Well, it seems the only people who like the epoxy coated rebar are the epoxy manufacturers. In theory it works well because the epoxy is an electrical insulator. Without an electrical pathway between the steel and concrete, no corrosion can occur.
In practice, structures with epoxy rebar deteriorate faster than with normal uncoated rebar. The reason for this is if there are any nicks in the epoxy coating, all of the corrosion potential of the system drives corrosion to occur at very fast rates in small localized areas. Thus, a bar can corrode right thru in one spot while everywhere else it is in perfect shape. THere are many precautions that must be used when handling shipping and installing epoxy rebar to avoid nicks. But it is almost impossible to avoid damaging the coating. Even something like the vibrator (which is supposed to be covered with rubber) can damage it by vibrating a sharp peice of aggragate against a bar, and WAMMO you got a nick. Most highway departments have outlawed it if they are smart. Otherwise they absolutely require it.
Stay away from it if you can. A good quality concrete whith proper mix design and cover will provide you all the corrosion free service life you need. If you really need a super high corrosionm resistance, consider MMFX steel rebar, or even stainless steel. THe MMFX is somewhat more expensive than normal rebar, but it also has higher strength. Plus it has the corrosion resistance similar to that of stainless steel.
