Exploratory study on the short- and long-term bond between ribbed CFRP bars and additional aluminum alloy ribs anchorage

Abstract

Innovative additional aluminum alloy ribs (ARs) anchorage has been recently developed to enhance the bond for FRP bars in pretensioned prestressed concrete. Studies have demonstrated the feasibility of using the ARs anchorage to improve the bond of FRP bars to concrete. However, the bond performance between FRP bar and ARs anchorage remains unclear. The present study reported an experimental programme to explore both the short- and long-term bond performance at ribbed CFRP bar-AR interface. The failure modes and bond-slip curves of short-term pull-out specimens were presented. Microstructure at the bar-AR interface was identified to explain the bond failure characteristic. Besides, the short beam test for the CFRP bars was conducted to support the findings obtained from the short-term pull-out test. The long-term bond at bar-AR interface was evaluated by subjecting the pull-out specimens to sustained loading for 500 days. Through the testing results, the bond mechanism of the bar-AR interface was identified, and the reasons behind bond enhancement caused by the prsence of ARs anchorage for CFRP bars in concrete were revealed. This exploratory study could be regarded as the most basic support for the application of ARs anchorage for enhancing the performance of prestressed CFRP reinforced concrete.