Computational approach to the bond behaviour between FRP rebars and concrete
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The application of fiber-reinforced polymer rebars as reinforcement in concrete structures has been growing in recent years. One of the most relevant aspects of the efficiency of this solution is related to the bond performance between these two different materials. Surface treatment has been used as a solution to improve the bond behaviour, but there is still no standardization for this type of procedure for FRP rebars. Besides the lack of standardization, the bond behaviour of FRP rebars in concrete structures is affected by many parameters, such as: the concrete strength, the embedment length, the rebar diameter, the surface treatment adopted, and the type of fibers used to make the rebar. Therefore, experimental campaigns based on pullout tests have been used to assess the bond behaviour of these rebars to concrete surfaces to evaluate the effect of each parameter involved in the transmission of load between rebars and concrete. In addition to experimental tests, numerical analyses are often carried out to complement the study. Different methodologies can be used to simulate the contact between the rebar and the concrete, such as surface-based cohesive behaviour [1], cohesive elements [2,3] and translator elements[4]. This paper aims to compare different methodologies to simulate FRP to concrete interaction in pullout tests and find out which of these methodologies most closely matches experimental results. Three methodologies are tested: cohesive elements, surface-based behaviour, and friction with some adaptations to create a simpler model. REFERENCES [1] Tekle BH, Khennane A, Kayali O. Bond Properties of Sand-Coated GFRP Bars with Fly Ash–Based Geopolymer Concrete. J Compos Constr 2016;20. https://doi.org/10.1061/(asce)cc.1943-5614.0000685. [2] Lee JY, Kim TY, Kim TJ, Yi CK, Park JS, You YC, et al. Interfacial bond strength of glass fiber reinforced polymer bars in high-strength concrete. Compos Part B Eng 2008;39:258–70. https://doi.org/10.1016/j.compositesb.2007.03.008. [3] Rolland A, Argoul P, Benzarti K, Quiertant M, Chataigner S, Khadour A. Analytical and numerical modeling of the bond behavior between FRP reinforcing bars and concrete. Constr Build Mater 2020;231:117160. https://doi.org/10.1016/j.conbuildmat.2019.117160. [4] Gooranorimi O, Suaris W, Nanni A. A model for the bond-slip of a GFRP bar in concrete. Eng Struct 2017;146:34–42. https://doi.org/10.1016/j.engstruct.2017.05.034.
