Self-sensing properties and piezoresistive effect of high ductility cementitious composite

Abstract

Self-sensing high ductility cementitious composite (HDCC) has unique advantages in structural health monitoring. In this paper, the carbon fiber (CF) reinforced HDCC with the addition of nano-carbon black (NCB) was designed and tested under compression and tension conditions. The sensing properties and piezoresistive effect of the proposed HDCC were analyzed based on the experimental results. The optimal mix design of HDCC was proposed with the consideration of both mechanical and electrical characteristics, i.e., tensile ductility, strain sensitivity, signal-to-noise ratio, and signal linearity. It was concluded that the ultimate tensile strain of the proposed HDCC can be as high as 3.5% with the water-binder ratio of 0.3, indicating that it is feasible to develop conductive HDCC with the addition of hybrid fibers, i.e., polyvinyl alcohol fiber and CF. It was also found that the addition of CF is conducive to the electrical sensitivity and signal linearity of HDCC, while the addition of NCB is effective to improve the signal-to-noise ratio. The piezoresistive effect model of HDCC was also proposed based on the tunnel effect theory, in which the relationship between mechanical and electrical characteristics was established, and the validity of the proposed model was verified experimentally.