Yüksek Sıcaklık Etkisindeki CFRP Donatıların Dayanım Kayıplarının Matematiksel Yöntemlerle Tespiti

Year 2023, Volume: 13 Issue: 3, 926 - 942, 15.09.2023

Şeymanur Arslan , Ferhat Aydın

https://doi.org/10.31466/kfbd.1273294

Abstract

Liflerle güçlendirilmiş polimer (FRP) donatılar günümüzde çelik donatıya alternatif olarak kullanılmaktadır. Ancak FRP donatılar yüksek sıcaklıklara karşı hassas bir malzemedir. Bu nedenle bu malzemelerin yüksek sıcaklıklardaki çekme dayanımındaki değişimiyle alakalı tahmin modellerinin oluşturulması önem arz etmektedir. Bu çalışmada literatürdeki CFRP donatıların yüksek sıcaklıklarda meydana gelen çekme dayanımındaki kayıpları araştırılmış ve literatürde üç araştırmacı tarafından sunulan matematiksel modellerle deneysel sonuçlar regresyon ve korelasyon analizleri yapılarak kıyaslanmıştır. Alternatif yeni bir model sunmak amacıyla literatürdeki CFRP (karbon fiber takviyeli polimer) donatıların yüksek sıcaklıklardaki çekme dayanımındaki değişimlerinin deneysel verileri incelenerek analiz edilmiştir. Çalışma sonucunda 60°C sıcaklık seviyesinin CFRP donatıların mekanik ve fiziksel özelliklerinde zarar görmediği bu nedenle bu sıcaklık seviyesinin öncesinde dayanım kaybı olmadığı ve bu sıcaklık sonrasında parabolik bir değişiminin olduğu kabulü yapılarak alternatif matematiksel model oluşturulmuştur. Sonuç olarak önerilen yeni modelin deneysel çalışmalarla uyumlu olduğu modelin yapısal uygulamalarda etkili bir tahmin aracı olabileceği düşünülmektedir.

Keywords

Yüksek sıcaklık, CFRP donatı, matematiksel model, çekme dayanımı

Determination of Strength Loss of CFRP Bars Under High Temperature by Mathematical Methods

Abstract

Fiber reinforced polymer (FRP) bars are currently used as an alternative to steel reinforcement. However, FRP bars are sensitive to high temperatures. For this reason, it is important to establish prediction models related to the change in tensile strength of these materials at high temperatures. In this study, the tensile strength losses of CFRP bars at elevated temperatures were investigated and the mathematical models presented by three researchers in the literature were compared with the experimental results through regression and correlation analyses. In order to present a new alternative model, the experimental data of CFRP (carbon fiber reinforced polymer) bars at high temperatures were analyzed As a result of the study, an alternative mathematical model was created by assuming that the 60°C temperature level does not damage the mechanical and physical properties of CFRP reinforcements, therefore there is no strength loss before this temperature level and there is a parabolic change after this temperature. As a result, it is thought that the proposed new model is compatible with experimental studies and can be an effective prediction tool in structural applications.

