Effects on Impact-Echo Signals Caused by Adjacent Steel Reinforcing Bars and Defects in Lap-Splice Regions: Experimental Study
Alex Pagnotta, David Trejo, Paolo Gardoni and Qindan Huang
Appears on pages(s):
impact-echo, defect around reinforcing bar, alkali-silica reaction, corrosion, steel-concrete interface, impact-echo transfer function
Previous studies have identified the impact-echo method as a viable technique for detecting defects around steel reinforcing bars in reinforced concrete (RC) members. Defects can form around reinforcement as a result of corrosion, alkali-silica reactions, delayed ettringite formation, freezing and thawing, and other deterioration mechanisms. This paper investigates the feasibility of using impact echo testing on RC members to evaluate defects in lap-splice regions. In lapped bars challenges exist because adjacent bars may have different defect conditions. A small-scale experimental setup for making this determination is designed to replicate field conditions. Variables in the experiment include defect thickness and defect length. Impact-echo results from the small-scale experimental design are presented to determine if impact-echo testing can be used to identify the presence of defects at the steel concrete interface in specimens containing adjacent steel reinforcing bars.