Evaluation of Pull-Off Tests as a FRP–Concrete Bond Testing Method in the Laboratory and Field
Publication: Practice Periodical on Structural Design and Construction
Volume 19, Issue 2
Abstract
The direct tension pull-off test has gained popularity as a test method used in the laboratory and especially in the field to assess the quality of bond between externally bonded fiber-reinforced polymer (FRP) repair materials and concrete owing to its low cost and simple procedure. However, the small scale and localized nature of the test can lead to high variability in the results. Furthermore, the test does not load the bond in a way that is representative of service conditions. Because of these limitations, satisfactory interpretation of results can be difficult. This paper examines the challenges that may be encountered when analyzing the data obtained during testing, including the high variances. Past research efforts using pull-off tests, and results of recent field and laboratory testing by the authors, are discussed to evaluate the benefits and weaknesses of pull-off tests as a quality control and research tool. The authors conclude that pull-off tests have many drawbacks, and if they are used, great care is needed in their application. It is recommended that if this method is to be used as a quality control procedure in the field, pull-off tests on the concrete alone should be conducted to obtain baseline values, and supplementary tests such as acoustic sounding also be used. For laboratory conditions, it is advised that alternative testing procedures be considered and large sample sizes be used to make statistical validation possible.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors acknowledge the Colorado DOT and Mountain Plains Consortium, a U.S. DOT University Transportation Center, for providing the funding for the laboratory study. The authors also thank HJ3 Composite Technologies and Envirotech for supplying the FRP materials and deicing agents used in the project, respectively. Finally, the authors thank Doug Allen for assisting in the fabrication of the concrete specimens.
References
Allen, D. G. (2011). “Evaluating the long-term durability of fiber reinforced polymers via field assessments of reinforced concrete structures.” Master’s thesis, Colorado State Univ., Fort Collins, CO.
Allen, D. G., and Atadero, R. A. (2012). “Evaluating the long-term durability of externally-bonded FRP via field assessments.” J. Compos. Constr., 737–746.
American Concrete Institute (ACI). (1993). “Use of epoxy compounds with concrete.” ACI 503R-93, reapproved 1998, Farmington Hills, MI.
American Concrete Institute (ACI). (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” ACI 440.2R-08, Farmington Hills, MI.
ASTM. (2004). “Standard test method for tensile strength of concrete surfaces and the bond strength or tensile strength of concrete repair and overlay materials by direct tension (pull-off method).” C1583/C1583M-04, West Conshohocken, PA.
ASTM. (2009a). “Standard test method for pull-off strength for FRP bonded to concrete substrate.” D7522, M-09, West Conshohocken, PA.
ASTM. (2009b). “Standard test method for pull-off strength of coatings using portable adhesion testers.” D4541, M-09, West Conshohocken, PA.
Banthia, N., et al. (2009). “Field assessment of FRP sheets-concrete bond durability.” Proc., 1st Int. Conf. Sustainable Built Environment Infrastructures in Developing Countries (SBEIDCO), Laboratoire Matériaux (LABMAT), Oran, Algeria, 301–306.
Eveslage, T., Aidoo, J., Harries, K. A., and Bro, W. (2010). “Effect of variations in practice of ASTM D7522 standard pull-off test for FRP-concrete interfaces.” J. Test. Eval., 38(4), 424–430.
Gartner, A., Douglas, E. P., Dolan, C. W., and Hamilton, H. R. (2011). “Small beam bond test method for CFRP composites applied to concrete.” J. Compos. Constr., 52–61.
International Concrete Repair Institute (ICRI). (2004). “Guide to using in-situ tensile pull-off tests to evaluate bond of concrete surface materials.” Guideline No. 03739, Des Plaines, IL.
Karbhari, V. M., and Ghosh, K. (2009). “Comparative durability evaluation of ambient temperature cured externally bonded CFRP and GFRP composite systems for repair of bridges.” Compos. Part A, 40, 1353–1363.
Information & Authors
Information
Published In
Practice Periodical on Structural Design and Construction
Volume 19 • Issue 2 • May 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Nov 19, 2012
Accepted: Mar 25, 2013
Published online: Apr 1, 2013
Published in print: May 1, 2014
Discussion open until: Jul 5, 2014
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.