Improved piezoresistive sensitivity and stability of CNT/cement mortar composites with low water–binder ratio

In previous studies by the authors, it was found that a lower water–binder ratio led to enhanced dispersion of carbon nanotube (CNT) in the cement matrix. The objective of this study was to investigate the piezoresistive sensitivity and stability of CNT/cement mortar composites with low water–binder ratio. The effect of absorbed water on the piezoresistivity of the composites was also investigated, since it strongly affects the electrical properties of the composites. The changes in the electrical resistance of composite specimens induced by external cyclic loading were measured to investigate their piezoresistive sensitivity and stability. The experimental results indicates that the stability of piezoresistivity under cyclic loading and their time-based sensitivity can be improved by decreasing the water–binder ratio of the cement composites. Moreover, the variation of piezoresistivity induced by the moisture content can be decreased by low water–binder ratio.