Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
권호 표지
DOI QR코드

DOI QR Code

Material Performance Evaluation of PolyUrea for Structural Seismic Retrofitting

구조물 내진 보강용 폴리우레아의 재료 성능 평가

  • 조철민 (연세대학교 사회환경시스템공학부) ;
  • 최지훈 (연세대학교 사회환경시스템공학부) ;
  • 이승훈 (ECO 산업) ;
  • 김태균 ((주)홍지 기술연구소) ;
  • 김장호 (연세대학교 사회환경시스템공학부)
  • Received : 2016.08.23
  • Accepted : 2017.01.20
  • Published : 2017.04.30
Download PDF
⟨ Previous Next ⟩

Abstract

Recently, earthquakes have frequently occurred near Korean peninsula. An experimental study is needed for developing a reinforcing method for seismic strengthening to apply to RC structures. Recently, PolyUrea (PU) as structural reinforcement materials has been receiving great interest from construction industry. The reinforcing effect of PU appeared to be excellent under blast and impact as well as earthquakes. In this study, Flexible Type PolyUrea (FTPU) developed in preceding studies was modified to develop Stiff Type PolyUrea (STPU) by varying the ratio of the components of prepolymer and hardener of FTPU. The material performance evaluation has been performed through hardening time, tensile strength and percent elongation test, pull-off test, and shore hardness test. The experimental results showed that STPU has higher tensile strength and lower elongation than FTPU. Therefore, STPU coating agent can be used for semi-permanent products. By using STPU with Fiber-Reinforced Polymer (FRP) on concrete columns, confinement effect can be enhanced to maximize seismic strength and ductility.

현재 우리나라 주변에서 지진 발생이 빈번하며 철근콘크리트 구조물에 적용할 수 있는 내진보강 방법에 대한 연구가 필요한 실정이다. 최근 보수 보강 재료로 각광받고 있는 폴리우레아는 철근콘크리트 구조물 뿐 아니라 폭발 및 충격에도 우수한 성능을 검증된 바 있다. 폴리우레아를 이용하여 보강성능을 향상시킨 연질형 폴리우레아는 보수 보강의 한계점이 있기 때문에 연질형 폴리우레아의 주제와 경화제 함유량을 단계별로 달리하여 내진보강용 경질형 폴리우레아를 개발하였다. 개발된 재료의 성능을 검토하기 위하여 지속시간, 인장강도, 신장률, 부착성능, 경도 시험을 수행하였다. 내진보강용 폴리우레아의 경우 기존의 연질형 폴리우레아보다 높은 인장강도와 낮은 신장률의 성능을 나타냈다. 신장률이 높아지게 되면 보강된 구조물의 강성 효과가 저하되기 때문에 단계별 재료개발에서 낮은 신장률을 유도하였다. 따라서 내진보강용 폴리우레아 피막제의 제조는 피복에 의한 반영구적 제품을 제조할 수 있을 뿐 아니라 FRP, 강재, 부직포 등으로 보강된 기둥에 피복한다면 내진성 및 내구성을 최대로 할 수 있을 것이다.

