Electrical impedance based models for prediction of microstructure and concrete properties
Electrical response of cementitious systems can be used to understand the evolving microstructure, and thus to provide indications of the performance of such systems. Our studies have focused on the use of impedance techniques to determine the microstructure of cement pastes as well as to understand the microstructural changes occurring as a result of accelerated chloride ion transport into concretes.
We have extensively used electrical impedance spectroscopy (EIS) coupled with effective medium theories to predict hydration-dependent properties (both microstructure and strength) of cement pastes. We have demonstrated equivalence between the effective age (from the maturity method) and a pore structure factor determined from electrical impedance towards the prediction of mature properties. This is expected to contribute to the development of electrical impedance based sensing methods for fresh and hardened concrete properties.
The use of EIS to quantify the relative influence of pore structure refinement and pore solution conductivity on commonly adopted transport indicators such as rapid chloride permeability (RCPT) has been elucidated for the first time by our group. We have also successfully used EIS and circuit models (containing capacitances and resistances relating to unique microstructural features) to evaluate the pore structural changes occurring as a result of accelerated transport.