[You Need A Thneed]

[QUOTE=harryc;3275012]In Chicago it is vinyl coated (from GE), used in parking and roadways where salt is expected.

It's definately epoxy coated rebar, not vinyl coated.

And a follow-up to the original question: It's used where water will be in contact with the concrete and especially in bridges where salt is used so that it keeps the rebar from rusting. When rebar rusts, that's when concrete structures fall apart.

Concrete has excellent compressive strength, but isn't very good for shear strength or tensile strength. when you add rebar, the rebar adds the shear and the tensile strength. If the rebar rusts, that added tensile and shear strength is compromised.