## 2 Outline of the Existing Research Conducted by Authors
### Experimental Method and Test Results  
As illustrated in Figure 6, all beam members were loaded by a four-point bending test method. The pure bending span between two loading points was 600 mm for the flexural failure type beam and 500 mm for the shear failure type beam. In the structural test, the load was controlled at the loading speed of 20 kN/min until 50% of the expected ultimate load was reached using a monotonic transverse loading method, followed by a speed of 0.7 mm/min using a displacement control method. The experiment was terminated when the maximum tensile strength was reduced to 70% after reaching the peak tensile strength. Figure 5: Reinforcement details of beams: (**a**) flexural failure type beam and (**b**) shear failure type beam. In accordance with ASTM C876 [23], each specimen corroded by the impressed current technique was subjected to quantitative measurement of the potential of the member with corroded rebars at 24 measurement points by the HCP [24]. The second column of Table 2 shows the average potential difference of the 24 measurement points for the reinforcement corrosion potential difference of each specimen. The potential difference sequentially increases in the order of specimens FB-C1 through FB-C7 and SB-C1 through SB-C7. This is related to the increase or decrease of the corrosion acceleration rate of the specimen in the process of corrosion by the impressed current technique. Table 2 presents the ultimate load and deflection of each flexural and shear beam specimen, and also the energy dissipation area calculated based on the strength and deformation caused by corrosion of rebars and the performance degradation factor (\(\phi\)) defined by Equation (2). In a previous study [1], the correlation between the average \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Beam**} & \multicolumn{2}{c}{**Average Potential**} & \multicolumn{2}{c}{**Ultimate**} & \multicolumn{2}{c}{**Dissipation**} & \multicolumn{2}{c}{**Performance**} \\ \cline{2-6}  & **Difference in Voltage** & & & **Energy (kN-mm)** & **Degradation Factor \(\phi\) (\%)** \\ \cline{2-6}  & **mV CSE** & **Load** & **Deflection** & **Energy (kN-mm)** & **Degradation Factor \(\phi\) (\%)** \\  & **(Copper Sulfate Electrode)** & **(kN)** & **(mm)** & & \\ \hline FB-C0 & \(-63\) & \(81.6\) & \(116.7\) & \(8298\) & \(100.0\) \\ FB-C1 & \(-254\) & \(78.9\) & \(100.9\) & \(7521\) & \(90.6\) \\ FB-C2 & \(-265\) & \(77.4\) & \(110.9\) & \(7639\) & \(92.1\) \\ FB-C3 & \(-280\) & \(80.7\) & \(101.4\) & \(7404\) & \(89.2\) \\ FB-C4 & \(-292\) & \(78.4\) & \(95.6\) & \(6683\) & \(80.5\) \\ FB-C5 & \(-298\) & \(72.0\) & \(98.7\) & \(6659\) & \(80.3\) \\ FB-C6 & \(-374\) & \(74.3\) & \(97.4\) & \(6651\) & \(80.2\) \\ FB-C7 & \(-700\) & \(77.2\) & \(76.9\) & \(5797\) & \(69.9\) \\ \hline SB-C0 & \(-171\) & \(181.9\) & \(11.3\) & \(1301\) & \(100.0\) \\ SB-C1 & \(-269\) & \(169.8\) & \(10.0\) & \(1267\) & \(97.3\) \\ SB-C2 & \(-344\) & \(172.3\) & \(11.0\) & \(1178\) & \(90.5\) \\ SB-C3 & \(-551\) & \(187.7\) & \(9.0\) & \(1121\) & \(86.2\) \\ SB-C4 & \(-576\) & \(186.7\) & \(12.5\) & \(1090\) & \(83.7\) \\ SB-C5 & \(-659\) & \(178.1\) & \(11.1\) & \(1101\) & \(84.6\) \\ SB-C6 & \(-700\) & \(171.4\) & \(7.8\) & \(1056\) & \(81.1\) \\ SB-C7 & \(-700\) & \(181.9\) & \(10.3\) & \(995\) & \(76.4\) \\ \hline \hline \end{tabular} Note: FB and SB indicate beams controlled by flexure and by shear, respectively, and \(\phi\) shows the performance degradation factor.  
\end{table} 
Table 2: Test results for each specimen. Figure 6: Test setup. potential difference in voltage (mV) and the performance degradation factor (\(\phi\)) of each specimen presented in Table 2 was proposed, as illustrated in Figure 4.  
\[\phi=\frac{E_{r}}{E_{t}} \tag{2}\]  
where \(E_{t}\) and \(E_{r}\) denote the energy dissipation areas of the beam member before and after rebar corrosion, respectively.