한국건설순환자원학회논문집 (Journal of the Korean Recycled Construction Resources Institute)

한국건설순환자원학회 (Korean Recycled Construction Resources Institute)
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나노 인덴테이션을 통한 경량 고강도 콘크리트 Interfacial Transition Zone (ITZ)의 역학적 특성에 관한 연구

A Study on the Mechanical Properties of Interfacial Transition Zone (ITZ) of Lightweight High Strength Concrete Via Nanoindentation

  • 임수민 (한양대학교 건축공학과) ;
  • 배성철 (한양대학교 건축공학과)
  • Im, Su-Min (Department of Architectural Engineering, Hanyang University) ;
  • Bae, Sung-Chul (Department of Architectural Engineering, Hanyang University)
  • 투고 : 2020.11.09
  • 심사 : 2020.11.12
  • 발행 : 2020.12.30
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초록

Interfacial transition zone (ITZ)은 골재-시멘트 복합체 사이의 영역으로써, 콘크리트에서 가장 취약한 영역으로 알려져 있으며, 이는 점진적으로 변화하는 불균질한 상으로 이루어져 있다. 경량 고강도 콘크리트 개발을 위해 물-바인더 비가 낮은 고강도 시멘트 복합체와 경량골재 사이의 Interfacial transition zone (ITZ)의 역학적 특성 평가는 필수적이다. 하지만 ITZ는 복잡하고 다공성 구조를 가지고 있기 때문에, 이의 역학적 특성은 아직 명확하지 않다. 또한, 경량골재 ITZ는 일반골재보다 다양한 변수 (물-바인더 비, 골재의 흡수율, 양생조건 등)에 의해 변화한다. 따라서 본 연구에서 골재의 종류 및 크기에 따른 ITZ의 역학적 특성을 분석하고자 한다. 이를 위해 나노 인덴테이션 기법을 이용하여 물-바인더 비가 0.2인 고강도 시멘트 복합체와 표준사 및 최대치수가 각각 2mm, 5mm인 경량골재 ITZ의 탄성계수를 측정하였다.

The interfacial transition zone(ITZ) which is the boundary layer between cement composites and aggregates is considered to be the region of gradual transition, heterogeneous, and the weakest part of concrete. For the development of lightweight high strength concrete, it is essential to evaluate the mechanical properties of ITZ between high strength concrete with low water-binder ratio and lightweight aggregates. However, the mechanical properties of ITZ are not well established due to its high porosity and complex structure. Furthermore, the properties of ITZ in concrete using lightweight aggregates are dominated by more various variations (e.g. water-binder ratio, water absorption capacity of aggregate, curing conditions) than normal-weight aggregate concrete. This study aims to elucidate the mechanical properties of ITZ in lightweight high-strength cement composites according to the types of aggregates and the aggregate sizes. Nanoindentation analysis was used to evaluate the elastic modulus of ITZ between high strength cement composites with the water-binder ratio of 0.2 and normal sand, lightweight aggregate with different aggregate siz es of 2mm and 5mm in this study.

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참고문헌

  1. Elsharief, A., Cohen, M.D., Olek, J. (2003). Influence of aggregate size, water cement ratio and age on the microstructure of the interfacial transition zone, Cement and Concrete Research, 33(11), 1837-1849. https://doi.org/10.1016/S0008-8846(03)00205-9
  2. Fu, J., Kamali-Bernard, S., Bernard, F., Cornen, M. (2018). Comparison of mechanical properties of CSH and portlandite between nano-indentation experiments and a modeling approach using various simulation techniques, Composites Part B: Engineering, 151, 127-138. https://doi.org/10.1016/j.compositesb.2018.05.043
  3. Huang, H., Yuan, Y., Zhang, W., Liu, B., Viani, A., Macova, P. (2019). Microstructure investigation of the interface between lightweight concrete and normal-weight concrete, Materials Today Communications, 21, 100640. https://doi.org/10.1016/j.mtcomm.2019.100640
  4. Ke, Y., Ortola, S., Beaucour, A.L., Dumontet, H. (2010). Identification of microstructural characteristics in lightweight aggregate concretes by micromechanical modelling including the interfacial transition zone (ITZ), Cement and Concrete Research, 40(11), 1590-1600. https://doi.org/10.1016/j.cemconres.2010.07.001
  5. Kong, L., Hou, L., Bao, X. (2015). Application of AC impedance technique in study of lightweight aggregate-paste interface, Construction and Building Materials, 82, 332-340. https://doi.org/10.1016/j.conbuildmat.2015.02.079
  6. Li, Y., Li, Y., Wang, R. (2019). Quantitative evaluation of elastic modulus of concrete with nanoidentation and homogenization method, Construction and Building Materials, 212, 295-303. https://doi.org/10.1016/j.conbuildmat.2019.04.002
  7. Mondal, P., Shah, S.P., Marks, L.D. (2009). Nanomechanical properties of interfacial transition zone in concrete, In Nanotechnology in Construction 3, Springer, Berlin, Heidelberg, 315-320.
  8. Nili, M., Ehsani, A. (2015). Investigating the effect of the cement paste and transition zone on strength development of concrete containing nanosilica and silica fume, Materials & Design, 75, 174-183. https://doi.org/10.1016/j.matdes.2015.03.024
  9. Oliver, W.C., Pharr, G.M. (1992). An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments, Journal of Materials Research, 7(6), 1564-1583. https://doi.org/10.1557/JMR.1992.1564
  10. Xiao, J., Li, W., Sun, Z., Lange, D.A., Shah, S.P. (2013). Properties of interfacial transition zones in recycled aggregate concrete tested by nanoindentation, Cement and Concrete Composites, 37, 276-292. https://doi.org/10.1016/j.cemconcomp.2013.01.006
  11. Yang, L., Shi, C., Wu, Z. (2019). Mitigation techniques for autogenous shrinkage of ultra-high-performance concrete-a review, Composites Part B: Engineering, 178, 107456. https://doi.org/10.1016/j.compositesb.2019.107456