Monitoring of Compression and Bending Process of Reactive Powder Concrete Using MWCNTs/PDMS Composite Sensors

In the structural healthy monitoring of bridges, pavements of concrete or asphalt, flexible conductive sensors exhibit so many advantages, such as low cost, high durability, and large deformation monitoring. Herein, we report a low cost flexible composite sensor of multi-walled carbon nanotubes/Polydimethylsilosane (MWCNTs/PDMS) nanocomposites via solution casting method. Results show that MWCNTs/PDMS reveals excellent sensitivity and good stability when the fraction of MWCNTs is larger than the threshold (~2.5 wt%). The compressive strain of reactive powder concrete was lineal with the resistance change of sensor ( $\Delta R/R_{0})$ in the range of elastic deformation, while the deflection of reactive powder concrete could be predicted by the fitting exponential equation from the electric resistance change of MWCNTs/PDMS. These results highlight MWCNTs/PDMS nanocomposite as strain sensor in the structural health monitoring of reactive powder concrete structures.