Identification of the bond between ribbed CFRP bars and novel ARs anchorage

Abstract

The novel additional aluminum alloy ribs (ARs) anchorage, fabricated through radially extruding the aluminum alloy (AA) tube to attach to the CFRP bar, was recently developed by the authors. Though effectiveness of using the ARs anchorage to improve the bond quality of CFRP bar in concrete has been already validated, the bond at bar-anchorage interface itself has yet been unclear. In order to afford an overall insight into the bond performance between ribbed CFRP bar and ARs anchorage, the present study initiated a pull-out test for a total of 81 bar-anchorage bonded joints. The investigated design parameters of the ARs anchorage consisted of the initial wall-thickness, radial deformation, and the extruded length. Scanning-Electron-Microscope (SEM) observations were also performed to accurately observe the interfacial zone before and after pull-out test. Based on the analysis of the tested results, four typical bond stress-slip laws of the bar-anchorage interface were identified, and recommendations for the anchorage design were further given. Meanwhile, this paper proposed a mathematical model for predicting the nominal bond strength for bar-anchorage interface.