## 3 Results and Discussion
### Polarization of GO/CC Specimens
#### 3.3.2 Spike Fluctuation of the Current Curve at Low Moisture Content State  
Figure 8 shows the current curves for drying state VI. The WL values of the specimens at this point are greater than 8.8%. There were three parallel specimens for each GO concentration to ensure the reproducibility of the experimental phenomena. As shown in the figure, the GO/CCs with GO concentrations of 0.025%, 0.05%, and 0.075% showed a spike fluctuation phenomenon. This was due to a sudden increase in current intensity followed by a return to the original current intensity in this state. This indicates a sudden decrease in resistance value followed by an immediate return to the original resistance value. This phenomenon occurs frequently in specimens with 0.05% and 0.075% GO concentrations and less frequently in specimens with 0.025% GO concentration. The current curve of the blank group without GO concentration is very smooth without any spike fluctuations. Therefore, GO concentration is believed to be responsible for this phenomenon. Interestingly, the current curves of the specimens with 0.1% GO concentration were similarly smooth, which may be a result of the combined effect of ionic and electronic conductivity; however, higher GO concentration (0.1%) did not lead to a more pronounced phenomenon. This result may be due to the fact that the GO/CCs with 0.1% GO concentration reached the percolation threshold, forming a conductive network with a conductivity dominated by electronic conductivity and less affected by ionic conductivity [17]. There is a complex interaction between ionic conductivity and electronic conductivity [34]. Some scholars have equated this to a parallel resistive equivalent circuit consisting of pore water, cement, and carbon nanomaterials [35]. Figure 9 shows the electronic and ionic conduction mechanism of microscopic GO/CCs in two-dimensional form. The blue part represents the pore water in the microscopic cracks of the cement, where water-based ionic conductivity exists. The black hexagon represents the GO particles dispersed in the cement matrix. The yellow arrows between neighboring GO particles indicate the pathway of the electron tunneling effect, and the green arrows indicate the migration pathway of ion-conducting ions. Electrical resistivity is a reliable indicator of composite self-perception. It has been shown that two mechanisms exist for CC conductivity. Ionic conductivity is present in cement matrix pore water and electronic conductivity is generated by carbon nanomaterials. The ionic conductivity is caused by the movement of ions such as Ca\({}^{+}\), Na\({}^{+}\), OH \({}^{-}\), and (SiO\({}_{4}\)\({}^{2-}\)) in the cement matrix pore fluid. Electronic conductivity is caused by electron movement on the surface of carbon nanomaterials. The electrons can jump between neighboring carbon nanomaterials to form a tunneling effect, or they can produce contact conductivity through connected carbon nanomaterials. The final electrical conductivity of GO/CCs is the result of the combined effect of ionic conductivity and electronic conductivity [22; 32]. Figure 8: Current curve spike fluctuation phenomenon of GO/CCs in low water content state. Current curves of different GO concentration specimens: (**a**) 0% GO concentration; (**b**) 0.025% GO concentration; (**c**) 0.05% GO concentration; (**d**) 0.075% GO concentration; and (**e**) 0.1% GO concentration. [PERSON] et al. argued that water forms an energy barrier in the moving direction of the carrier [36]. This solid-liquid interface constitutes an energy barrier in the direction of the movement of the carrier [25]. According to [PERSON] et al., when the bare ion is near and above the molecule sheet, it can capture electrons from the graphene fragment via polarization interaction [37]. The more probable cause is that the ions in the water are preventing electron migration. Since ionic conductivity coexists with electronic conductivity, ions migrating in water may prevent electron movement between two neighboring GO particles.