When concrete is mixed and poured correctly the concrete is impermeable.
Concrete should not be able to allow fluids such as water etc to pass through it like soil would because if it did then concrete tanks etc would not hold any water.
At an old house we lived in we had a concrete septic tank which was impermeable and didn't allow the water to pass through and it held water.
If the concrete was permeable it would allow water too pass through it but since concrete holds water the concrete would be impermeable which means it holds water and is not porous.
If the concrete was not poured properly or mixed properly then there might be tiny holes in the concrete that would allow water to pass through which would then make that concrete permeable.
But properly mixed and poured concrete is impermeable and not porous.