Determination of the GFRP Reinforcement-Concrete Bond Strength from Pull-Out Tests Resulting in the Debonding Failure

Abstract

Fiber reinforced polymer (FRP) bars have begun to be used as an alternative to conventional steel reinforcing bars in reinforced concrete structures, especially due to their high resistance to corrosion and high tensile strength. However, their bond behavior with concrete is different than steel because of their different mechanical and physical properties compared to steel reinforcing bars. The bond behavior of FRP bars with concrete depends on many parameters such as concrete compressive strength, clear cover, embedment length, bar diameter, location of the bar, bar surface properties. Different international FRP-reinforced concrete codes recommended various equations for estimating the FRP-concrete bond strength. These equations were established using experimental results that resulted in splitting concrete failure. However, the maximum bond strength cannot be determined from the loss of bond strength due to the fracture of concrete and the parameters affecting the bond strength cannot be fully determined from the specimens failed in splitting. For this reason, the validity of the equations originating from the experiments ended up in the splitting failure must be discussed. The present study aimed at developing a bond strength equation between concrete and glass reinforced polymer (GFRP) by using multiple linear regression analysis on a total of 243 pull-out experiments from the literature that resulted in pullout failure. The proposed bond strength equation was observed to yield to more consistent values with the experimental results compared to the respective values from the international code equations.

Keywords

• GFRP rebar,bond strength,glass fiber reinforced polymer rebar

GFRP DONATI-BETON ARASINDAKİ ADERANS GERİLMESİNİN SIYRILMA GÖÇME TİPİ İLE SONUÇLANAN ÇEKİP ÇIKARMA DENEYLERİ İLE TESPİTİ

Abstract

Lif takviyeli polimer donatılar (FRP) özellikle korozyona uğramama ve yüksek çekme dayanımları nedeniyle betonarme yapılarda çelik donatıya alternatif olarak kullanılmaya başlanmıştır. Ancak, mekanik ve fiziksel özelliklerinin çelik donatıya göre farklı olmasından dolayı, FRP donatıların beton ile olan aderans davranışları çelikten farklıdır. FRP donatının beton ile olan aderans davranışı, beton basınç dayanımına, pas payına, donatı gömülme boyuna, donatı çapına, donatının konumuna ve donatı yüzey özelliği gibi daha birçok değişkene bağlıdır. Farklı uluslararası FRP donatılı beton yönetmelikleri, donatı aderansının tahmininde kullanılacak çeşitli bağıntılar önermişlerdir. Bu bağıntılar, donatının betondan ayrışması ile sonuçlanan deneylerin sonuçları kullanılarak oluşturulmuştur. Ancak, ayrışma ile sonuçlanan numunelerde, betonun çatlamasından doğan aderans kaybı neticesinde maksimum aderans belirlenemeyeceği için aderansı etkileyen değişkenler tam olarak tespit edilemez. Bu nedenle ayrışma göçme tipi ile sonuçlanan deneyler ile ortaya konan bağıntıların geçerliliği tartışmalıdır. Bu çalışmada, literatürde mevcut donatı sıyrılması ile sonuçlanan 243 adet çekip çıkarma deneyinden yararlanılarak,  çoklu doğrusal regresyon analizi ile cam takviyeli polimer donatıların (GFRP) beton ile aralarındaki aderans bağıntısının tespit edilmesi amaçlanmıştır. Çalışma sonucunda önerilen bağıntı kullanılarak tahmin edilen aderans gerilmesi değerlerinin, uluslararası yönetmeliklerde geçen bağıntılar ile elde edilen değerlerden daha tutarlı sonuçlar verdiği görülmüştür.

