Percolation effects in the electrical conductivity of porous cement mortar
We have studied the electrical properties of cement mortars in the frequency range 10-3 to 107 Hz. The bulk d.c. conductivity was distinguished from electrode polarization effects at low frequencies as well as from a frequency dispersion at high frequencies. The bulk conductivity displays a dramatic variation with the water content of the samples. A percolation threshold can be seen at very low wa