Flexural Behavior of Concrete Beams Strengthened with Polyurethane-Matrix Carbon-Fiber Composites
Publication: Journal of Composites for Construction
Volume 24, Issue 4
Abstract
Fiber-reinforced polymer (FRP) materials have been increasingly used for external strengthening of reinforced concrete (RC) infrastructure. However, the focus has been almost exclusively on epoxy-based composites, and other potential options such as polyurethane (PU) have not been fully investigated. This paper characterizes the flexural behavior of concrete strengthened with PU matrix–adhesive laminates using small-scale single lap shear specimens, unreinforced flexural specimens, and large-scale RC girders. Experimental results demonstrate that although the normal and shear strengths of PU-based adhesives are low, PU-strengthened beams show increased strength and deformability, owing to the load redistribution ability within the bond line. It is found that a linear brittle bond–slip model adequately predicts the interfacial shear behavior of the PU adhesive, exhibiting a lower stiffness and comparable cohesive energy to epoxy. Finite element (FE) analysis was performed to validate the effect of the bond–slip model relative to the experimental results.
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Acknowledgments
The authors thank Neptune Research Inc. (NRI) for providing the composite materials utilized in this study and for guidance on installation. In particular, the authors acknowledge the assistance of Eri Vokshi and Chris Lazzara. The views and findings reported here are those of the writers alone, and not necessarily the views of NRI.
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Published In
Journal of Composites for Construction
Volume 24 • Issue 4 • August 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Aug 23, 2019
Accepted: Jan 27, 2020
Published online: May 6, 2020
Published in print: Aug 1, 2020
Discussion open until: Oct 6, 2020
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