Anisotropic electrical and piezoresistive sensing properties of cement-based sensors with aligned carbon fibers

Abstract

This paper aims to examine the effect of orientation and alignment of carbon fibers contained in a cement-based sensor under a magnetic field (MF) on the electrical and piezoresistive sensing properties of the resulting cement-based composite. The electrical conductivity and piezoresistive responses in two directions of aligned carbon fiber cement-based composites, i.e., parallel and perpendicular to MF, were measured. The effects of several variables on anisotropic electrical property were studied, e.g. carbon fiber content, humidity and temperature. The cyclic and failure response in different directions were tested. The results indicate that the aligned carbon fiber cement-based sensors exhibit the anisotropic electrical and piezoresistive properties at the same carbon fiber content. At the carbon fiber content of 0.3 wt%, the sensors achieved the maximal anisotropy. The percolation thresholds for the carbon fiber cement-based sensors with MF and without MF have the sequencing order: parallel to MF < without MF < perpendicular to MF. Under cyclic loading and failure loading, the piezoresistive properties of aligned carbon fibers sensors in the direction parallel to MF show the excellent repeatability, stability and sensitivity.