DOI QR코드

DOI QR Code

팽창재와 수축저감제를 사용한 HPFRCC의 수축 저감 성능

Shrinkage Reduction Performance of HPFRCC Using Expansive and Srhinkage Reducing Admixtures

  • 박정준 (한국건설기술연구원 인프라구조연구실) ;
  • 문재흠 (한국건설기술연구원 인프라구조연구실) ;
  • 박준형 (한국건설기술연구원 인프라구조연구실) ;
  • 이장화 (한국건설기술연구원 인프라구조연구실) ;
  • 김성욱 (한국건설기술연구원 인프라구조연구실)
  • 투고 : 2014.06.26
  • 심사 : 2014.08.01
  • 발행 : 2014.09.30

초록

HPFRCC는 물-결합재비 (W/B)가 20%로 상당히 낮고 굵은 골재를 사용하지 않으며, 고분말 혼화재료를 혼입하기 때문에 자기수축이 상당히 크게 발생하여 구조물 적용 시 균열저감대책이 필요하다. 따라서 이 연구에서는 HPFRCC의 수축을 효율적으로 저감시키기 위한 방법으로 수축저감제와 팽창재의 사용을 검토하기 위하여 이들의 단독 또는 병행 혼입률에 따른 역학적 특성과 구속 수축특성을 평가하였다. 구속수축 실험 중에서 링-테스트 (Ring-test)를 통하여 HPFRCC에 사용되는 시멘트에 대하여 중량비로 수축저감제 1%와 팽창재를 7.5%를 병행 사용하였을 경우 압축강도와 인장강도가 크게 저하되지 않으면서도 수축을 가장 효율적으로 저감시킬 수 있는 최적 배합임을 도출하였고 수정된 건조수축 균열실험을 통하여 이를 검증하였다.

High-performance fiber-reinforced cement composite (HPFRCC) shows very high autogenous shrinkage, because it contains a low water-to-binder ratio (W/B) of 0.2 and high fineness admixture without coarse aggregate. Thus, it needs a method to decrease the cracking potential. Accordingly, in this study, to effectively reduce the shrinkage of HPFRCC, a total of five different ratios of SRA (1% and 2%), EA (5% and 7.5%), and a combination of SRA and EA (1% and 7.5%) were considered. According to the test results of ring-test, a combination of SRA and EA (1% and 7.5%) showed best performance regarding restrained shrinkage behavior without significant deterioration of compressive and tensile strengths. This was also verified by performing modified drying shrinkage crack test.

키워드

참고문헌

  1. Bentz, D. P. (2006), Influence of shrinkage-reducing admixtures on early-age properties of cement pastes, Journal of Advanced Concrete Technology, 4(3), 423-429. https://doi.org/10.3151/jact.4.423
  2. Graybeal, B. A. (2008), Flexural behavior of an ultra high performance concrete I-girder, Journal of Bridge Engineering, ASCE, 13, 602-610. https://doi.org/10.1061/(ASCE)1084-0702(2008)13:6(602)
  3. Hossain, A. B., and Weiss, W. J. (2004), Assessing Residual Stress Development and Stress Relaxation in Restrained Concrete Ring Specimens, Cement and Concrete Composites, 26, 531-540. https://doi.org/10.1016/S0958-9465(03)00069-6
  4. Kamen, A., Denarie, E., Sadouki, H., and Bruhwiler, E. (2009), UHPFRC Tensile Creep at Early Age, Materials and Structures, 42(1), 113-122. https://doi.org/10.1617/s11527-008-9371-0
  5. Kang, S. T., and Kim, J. K. (2011), The relation between fiber orientation and tensile behavior in an Ultra High Performance Fiber Reinforced Cementitious Composites (UHPFRCC), Cement and Concrete Research, 41, 1001-1014. https://doi.org/10.1016/j.cemconres.2011.05.009
  6. KICT (2012), Development of Ultra High Performance Concrete for Hybrid Stayed Cable Bridge, Report No. KICT 2012-083, Korea Institute of Construction Technology, Korea (in Korean, with English abstract).
  7. Kim, S. W., Park, J. J, Kang, S. T., Ryo, G. S., and Koh, K. T. (2008), Development of ultra high performance cementitious composites (UHPCC) in Korea, Proceedings of the Fourth International IABMAS Conference, Seoul, Korea, 110.
  8. Li, Z., Qi, M., Li, Z., and Ma, B. (1999), Crack width of highperformance concrete due to restrained shrinkage, Journal of Materials in Civil Engineering, ASCE, 11, 214-223. https://doi.org/10.1061/(ASCE)0899-1561(1999)11:3(214)
  9. Maltese, C., Pistolesi, C., Lolli A, Bravo, A., Cerulli, T., and Salvioni, D. (2005), Combined effect of expansive and shrinkage reducing admixtures to obtain stable and durable mortars, Cement and Concrete Research, 35(12), 2244-2251. https://doi.org/10.1016/j.cemconres.2004.11.021
  10. Park, J. J., Kim, S. W., Ryu, G. S., and Lee, K. M. (2011), The influence of chemical admixtures on the autogenous shrinkage ultra-high performance concrete, Key Engineering Materials, 425-453, 725-728.
  11. Park, J. J., Yoo, D. Y., Kim, S. W., and Yoon, Y. S. (2013), Drying Shrinkage Cracking Characteristics of Ultra-High Performance Fiber Reinforced Concrete with Expansive and Shrinkage Reducing Agents, Magazine of Concrete Research, 65, 248-256. https://doi.org/10.1680/macr.12.00069
  12. Park, J. J., Yoo, D. Y., Kim, S. W., and Yoon, Y. S. (2014), Benefits of using expansive and shrinkage-reducing agents in UHPC for volume stability, Magazine of Concrete Research, 66, 745-750. https://doi.org/10.1680/macr.13.00317
  13. Park, S. H., Kim, D. J., Koh, K. T., and Ryu, G. S. (2012), Influence of adding shrinkage reducing agent on the interfacial bond strength of steel fibers embedded in UHPC, Proceeding of the Korea Concrete Institute, 24(2), 535-536 (in Korean, with English abstract).
  14. See, H. T., Attiogbe, E. K., and Miltenberger, M. A. (2003), Shrinkage Cracking Characteristics of Concrete Using Ring Specimens, ACI Materials Journal, 100(3), 239-245.
  15. Weiss, W. J. (1999), Prediction of Early-Age Shrinkage Cracking in Concrete, Ph.D. thesis, Northwestern University, Evanston, IL, USA.
  16. Yoo, D. Y., Park, J. J., Kim, S. W., and Yoon Y. S. (2011), Characteristics of Early-Age Restrained Shrinkage and Tensile Creep of Ultra-High Performance Cementitious Composites (UHPCC), Journal of Korea Concrete Institute, 23(5), 581-590 (in Korean, with English abstract). https://doi.org/10.4334/JKCI.2011.23.5.581
  17. Yoo, D. Y., Park, J. J., Kim, S. W., and Yoon, Y. S. (2011), Characteristics of Early-Age Restrained Shrinkage and Tensile Creep of Ultra-High Performance Cementitious Composites (UHPCC), Journal of Korea Concrete Institute, 23(5), 581-590 (in Korean). https://doi.org/10.4334/JKCI.2011.23.5.581
  18. Yoo, D. Y., Park, J. J., Kim, S. W., and Yoon, Y. S. (2013), Early age setting, shrinkage and tensile characteristics of ultra high performance fiber reinforced concrete, Construction and Building Materials, 41, 427-438. https://doi.org/10.1016/j.conbuildmat.2012.12.015