Title:
Quasi-Static and Fatigue Behavior of GFRP Bars Embedded in Concrete: A Comparison Between Pull-Out Tests and Flexural Tests of Slabs
Author(s):
Charles Tucker Cope III, Mohammod Minhajur Rahman, Francesco Focacci, Tommaso D’Antino, Iman Abavisani, and Christian Carloni
Publication:
Symposium Paper
Volume:
360
Issue:
Appears on pages(s):
709-728
Keywords:
GFRP bars; Bond; Fatigue; Pull-out test; Slab; Frequency.
DOI:
10.14359/51740658
Date:
3/1/2024
Abstract:
GFRP bars are considered an alternative to steel for concrete reinforcement. This project investigated the fatigue behavior of GFRP bars embedded in concrete, studying bond behavior at material and structural scales. GFRP bars (12 mm [0.47 in.] nominal diameter) were embedded in concrete cylinders leaving a 50 mm [2 in.] protrusion at the free end and featuring different bonded lengths. Two types of GFRP bars with different surface treatment (lacquered and unlacquered) were used. Static tests were used to determine the bonded length required for cyclic pull-out tests, Cyclic tests at 1.5 Hz showed GFRP bar failure was possible at just 20% of their reduced tensile strength (0.8ffu) as prescribed in ACI 440.1R-15. Two full-scale slabs internally reinforced with unlacquered GFRP bars were tested using a four-point bending configuration. A quasi-static test was used as a control to determine the fatigue amplitude, considering the fatigue loading provided by the ACI 440.1R-15 document and the pull-out test results with cyclic loading presented in this work. Cyclic load between 10 kN [2.25 kips] and 40 kN [9 kips] at a 1.5 Hz frequency was applied up to 5 million cycles before a subsequent quasi-static test was conducted. The load range was determined using cross-section analysis to cycle the bars between 5% and 20% of their reduced tensile strength (0.8ffu). Both slabs ultimately failed due to shear failure, with cyclic loading having little impact on the slab compliance. Displacements of the load points and supports were measured using linear variable displacement transformers (LVDTs), while digital image correlation (DIC) was utilized to obtain the full-field displacement and strain in the central region of the slab. The strain and displacement fields from DIC were used to determine the opening of flexural cracks and relate it to the stress level in the GFRP bars. A comparison between the static pull-out tests and the four-point bending tests of slabs indicated that the pull-out test could be used to describe the flexural behavior of the slab at low stress level. However, in terms of fatigue behavior, the comparison between the small- and large-scale tests indicated that the fatigue phenomenon in the slab was quite complex and could not be directly described by the results of pull-out tests.
Related References:
1. Qiao C, Chen X, Suraneni P, Weiss WJ, Rothstein D. Petrographic analysis of in-service cementitious mortar subject to freeze-thaw cycles and deicers. Cement and Concrete Composites 2021;122:104112. doi: 10.1016/j.cemconcomp.2021.104112
2. Carvelli V, Pisani MA, Poggi C. Fatigue behaviour of concrete bridge deck slabs reinforced with GFRP bars. Composites Part B: Engineering 2010;41:560–7. doi: 10.1016/j.compositesb.2010.06.006
3. Das JK, Pradhan B. Study on influence of nitrite and phosphate based inhibiting admixtures on chloride interaction, rebar corrosion, and microstructure of concrete subjected to different chloride exposures. Journal of Building Engineering 2022;50:104192. doi: 10.1016/j.jobe.2022.104192
4. Mufti AA, Neale KW. State-of-the-Art of FRP and SHM Applications in Bridge Structures in Canada 2008;2:10.
5. Zhao X, Minhajur Rahman M, D’Antino T, Focacci F, Carloni C. Effect of bonded length on the load response and failure mode of pull-out tests of GFRP bars embedded in concrete. Construction and Building Materials 2022;347:128425. doi: 10.1016/j.conbuildmat.2022.128425
6. ACI 440. ACI 440.1R-15 - Guide for the design and construction of structural concrete reinforced with fiberreinforced polymer (FRP) bars. American Concrete Institute; 2015.
