Performance of different types of FRP sheets bonded to concrete using flexible adhesive

Year 2013, Volume: 3 Issue: 2, 116 - 126, 23.07.2016

Hesham M. Diab

Abstract

De-bonding problems stand as a critical barrier against a wide range of usages of FRP composites in structural strengthening and repairing applications. Results of an experimental campaign on FRP-concrete debonding are presented in this study. Specimens with different types of FRP sheets bonded to concrete prism using flexible adhesive were conducted to determine the effective bonding length and ultimate bond capacity of FRPconcrete interface. The experimental results from double lap shear specimens indicated that the flexible adhesive has increased both of the effective bonding length and the ultimate bond capacity of FRP-concrete interface. Increase of fracture energy of FRP-concrete interface has been clearly observed due to flexible adhesive for all different types of FRP sheets. Analytical models available in the literature were adopted to evaluate the bond strength and the effective bond length of the experiment results in this study. Consequently, the existing models need to be modified to consider the type of adhesive layer. A unique feature of the present study is that a simple modification done to the most popular bond strength model, Chen and Teng model (2001), to predict both bond strength and effective bonding length considering the type of adhesive layer. The validation of bond strength model is supported via experiment test results

Keywords

Bond strength model, Flexible adhesive, FRP sheet, Concrete

References

• Buyukozturk, O., Gunes, O., & Karaca, E. (2002). Characterization and Modeling of Debonding in RC Beams Strengthened with FRP Composites. Proceeding of the 15th ASCE Engineering Mechanics Conference, Columbia University, New York, 1-8.
• Caggiano, Antonio, Enzo Martinelli, & Ciro Faella (2012). A fully-analytical approach for modelling the response of FRP plates bonded to a brittle substrate. International Journal of Solids and Structures 49, 2291-2300.
• Chen, J. F., & Teng, J. G. (2001). Anchorage strength models for FRP and steel plates bonded to con-crete. Journal of structural engineering, ASCE, 127(7), 784-791.
• Dai, J.G, Ueda, T., Ito, T. (2005). Flexural strengthening of RC beams using externally bonded FRP sheets through flexible adhesive bonding. Proceedings of the International Symposium on Bond Behaviour of FRP in Structures (BBFS 2005), 205- 213.
• Dai, J.G. & Ueda, T. (2003). Local Bond Stress Slip Relations for FRP Composites-concrete Interfaces. Proceedings of FRPRCS-6, Edited by Tan, K. H., l, 143-152.
• Diab H.M., &Wu Z. (2009). Bond Behaviour of Different FRP Sheets. Proceedings of FRPRCS-9, Sydney, Australia, 2009.
• Hamoush, SA., & Ahmad SH. (1990). Debonding of Steel Plate-StrengthenedConcrete Beams. J Struct Eng,116(2),356–71.
• Lu, X.Z., Teng, J.G., Ye, L.P & Jiang, J.J. (2005). Bond-slip models for FRP sheets/plates bonded to concrete. Engineering Structures, 27(6), 920-937.
• Mazzotti C., Savoia M., & Ferracuti B.(2008). An Experimental Study on Delamination of FRP Plates Bonded to Concrete. Construction and Building Material, 22, 1409-1421.
• Mitolidis, G., Kappos, A., & Salonikios T. (2008). Bond tests of SRP and CFRP – strengthened concrete prisms. Proceeding of the 4th International Conference on FRP Composites in Civil Engineering (CICE2008), Zurich, Switzerland.
• Nakaba K, Kanakubo T, Yoshizawa T, & Yoshizawa H. (2001). Bond behaviour between fibre-reinforced polymer laminates and concrete. ACI Struct. J ,98(3),359–67.
• Neubauer U, & Rostasy FS. (1997). Design aspects of concrete structures strengthened with externally bonded FRPplates. Proceedings of the seventh international conference on structural faults and repair, 2. Edinburgh: ECS Publications,109-127.
• Tuakta, C., & Büyüköztürk, O. (2012). Conceptual model for prediction of FRP-concrete bond strength under moisture cycles. Journal of Composites for Construction 15( 5) , 743-756.
• Wu Z, Islam SM, & Said H.(2009). A three-parameter bond strength model for FRP-concrete interface. Journal of reinforced plastics and composites , 28(19), 2309-2323.
• Wu, Y., Zhou, Z., Yang, Q., & Chen, W. (2010). On shear bond strength of FRP-concrete structures. Engineering Structures, 32(3), 897-905.
• Wu, Yu-Fei, Xin-Sheng Xu, Jia-Bin Sun, & Cheng Jiang. (2012). Analytical solution for the bond strength of externally bonded reinforcement. Composite Structures 94 (2012), 3232-3239.
• Wu, Z.S., & Diab, H.M. (2007). Constitutive Model for Time-Dependent Behavior of FRP-Concrete Interface. Journal of Composites for Construction, ASCE, Vol. (11), 477-486.
• Xia, S.H, & Teng, J.G.(2005). Behaviour of FRP-to-steel bonded joints. Proceedings of the International Symposium on Bond Behaviour of FRP in Structures (BBFS 2005), 411-418.
• Yoshizawa, H., Wu, Z. S., Yuan, H. & Kanakubo, T. (2000). Study on FRP-Concrete Interface Bond Performance. Journal of Materials, Concrete Structures and Pavement, JSCE, 662(V-49), 105-119.