 실시하였다. 여러가지 조건하에서 부착특성을 평가하기 위해 신 구 콘크리트의 접합부를 모사하는 시편들을 제작하여 접합부의 접착강도, 휨강도 및 쪼갬인장강도를 측정하였다. 주요 실험 변수는 혼화재의 종류 및 혼입률, 접합면의 처리 방법, 지수판의 종류였다. 그 외 신 구 콘크리트 타설 간격의 영향, 강도시험 재령에 따른 영향도 고찰하였다. 실험 결과 혼화재 사용에 따라 부착강도가 어느정도 증가하는 것으로 나타났는데, 이는 포졸란 반응에 의해 생성되는 칼슘실리케이트 수화물이 접합부의 공극을 메우기 때문으로 생각된다. 한편, 접합면이 거칠고 건조할수록 부착성능이 향상되었으며, 지수판의 표면 거칠기는 지수판의 부착성능에 영향을 미치는 것으로 나타났다. 또한 시험 방법에 따른 부착강도의 차이가 발생하므로 이를 고려한 평가가 요망된다.

Keywords

References

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