Enhanced sensing performance of cement-based composites achieved via magnetically aligned nickel particle network

Abstract

Cement-based sensors, consisting of a cementitious matrix filled with electrically conductive fillers, are one of the most promising sensing composites to monitor and track the status of structural systems continuously. This study proposes a new type of cement-based sensor with a unique anisotropic conductive chains activated by magnetically aligned nickel particles in a chain form structure. The piezoresistivity is significantly enhanced along the direction of the chain structure and the gauge factor ranges from 2491 to 3626, providing the sensors with excellent piezoresistivity and sensitivity. In the meantime, the usage of nickel particles drops significantly compared to the composites with randomly dispersed nickel particles. To explore its potential in engineering applications, the developed sensors are embedded in the compression zone of a beam structure. Three-point-bending test result shows that under same condition, the anisotropic sensors exhibits superior piezoresistive performance and higher sensitivity than the isotropic sensors.