Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Autogeneous Shrinkage Characteristics of Ultra High Performance Concrete

초고성능 콘크리트의 자기수축 특성

  • Kim, Sung-Wook (Structural Engineering & Bridges Research Division Infrastructure Research Dept., Korea Institute of Construction Technology) ;
  • Choi, Sung (Technology Research Center, Tong Yang Major Corporation) ;
  • Lee, Kwang-Myong (Dept. of Civil and Environmental Engineering System, Sungkyunkwan University) ;
  • Park, Jung-Jun (Structural Engineering & Bridges Research Division Infrastructure Research Dept., Korea Institute of Construction Technology)
  • 김성욱 (한국건설기술연구원 구조교량연구실) ;
  • 최성 (동양메이저 기술연구소) ;
  • 이광명 (성균관대학교 건설환경시스템공학과) ;
  • 박정준 (한국건설기술연구원 구조교량연구실)
  • Received : 2010.12.27
  • Accepted : 2011.03.24
  • Published : 2011.06.30
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Abstract

Recently, the use of UHPC made of superplasticizers, silica fume, and steel fibers has been increasing worldwide. Although UHPC has a very high strength as well as an excellent durability performance due to its dense microstructures, earlyage cracks may occur due to the high heat of hydration and autogenous shrinkage caused by low W/B and high unit cement content. The early-age shrinkage cracking of UHPC can be controlled by using the shrinkage reducers and expansive admixtures having autogenous shrinkage compensation effect. In this paper, ultrasonic pulse velocity of UHPC containing shrinkage reducers and expansive agents was measured to predict its stiffness change. Also, the effect of shrinkage reducers and expansive agents on the autogenous shinkage of UHPC was investigated through the shrinkage test of UHPC specimens. Furthermore, the material coefficients of autogenous shrinkage prediction model were determined using the autogenous shrinkage values of UHPC with age. Consequently, the test results showed that, by adding shrinkage reducers and expansive agents, the stiffness of UHPC was rapidly developed at early-ages and the autogenous shrinkage was considerably reduced.

최근 고성능 감수제, 실리카 퓸과 강섬유 등을 사용하여 제조한 초고성능 콘크리트(UHPC)의 사용이 전 세계적으로 증가하고 있다. UHPC는 강도가 높을 뿐만 아니라 조직이 치밀하여 내구성 측면에서도 우수한 성능을 갖고 있지만 W/B가 낮고 단위 시멘트량이 많기 때문에 초기 수화열과 자기수축이 많이 발생하여 재령 초기에 균열 발생 위험성이 높아지게 된다. UHPC의 초기 수축균열은 수축 저감제 및 팽창재의 자기수축 보상 효과에 의하여 제어할 수 있다. 이 연구에서는 수축 저감제 및 팽창재를 혼입한 UHPC의 초음파 속도를 측정하여 재령 초기 강성 변화를 추정하였고, 수축 실험을 통하여 수축 저감제 및 팽창재가 UHPC의 자기수축에 미치는 영향을 조사하였다. 또한 UHPC의 자기 수축 실험 결과로부터 자기수축 예측 모델의 재료 상수를 결정하였다. 결론적으로 수축 저감제 및 팽창재를 혼입함에 따라 UHPC 강성이 신속하게 발현되며, 자기수축 저감에 효과가 있음을 알 수 있었다.

Keywords

References

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  1. Tensile Stress-Crack Opening Relationship of Ultra High Performance Cementitious Composites(UHPCC) Used for Bridge Decks vol.17, pp.1, 2013, https://doi.org/10.11112/jksmi.2013.17.1.046
  2. Mechanical Properties and Autogenous Shrinkage of Ultra High Performance Concrete Using Expansive Admixture and Shrinkage Reducing Agent depending on Curing Conditions vol.16, pp.11, 2015, https://doi.org/10.5762/KAIS.2015.16.11.7910
  3. Effect of Internal Curing by Super-Absorbent Polymer (SAP) on Hydration, Autogenous Shrinkage, Durability and Mechanical Characteristics of Ultra-High Performance Concrete (UHPC) vol.28, pp.3, 2016, https://doi.org/10.4334/JKCI.2016.28.3.317