Hybrid Effect of Carbon Fiber on Piezoresistivity of Carbon Nanotube Cement-based Composite

Cement-based nanocomposite filled with only 0.1 wt.% multi-wall carbon nanotube (MWNT) (MNFRC), or hybrid with 0.1 wt.% MWNT and 0.5 wt.% microsized short carbon fiber (SCF) (SF/MNFRC), were prepared employing surfactant ultrasonic dispersion and high-speed mixing process. The electrical resistivities (rho), compressive stresses (sigma), and longitudinal strains (epsilon(1)) of these cured nanocomposites under cyclic uploading/unloading were simultaneously collected, to characterize their stress/strain-sensitive properties. There exists good piezoresisitivity and high strain sensitivity for MNFRC. The fractional change in rho (Delta rho) regularly descends or ascends following the sigma, or the El of MNFRC (the Delta rho/epsilon(1) sensitivity near 68). Hybrid of SCF is found to be more effective to improve the self-sensing repeatability and variation stability of the SF/MNFRC rather than the self-sensing sensitivity (the Delta rho/epsilon(1) sensitivity only about 64).