PSI - Issue 10

A. Drakakaki et al. / Procedia Structural Integrity 10 (2018) 59–65 A. Drakakaki et al. / Structural Integrity Procedia 00 (2018) 000 – 000

64

6

Table 2 shows that the content of S in S500s steel bar category is twice as much as the content of S in S400. Therefore, this suggests that in S500s the expected sulfide areas (corrosion-vulnerable sites) are more than the areas expected in S400. This is a fact that has already been confirmed in studies, such as Apostolopoulos et al. (2017), Apostolopoulos et al. (2018) and Apostolopoulos et al. (in press).

Short specimens 0.5 mA/cm 2 Long specimens 0.5 mA/cm 2

0 1 250 200 150 100 50 0 Corrosion duration [hours]

2

3

Mass loss (%)

Fig. 5. Graphical presentation and comparison of two series of specimens (short and long), of the same diameter Φ12, that were cor roded under 0.5mA/cm 2 current density (wet/dry conditions).

20 μ m

Fig. 6. View of corrosion path presented also by Apostolopoulos et al.(2017)

4. Conclusions

The conclusions of the present study are the following:  Mechanical performance of both S400 single-phase and S500s dual-phase steel bar categories is clearly differentiated and degraded in terms of both their corrosion resistance (mass loss) and their mechanical performance over time.  In specimens of short exposed length, the corrosion damage developed is harsher and more intense in comparison to the specimens of long exposed length.  It seems that 1 hour of the day of exposure to 0.5mA/cm 2 constant current density in the electrochemical corrosion system (wet conditions), corresponds to 10.5 days of exposure to the real aggressive- coastal environment, for both S400 single phase and S500s dual phase steel grades.  The performance of dual phase S500s steel grade, demonstrated higher drop under Low Cycle Fatigue tests- after corrosion- in comparison to the single phase S400 steel grade, even though the latter recorded higher mass loss. References Almusallam, A.A., 2001. Effect of degree of corrosion on the properties of reinforcing steel bars. Construction and Building Materials 15, 361-368. Alvarez, M.G., Galvele, J.R.,1984. The mechanisms of pitting of high purity iron in NaCl solutions. Corros. Sci. 24, 27-48. Angst, U.M., Elsener, B., 2017. The size effect in corrosion greatly influences the predicted life span of concrete infrastructures. Applied Sciences and Engineering 3(8), e1700751.