Piezoresistance under Multi-Axis Strain of Cement-Based Composites Filled with Carbon Black: Theoretical Model and Experimental Results

Based on the tunneling effect theory, a piezoresistivity model is presented to predict the resistance change of composite under multi-axis strain. Cement-based composites filled with carbon black (CB) was prepared and the electrical conduct mechanism was found agreement with tunneling effect theory, so resistance between two CB particles is a exponential function of barrier length. Conductive network is composed by infinite of unidirectional CB particles barrier. The external strain applied on composite performed various effect on each barrier because of the orientation angle. The relation between external strain and the deformation behavior of barriers was established, and then the piezoresistance model was established. The model indicated that piezoresistance property of conduct composite is multi-axis strain dependent and can be predicted. Experimental results of piezoresistance agreed well with the theoretical prediction results.