Keywords

• GFRP donatı,donatı aderansı,cam takviyeli polimer donatı

References

1. 1. Achillides, Z. (1998) Bond behaviour of FRP bars in concrete, PhD Thesis, The University of Sheffield.
2. 2. Achillides, Z. and Pilakoutas, K. (2004) Bond Behavior of Fiber Reinforced Polymer Bars under Direct Pullout Conditions, Journal of Composites for Construction, 8(2), 173–181. doi:10.1061/(ASCE)1090-0268(2004)8:2(173)
3. 3. ACI 440 1R-06, (2006) Guide for the Design and Construction of Structural Concrete Reinforced with Fiber-Reinforced Polymer (FRP) Bars, American Concrete Institute (ACI).
4. 4. ACI 440 1R-15, (2015) Guide for the Design and Construction of Structural Concrete Reinforced with Fiber-Reinforced Polymer (FRP) Bars, American Concrete Institute (ACI).
5. 5. Aiello, M. A., Leone, M. and Pecce, M. (2007) Bond Performances of FRP Rebars-Reinforced Concrete, Journal of Materials in Civil Engineering, 19(3), 205–213. doi:10.1061/(ASCE)0899-1561(2007)19:3(205)
6. 6. Ametrano, D. (2011) Bond Characteristics of Glass Fibre Reinforced Polymer Bars Embedded in High Performance And Ultra-High Performance Concrete, Master Thesis, Ryerson University.
7. 7. Arias, J. P. M., Vazquez, A. and Escobar, M. M. (2012) Use of sand coating to improve bonding between GFRP bars and concrete, Journal of Composite Materials, 46(18), 2271–2278. doi:10.1177/0021998311431994
8. 8. Choi, D.-U., Ha, S.-S. and Lee, C.-H. (2007) Development Length of GFRP Rebars Based on Pullout Test, Journal of the Korea Concrete Institute, 19(3), 323–331. doi:10.4334/JKCI.2007.19.3.323

