Title :
Electrically-induced shape changes in cement-based materials
Author :
Ai, Hua ; Li, Jie-Fang ; Viehland, Dwight
Author_Institution :
Dept. of Mater. Sci. & Eng., Illinois Univ., Urbana, IL, USA
Abstract :
The electromechanical behavior of hardened portland cement paste has been investigated as a function of measurement frequency and DC electrical bias using an interferometric technique. Large field induced shape changes on the order of 100 A have been found in millimeter thick specimens exposed to moisture. In addition, strong hysteresis effects were found on cycling a large AC field. Dry samples were found to exhibit no field-induced deformations. The mechanism underlying this anomalous behavior is believed to be an electro-osmotically induced swelling of the pore structures. Evidence in support of this hypothesis was found by corresponding investigations of porous silica gels
Keywords :
cements (building materials); deformation; electromechanical effects; hysteresis; light interferometry; moisture; osmosis; piezoelectricity; porous materials; swelling; DC electrical bias; cement-based materials; cycling; electrically-induced shape changes; electro-osmotically induced swelling; electromechanical behavior; field-induced deformations; hardened portland cement paste; hysteresis effects; interferometric technique; large AC field; measurement frequency; mechanism; millimeter thick specimens; moisture; piezoelectric measurements; pore structures; porous silica gels; Atmospheric measurements; Building materials; Capacitive sensors; Humidity; Hysteresis; Optical interferometry; Plugs; Shape; Silicon compounds; Voltage;
Conference_Titel :
Applications of Ferroelectrics, 1994.ISAF '94., Proceedings of the Ninth IEEE International Symposium on
Conference_Location :
University Park, PA
Print_ISBN :
0-7803-1847-1
DOI :
10.1109/ISAF.1994.522482
