Health Monitoring of GFRP Repaired Reinforced Concrete and Steel Fiber Reinforced Concrete Beams using Acoustic Emission Technique

Abstract

The vulnerability of concrete and reinforced concrete structures induced by deterioration and corrosion over a period of time makes it essential to continuously monitor these kind of structures. Damage monitoring becomes important for the purpose of further suggesting repair and retrofitting strategy for the structures for their sustenance over a longer period of time. Nowadays, numerous techniques have made it feasible to study and examine the behavior and damage characteristics of these structures by means of non-destructive testing techniques which are favorable as against destructive testing. Out of the various NDT techniques, AE has proven to be successful for real time diagnosis of damage in different kinds of structures including reinforced concrete (RC) structures. An attempt has been made in this research effort to utilize, Acoustic Emission (AE) Technique effectively to monitor damage in RC and steel fiber reinforced beams (SFRB) subjected to half cyclic load at various stages of initiation and progression of damage. Half cyclic load is applied with increasing loading levels, and an increment of 5 kN, is given at each load cycle. Further the damaged RC and SFRB beams repaired with GFRP (Glass Fiber Reinforced Concrete) wrapping are monitored using AE Technique when subjected to half cyclic loading to understand the variation in their damage mechanisms and prove the effectiveness of Acoustic Emission in predicting the damage progression after repairing. It was found that Acoustic Emission Technique is effective in monitoring damage initiation and progression in RC and SFRB beams when subjected to half cyclic loading. Additionally, in GFRP repaired RC and SFRB beams, fewer AE events and less release of AE energy due to pre-cracked condition of the beams clearly indicated efficacy of AE Technique in monitoring the damage after repair. The decrease in total acoustic energy for the repaired beams is approximately one-third to that of control RC beams.