## 4 Methods
### Installation of SACP System to the Bridge Pier  
Figures 5 and 6 show the SACP installation drawing and installation process, respectively. SACP using conductive mortar was implemented for seven piers among the 60 piers. The sides of the columns were washed with high-pressure water to remove impurities. Subsequently, two types of anodes were installed on the bridge pier, as shown in Figure 5. The zinc mesh was affixed to the sidewalls of the structure, and the four zinc bulk anodes were positioned on the topsoil of the expanded foundation beneath the pier. Based on the National Association of Corrosion Engineers (NACE) CP Standard [36], the lifetime of the zinc mesh anode was expected to be 37.2 years with an anode weight of 88.27 kg, utilization factor of 85%, zinc mesh efficiency of 90%, and consumption rate of zinc of 10.7 kg/A-year. Next, the installation of the Zn bulk anodes involved an excavation of approximately 0.5 m, securing the installation location beforehand, and leveling the ground. After placing the four Zn bulk anodes in the north, south, east, and west directions, they were electrically linked using cables. The Zn bulk anode had dimensions of 161 mm \(\times\) 80 mm \(\times\) 570 mm and a weight of 25.2 kg. It has a current efficiency of 95% or higher and a consumption rate of 11.23 kg/A-year or less. Subsequently, a conductive mortar was placed. After the conductive mortar was cured, an FRP cover was installed to prevent a decrease in current flow and efficiency reduction owing to the increased resistivity of the mortar caused by moisture evaporation from the surface. The FRP cover was made of a high-strength glass fiber composite material and was installed not only to enhance the performance of the method but also for aesthetic considerations. To operate the SACP system, the wires connected to the anodes on the column sidewalls were connected to a junction box. The terminal box was installed on the sidewalls of the columns, and the wires connected to the zinc mesh, bulk zinc, and reinforcing bars were connected to the junction box. It was designed and installed to allow on-off control of the CP system using a switch to measure the 4 h depolarization potential. Note that various standards such as ASTM and ACI standards can be employed for the CP system design and measurement for concrete or mortar specimens [37; 38; 39].  
Figure 5: _Cont._Figure 5: SACP installation drawing.  
Figure 6: Entire view of the bridge before the CP application. **(a)** Grinding; **(b)** Zinc mesh installation; **(c)** Conductive mortar grouping; **(d)** Zinc bulk anode installation and FPR cover attachment; **(e)** Junction box installation; **(f)** Paint application.  
ICCP performance was evaluated using the NACE standard with a depolarization potential of 100 mV [36]. This approach involves inducing depolarization of the potential of the reinforcing steel to over 100 mV. The electrical linkage between the Zn anode and the reinforcing steel was severed, and the potential was promptly gauged. After a 4 h interval with an interrupted electrical connection, the depolarization potential was measured. A disparity exceeding 100 mV between the final recorded potential and the initial potential signifies appropriate implementation of the CP system. Notably, the depolarization potential should exceed 100 mV, excluding changes attributable to the IR drop.