Nondestructive Evaluation (NDE)-based Condition Assessment of Sub-surface Concrete with Limited Access

The Air Force stores some critical components in steel, cubic shaped chambers. These chambers are underground and are encased with reinforced concrete. There is no direct access to the concrete, making inspection very difficult. We propose to develop a nondestructive system to detect, locate, and assess degradation of reinforced concrete encasing the steel chambers. We propose use of piezoelectric based assessment of stress waves produced directly by degradation processes. Acoustic emission testing is well established for inspecting accessible reinforced concrete. We propose to adapt these methods to inspecting reinforced concrete behind steel plate. Our LAHMPTM system will be modified specifically to perform the automated diagnostic and location calculations developed in this research program. In Phase II we will: construct steel reinforced concrete blocks with steel plates on one side; accelerate damage to the blocks; piezoelectrically monitor the blocks both directly (on concrete) and indirectly (through steel plate); modify damage detection algorithms to account for the steel; build, test and field trial a LAHMP system for this application; and prepare for Phase III commercialization/manufacturing.