Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
권호 표지
DOI QR코드

DOI QR Code

Rheology Control of Cement Paste for Applying ECC Produced with Slag Particles to Self-Consolidating and Shotcreting Process

고로슬래그 미분말이 혼입된 자기충전 및 숏크리트용 ECC의 개발을 위한 시멘트풀 레올로지 제어

  • Park, Seung-Bum (Dept. of Civil Engineering, Chungnam National University) ;
  • Kim, Jeong-Su (Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, Yun-Yong (Dept. of Civil Engineering, Chungnam National University)
  • 박승범 (충남대학교 토목공학과) ;
  • 김정수 (한국과학기술원 건설및환경공학과) ;
  • 김윤용 (충남대학교 토목공학과)
  • Published : 2008.02.29
Download PDF
⟨ Previous Next ⟩

Abstract

An engineered cementitious composite produced with slag particles (Slag-ECC) had been developed based on micromechanical principle. Base grain ingredients were properly selected, and then the mixture proportion was optimized to be capable of achieving robust tensile ductility in the hardened state. The rheological design is performed in the present study by optimizing the amount of admixtures suitable for self-consolidating casting and shotcreting process in the fresh state. A special focus is placed on the rheological control which is directly applicable to the construction in field, using prepackaged product with all pulverized ingredients. To control the rheological properties of the composite, which possesses different fluid properties to facilitate two types of processing (i.e., self-consolidating and shotcreting processing), the viscosity change of the cement paste suspensions over time was initially investigated, and then the proper dosage of the admixtures in the cement paste was selected. The two types of mixture proportion were then optimized by self-consolidating & shotcreting tests. A series of self-consolidating and shotcreting tests demonstrated excellent self-consolidation property and sprayability of the Slag-ECC. The rheological properties altered through this approach were revealed to be effective in obtaining Slag-ECC hardened properties, represented by pseudo strain-hardening behavior in uniaxial tension, allowing the readily achievement of the desired function of the fresh Slag-ECC. These ductile composites with self-consolidating and shotcreting processing can be broadly utilized for a variety of applications, e.g., in strengthening seismic resistant structures with congested reinforcements, or in repairing deteriorated infrastructures by shotcreting process.

마이크로역학을 기초로 하여 Slag-ECC (고로슬래그 미분말이 혼입된 ECC)가 개발되었으며, 기존의 연구에서는 Slag-ECC가 높은 연성을 나타내도록 마이크로역학을 도입하여 재료의 배합비가 제시되었다. 이 연구에서는 Slag-ECC의 자기충전과 숏크리트 시공성을 구현하기 위하여, Slag-ECC의 기본 배합에 혼화재료의 투입 순서에 상관없이 혼화재료를 한번에 투입하여 유동 특성을 제어하는 레올로지 개념을 도입하였으며, 이는 현장에서 시공성을 높이기 위하여 모든 재료를 분말의 형태로 사용하는 프리팩키지화를 위한 기초 자료로 사용될 것이다. 그리고 자기충전과 숏크리트의 서로 상반되는 레올로지 특성을 구현하기 위하여, 시멘트풀 레올로지 경시 변화 연구를 통해 대략적인 혼화재료의 첨가량을 선정하였고, 자기충전 및 숏크리트의 시공성 검증을 통해 재료의 배합비를 최적화 하였다. 개발된 Slag-ECC의 자기충전성과 숏크리트 적합성은 실험을 통하여 입증되었으며, 자기충전 및 숏크리트의 시공 방법에 의하여 타설된 재료가 굳은 이후에도 Slag-ECC의 역학적 특성인 고인성 특성을 유지하는 것으로 나타났다. 따라서 시멘트풀의 레올로지 특성을 조절하여 개발된 자기충전용 Slag-ECC와 숏크리트용 Slag-ECC는 재료의 고인성 특성을 유지하면서 다양한 현장 적용이 가능할 것으로 판단된다.

