Ultrasonic guided wave active sensing for monitoring of split failures in reinforced concrete

The detection of bond deterioration for reinforced concrete structure in its early stages and throughout its service life can help to ensure the safety of the structure. An active sensing system with lead zirconium titanate sensors and using ultrasonic guided waves has been studied for bond integrity detection of structures under split failures. A series of pullout tests for unconfined concrete specimens has been performed. Both lead zirconium titanate sensor clips and strain gages were used to monitor the bonding damage. A bond deterioration index is defined to measure the bond integrity of the structure. While the strain gage measurements did not indicate any reduction in bond stress as the specimens were pulled to failure, the active sensing system showed a linear increment of bond deterioration index with the applied loads, indicating the accumulation of bond deterioration in unconfined concrete structure.