What is Concrete exposure Class XAS?

[Sammut Eng]

What is Concrete exposure Class XAS in Eurocode 2 BS 8500 - Table 2 please?

And how does one calculate the cement type, w/c ratio etc?

 

[LittleWheels]

The table says XAS, Exposed to sea water, Concrete surfaces in contact with sea water.

Table A.13 Limiting values of composition for unreinforced concrete in contact with sea water (exposure class XAS) might apply.