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Acoustic emission (AE) has emerged as a powerful nondestructive tool to detect preexisting defects or to characterize
failure mechanisms. Recently, this technique or this kind of principle, that is an in-situ monitoring of inside damages of
materials or structures, becomes increasingly popular for monitoring the integrity of large structures. Concrete is one of
the most widely used materials for constructing civil structures. In the nondestructive evaluation point of view, a lot of
AE signals are generated in concrete structures under loading whether the crack development is active or not. Also, it
was required to find a symptom of damage propagation before catastrophic failure through a continuous monitoring.
Therefore we have done a practical study in this work to fabricate compact wireless AE sensor and to develop diagnosis
system. First, this study aims to identify the differences of AE event patterns caused by both real damage sources and
the other normal sources. Secondly, it was focused to develop acoustic emission diagnosis system for assessing the
deterioration of concrete structures such as a bridge, dame, building slab, tunnel etc. Thirdly, the wireless acoustic
emission system was developed for the application of monitoring concrete structures. From the previous laboratory study
such as AE event patterns analysis under various loading conditions, we confirmed that AE analysis provided a
promising approach for estimating the condition of damage and distress in concrete structures. In this work, the
algorithm for determining the damage status of concrete structures was developed and typical criteria for decision
making was also suggested. For the future application of wireless monitoring, a low energy consumable, compact, and
robust wireless acoustic emission sensor module was developed and applied to the concrete beam for performance test.
Finally, based on the self-developed diagnosis algorithm and compact wireless AE sensor, new AE system for practical
AE diagnosis was demonstrated for assessing the conditions of damage and distress in concrete structures.
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