## 2 Experimental Program
### Physical Characterizations  
First of all, in order to understand the methodology applied, it is necessary to understand that different scales of observation have been used, namely prism (Pn), slice (Ti) and square samples (Ei). Indeed, this methodology consists of three steps (Figures 3-7) and has been developed to characterize the observed corrosion-induced damage. Figure 4: Schematic representation of a sample preparation for step 2. Figure 3: Overview of step 1 of the methodology for physical characterizations (The orange square and blue line indicate the location of the PVC tank and the crack respectively). (1) On the concrete surface of the RC prisms. The corrosion degradations (rust stains, cracks, etc.) were visually observed on the RC prisms, considering the two faces (T and F) with the 30 mm concrete cover. Photographs of the T and F faces of each prism were taken. In addition, the maximum crack width on the T and F faces of the twenty-eight prisms was measured using a crack-measuring magnifier with transparent ruler, procured from Walmart, Bentonville, AR, USA (precision of 0.05 mm). (2) Inside the prisms at the level of the concrete cover. Slices 20 mm thick were drawn along the longitudinal X direction on prisms that had been marked with an asterisk (Figures 4 and 5 and Table 2). Each of the slices had been assigned a designation, ranging from T1 to T25 (Figures 4 and 5). The slices were sawn with dimensions of 125 \(\times\) 100 \(\times\) 20 mm\({}^{3}\). Slices T2 and T3 were considered as reference samples, as they were outside the accelerated corrosion test area. The slices from T10 to T17 were inside the accelerated corrosion test area. As expected, slices T2 and T3 exhibited no sign of corrosion and thus were excluded from the subsequent analysis. The total number of slices to be studied is therefore one hundred twelve. The two faces of slices T10 to T17 were photographed and examined in order to characterize their degradation based on the methodology developed by [51] and adapted  
Figure 5: Overview of the step 2 (prism cutting) of the methodology for physical characterizations. Figure 6: Overview of step 2 (analysis of the crack patterns) of the methodology for physical characterizations (the labels used were Pr-Xd-Y-Ti, where Pn refers to the RC prism name, Xd to the time of exposure (in days), Y to the impressed current (\(\mu\)A/cm\({}^{2}\)) and Ti to the slice name). Figure 7: Overview of the step 3 (analysis of the steel/concrete interface) of the methodology for physical characterizations (Ti refers to the slice name, Ei to the slice name and C) to the observed area name). for our study. In order to determine the angular position of the root of each visible crack in each face of the slices, a graduated circle was positioned on the photograph of each face (Figure 6a). The length of each crack was assessed using the concentric circles (one circle drawn every centimetre) (Figure 6b). The crack widths of all faces were subsequently measured using the same crack-measuring magnifier. At the steel/concrete interface close to the rebar. The steel/concrete interface was analysed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) (FEI QUANTA 400-EDAX, FEI, Villebon-sur-Yvette, France. In order to reduce the time required for analysis, three slices were selected from the eleven prisms. This approach was deemed to be more appropriate than analysing eight slices per prism, given the time constraints. The selected slices were T10, T13 and T16 per prism, thus allowing for the assessment of the steel/concrete interface degradation at each end and in the middle of the accelerated corrosion test area, with the same gap between the three slices. The total number of selected slices is therefore forty-two. Prior to analysis, the slices T10, T13 and T16 were impregnated with an epoxy resin under vacuum at room temperature and subsequently dried in an oven at 45 \({}^{\circ}\)C for 24 h in accordance with ASTM standard C642 [52].