9. 9. CSA S6-06, (2006) Canadian highway bridge design code, Canadian Standards Association.
10. 10. CSA S6-10, (2010) Canadian highway bridge design code, Canadian Standards Association.
11. 11. CSA S806-02, (2002) Design and construction of building structures with fibre-reinforced polymers. Canadian Standards Association.
12. 12. CSA S806-12, (2012) Design and construction of building structures with fibre-reinforced polymers, Canadian Standards Association.
13. 13. Ehsani, M. R., Saadatmanesh, H. and Tao, S. (1997) Bond Behavior of Deformed GFRP Rebars, Journal of Composite Materials, 31(14), 1413–1430.
14. 14. Esfahani, M. R., Kianoush, M. R. and Lachemi, M. (2004) A Comparison Between Bond Strength of Steel and GFRP Bars in Self-Consolidating Concrete (SCC), International Journal of Civil Engineering, 2(3), 193–200.
15. 15. Ha, S.-S. and Choi, D.-U. (2010) Development Length of GFRP Bars, Journal of the Korea Concrete Institute, 22(1), 131–141. doi:10.4334/JKCI.2010.22.1.131
16. 16. Hossain, K. M. A., Ametrano, D. and Lachemi, M. (2014) Bond Strength of Standard and High-Modulus GFRP Bars in High-Strength Concrete, Journal of Materials in Civil Engineering, 26(3), 449–456. doi:10.1061/(ASCE)MT.1943-5533.0000758
17. 17. Hossain, K. M. A., Ametrano, D., Lachemi, M. (2017) Bond Strength of GFRP Bars in Ultra-High Strength Concrete Using RILEM Beam Tests, Journal of Building Engineering, 10, 69–79. doi:10.1016/j.jobe.2017.02.005
18. 18. Huang, Z., Engström, B. and Magnusson, J. (1996) Experimental and Analytical Studies of the Bond Behaviour of Deformed Bars in High Strength Concrete, In Fourth International Symposium at the Utilization of High Strength/High Performance Concrete, Paris, France.
19. 19. Islam, S., Afefy, H. M., Sennah, K. and Azimi, H. (2015) Bond characteristics of straight- and headed-end, ribbed-surface, GFRP bars embedded in high-strength concrete, Construction and Building Materials, 83(2), 283–298. doi:10.1016/j.conbuildmat.2015.03.025
20. 20. JSCE, 1997 Recommendation for design and construction of concrete structures using continuous fiber reinforcing materials, Japan Society of Civil Engineers.
21. 21. Jung, W. T., Park, Y. H. and Park, J. S. (2011) An Experimental Study on Bond Characteristics of FRP Reinforcements with Various Surface-type, Journal of The Korean Society of Civil Engineers, 31(4a), 279–286.
22. 22. Kang, J., Kim, B., Park, J. and Lee, J. (2012) Influence Evaluation of Fiber on the Bond Behavior of GFRP Bars Embedded in Fiber Reinforced Concrete, Journal of the Korea Concrete Institute, 24(1), 79–86. doi:10.4334/JKCI.2012.24.1.079
23. 23. Kessler, R. J. and Powers, R. G. (1998) Corrosion of epoxy-coated rebars—Keys segmental bridge—Monroe County. Florida Department of Transportation, Materials Office, Rep. No. 88-8A.
24. 24. Khederzadeh, H. R. and Sennah, K. (2014) Pullout Strength of Pre-installed Sand-coated GFRP Bars for Bridge Barrier Construction, 4th International Structural Specialty Conference (CSCE 2014) (ss. 1–10), Halifax, NS.
25. 25. Larralde, J. and Silva‐Rodriguez, R. (1993) Bond and Slip of FRP Rebars in Concrete, Journal of Materials in Civil Engineering, 5(1), 30–40. doi:10.1061/(ASCE)0899-1561(1993)5:1(30)
26. 26. Lee, J.-Y., Kim, T.-Y., Kim, T.-J., Yi, C.-K., Park, J.-S., You, Y.-C. and Park, Y.-H. (2008) Interfacial bond strength of glass fiber reinforced polymer bars in high-strength concrete, Composites Part B: Engineering, 39(2), 258–270. doi:10.1016/j.compositesb.2007.03.008
27. 27. Lu, J. (2015) Investigation of Pullout Strength of Pre‐Installed Glass Fibre Reinforced Polymer Bars In High‐Performance Concrete, Master Thesis, Ryerson University.
28. 28. Mosley, C. P., Tureyen, A. K. and Frosch, R.J. (2008) Bond Strength of Nonmetallic Reinforcing Bars, ACI Structural Journal, 105 (5), 634-642.
29. 29. Newman, N., Ayoub, A. and Belarbi, A. (2010) Development Length of Straight FRP Composite Bars Embedded in Concrete, Journal of Reinforced Plastics and Composites, 29(4), 571–589. doi:10.1177/0731684408100262
30. 30. Park, J.-S., Lim, A.-R., Kim, J. and Lee, J.-Y. (2016) Bond performance of fiber reinforced polymer rebars in different casting positions, Polymer Composites, 37(7), 2098– 2108. doi:10.1002/pc.23388
31. 31. Pay, A. C., Canbay, E. and Frosch, R.J. (2014) Bond Strength of Spliced Fiber-Reinforced Polymer Reinforcement, ACI Structural Journal, 111 (2), 257-266. doi:10.14359/51686519
32. 32. Rakhshanimehr, M., Mousavi, S. R., Esfahani, M. R., & Shahri, S. F. (2018) Establishment and Experimental Validation of an Updated Predictive Equation for the Development and Lap-Spliced Length of GFRP Bars in Concrete, Materials and Structures, 51(1), 15. doi:10.1617/s11527-018-1137-8
33. 33. Shen, D., Ojha, B., Shi, X., Zhang, H. and Shen, J. (2016) Bond stress–slip relationship between basalt fiber-reinforced polymer bars and concrete using a pull-out test, Journal of Reinforced Plastics and Composites, 35(9), 747–763. doi:10.1177/0731684415627504
34. 34. Sulaiman, M. F., Ma, C.-K., Apandi, N. M., Chin, S., Awang, A. Z., Mansur, S. A. and Omar, W. (2017) A Review on Bond and Anchorage of Confined High-strength Concrete, Structures, 11, 97–109. doi:10.1016/j.istruc.2017.04.004
35. 35. Tekle, B. H., Khennane, A. and Kayali, O. (2015) Bond Properties of Glass Fibre Reinforced Polymer Bars With Fly-Ash Based Geopolymer Concrete, 10th International Conference on Composite Science and Technology (IDMEC 2015) (ss. 1–8), Lisboa, Portugal.
36. 36. Thamrin, R., and Kaku, T. (2005) Development Length Evaluation of Reinforced Concrete Beam with CFRP Bars, Proceedings of the International Symposium on Bond Behaviour of FRP in Structures (BBFS 2005) (ss. 385–392), Hong Kong.