An investigation of behavior and modeling of bond for reinforced concrete

Abstract

This research investigates bond between concrete and steel in reinforced concrete (RC) using X-Ray tomography image data and nonlinear analysis, with the objective of developing recommendations for design and modeling bond in RC structures. RC is a composite material that combines concrete, which is strong in compression and weak in tension, with reinforcing steel, which is strong in tension and buckles in compression. Bond is necessary to maintain the composite action and realized the full utility of the material. However, bond-zone response data are not easily collected and the mechanics of bond are not easily assessed using traditional experimental test methods as traditional instrumentation interfaces with bond mechanism and cannot provide high fidelity data. Recently, X-ray computed tomography (CT), which is non-invasive and provides high resolution data, has been used to monitor bond tests. In this study, state-of-the-art image processing techniques are applied to 3D X-Ray images of bond-zone specimens to characterize bond behavior. Bond-zone response data generated from X-Ray CT images are used to verify nonlinear high resolution finite element (FE) modeling of bond-zone specimens. These FE models are used to further investigate bond-zone response and the impact of modeling parameters on predicted response. The results of this research provide high fidelity data characterizing bond-zone response, improved understanding of bond-zone mechanism and recommendations for design and modeling of bond in RC structural components.