Pultruded GFRP Reinforcing Bars with Carbon Nanotubes

  • Rahulreddy Chennareddy
  • Amr Riad
  • Mahmoud M. Reda Taha
Conference paper


Pultrusion is a renowned method in industry to produce glass fiber reinforced polymer (GFRP) reinforcing bars. Pristine multiwalled carbon nanotubes (P-MWCNTs) and multiwalled carbon nanotubes (MWCNTs) with carboxyl functional group (COOH-MWCNTs) were dispersed into the vinyl ester resin to produce GFRP bars. The GFRP bars were produced using a pultrusion prototype facility recently developed at the University of New Mexico. Direct tension and short beam shear tests were conducted to determine the mechanical properties of the nano-modified GFRP reinforcing bars. The experimental program shows the ability of MWCNTs to improve the mechanical behavior of GFRP reinforcing bars by 20% and 111% for the tensile and shear strength, respectively. Of particular interest is the absence of the typical broom failure observed in neat GFRP when functionalized MWCNTs were used. The proposed nano-modification of GFRP using MWCNTs might enable overcoming many of the current limitations of GFRP reinforcing bars.



This work is funded by the TranSET University Transportation Center (UTC). The authors greatly acknowledge this support.


  1. 1.
    Nkurunziza, G., Debaiky, A., Cousin, P., & Benmokrane, B. (2005). Durability of GFRP bars: A critical review of the literature. Progress in Structural Engineering and Materials, 7(4), 194–209.CrossRefGoogle Scholar
  2. 2.
    Kumar, M. S., Raghavendra, K., Venkataswamy, M. A., & Ramachandra, H. V. (2012). Fractographic analysis of tensile failures of aerospace grade composites. Materials Research, 15(6), 990–997.CrossRefGoogle Scholar
  3. 3.
    Brown, D. L., & Berman, J. W. (2010). Fatigue and strength evaluation of two glass fiber-reinforced polymer bridge decks. Journal of Bridge Engineering, 15(3), 290–301.CrossRefGoogle Scholar
  4. 4.
    CSA S6. (2010). Canadian highway bridge design code (CHBCD). Mississauga: Canadian Standards Association International.Google Scholar
  5. 5.
    Yost, J. R., Gross, S. P., & Dinehart, D. W. (2001). Shear strength of normal strength concrete beams reinforced with deformed GFRP bars. Journal of Composites for Construction, 5(4), 268–275.CrossRefGoogle Scholar
  6. 6.
    Sobrino, J. A., & Pulido, M. (2002). Towards advanced composite material footbridges. Structural Engineering International, 12(2), 84–86.CrossRefGoogle Scholar
  7. 7.
    Sydlik, S. A., Lee, J. H., Walish, J. J., Thomas, E. L., & Swager, T. M. (2013). Epoxy functionalized multi-walled carbon nanotubes for improved adhesives. Carbon, 59, 109–120.CrossRefGoogle Scholar
  8. 8.
    Eklund, P., Ajayan, P., Blackmon, R., Hart, A. J., Kibng, J., Pradhan, B., et al. (2007). International assessment of research and development of carbon nanotube manufacturing and applications. Baltimore: World Technology Evaluation Center.Google Scholar
  9. 9.
    Mylvaganam, K., & Zhang, L. C. (2007). Fabrication and application of polymer composites comprising carbon nanotubes. Recent Patents on Nanotechnology, 1(1), 59–65.CrossRefGoogle Scholar
  10. 10.
    ASTM D7205/D7205M-06. (2016). Standard test method for tensile properties of fiber reinforced polymer matrix composite bars. West Conshohocken: ASTM International.Google Scholar
  11. 11.
    ASTM D4475-02. (2016). Standard test method for apparent horizontal shear strength of pultruded reinforced plastic rods. West Conshohocken: ASTM International.Google Scholar
  12. 12.
    ASTM D3171-15. (2015). Standard test methods for constituent content of composite materials. West Conshohocken: ASTM International.Google Scholar
  13. 13.
    Reda Taha, M., Chennareddy, R., & Riad, A. (2017) Smart ester-based high performance pultruded GFRP with self-sensing capabilities and methods of making, Provisional US Patent filed, October 2017.Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Rahulreddy Chennareddy
    • 1
  • Amr Riad
    • 2
  • Mahmoud M. Reda Taha
    • 1
  1. 1.Department of Civil EngineeringUniversity of New MexicoAlbuquerqueUSA
  2. 2.Department of Civil Engineering, Faculty of EngineeringAl-Azhar UniversityCairoEgypt

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