Bond performance of the additional aluminum alloy ribs anchored CFRP bars in concrete under sustained loading

Abstract

The novel additional aluminum alloy ribs (ARs) anchorage is a convenient and effective solution to improve the bond of FRP bars in concrete. Although the bond behavior between the ARs anchored FRP bars and concrete under the short-term loading has been recently investigated, its long-term behavior under sustained loading has yet been assessed. This paper aims to study the long-term bond behavior of both the unanchored and ARs anchored CFRP bars in concrete under sustained loading for a period of 380 days. 12 pull-out specimens were tested under sustained loading considering parameters including the bond length, sustained loading level, and the type of FRP bars. Results showed that the ARs anchored specimens effectively reduced the long-term slip by as much as 48.7%-52.5% compared to that of the referenced unanchored specimens due to an improved bond mechanism. In addition, an analytical model was proposed to predict the long-term end slip for both the unanchored and ARs anchored FRP bars in concrete.