Crack detector for concrete submerged in sea - has sensing electrodes connected via multiplexer to detector and demodulator

摘要

The reinforced concrete submerged in sea water is automatically examined for cracks by detector which senses modification to electric current or voltage density around the crack. An alternating current source is connected to a reinforcing core of concrete while second electrode is connected to an electrode plate comprising insulating panel with series of electrode elements on a conducting face. Electrodes connect via a multiplexer to a detector and a demodulator senses individual electrode current for observation on oscilloscope synchronised with the multiplexer. Observed signal peaks indicate the position of a crack.