Acoustic emission detection of damage in reinforced concrete conduit

Acoustic emission has been used to determine condition in reinforced concrete conduit. Acoustic data generated by PLB (pencil-lead break) were collected from both good PCCP (Prestressed Concrete Cylinder Pipe) and damaged PCCP as digital waveform files. These files were analyzed using the normalized frequency energy method. The results indicate that the energy in specific frequency segments can indicate the condition of the conduit, and with an appropriate tuning process, may show the type of damage; e.g., broken wire or delamination. A partial power function and a graphic alarm have been implemented in a standard AE instrument. A portable handheld sensor-head support structure has been designed and built to maintain a constant source-sensor distance spanning the width of the desired inspection region for a standard 1.2-m diameter PCCP.