Health monitoring of concrete structures by electromechanical impedance approach using PZT transducers.

Abstract

Advances in smart materials have attracted interests among researchers to develop new non-destructive evaluation and monitoring techniques. One such technique that has made much progress in the last decade is the electromechanical impedance (EMI) approach, which employs piezoelectric transducers. These transducers exhibit piezoelectric effects which means they can produce a voltage difference across its top and bottom faces when compressed (direct effect), and conversely, they can physically change shape when an external electric field is applied (converse effect). Experimental implementations for damage detection in concrete structures using the EMI approach have been successfully demonstrated by many researchers. Since then, constant researches in the field of structural health monitoring (SHM) of civil infrastructures have been carried out by various researchers. The EMI sensing technique offers many advantages. Piezoelectric transducers are lightweight, non-intrusive and can be used for monitoring inaccessible locations. The main advantage of this technique is that it is very sensitive to local minor changes. The advancement in impedance measurement chip has also motivated researchers to develop low cost wireless-based monitoring system for this technique. Overall, the aim of this research project is to further develop the application of the EMI method using the low cost piezoceramic (PZT) transducers for monitoring and evaluation of concrete structures. The research works in this dissertation can be summarized as (1) Monitoring strength development of concrete, (2) Non-destructive assessment of concrete quality, (3) Monitoring early-age development of steel-concrete bond, and (4) development of improved monitoring technique using reusable PZT transducers. In this dissertation, the background of study on inspection and quality control tools for assessing integrity of concrete structures, literature review on SHM using piezoelectric materials and scopes an...