Performance Degradation of Subsea Shield Tunnel Segment Accounting for Concrete Strength Loss and Steel Bar Corrosion

Table 1

The pretreatment methods for the three groups of concrete samples.

Groups of samples	Simulation object	Pretreatment method	Specific pretreatment processes
Group A	Uncorroded concrete	No treatment	None
Group B	Water saturated concrete	Soaking in warm pure water	Place the samples in an electric cooker filled with pure water, keep the water temperature at 60°C, and continue soaking for 24 hours to fully saturate the concrete samples
Group C	Chlorine-corroded saturated concrete	Soaking in warm chloride solution	Place the samples in an electric cooker filled with 2.5% NaCl solution, keep the water temperature at 60°C, and continue soaking for 24 hours to fully saturate the samples and ensure the chloride fully penetrates into the concrete, as demonstrated in Figure 2(b)