Damage Assessment in Concrete Structures using PZT patches

Abstract

Piezoelectric based PZT smart sensors offer significant \ud potential for continuously monitoring the development and \ud progression of internal damage in concrete structures. \ud PZT-based damage sensors consisting of piezo-electric \ud patches, which are bonded to the surface of a concrete \ud structure can be developed for assessing the damage \ud progression of concrete members. The primary challenge \ud in developing a PZT-based sensor lies in developing a \ud methodology to infer about the level of damage in the \ud material from measurement. Changes in the resonant \ud behavior in the measured electrical conductance obtained \ud from electro-mechanical (EM) response of a PZT bonded \ud to a concrete substrate is investigated for increasing \ud levels of damage. The sensitivity of EM impedance- \ud based measurements to level of damage in concrete is \ud reported. Incipient damage in the form of microcracks in \ud the concrete substrate produces a change in the electrical \ud conductance signature associated with the resonant \ud peaks. Changes in the conductance resonant signature \ud from EM conductance measurement are detected before \ud visible signs of cracking. The root mean square deviation \ud of the conductance signature at resonant peaks is shown \ud to accurately reflect the level of damage in the substrate. \ud The findings presented here provide a basis for developing \ud a sensing methodology using PZT patches for continuous \ud monitoring of concrete structures