ELECTRICAL-RESISTIVITY OF CARBON AND STEEL MICRO-FIBER REINFORCED CEMENTS

Electrical Resistivity measurements were conducted on cement pastes reinforced with conductive micro-fibers of carbon and steel both in mono and hybrid (combination) forms. A high frequency alternating current was employed. Effects of the alternating current frequency and inter-electrode spacing were investigated. Composites with various fiber volume fractions were tested. Notable reductions in the electrical resistivity with fiber reinforcement were observed. Although carbon fibers themselves are are far less conductive than steel fibers, cement composites with carbon fibers were found to be better conductors than those with steel fibers. It was concluded that more than the conductivity of the fiber material itself, it is the size and distribution of the fiber in a composite which is of importance. For the same reason, some hybrid-fiber composites were found to have conductivities better than their equivalent mono-fiber systems.