Abstract
Existing experimental research on bond properties of the interface between Carbon Fiber Reinforced Polymer (CFRP) and damaged concrete is limited, although CFRP strengthening technology has been widely used for corroded reinforced concrete structures. This work investigated the bond behavior of CFRP to the corrosion-cracked concrete interface, in which three factors were considered for experimentation, including corrosion degree, concrete strength and concrete cover thickness. The tests were conducted by developing a self-balancing double shear lap test device. In addition, a corrosion scene was provided simultaneously to simulate the external corrosion environment. The results showed that three peeling modes of CFRP sheets were observed with respect to corrosion degrees of the steel bars. The effects of the three factors on the stripping bearing capacity and effective bond length of CFRP sheets were discussed by systematic parametric analysis. Finally, a nonlinear degenerate law of CFRP-to-concrete interface considering the corrosion degree was improved and verified in this study.
Highlights
A steel plate was placed between the force sensor and the concrete specimen. This feasible device can avoid the problem of uneven stress on both sides of Carbon Fiber Reinforced Polymer (CFRP) sheets, which is common in conventional double shear tests
Static loading method controlled top view, a red trace along the axial direction of the steel bar can be seen on CFRP sheets view, trace along axial direction of and steel barholding can be seen sheets bytop force was adopted with the negative kN
Due to the combined negative effect of salt water immersion [27] and internal transverse tensile stress caused by concrete cracking, the adhesive layer cracked and the red corrosion medium soaked in chlorinated water, penetrated through the CFRP sheet and dyed it
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Externally bonded Carbon Fiber Reinforced Polymer (CFRP) sheets have received increasing attention in retrofitting corroded RC structures [1] In this technology, CFRP sheets are only applied to the concrete surface after the external surface of the concrete is prepared by grinding, sandblasting or high-pressure water spraying. Many researchers have been investigating the impact of the simulated marine environment on bond properties of CFRP-to-concrete interface [16,17,18,19,20] They investigated the deterioration effects of moisture conditions and the dry-wet cyclic conditions of salt solution on the durability of the bond behavior between CFRP and concrete interface. A standardized test method is required to investigate the bond behavior between corrosion-cracked concrete and CFRP sheets in the marine environment with consideration of other important parameters, such as concrete grade and concrete cover thickness. The understanding gained will help in interpreting durability-oriented CFRP applications in the marine environment
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