7. Adimi MR, Rahman AH, Benmokrane B. New Method for Testing Fiber-Reinforced Polymer Rods under Fatigue. J Compos Constr 2000;4:206–13. doi: 10.1061/(ASCE)1090-0268(2000)4:4(206)
8. Adimi R, Benmokrane B. Fatigue behaviour of GFRP bars embedded in concrete, 1997.
9. Januš O, Girgle F, Rozsypalová I, Kostiha V, Bodnárová L, Štěpánek P, et al. The fatigue behaviour of GFRP bars - Experimental study. Acta Polytechnica CTU Proceedings 2019;22:38–47. doi: 10.14311/APP.2019.22.0038
10. Baena M, Torres L, Turon A, Barris C. Experimental study of bond behaviour between concrete and FRP bars using a pull-out test. Composites Part B: Engineering 2009;40:784–97. doi: 10.1016/j.compositesb.2009.07.003
11. Yan F, Lin Z, Yang M. Bond mechanism and bond strength of GFRP bars to concrete: A review. Compos Part B 2016;98:56–69. doi: 10.1016/j.compositesb.2016.04.068
12. Wambeke BW, Shield CK. Development Length of Glass Fiber-Reinforced Polymer Bars in Concrete. ACI Struct J 2006;103:11–7. doi: 10.14359/15081
13. Mazaheripour H, Barros JAO, Sena-Cruz JM, Pepe M, Martinelli E. Experimental study on bond performance of GFRP bars in self-compacting steel fiber reinforced concrete. Composite Structures 2013;95:202–12. doi: 10.1016/j.compstruct.2012.07.009
14. Chai L-J, Guo L-P, Chen B, Carpinteri A, Scorza D, Vantadori S. Effects of BFRP Bar Diameter and Cover Thickness on Fracture Behavior of BFRP Bar–Reinforced Ecological High-Ductility Cementitious Composites. J Test Eval 2021;49:20200528. doi: 10.1520/JTE20200528
15. Rahman MM, Zhao X, D’Antino T, Focacci F, Carloni C. Fracture Behavior and Digital Image Analysis of GFRP Reinforced Concrete Notched Beams. Materials 2022;15:5981. doi: 10.3390/ma15175981
16. ASTM A944-22. Standard Test Method for Comparing Bond Strength of Steel Reinforcing Bars to Concrete Using Beam-End Specimens 2022.
17. ASTM D30. ASTM D7913/D7913M-14. Standard Test Method for Bond Strength of Fiber-Reinforced Polymer Matrix Composite Bars to Concrete by Pullout Testing 2020.
18. Kayali O, Yeomans SR. Bond of ribbed galvanized reinforcing steel in concrete. Cement and Concrete Composites 2000;22:459–67. doi: 10.1016/S0958-9465(00)00049-4
19. Erfan AM, Elnaby RMA, Badr AA, El-sayed TA. Flexural behavior of HSC one way slabs reinforced with basalt FRP bars. Case Studies in Construction Materials 2021;14:e00513. doi: 10.1016/j.cscm.2021.e00513
20. Alrousan RZ, Alnemrawi BR. Punching shear behavior of FRP reinforced concrete slabs under different opening configurations and loading conditions. Case Studies in Construction Materials 2022;17:e01508. doi: 10.1016/j.cscm.2022.e01508
21. Spathelf CA, Vogel T. Fatigue performance of orthogonally reinforced concrete slabs: Experimental investigation. Engineering Structures 2018;168:69–81. doi: 10.1016/j.engstruct.2018.04.058
22. Wang Y, Shao X, Cao J, Zhao X, Qiu M. Static and fatigue flexural performance of ultra-high performance fiber reinforced concrete slabs. Engineering Structures 2021;231:111728. doi: 10.1016/j.engstruct.2020.111728
23. Xie J, Zheng Y, Guo Y, Ou R, Xie Z, Huang L. Effects of crumb rubber aggregate on the static and fatigue performance of reinforced concrete slabs. Composite Structures 2019;228:111371. doi: 10.1016/j.compstruct.2019.111371
24. Zanuy C, Maya LF, Albajar L, De La Fuente P. Transverse fatigue behaviour of lightly reinforced concrete bridge decks. Engineering Structures 2011;33:2839–49. doi: 10.1016/j.engstruct.2011.06.008
25. El-Ragaby A, El-Salakawy E, Benmokrane B. Fatigue Life Evaluation of Concrete Bridge Deck Slabs Reinforced with Glass FRP Composite Bars. J Compos Constr 2007;11:258–68. doi: 10.1061/(ASCE)1090-0268(2007)11:3(258)
