Table 4 summarizes the parameters describing the electrical polarization corresponding to the four different evaluated electrodes. These polarization parameters consist of the initial electrical resistivity (ρ

_{0}), electrical resistivity at polarization time (ρ

_{P}), fractional change in the electrical resistivity from ρ

_{0} to ρ

_{P} (

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$), change in the electrical resistivity at polarization time (∆ρ

_{P}), slope at polarization time (ρ’

_{P}), and polarization time (t

_{p}).

Figure 9 shows the measured change in the electrical resistivity (∆ρ) and the variation in the slope (ρ’) of that change corresponding to the different types of electrodes evaluated, used to determine the polarization time (t

_{p}) required to establish stable electrical resistivity, defined in this study as the time satisfying both of the following conditions: 1) when ∆ρ is less than 0.09 kΩ·cm, and 2) when ρ’ is less than 0.009 kΩ·cm/sec. To minimize noise when determining t

_{p}, the data measured at a frequency of 6 Hz was calibrated to the data measured at a frequency of 0.1 Hz, as can be seen in

Figure 9a,b. The above conditions for determining t

_{p} could then be obtained using the measured data calibrated to 0.1 Hz. As a result, the t

_{p} for the specimens equipped with the CS, CC1, and CC2 electrodes was determined to be 25 s, 80 s, and 107 s, respectively.

Figure 10 shows the relationships between the fractional change in the electrical resistivity and polarization time of the CS-, CC1-, and CC2-equipped HPFRCCs. The fractional changes in the electrical resistivity at the polarization time (

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$) of the CS-, CC1-, and CC2-equipped HPFRCCs were 186.7%, 240.7%, and 190.5%, respectively. The value of

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$ can be observed to be closely related to the value of t

_{p}—the

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$ of the CS- and CC1-equipped HPFRCCs increased from 186.7% to 240.7%, as the t

_{p} increased from 25 s to 80 s.

The correlation between

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$ and t

_{p}, describing the polarization phenomenon, can be explained by the electron flow at the interface between the electrode probes and the HPFRCCs. Suryanto et al. [

35] reported that the electrical resistance of cementitious composites was affected not only by the matrix characteristics (compressive strength, temperature, humidity, etc.) but also the electrical resistance of the interface.

Figure 11a–c illustrates the electron accumulation phenomenon at the interface between each electrode type and the HPFRCCs. When the input current (i) flows from the probe into the cement based material, negative electrons (e

^{-}) move in the opposite direction [

36]. At this time, electron accumulation, which causes the polarization effect, occurs between the probe (which has a high conductivity) and the cement based material (which has a low conductivity). As the electron accumulation increases, both the polarization time (t

_{p}) and the fractional change in the electrical resistivity at polarization time (

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$) increase. Therefore, as can be seen in

Figure 11a, electrons at the interface between the CS electrode and the HPFRCC, which exhibited a shorter t

_{p}, accumulated less than for other electrodes, whereas the electrons at the interface between the CC2 electrode and the HPFRCC, which exhibited a longer t

_{p}, accumulated more, as can be seen in

Figure 11c. Consequently, the

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$ and t

_{p} of the CC1-equipped HPFRCC, which exhibits more electron accumulation between the specimen and the electrode than the CS-equipped HPFRCC, were higher than those of the CS-equipped HPFRCC. The results obtained using the CC2 electrode showed the highest t

_{p} (107 s), and a

$\overline{{\mathsf{\rho}}_{\mathrm{p}}}$ (190.5%) lower than that when using CC1 electrode, as the CC2 electrode (which used a smaller-area carbon tape as the adhesive) seemed to generate significantly more electron accumulation at the interface between the specimen and the electrode. Thus, the CC2 electrode was determined to be unsuitable for measuring the electrical resistance of HPFRCCs. Among the evaluated electrodes, the CS electrode exhibited the shortest t

_{p} (25 s). Among the remaining electrodes, because electrode CC1 exhibited a shorter t

_{p} (80 s) than electrode CC2 (107 s), CC1 was determined to be more suitable than CC2 for measuring electrical polarization. Accordingly, the CS and CC1 electrodes were selected as the focus of the remaining investigation.