Advances in concrete construction

  • 제6권6호
  • /
  • Pages.645-658
  • /
  • 2018
  • /
  • 2287-5301(pISSN)
  • /
  • 2287-531X(eISSN)
테크노프레스 (Techno-Press)
권호 표지
DOI QR코드

DOI QR Code

Strengthening of concrete damaged by mechanical loading and elevated temperature

  • Ahmad, Hammad (Department of Civil Engineering, University of Engineering and Technology) ;
  • Hameed, Rashid (Department of Civil Engineering, University of Engineering and Technology) ;
  • Riaz, Muhammad Rizwan (Department of Civil Engineering, University of Engineering and Technology) ;
  • Gillani, Asad Ali (Department of Civil Engineering, University of Engineering and Technology)
  • 투고 : 2018.09.12
  • 심사 : 2018.11.24
  • 발행 : 2018.12.25
⟨ 이전 논문 다음 논문 ⟩

초록

Despite being one of the most abundantly used construction materials because of its exceptional properties, concrete is susceptible to deterioration and damage due to various factors particularly corrosion, improper loading, poor workmanship and design discrepancies, and as a result concrete structures require retrofitting and strengthening. In recent times, Fiber Reinforced Polymer (FRP) composites have substituted the conventional techniques of retrofitting and strengthening of damaged concrete. Most of the research studies related to concrete strengthening using FRP have been performed on undamaged test specimens. This contribution presents the results of an experimental study in which concrete specimens were damaged by mechanical loading and elevated temperature in laboratory prior to application of Carbon Fiber Reinforced Polymer (CFRP) sheets for strengthening. The test specimens prepared using concrete of target compressive strength of 28 MPa at 28 days were subjected to compressive and splitting tensile testing up to failure and the intact pieces of the failed specimens were collected for the purpose of repair. In order to induce damage as a result of elevated temperature, the concrete cylinders were subjected to $400^{\circ}C$ and $800^{\circ}C$ temperature for two hours duration. Concrete cylinders damaged under compressive and split tensile loads were re-cast using concrete and rich cement-sand mortar, respectively and then strengthened using CFRP wrap. Concrete cylinders damaged due to elevated temperature were also strengthened using CFRP wrap. Re-cast and strengthened concrete cylinders were tested in compression and splitting tension. The obtained results revealed that re-casting of specimens damaged by mechanical loadings using concrete & mortar, and then strengthened by single layer CFRP wrap exhibited strength even higher than their original values. In case of specimens damaged by elevated temperature, the results indicated that concrete strength is significantly dropped and strengthening using CFRP wrap made it possible to not only recover the lost strength but also resulted in concrete strength greater than the original value.