26. Hudhayfah AD. MATEENBAR TM CERTIFICATE OF ANALYSIS 2021.
27. ISO. Fibre-reinforced polymer (FRP) reinforcement of concrete -- Test methods. ISO 2015. https://www.iso.org/cms/render/live/en/sites/isoorg/contents/data/standard/06/36/63657.html (accessed March 24, 2022).
28. ASTM C09. C143/C143M − 20 - Standard Test Method for Slump of Hydraulic-Cement Concrete. ASTM International; 2020. doi: 10.1520/C0143_C0143M-20
29. ASTM C09. ASTM C39/C39M-21 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. ASTM International; 2020. doi: 10.1520/C0039_C0039M-20
30. ASTM C09. ASTM C496/C496M-17 - Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens. ASTM International; 2017. doi: 10.1520/C0496_C0496M-17
31. Owens Corning, E.L. Robinson Engineering. Glass FIber Reinforced Polymer (GFRP) Reinforced Concrete Deck Design Table 2021.
32. Mai G, Li L, Chen X, Xiong Z, Liang J, Zou X, et al. Fatigue performance of basalt fibre-reinforced polymer bar-reinforced sea sand concrete slabs. Journal of Materials Research and Technology 2023;22:706–27. doi: 10.1016/j.jmrt.2022.11.135
33. Matthys S, Taerwe L. Concrete Slabs Reinforced with FRP Grids. I: One-Way Bending. J Compos Constr 2000;4:145–53. doi: 10.1061/(ASCE)1090-0268(2000)4:3(145)
34. Carloni C, Santandrea M, Baietti G. Influence of the width of the specimen on the fracture response of concrete notched beams. Engineering Fracture Mechanics 2019;216:106465. doi: 10.1016/j.engfracmech.2019.04.039
35. D’Antino T, Focacci F, Sneed LH, Carloni C. Relationship between the effective strain of PBO FRCMstrengthened RC beams and the debonding strain of direct shear tests. Engineering Structures 2020;216:110631. doi: 10.1016/j.engstruct.2020.110631
36. Eurocode 2. European Committee for Standardization. Eurocode 2: Design of concrete structures - Part 1-1: General rules and rules for buildings 2004.
37. Kara IF, Ashour AF. Flexural performance of FRP reinforced concrete beams. Composite Structures 2012;94:1616–25. doi: 10.1016/j.compstruct.2011.12.012
38. Shield C, Brown V, Bakis CE, Gross S. A Recalibration of the Crack Width Bond-Dependent Coefficient for GFRP-Reinforced Concrete. J Compos Constr 2019;23:04019020. doi: 10.1061/(ASCE)CC.1943-5614.0000978
39. ACI Code-440.11-22. Building code requirements for structural concrete reinforced with GFRP bars and commentary. Farmington Hills, MI: American Concrete Institute; 2022.
40. Building code requirements for structural concrete (ACI 318-19): an ACI standard ; Commentary on building code requirements for structural concrete (ACI 318R-19). Farmington Hills, MI: American Concrete Institute; 2019.