Sensors to Monitor CFRP/Concrete Bond in Beams Using Electrochemical Impedance Spectroscopy
Publication: Journal of Composites for Construction
Volume 9, Issue 6
Abstract
The use of inexpensive electrochemical impedance spectroscopy based sensor technology for nondestructive evaluation (NDE) of bond degradation between external carbon fiber-reinforced polymer (CFRP) reinforcement and concrete is examined. Copper tape on the surface of the CFRP sheet, stainless steel wire embedded in the concrete, and reinforcing bars were used as the sensing elements. Laboratory experiments were designed to test the capability of the sensors to detect the debonding of the CFRP from the concrete and to study the effect of short-term (humidity and temperature fluctuations) and long-term (freeze-thaw and wet-dry exposure and rebar corrosion) environmental conditions on the measurements. The CFRP sheet was debonded from the concrete, and impedance measurements were taken between various pairs of electrodes at various interfacial crack lengths. The dependence of the impedance spectra, and of the parameters obtained from equivalent circuit analysis, on the interfacial crack length was studied. Capacitance parameters in the equivalent circuit correlated strongly with the interfacial crack length and can be used to assess the global state of the bond between CFRP sheets and concrete. Impedance measurements taken between embedded wire sensors can be used to detect the location of debonded regions.
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Acknowledgments
The Michigan State Department of Transportation (MDOT) funded this research. The project manager was Roger D. Till. Dr. Guy Davis from DACCO SCI Inc., Columbia, Maryland, shared with the writers the basic techniques he developed for the use of EIS for NDE. Dr. Ahmed Alostaz, presently with the Department of Civil Engineering, University of Mississippi, Oxford, Mississippi, was involved in this project during the early stages.
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Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 9 • Issue 6 • December 2005
Pages: 515 - 523
Copyright
© 2005 ASCE.
History
Received: Aug 24, 2004
Accepted: Mar 21, 2005
Published online: Dec 1, 2005
Published in print: Dec 2005
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