Impedance measurement to characterize the pore structure in Portland cement paste

•We developed an innovative non-contact impedance measurement.•The relationship between the impedance response and cumulative pore volume is revealed.•The methodology in this work is the pore fractal theory.•Porosity and fraction of pore volume are obtained from impedance measurement and mercury, respectively.

This paper proposes an alternative way to characterize the pore structure in cement pastes using an innovative non-contact impedance measurement. This methodology is based on the pore fractal theory: the fractal dimension for pore space is solved from two networks (fractal electrical network and pore structure network); the minimal pore diameter in the pore fractal theory is evaluated from electrical double layers model; the applicable scope of non-contact impedance measurement is addressed through frequency dispersion mechanism. Through the pore fractal theory and this impedance measurement, the relationship between the cumulative pore volume and impedance response of cement pastes is revealed.