Concrete-Galvanized Steel Pull-Out Bond Assessed by Acoustic Emission

Abstract

This paper experimentally investigates the steel-to-concrete bond phenomenon in two kinds of deformed bars: black steel and hot-dip galvanized steel. The differences in the steel-to-concrete bond behavior are identified in terms of the load-slip curves and the acoustic emission (AE) patterns measured during pull-out tests. Test results show that the bond capacity and the initial stiffness of the bond stress-slip curve of black steel are approximately 20 and 50% greater, respectively, than those of galvanized steel, and the slip corresponding to the maximum bond stress is approximately 20% times larger in the latter. By measuring the AE activity, it is possible to identify the transitional points between the four stages characterizing interaction between the concrete and the bar subjected to pull-out force. Each transition coincides with a sudden drop in the AE activity. (C) 2015 American Society of Civil Engineers.