<p>Impedance spectroscopy was applied to determine the simultaneous effect of the cement hydration time and internal moisture on the electrical properties of cement composites with expanded graphite content within the percolation zone and above the percolation threshold. Impedance spectroscopy was used for electrical properties measurements of cement pastes to 90 days of hydration for different moisture content. Measurements were made in a frequency range of 5 to 13&#xa0;MHz. Nyquist plots were prepared from the data obtained and appropriate electrical equivalent circuits were fitted. Then, resistivity and capacitance values of the composites were calculated from the fitted equivalent circuits. The results showed influence of hydration time on electric properties of cement composites with EG content in percolation zone. For these composites, impedance spectra change with hydration time. The resistivity values increase with the hydration time, whereas the capacitance decreases. Spectra include two semicircles, whereas spectra consist of vertical lines for a lower saturation degree. The lower the water content, the change in the nature of the reactance occur at shorter hydration time. Instead, no changes were observed for composites with EG above the percolation threshold.</p>