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.

本文旨在研究磁场（MF）下水泥基传感器中包含的碳纤维的取向和排列对所得水泥基复合材料的电和压阻感测性能的影响。测量了取向碳纤维水泥基复合材料在两个方向上（即平行于和垂直于MF）的电导率和压阻响应。研究了几个变量对各向异性电性能的影响，例如碳纤维含量，湿度和温度。测试了不同方向的循环响应和失效响应。结果表明，对齐的碳纤维水泥基传感器在相同的碳纤维含量下表现出各向异性的电和压阻特性。碳纤维含量为0.3 wt％时，传感器实现了最大的各向异性。具有MF和不具有MF的碳纤维水泥基传感器的渗透阈值具有以下排序顺序：平行MF <，而MF <垂直于MF。在循环载荷和破坏载荷下，对齐的碳纤维传感器在平行于MF方向上的压阻特性显示出极好的可重复性，稳定性和灵敏度。