Strain-sensing characteristics of carbon fiber-reinforced cement

Strain sensing in carbon fiber reinforced cement, as enabled by piezoresistivity, is characterized by the gauge factor, which is defined as the fractional change in electrical resistance per unit strain. Under uniaxial compression, the gauge factor in both longitudinal and transverse directions decrease in magnitude with increasing specimen size from 13 to 51 mm, due to a slight decrease in the degree of preferred orientation of the 5 mm-long fibers. Also under uniaxial compression, the gauge factor in both directions decreases in magnitude as the fiber content increases beyond the percolation threshold.