Electrical characteristic and piezoresistivity of carbon fiber graphite cement-based composites containing CCCW

The electrical conductivity and pressure-sensitivity of carbon fiber (1% mass fraction of cement) graphite (0% 50% mass fraction of cement) cement-based composites samples (40 mm×40 mm×40 mm) containing CCCW (cementitious capillary crystalline waterproofing materials，4% mass fraction of cement) were measured by the four-probe method and Instron 5882 system. The variation trend of volume resistivity with graphite contents and pressure sensitivity at different mixing amounts of the graphite were discussed. The results show that the resistivity of carbon fiber graphite cement-based composites containing CCCW versus the concent ration of graphite curves has typical features of percolation phenomena. The percolation threshold is 20% (mass fraction of cement). The corresponding relationship between stress and resistance exists with different contents of graphite under the action of cyclic loading，and it comes to the conclusion that when the content of graphite is up to 20%～30% mass fraction of cement，the pressure sensitivity is the best.