Keywords

References

  1. Li, V. C. and Wu, H. C., "Conditions for Pseudo Strain-Hardening in Fiber Reinforced Brittle Matrix Composites", Journal Applied Mechanics Review, Vol.45, No.8, 1992, pp.390-398 https://doi.org/10.1115/1.3119767
  2. Li, V. C. and Leung, C. K. Y., "Steady State and Multiple Cracking of Short Random Fiber Composites", Journal of Engineering Mechanics, ASCE, Vol.188, No.11, 1992, pp.2246-2264
  3. Marshall, D. B. and Cox, B. N., "A J-Integral Method for Calculating Steady-State Matrix Cracking Stresses in Composites", Mechanics of Materials, No.8, 1988, pp.127-133
  4. 김윤용, 김정수, 김희신, 하기주, 김진근, "마이크로역학에 의하여 설계된 ECC (Engineered Cementitious Composite)의 역학적 특성", 콘크리트학회 논문집, 17권 5호, 2005, pp.707-714
  5. 김윤용, 김정수, 하기주, 김진근, "고로슬래그 미분말이 혼입된 ECC의 개발", 콘크리트학회 논문집, 18권 1호, 2006, pp.21-28 https://doi.org/10.4334/JKCI.2006.18.1.021
  6. Kim, Y. Y., Kong, H. J, and Li, V. C., "Design of Engineered Cementitious Composite Suitable for Wet-Mixture Shotcreting", ACI Materials Journal, Vol.100, No.6, 2003, pp.511-518
  7. Kong, H. J., Bike, S., and Li, V. C., "Development of a Self-Consolidating Engineered Cementitious Composite Employing Electrosteric Dispersion/Stabilization", J. Cement and Concrete Composites, Vol.25, No.3, 2003, pp.301-309 https://doi.org/10.1016/S0958-9465(02)00057-4
  8. Kanda, T. and Li, V. C., "A New Micromechanics Design Theory for Pseudo Strain Hardening Cementitious Composite", ASCE Journal of Engineering Mechanics, Vol.125, No.4, 1999, pp.373-381 https://doi.org/10.1061/(ASCE)0733-9399(1999)125:4(373)
  9. Wu, C., "Micromechanical Tailoring of PVA-ECC for Structural Applications", Ph. D. Thesis, Ann Arbor, University of Michigan, 2000, 238pp.
  10. Kim, J. K., Kim, J. S., Ha, G. J., and Kim, Y. Y., "Tensile and Fiber Dispersion Performance of ECC Produced with Ground Granulated Blast Furnace Slag", Cement and Concrete Research, Vol.37, No.7, 2007, pp.1096-1105 https://doi.org/10.1016/j.cemconres.2007.04.006
  11. Li, V. C., "Reflections on the Research and Development of Engineered Cementitious Composites (ECC)", Proceedings of the JCI International Workshop on Ductile Fiber Reinforced Cementitious Composites (DFRCC) - Application and Evaluation (DRFCC- 2002), Takayama, Japan, 2002, pp.1-21
  12. Li, V. C., Wu, C., Wang, S., Ogawa, A., and Saito, T., "Interface Tailoring for Strain-Hardening PVA-ECC", ACI Materials Journal, Vol.99, No.5, 2002, pp.463-472
  13. Lewis, J. A., "Polyelectrolyte Effects on the Rheological Properties of Concentrated Cement Suspensions", Journal of the American Ceramic Society, Vol.83, 2000, pp.1905-1913 https://doi.org/10.1111/j.1151-2916.2000.tb01489.x
  14. Yoshioka, K., Sakai, E., Daimon, M., and Kitahara, A., "Role of Steric Hindrance in the Performance of Superplasticizers for Concrete", Journal of the American Ceramic Society, Vol.80, No.10, 1997, pp.2667-2671 https://doi.org/10.1111/j.1151-2916.1997.tb03169.x
  15. Kong, H. J., Bike, S., and Li, V. C., "Effects of a Strong Polyelectrolyte on the Rheological Properties of Concentrated Cementitious Suspensions", Cement and Concrete Research, 2006, Vol.36, pp.851-857 https://doi.org/10.1016/j.cemconres.2006.02.006
  16. Kong, H. J., Bike, S., and Li, V. C., "Electrosteric Stabilization of Concentrated Cement Suspensions Imparted by a Strong Anionic Polyelectrolyte and a Non-ionic Polymer", Cement and Concrete Research, 2006, Vol.36, pp.842-850 https://doi.org/10.1016/j.cemconres.2006.02.012
  17. Okamura, R. H. and Ozawa, K., "Mix-Design for Self-Compacting Concrete", Concr Lib JSCE, Vol.25, 1995, pp.107-120

Cited by

  1. Bond Properties of Structural Poly Vinyl Alcohol Fiber in Cement Based Composites with Metakaolin and Silica Fume Contents vol.54, pp.5, 2012, https://doi.org/10.5389/KSAE.2012.54.5.009
  2. Characteristics of Natural Hydraulic Lime Mortar Mixed with Basalt Fiber vol.24, pp.6, 2015, https://doi.org/10.7844/kirr.2015.24.6.61