Direct Measurement of Traction–Separation Law of Concrete–Epoxy Interfaces Subjected to Moisture Attack under Mode-I Loading
Publication: Journal of Composites for Construction
Volume 21, Issue 5
Abstract
A proper traction–separation law based on the physical behaviors of the concrete–epoxy interface is needed to simulate the debonding behavior of fiber-reinforced polymers–strengthened concrete structures. However, no method is available to measure the traction–separation law of the concrete–epoxy interface under mode-I loading. To address this gap, this study proposes a novel testing method to directly measure the traction–separation law of the concrete–epoxy interface. This method uses a wedge-splitting test specimen that not only requires simple testing setups but also produces stable crack propagation in the specimen. By adopting a rigid body moment assumption, the traction in the concrete–epoxy interface is expressed as a function of the applied load and the crack opening displacement. As a result, this method can directly calculate the relationship between the traction and the separation of the concrete–epoxy interface by simply recording the crack opening displacement and the applied load during the test. The success of the new method has been confirmed through experimental study. Testing results show the traction–separation law of the concrete–epoxy interface under mode-I loading can be approximated by a tri-linear law. The new method is also used to evaluate the long-term durability of concrete–epoxy interface subjected to moisture attack. It has been found that conditioning the interface specimens in water can significantly reduce the tensile strength and fracture toughness of the interface. The effectiveness of applying silane coupling agent to enhance the durability of the concrete–epoxy interface has also been confirmed by this new testing method.
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Acknowledgments
This work was supported by the National Science Foundation under Grant CMMI–0927938. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect those of the National Science Foundation.
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Published In
Journal of Composites for Construction
Volume 21 • Issue 5 • October 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: May 27, 2016
Accepted: Oct 31, 2016
Published online: Mar 21, 2017
Discussion open until: Aug 21, 2017
Published in print: Oct 1, 2017
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