*2.2. Specimen Preparation*

RC samples used in this study were composed of concrete (cracked or sound) and rebar. Samples were made with artificial cracks by means of positing and removal of required thin copper sheets with different number, width and spacing inside samples. Figure 1 shows the dimensions of the specimen and relative position among concrete, crack and rebar. The length of each crack is 60 mm and the depth is 19 mm. The length direction of each crack is perpendicular to the length direction of rebar. The combinations of crack width, number and spacing in samples are given in Table 2.



Cylinders of φ100 mm × 50 mm were casted in plastic modules and compacted by vibrating table. They were allowed to cure at the condition of 20 ◦C and 95% relative humidity. Copper sheets were removed from specimens after a 4-h curing period. Specimens were removed from moulds after a 24-h curing period. Besides, the weld and exposed parts of rebar must be covered with a layer of epoxy resin to protect rebar from corrosion during the curing time. After that, all specimens were cured under the normal curing condition (20 ◦C and 95% relative humidity) for 28 days before further experiments.

**Figure 1.** Specimen dimension and rebar arrangement: (**a**) Front view of the sample; (**b**) Stereoscopic view of the sample.