Keywords

References

  1. KMA, Korea Meteorological Administration, Earthquake, http://www.kma.go.kr/mini/earthquake/main.jsp
  2. Woo, W.T., Kown, Y.H., and Chung, L., "Evaluation of the Seismic Performance of Existing Building Structures", Journal of the earthquake engineering society of Korea, Vol.4, No.4, 2000, pp.105-110.
  3. Chung, L., Park, T.W., and Lee, S.G., "Retrofitting Effects on Seismic Resistance Capacity of Reinforced Concrete Framed Structure", Journal of the Architectural Institute of Korea, Vol. 20, No. 9, 2004, pp. 37-44.
  4. Kim, T.H., Seong, D.J., and Shin, H.M., "Seismic Performance Assessment of Hollow Reinforced Concrete and Prestressed Concrete Bridge Columns", International Journal of Concrete Structures and Materials, Vol.6, No.3, 2012, pp.165-176. https://doi.org/10.1007/s40069-012-0015-y
  5. Heo, Y.A., and Kunnath, S.K., "Damage-Based Seismic Performance Evaluation of Reinforced Concrete Frames", International Journal of Concrete Structures and Materials, Vol.7, No.3, 2013, pp.175-182. https://doi.org/10.1007/s40069-013-0046-z
  6. Kim, S.D., "Seismic Evaluation and Retrofit of Low-rise RC Buildings in Korea", Ministry of Land Infrastructure and Transport, Business of Research and Development Annual Report, 2002.
  7. Chen, J.F., and Teng, J.G., "Anchorage Strength Models for FRP and Steel Plates Bonded to Concrete", Journal of Structural Engineering, Vol.127, No.7, 2001, pp.784-791. https://doi.org/10.1061/(ASCE)0733-9445(2001)127:7(784)
  8. Bonacci, J.F. and Maalej, M., "Behavioral Trends of RC Beams Strengthened with Externally Bonded FRP", Journal of Composites for Construction, Vol.5, No.2, 2001, pp.102-113. https://doi.org/10.1061/(ASCE)1090-0268(2001)5:2(102)
  9. Lee, S.K., Chen, Z.F., Ng, M., Tang, J.M., Wan, L. L., Liu, M., and Lee, L., "Evaluation of CFRP, GFRP and BFRP Material Systems for the Strengthening of RC Slabs", Journal of Reinforced Plastics and Composites, 2008, pp.1233-1243
  10. Kang, T.H.K., Kim, W.S., Ha, S.S., and Choi, D.U., "Hybrid Effects of Carbon-Glass FRP Sheets in Combination with or without Concrete Beams", International Journal of Concrete Structures and Materials, Vol.8, No.1, pp.27-41. https://doi.org/10.1007/s40069-013-0061-0
  11. Lorenzis, L.D., and Teng, J.G., "Near-surface Mounted FRP Reinforcement: An Emerging Technique for Strengthening Structures", Composites Part B: Engineering, Vol.38, No.2, 2007, pp.119-143. https://doi.org/10.1016/j.compositesb.2006.08.003
  12. Kang, T.H.K., and Ibrahim Ary, M., "Shear- Strengthening of Reinforced & Prestressed Concrete Beams Using FRP: Part II - Experimental Investigation", International Journal of Concrete Structures and Materials, Vol.6, No.1, 2012, pp.49-57. https://doi.org/10.1007/s40069-012-0005-0
  13. Seo, S.Y., and Kim, M.S., "Bond Strength of Near Surface- Mounted FRP Plate in Concrete Corresponding to Space and Bond Length", Journal of the Korea Concrete institute, Vol.25, No.1, 2013, pp.37-43. https://doi.org/10.4334/JKCI.2013.25.1.037
  14. Hong, S.N., Park, J.M., Park, S.K., Park, J.S., and Park, Y.H., "An Experimental Study on Flexural Behavior of RC Beams Strengthened with Near Surface Mounted Prestressed FRP", Journal of the Korea Concrete institute, Vol.18, No.6, 2006, pp.737-742. https://doi.org/10.4334/JKCI.2006.18.6.737
  15. Jang, H.N. and Lee, J.Y., "Case Study of Earthquake Damage in Korea and Other Countries", Journal of the Korean Society of Civil Engineers, Vol.55, No.4, 2007, pp.133-139.
  16. Rodrigues, H., Varum, H., Arede, A., and Costa, A.G., "Behaviour of Reinforced Concrete Column Under Biaxial Cyclic Loading-state of the Art", International Journal of Advanced Structural Engineering, Vol.5, No.1, 2013, pp. 1-12. https://doi.org/10.1186/2008-6695-5-1
  17. Kim, S.B., Kim, J.H.J., Choi, H.S., and Heo, G., "Development and Applicability Evaluation of High Performance Poly-urea for RC Construction Reinforcement", Journal of the Korean Society of Civil Engineers, Vol.30, No.2, 2010, pp.169-176.
  18. Kim, J.H.J., Park, J.C., Lee, S.W., and Kim, S.B., "Evaluation of Strengthening Performance of Stiff Type Polyurea Retrofitted RC Slab Based on Attachment Procedure", Journal of the Korea Concrete Institute, Vol.23, No.4, 2011, pp.511-520. https://doi.org/10.4334/JKCI.2011.23.4.511
  19. Park, J.C., Lee, S.W., Kim, S.B., and Kim, J.H.J., "Performance Evaluation of RC Slabs Strengthened by Stiff Type PolyUrea", Journal of the Korean Society of Civil Engineers, Vol.31, No.6, 2011, pp.457-464.
  20. Lamba, N.M.K., Woodhouse, K.A., and Cooper, S.L., "Polyureathanes in Biomedical Applications", CRC PRESS, United States of America, 1998, pp.14-23.
  21. Ha, J.H., Yi, N.H., Cho, Y.G., and Kim, J.H.J., "Experimental Study on Bond Behavior of Retrofit materials by Bond-Shear Test", Journal of the Korea Concrete institute, Vol.24, No.1, 2012, pp.45-52. https://doi.org/10.4334/JKCI.2012.24.1.045
  22. Greene, C.E., and Myers, J.J., "Flexural and Shear Behavior of Reinforced Concrete Members Strengthened with a Discrete Fiber-reinforced Polyurea System", Journal of Composites for Construction, Vol.17, No.1, 2012, pp.108-116. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000308

Cited by

  1. Performance of Combined Organic and Inorganic Hybrid Mortar as Repair Materials for Concrete Road Facilities vol.20, pp.6, 2018, https://doi.org/10.7855/IJHE.2018.20.6.109