Whatever you do use a good two part epoxy, not the cheap stuff you can get at home depot but a good industrial one. Also etch the surface really good prior to coating. surface prep is 3/4 of the battle. Amerlock makes a great two part that will be hard as rock. You really have to watch when you apply it you don't want to be trapped in the room and it needs a few days to air out but you won't wreck it. It doesn't cost much more than the cheap kits at the major lumber stores either.
NOT SO GOOD: http://www.behr.com/behrx/act/view/p...tings&catId=16