Piezoresistivity performance of cementitious composites containing activated carbon powder, nano zinc oxide and carbon fibre

Intrinsic self-sensing cement-based structures or sensors have a great potential for structural health monitoring applications, which can be achieved by incorporating conductive functional fillers into the cementitious composites. This study examined the mechanical, electrical and piezoresistivity of two types of cementitious composites, one with mono activated carbon powder (ACP)/nano zinc oxide (ZnO) and other carrying a hybrid of both carbon fibre (CF) and ACP/nano ZnO. The performance of mono fillers were investigated by fabricating the cementitious composites with different content of ACP (0.5%, 1%, 2% and 4% by weight of binder) and nano ZnO (0.05%, 0.1%, 0.3% and 0.5% by weight of binder). Moreover, the hybrid effect was studied by incorporating CF at 0.7 wt% with the additional ACP/nano ZnO at various concentration. The result showed that ACP/nano ZnO could improve the mechanical properties of cementitious composites. In terms of piezoresistivity behaviour, composites containing 2 wt% of ACP have favourable performance parameters with a sensitivity of 3.571%/MPa and linearity of 7.849%. Composites containing 4 wt% of ACP can achieve repeatability at 0.952%, which indicate a good reproducibility of the piezoresistivity. Although the developed cementitious composites cannot achieve a sensitivity as high as carbon fibre reinforced cementitious composites (CFRCCs), the linearity of the piezoresistive response of the composites containing hybrid ACP/CF and nano ZnO/CF has improved compared to CFRCCs.