Using rusted rebar

[mattd]

I am getting ready to build my own home and was told to make sure that whoever does the foundation work, make sure they use unrusted rebar. Does it matter and would it be better to use stainless steal rebar?

[Rich]

Rusted rebar is a no-no. It doesn't allow the concrete to adhere as well - but mostly it's a visual thing. The rust from the rebar will eventually come to the surface. Awhile after that the rebar will have a space between it and the concrete which takes all the reasons for using rebar in the first place away.
Stainless steel rebar? The cost :shock: would be astronomical to begin with. If you just take care of the rebar before placing it you should have no problem. There's always a little rust on it which is not worrisome. I'm talking about a layer of rust on the whole thing and flaking off.
If you are really worried about it you can ask them to use a corrosion inhibitor in the concrete from the plant. It costs more but will give you a little more piece of mind.
Overall I've never worried about rust on rebar unless it's so bad to be unusable.

[Rich]

I was talking to an engineer the other day regarding some tests they had done with some technical group regarding rust on rebar. The findings were that with some slight rusting the rebar performed better than "clean" bar. Until the rebar started to begin actually scaling - it performed pretty well.