Development of an equivalent circuit model for cement pastes from microstructural considerations

The general approach to equivalent circuit modeling of cement pastes has been to interpret spectra obtained from ac impedance measurements, assigning electrical responses to microstructural features such as hydration products and fluid-filled porosity. In this paper, we take an alternative approach. Starting with a consideration of paste microstructures and the potential conduction pathways that such microstructures could support, we propose an equivalent circuit model, Ac impedance data from pore-reduced cements have been measured for the first time and are used to test the model, This approach has permitted estimation of conductivities of ill situ pore fluid, which we believe to be influenced by hydrogen bonding to varying extents depending on pore size, and hydration product. Preliminary results are in broad agreement with data obtained by alternative methods.