Model of piezoresistivity in carbon fiber cement

Piezoresistivity in carbon fiber cement allows strain sensing. It was first reported in 1993, but this paper provides the first theoretical model for this phenomenon. The model is based on the concept that the piezoresistivity is due to the slight pull-out of crack-bridging fibers during crack opening and the consequent increase in the contact electrical resistivity of the fiber–matrix interface. Good agreement is found between theory and experimental results obtained under tension/compression.