Electrical conductivity characterization and variation of carbon fiber reinforced cement composite

Electrical conductivity of carbon fiber reinforced cement composite (CFRCC) was measured. The conductivity of specimens increased by several orders of magnitude while the volume fraction of fibers reached a higher value than the critic concentration. The microstructure associated with electrical percolation phenomena was observed. The mechanism of conduction was interpreted as being due to fibers touching each other. The changes of electrical conductivity under three different loading levels were investigated. The percolation threshold value decreased with loading. The relative changes of electrical conductivity both under single loading and cyclic loading could sense the stress in non-elastic, elastic and fracture region with sensitive response. The influences of fiber volume fraction and fiber length on the sensitivity of electrical conductivity measurement were discussed. The results provide some new information for the fabrication of conductive and intrinsically smart carbon fiber reinforced cement composites. (C) 2002 Kluwer Academic Publishers.