Within the past 7 years, the use of stainless steel rebar has been used increasingly in a number of new bridge construction projects throughout the country.  One of only two North American fabricators is located right here in Evendale Ohio.  http://cmcmmi.com/projects/

 

Bridges made with 2304 Stainless are 100+ year design life.

 

Some North American projects under construction currently are:

Bayonne Bridge in NewYork/New Jersey

St Croix Crossing in Minnesota

Dresbach Bridge in Minnesota

 

Just a few of the State DOT's now using Stainless rebar in bridges:

Minnesota

New York

New Jersey

Vermont

West Virginia

Virginia

North Carolina

Iowa

Wisconsin

Illinois

Colorado

New Hampshire

Thanks for posting.  I had no idea.

Interesting. Does stainless have all the same physical characteristics as regular rebar? I'm wondering if there are any downsides besides cost.

It's really fascinating stuff.  Stainless can be anywhere from 800x to 1500x more corrosive resistant than black bar.  Epoxy coated rebar has been what most DOT's have used on large scale public works projects which on the lower end is only 65x more corrosive resistant than black bar.  Most epoxy coated structures normally may have a design life of 50-60 years and that steel needs to be touched up on ends where it's cut.  Epoxy is very easy to damage and if it is placed in the concrete damaged it renders that entire bar no better than just using plain black bar at that point because when one area is compromised to corrosion, eventually the entire bar goes much sooner than it would undamaged.  Stainless is much more durable and harder to damage in the fabrication, shipping, and placing process.  Plus, having 100+ design life I'd imagine that the steel may outlast even the concrete at that point.

 

Stainless plays a huge role into the longevity of a structure in areas of the world where road salt or sea salt in the air are everyday factors.

 

Cost has come way down in the past few years.  I would imagine since it's now only a little more than double the cost of epoxy that we may start seeing more DOT's sign on.  I've heard ODOT is building a stainless test bridge in Hamilton County. 

 

I believe stainless rebar ranges from $2.20 to $2.50 per lbs these days obviously depending on market fluctuations.  A few years back when it came out it was around the $4 range.  I think black bar may range is around .50 per lbs while epoxy is around .90 per lbs.

Here are some images from construction of the St Croix Crossing connecting Stillwater MN to Houlton WI.

 

The Minnesota DOT has done a great job updating the videos and information online for this project.  This is just one of many that are out there.

 

Young concrete is alkaline and this helps protect the rebar from corrosion, but over time this alkalinity decreases and so does the protection. 

 

Much will depend on the application.  Hot dip galvanized rebar will also resist corrosion significantly better than epoxied steel, though care must be taken welding.  Of course stainless is a Bit*h to weld, and is going to cost much more.

 

Either steel having its own corrosion resistance probably allows a more porous concrete matrix less prone to cracking, which of course is how a lot of corrosion begins.

 

PS:  Whoops!  Didn't know we had a cuss filter here.  :o

 

Here is a link to an article with some good pictures of the Bayonne Bridge project in New York/New Jersey. 

 

The Bayonne Bridge's New and Higher Road Deck

http://www.enr.com/articles/41611-the-bayonne-bridges-new-and-higher-road-deck