Front and Side View Image Correlation Measurements on FRP to Concrete Pull-Off Bond Tests
Publication: Journal of Composites for Construction
Volume 14, Issue 4
Abstract
Understanding the transfer of force by bond between externally bonded fiber-reinforced polymer (FRP) reinforcement and concrete is an important step in formulating good models for predicting debonding failures observed in externally bonded reinforcement strengthened systems. In this paper, a 3D optical displacement measurement system was used to capture the full-field displacements from the front and side view in pull-off bond specimens. The experiments were carried using six specimens with carbon FRP (CFRP) strips having different axial stiffnesses but a constant bond length to the concrete substrate. Using the optical measurements, it was possible to obtain the in-plane displacement or slip and the out-of-plane displacement or separation between the CFRP strip and the concrete. It was demonstrated, that the usual assumption of pure shear stresses in such pull-off tests is not true and that the bond behavior is a two-dimensional problem involving shear and peeling stresses. The bond behavior in CFRP strip to concrete pull-off tests was characterized by three stages: (1) the initiation of the first crack; (2) the initiation of debonding; and (3) failure by complete debonding. Based on the test results it was found that there was a dependency between the maximum bond shear stress, the maximum fracture energy of the FRP-concrete interface, and the stiffness of the FRP. However, the slip values after initiation of debonding (Stage 2) were independent of the FRP stiffness. The measured anchorage force and anchorage length were in good agreement with predictions from existing code equations.
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References
Ali-Ahmad, M., Subramaniam, K., and Ghosn, M. (2006). “Experimental investigation and fracture analysis of debonding between concrete and FRP sheets.” J. Eng. Mech., 132(9), 914–923.
American Concrete Institute (ACI). (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” ACI 440.2R-08, Detroit.
Aram, M. R., Czaderski, C., and Motavalli, M. (2008). “Debonding failure modes of flexural FRP-strengthened RC beams.” Composites, Part B, 39(5), 826–841.
Bažant, Z. P., and Gambarova, P. (1980). “Rough cracks in reinforced concrete.” J. Struct. Div., 106(4), 819–842.
Bažant, Z. P., and Pfeiffer, P. (1986). “Shear fracture tests of concrete.” Mater. Struct., 19(2), 111–121.
Bigwood, D. A., and Crocombe, A. D. (1989). “Elastic analysis and engineering design formulas for bonded joints.” Int. J. Adhes. Adhes., 9(4), 229–242.
Cao, S. Y., Chen, J. F., Pan, J. W., and Sun, N. (2007). “ESPI measurement of bond-slip relationships of FRP-concrete interface.” J. Compos. Constr., 11(2), 149–160.
Carpinteri, A., Valente, S., Ferrara, G., and Melchiorri, G. (1993). “Is mode-II fracture energy a real material property.” Comput. Struct., 48(3), 397–413.
Concrete Society. (2004). “TR55: Design guidance for strengthening concrete structures using fibre composite materials.” 2nd Ed., Technical Rep. No. 55, Concrete Society, Camberley, Surrey, U.K.
Consiglio Nazionale delle Ricerche (CNR). (2004). “Guide for the design and construction of externally bonded FRP systems for strengthening existing structures.” CNR-DT 200/2004, CNR-Advisory Committee on Technical Recommendations for Construction, Rome, 144.
Czaderski, C. (2000). “Shear strengthening of reinforced concrete with CFRP.” Proc., 45th Int. SAMPE Symp., Society for the Advancement of Materials and Process Engineering, Long Beach, Calif., 880–894.
Dai, J. G., Ueda, T., and Sato, Y. (2005). “Development of the nonlinear bond stress-slip model of fiber reinforced plastics sheet-concrete interfaces with a simple method.” J. Compos. Constr., 9(1), 52–62.
De Lorenzis, L., Miller, B., and Nanni, A. (2001). “Bond of fiber-reinforced polymer laminates to concrete.” ACI Mater. J., 98(3), 256–264.
Hack, E., and Schumacher, A. (2007). “DSPI strain measurement on an externally reinforced bending beam: A comparison of step-by-step addition and pixel shift correlation.” Opt. Lasers Eng., 45(5), 589–595.
Hillerborg, A. (1985). “Results of three comparative test series for determining the fracture energy Gf of concrete.” Mater. Struct., 18(5), 407–413.
Hillerborg, A., Modéer, M., and Petersson, P. E. (1976). “Analysis of crack formation and crack growth in concrete by means of fracture mechanics and finite elements.” Cem. Concr. Res., 6(6), 773–781.
Hilsdorf, H. K., and Brameshuber, W. (1991). “Code-type formulation of fracture-mechanics concepts for concrete.” Int. J. Fract., 51(1), 61–72.
International Federation for Structural Concrete (fib). (2001). Externally bonded FRP reinforcement for RC structures—Bulletin 14, Switzerland.
