Crack growth and closure in cementitious composites: monitoring using piezoceramic sensors

Coupling piezoceramics with civil-structures represents an important approach for the development of cost-effective, fully automated damage detection systems. Such systems are particularly suited for integration with autonomic technologies for self-sensing and self-healing of cementitious members. Here we present a novel study investigating both the effect of damage (cracking) and crack-closure, on the electromechanical response of mortars, with surface attached Lead Zirconate Titanate (PZT) sensors. Transducer signals were interpreted using a new analytical procedure which effectively increases the sensitivity of the electromechanical technique for both damage and repair detection compared to conventional methods of analysing the PZT response. The frequency ranges most sensitive to the presence of damage, were demonstrated to be influenced by the distance to the sensors. Furthermore, for pre-cracked specimens, it was shown that the electromechanical impedance can act as an indirect method to detect crack-closures by detecting the increase in the efficacy of load transmission in the sample. This findings of this research will enable the cost-effective monitoring and initiation of repair for self-healing cementitious infrastructure, which is expected to pave the way for self-sensing / self-healing cementitious structures.