Keywords

Elevated temperature, CFRP bar, Mathematical model, Tensile strength

References

• ACI. (2015). “(American Concrete Institute). Guide for the design and construction of concrete reinforced with FRP bars. ACI 440.1R-15. Farmington Hills, MI.”
• Ashrafi, H., Bazli, M., Najafabadi, E. P., & Vatani Oskouei, A. (2017). The effect of mechanical and thermal properties of FRP bars on their tensile performance under elevated temperatures. Construction and Building Materials, 157, 1001–1010. https://doi.org/10.1016/J.CONBUILDMAT.2017.09.160
• Aydın, F., & Arslan, Ş. (2021). Investigation of the durability performance of FRP bars in different environmental conditions. Advances in Concrete Construction, 12(4), 295–302. https://doi.org/10.12989/acc.2021.12.4.295
• Bazli, M., & Abolfazli, M. (2020). Mechanical Properties of Fibre Reinforced Polymers under Elevated Temperatures: An Overview. Polymers 2020, Vol. 12, Page 2600, 12(11), 2600. https://doi.org/10.3390/POLYM12112600
• Bisby, L. A., & Kodur, V. K. R. (2007). Evaluating the fire endurance of concrete slabs reinforced with FRP bars: Considerations for a holistic approach. Composites Part B: Engineering, 38(5–6), 547–558. https://doi.org/10.1016/J.COMPOSITESB.2006.07.013
• Cerniauskas, G., Tetta, Z., Bournas, D. A., & Bisby, L. A. (2020). Concrete confinement with TRM versus FRP jackets at elevated temperatures. Materials and Structures/Materiaux et Constructions, 53(3), 1–14. https://doi.org/10.1617/s11527-020-01492-x
• Chen, J., & Young, B. (2006). Stress–strain curves for stainless steel at elevated temperatures. Engineering Structures, 28(2), 229–239. https://doi.org/10.1016/J.ENGSTRUCT.2005.07.005
• Chowdhury, E. U., Eedson, R., Bisby, L. A., Green, M. F., & Benichou, N. (2011). Mechanical Characterization of Fibre Reinforced Polymers Materials at High Temperature. Fire Technology, 47(4), 1063–1080. https://doi.org/10.1007/S10694-009-0116-6/FIGURES/13
• Hajiloo, H., Green, M. F., & Gales, J. (2018). Mechanical properties of GFRP reinforcing bars at high temperatures. Construction and Building Materials, 162, 142–154. https://doi.org/10.1016/J.CONBUILDMAT.2017.12.025
• Katz, A., Berman, N., & Bank, L. C. (1999). Effect of high temperature on bond strength of FRP bars. Journal of Composites for Construction, 3(2), 73–81. https://doi.org/10.1061/(ASCE)1090-0268(1999)3:2(73)
• Khaneghahi, M. H., Najafabadi, E. P., Shoaei, P., & Oskouei, A. V. (2018). Effect of intumescent paint coating on mechanical properties of FRP bars at elevated temperature. Polymer Testing, 71(May), 72–86. https://doi.org/10.1016/j.polymertesting.2018.08.020
• Kumahara, S., Masuda, Y., Tanano, H., & Shimizu, A. (1993). Tensile Strength of Continuous Fiber Bar Under High Temperature. Special Publication, 138, 731–742. https://doi.org/10.14359/3954
• Mouritz, A. P., & Arthur, G. G. (2007). Fire properties of polymer composite materials. Springer Science & Business Media.
• Nadjai, A., Talamona, D., & Ali, F. (2005). Fire performance of concrete beams reinforced with FRP bars. Proceeding of the Int Sympsium on Bond Behaviour of FRP in Structures, 401–410.
• Najafabadi, E. P., Oskouei, A. V., Khaneghahi, M. H., Shoaei, P., & Ozbakkaloglu, T. (2019). The tensile performance of FRP bars embedded in concrete under elevated temperatures. Construction and Building Materials, 211, 1138–1152. https://doi.org/10.1016/J.CONBUILDMAT.2019.03.239
• Nguyen, P. L., Hong Vu, X., & Ferrier, E. (2019). Thermo-mechanical performance of Carbon Fiber Reinforced Polymer (CFRP), with and without fire protection material, under combined elevated temperature and mechanical loading conditions. Composites Part B: Engineering, 169(April 2018), 164–173. https://doi.org/10.1016/j.compositesb.2019.03.075
• Nigro, E., Bilotta, A., Cefarelli, G., Manfredi, G., & Cosenza, E. (2012). Performance under Fire Situations of Concrete Members Reinforced with FRP Rods: Bond Models and Design Nomograms. Article in Journal of Composites for Construction. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000279
• Rafi, M. M., Nadjai, A., Ali, F., & O’Hare, P. (2011). Evaluation of Thermal Resistance of FRP Reinforced Concrete Beams in Fire. Journal of Structural Fire Engineering, 2(2), 91–107.
• Rami Hamad, J. A., Megat Johari, M. A., & Haddad, R. H. (2017). Mechanical properties and bond characteristics of different fiber reinforced polymer rebars at elevated temperatures. Construction and Building Materials, 142, 521–535. https://doi.org/10.1016/J.CONBUILDMAT.2017.03.113
• Rosa, I. C., Firmo, J. P., Correia, J. R., & Barros, J. A. O. (2019). Bond behaviour of sand coated GFRP bars to concrete at elevated temperature – Definition of bond vs. slip relations. Composites Part B: Engineering, 160, 329–340. https://doi.org/10.1016/J.COMPOSITESB.2018.10.020
• Saafi, M. (2002). Effect of fire on FRP reinforced concrete members. Composite Structures, 58(1), 11–20. https://doi.org/10.1016/S0263-8223(02)00045-4
• Sharifianjazi, F., Zeydi, P., Bazli, M., Esmaeilkhanian, A., Rahmani, R., Bazli, L., & Khaksar, S. (2022). Fibre-Reinforced Polymer Reinforced Concrete Members under Elevated Temperatures: A Review on Structural Performance. Polymers, 14(3). https://doi.org/10.3390/polym14030472
• Wang, K., Young, B., & Smith, S. T. (2011). Mechanical properties of pultruded carbon fibre-reinforced polymer (CFRP) plates at elevated temperatures. Engineering Structures, 33(7), 2154–2161. https://doi.org/10.1016/J.ENGSTRUCT.2011.03.006
• Wang, Y. C., Wong, P. M. H., & Kodur, V. (2007). An experimental study of the mechanical properties of fibre reinforced polymer (FRP) and steel reinforcing bars at elevated temperatures. Composite Structures, 80(1), 131–140. https://doi.org/10.1016/J.COMPSTRUCT.2006.04.069
• Yoo, S. J., Kim, Y. H., Yuan, T. F., & Yoon, Y. S. (2022). Evaluation of residual bond behavior of CFRP and steel bars embedded in UHPC after exposure to elevated temperature. Journal of Building Engineering, 56, 104768. https://doi.org/10.1016/J.JOBE.2022.104768
• Yoo, S. W., & Choo, J. F. (2022). Behavior of CFRP-reinforced concrete columns at elevated temperatures. Construction and Building Materials, 358(October), 129425. https://doi.org/10.1016/j.conbuildmat.2022.129425
• Yu, B., & Kodur, V. (2014). Effect of temperature on strength and stiffness properties of near-surface mounted FRP reinforcement. Composites Part B: Engineering, 58, 510–517. https://doi.org/10.1016/J.COMPOSITESB.2013.10.055