키워드

참고문헌

  1. ACI 440.2R-08 (2008), Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures, American Concrete Institute Committee 440, Framingham Hills, Detroit, USA.
  2. Alsaada, A. and Hassan, G. (2017), "Utilization of CFRP for strengthening RC columns in marine environment", Case Stud. Constr. Mater., 7, 30-35. https://doi.org/10.1016/j.cscm.2017.05.002
  3. Attari, N., Amziane, S. and Chemrouk, M. (2012), "Flexural strengthening of concrete beams using CFRP, GFRP and hybrid FRP sheets", Constr. Build. Mater., 37, 746-757. https://doi.org/10.1016/j.conbuildmat.2012.07.052
  4. Bahar, D. and Oguzhan, K.T. (2010), "Effect of elevated temperature on the mechanical properties of concrete produced with finely ground pumice and silica fume", Fire Saf. J., 45, 385-391. https://doi.org/10.1016/j.firesaf.2010.08.002
  5. Bisby, L.A., Chen, J.F., Li, S.Q., Stratford, T.J., Cueva, N. and Crossling, K. (2011), "Strengthening fire-damaged concrete by confinement with fibre-reinforced polymer wraps", Eng. Struct., 33, 3381-3391. https://doi.org/10.1016/j.engstruct.2011.07.002
  6. Campione, G., La Mendola L., Monaco, A., Valenza, A. and Fiore, V. (2015), "Behavior in compression of concrete cylinders externally wrapped with basalt fibers", Compos. Part B: Eng., 69, 576-586. https://doi.org/10.1016/j.compositesb.2014.10.008
  7. Concrete Society (2008), "Assessment, design and repair of fire-damaged concrete structures", Technical Report No. 68, The Concrete Society, Camberley, Surrey, UK.
  8. Dan, D. (2012), "Experimental tests on seismically damaged composite steel concrete walls retrofitted with CFRP composites", Eng. Struct., 45, 338-348. https://doi.org/10.1016/j.engstruct.2012.06.037
  9. Freskakis, G.N., Burrow, R.C. and Debbas, E.B. (1979), "Strength properties of concrete at elevated temperature", Civil Engineering Nuclear Power, ASCE National Convention, American Soc. of Civil Eng., Boston, USA.
  10. Gao, M., Hui, L., Libo, Y. and Liang, H. (2018), "Testing and analysis of basalt FRP-confined damaged concrete cylinders under axial compression loading", Constr. Build. Mater., 169, 762-774. https://doi.org/10.1016/j.conbuildmat.2018.02.172
  11. Gao, P., Wang, J., Li, Z., Hong, L. and Wang, Z. (2018), "Effects of predamage on the compression performance of CFRP-confined rectangular steel reinforced concrete columns", Eng. Struct., 162, 109-112. https://doi.org/10.1016/j.engstruct.2018.02.026
  12. Hager, I. (2013), "Behaviour of cement concrete at high temperature", Bull. Pol. Acad. Sci., Tech. Sci., 61, 145-154.
  13. Hawileh, R.A., Rasheed, H.A., Abdalla, J.A. and Al-Tamimi, A.K (2014), "Behavior of reinforced concrete beams strengthened with externally bonded hybrid fiber reinforced polymer systems", Mater. Des., 53, 972-982. https://doi.org/10.1016/j.matdes.2013.07.087
  14. Javed, M.A., Irfan, M., Khalid, S., Chen, Y. and Ahmed, S. (2016), "An experimental study on the shear strengthening of reinforced concrete deep beams with carbon fiber reinforced polymers", KSCE J. Civil Eng., 20(7), 2802-2810. https://doi.org/10.1007/s12205-016-0739-3
  15. Jiangfeng, D., Qingyuan, W. and Zhongwei, G. (2013), "Structural behaviour of RC beams with external flexural and flexural-shear strengthening by FRP sheets", Compos. Part B: Eng., 44(1), 604-612. https://doi.org/10.1016/j.compositesb.2012.02.018
  16. Kabir, M.I., Subhani, M., Shrestha, R. and Samali, B. (2018), "Experimental and theoretical analysis of severely damaged concrete beams strengthened with CFRP", Constr. Build. Mater., 178, 161-174. https://doi.org/10.1016/j.conbuildmat.2018.05.038
  17. Kaish, A.B.M.A., Jamil, M., Raman, S.N. and Zain, M.F.M. (2015), "Axial behavior of ferrocement confined cylindrical concrete specimens with different sizes", Constr. Build. Mater., 78, 50-59. https://doi.org/10.1016/j.conbuildmat.2015.01.044
  18. Kumar, V. and Patel, P.V. (2016), "Strengthening of axially loaded circular concrete columns using stainless steel wire mesh (SSWM) - Experimental investigations", Constr. Build. Mater., 124, 186-198. https://doi.org/10.1016/j.conbuildmat.2016.06.109
  19. Kumutha, R. Vaidyanathan, R. and Palanichamy, M.S. (2007), "Behaviour of reinforced concrete rectangular columns strengthened using GFRP", Cement Concrete Compos., 29(8), 609-615. https://doi.org/10.1016/j.cemconcomp.2007.03.009
  20. Mehdi, Z., Guang, Y., Abdeldjelil, B. and Ashraf, A. (2018), "Behavior of FRP-strengthened RC elements subjected to pure shear", Constr. Build. Mater., 170(10), 378-391. https://doi.org/10.1016/j.conbuildmat.2018.03.004
  21. Meisami, M.H., Mostofinejad, D. and Nakamura, H. (2015), "Strengthening of flat slabs with FRP fan for punching shear", Compos. Struct., 119, 305-314. https://doi.org/10.1016/j.compstruct.2014.08.041
  22. Mohamedbhai, G.T.G. (1986), "Effect of exposure time and rates of heating and cooling on residual strength of heated concrete", Mag. Concrete Res., 38(136), 151-158. https://doi.org/10.1680/macr.1986.38.136.151
  23. Napoli, A. and Realfonzo, R. (2016), "Compressive behavior of concrete confined by SRP wraps", Constr. Build. Mater., 127, 993-1008. https://doi.org/10.1016/j.conbuildmat.2016.01.055
  24. Omer, A. (2007), "Effects of elevated temperatures on properties of concrete", Fire Saf. J., 42, 516-522. https://doi.org/10.1016/j.firesaf.2007.01.003
  25. Qianmin, M., Rongxin, G., Zhiman, Z., Zhiwei, L. and Kecheng, H. (2015), "Mechanical properties of concrete at high temperature-A review", Constr. Build. Mater., 93, 371-383. https://doi.org/10.1016/j.conbuildmat.2015.05.131
  26. Ruili, H., Lesley, H.S. and Belarbi, A. (2013), "Rapid repair of severely damaged RC columns with different damage conditions: An experimental study", Int. J. Concrete Struct. Mater., 7(1), 35-50. https://doi.org/10.1007/s40069-013-0030-7
  27. Wensu, C., Thong, M. P., Henry, S., Li, C. and Hong, H. (2018), "Experimental study of flexural behaviour of RC beams strengthened by longitudinal and U-shaped basalt FRP sheet", Compos. Part B: Eng., 134, 114-126. https://doi.org/10.1016/j.compositesb.2017.09.053
  28. Wu, H. and Wang, Y. (2010), "Experimental study on high-strength concrete short columns confined with AFRP sheets", Steel Compos. Struct., 10(6), 501-516. https://doi.org/10.12989/scs.2010.10.6.501
  29. Yaqub, M. and Bailey, C.G. (2011), "Repair of fire damaged circular reinforced concrete columns with FRP composites", Constr. Build. Mater., 25(1), 359-370. https://doi.org/10.1016/j.conbuildmat.2010.06.017
  30. Yaqub, M., Bailey, C.G., Nedwel, P., Khan, Q.U.Z. and Javed, I. (2013), "Strength and stiffness of post-heated columns repaired with ferrocement and fibre reinforced polymer jackets", Compos. Part B: Eng., 44(1), 200-211. https://doi.org/10.1016/j.compositesb.2012.05.041