ISIS. (2008). “FRP rehabilitation of reinforced concrete structures.” Design manual no. 4, version 2, ISIS Canada, Winnipeg, 178.
Kaiser, H. (1989). “Bewehren von Stahlbeton mit kohlenstoffaserverstärkten Epoxidharzen [Reinforcing of reinforced concrete using carbon fiber reinforced epoxy resins].” Ph.D. thesis, ETH Zürich, Zurich, Switzerland (in German), p. 224.
Kurtz, S., Balaguru, P., and Helm, J. (2008). “Experimental study of interfacial shear stresses in FRP-strengthened RC beams.” J. Compos. Constr., 12(3), 312–322.
Lee, Y. J., Boothby, T. E., Bakis, C. E., and Nanni, A. (1999). “Slip modulus of FRP sheets bonded to concrete.” J. Compos. Constr., 3(4), 161–167.
Lu, X. Z., Teng, J. G., Ye, L. P., and Jiang, J. J. (2005). “Bond-slip models for FRP sheets/plates bonded to concrete.” Eng. Struct., 27(6), 920–937.
Mazzotti, C., Savoia, M., and Ferracuti, B. (2008). “An experimental study on delamination of FRP plates bonded to concrete.” Constr. Build. Mater., 22(7), 1409–1421.
Meier, U. (1987). “Brückensanierungen mit Hochleistungs-Faserverbundwerkstoffen (Rehabilitation of bridges with high performance fiber composites).” Material und Technik, 15(4), 125–128 (in German and French).
Meier, U., and Deuring, M. (1991). “The application of fiber composites in bridge repair—A world premiere at the gates of Lucerne.” Strasse und Verkehr, 77(9), 534–535.
Nakaba, K., Kanakubo, T., Furuta, T., and Yoshizawa, H. (2001). “Bond behavior between fiber-reinforced polymer laminates and concrete.” ACI Struct. J., 98(3), 359–367.
Neubauer, U. (2000). “Verbundtragverhalten geklebter Lamellen aus Kohlenstoffaser-Verbundwerkstoff zur Verstärkung von Betonbauteilen [Bond behavior of bonded CFRP strips for the strengthening of concrete members].” Ph.D. thesis, TU Braunschweig, (in German), p. 242.
Oehlers, D. J. (2006). “FRP plates adhesively bonded to reinforced concrete beams: Generic debonding mechanisms.” Adv. Struct. Eng., 9(6), 737–750.
Pellegrino, C., Tinazzi, D., and Modena, C. (2008). “Experimental study on bond behavior between concrete and FRP reinforcement.” J. Compos. Constr., 12(2), 180–189.
Qiao, P., and Xu, Y. (2004). “Evaluation of fracture energy of composite-concrete bonded interfaces using three-point bend tests.” J. Compos. Constr., 8(4), 352–359.
Schweizerischer Ingenieur- und Architektenverein (SIA). (2004). “Klebebewehrungen [Externally bonded reinforcement].” SIA166, Zurich, Switzerland.
Shah, S. P., Swartz, S. E., and Ouyang, C. (1995). Fracture mechanics of concrete, application of fracture mechanics to concrete, rock and other quasi-brittle materials, Wiley, New York, 552.
Smith, S. T., and Teng, J. G. (2002). “FRP-strengthened RC beams. I: Review of debonding strength models.” Eng. Struct., 24(4), 385–395.
Toutanji, H., Saxena, P., Zhao, L. Y., and Ooi, T. (2007). “Prediction of interfacial bond failure of FRP-concrete surface.” J. Compos. Constr., 11(4), 427–436.
Tripi, J. M., Bakis, C. E., Boothby, T. E., and Nanni, A. (2000). “Deformation in concrete with external CFRP sheet reinforcement.” J. Compos. Constr., 4(2), 85–94.
Ulaga, T., and Vogel, T. (2007). “Concrete members with plate reinforcement: Mechanical bond analysis.” Structural Concrete, Journal of the fib, 8(4), 165–173.
Wan, B. L., Sutton, M. A., Petrou, M. F., Harries, K. A., and Ning, U. (2004). “Investigation of bond between fiber reinforced polymer and concrete undergoing global mixed mode I/II loading.” J. Eng. Mech., 130(12), 1467–1475.
Wang, J. L. (2007). “Cohesive zone model of FRP-concrete interface debonding under mixed-mode loading.” Int. J. Solids Struct., 44(20), 6551–6568.
Wu, Z. S., Yuan, H., and Niu, H. D. (2002). “Stress transfer and fracture propagation in different kinds of adhesive joints.” J. Eng. Mech., 128(5), 562–573.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 14 • Issue 4 • August 2010
Pages: 451 - 463
Copyright
© 2010 ASCE.
History
Received: Dec 16, 2008
Accepted: Jan 25, 2010
Published online: Jan 29, 2010
Published in print: Aug 2010
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