Impedance studies of wollastonite micro-fibre-reinforced cement paste systems

The impedance behaviour of wollastonite micro-fibre-reinforced cement-based composites at various degrees of hydration has been investigated. The observation of larger high-frequency arcs accompanying wollastonite micro-fibre addition to the Portland cement system at a hydration time greater than 3 days is an indication that the fibre matrix interface zone is less porous than the matrix itself. This conclusion is supported by SEM examination and porosimetry determinations. It is demonstrated that differences in the value of R₂ (the diameter of the high-frequency arc) for pastes with and without fibre reinforcement can be explained by the contribution to pore structure of both the fibre—cement interface and the cement matrix.