[mikehotel]

Water could reach the rebar from the ground, but I would think waterproof membranes and proper drainage should allow it to remain mostly dry. The foam panels should also reduce the amount of air that gets to the concrete and the rebar. Of course, you want concrete to be wet for curing, but how would water and oxygen reach it after it drys out? Do you think the oxidization process will not stop after curing?

[LegitShady]

concrete is porous. IF you wrapped your concrete in a waterproof membrane, the first tear or piercing in the membrane would then become an entryway for water and there would be no way for the water to leave because of the rest of the membrane. Proper drainage is a better solution.

It's like the bridges that used epoxy coated rebar for chloride corrosion resistance and then found out that any tiny nick in the epoxy coating then causes that rebar to somehow corrode FASTER than uncoated rebar.