Application of Electro-active Materials Toward Health Monitoring of Structures: Electrical Properties of Smart Aggregates

Electro-active polymers and piezoelectric energy harvesting materials offer enormous potential for developing smart damping devices for the health monitoring of civil structures during unknown excitations (e.g., earthquakes, blasts, etc.). These auto-adaptive and intelligent composites convert mechanical energy to electric energy by generating an electric field when subjected to mechanical excitation. Variation in the strength of the electric field response can detect any change in the structural properties due to damage in the host structure. An experimental research plan is developed to investigate the effectiveness of these smart materials in structural engineering applications with the purpose of damage detection and mitigation. To this end, two phases of this research study are outlined as follows: (1) materials fabrication: the piezoelectric composites were fabricated using a solution based wet lab fabrication methodology. Bulk sample geometries (such as bulk cylinders) of the two phase (such as BaTiO3-Cement) composite electro-active materials were tested for their impedance and piezoelectric properties. The microstructure and elemental distribution of these materials were characterized using the Scanning Electron Microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS/EDX) to understand the proces-sstructure-property relationships. The final composite product is labeled as electro-active smart aggregates in this project; (2) structural component testing: smart aggregates were embedded in a simply supported concrete beam to investigate their effectiveness in monitoring deflections of the beam under flexural testing. Electrical properties of smart aggregates will be presented herein.