Understanding Acoustic Emission Testing- Reading 1 Part B-A

16.9 Conclusions
From the discussion above, it appears that acoustic emission techniques may
be very useful in the laboratory to supplement other measurements of
concrete properties. However, their use in the field remains problematic.
Many of the earlier studies held out high hopes for acoustic emission
monitoring of structures. For instance, McCabe et al. suggested that, if a
structure was loaded, the absence of acoustic emissions would indicate that it
was safe under the existing load conditions; a low level of acoustic emissions
would indicate that the structure should be monitored carefully, while a high
level of acoustic emission could indicate that the structure was unsafe. But
this is hardly a satisfactory approach, since it does not provide any help with
quantitative analysis. In any event, even the sophisticated (and expensive)
equipment now available still provides uncertain results when applied to
structures, because of our lack of knowledge about the characteristics of
acoustic emissions due to different causes, and because of the possibility of
extraneous noise (vibration, loading devices, and so on).
Charlie Chong/ Fion Zhang