Why are rusty steel used to reinforce concrete?

[StrangerGuy]

Common sense says: "Won't that make the whole thing weaker?"

 

[Hacp]

Common sense says: "Won't that make the whole thing weaker?"

Steel doesn't rust like iron?

 

[dawp]

because it sits in the yard unprotected prior to use and it really doesn't, it's mostly surface rust and doesn't affect the strength of the construction. there isn't any coating that would protect it that wouldn't affect the bond to concrete adversely.

 

[Colt45]

Because steel rusts.

 

[Locut0s]

It's just surface rust.

 

[oiprocs]

Why so many concrete questions? I didn't think the stimulus was working that quickly.

 

[Spike]

I actually wondered this a well but never bothered looking into it. Thanks!

 

[jvroig]

I notice this myself, all the steel bars always seem to have a bit of rust on them. Well, this thread explains it, I guess. What a memorable piece of trivia At least now I know what to say if someone actually asks me

 

[SunSamurai]

10lbs of rebar is not bulk.

 

[edro]

I bet the oxidation occurs very quickly.
Once the layer is established, it acts as a protective coating, slowing further oxidation.

 

[FelixDeCat]

>Why are rusty steel used to reinforce concrete?

How are rusty steel formed? How concrete get reinforced?

 

[nerp]

rebar. technique fundamental construction usage quite some time.

 

[AeroEngy]

I bet the oxidation occurs very quickly.
Once the layer is established, it acts as a protective coating, slowing further oxidation.

Not exactly...

The rebar can continue to rust inside the concrete under certain circumstances which causes it to expand. This causes the concrete crack and pieces to start breaking off which is called spalling.

They make epoxy coated or Hot Dipped Galvanized (HDG) rebar to prevent the corrosion and spalling.

I did an internship in college and worked on a project at NIH where they were using hydro-demolition robots to take off the the top half of a concrete slab to expose the rebar. Then cut out the old rusted rebar and replace it with epoxy coated rebar and re-pour the concrete.

 

[skyking]

All the bridge jobs I have worked on use epoxy coated steel due to the high temperature range and freeze/thaw cycles. buildings do not move about as much and are more stable thermally, and do not require epoxy coatings.

 

[AlienCraft]

Not exactly...

The rebar can continue to rust inside the concrete under certain circumstances which causes it to expand. This causes the concrete crack and pieces to start breaking off which is called spalling.

They make epoxy coated or Hot Dipped Galvanized (HDG) rebar to prevent the corrosion and spalling.

I did an internship in college and worked on a project at NIH where they were using hydro-demolition robots to take off the the top half of a concrete slab to expose the rebar. Then cut out the old rusted rebar and replace it with epoxy coated rebar and re-pour the concrete.

Camera fades into a boardroom, where a meeting is taking place between two sets of people, some in suits and the others in "work clothes"...
Man in suit..." so what you're saying is we have to slice off the top of the already poured and cured concrete slab, cut out the affected rebar which is embedded in that concrete, lay in this newer, more expensive rebar in it's place, glue the whole thing down and re-pour the top of that slab?"
Man in work clothes..."yep."
Men in Suits heads then explode.



Awesome. I'ld pay to see that movie.... we'll call it CAD Men and it's about the hijinks of a group of designers in the first part of the '70's.....

 

[boomerang]

I bet the oxidation occurs very quickly.
Once the layer is established, it acts as a protective coating, slowing further oxidation.

I believe you're thinking of aluminum.

 

[boomerang]

Not exactly...

The rebar can continue to rust inside the concrete under certain circumstances which causes it to expand. This causes the concrete crack and pieces to start breaking off which is called spalling.

They make epoxy coated or Hot Dipped Galvanized (HDG) rebar to prevent the corrosion and spalling.

I did an internship in college and worked on a project at NIH where they were using hydro-demolition robots to take off the the top half of a concrete slab to expose the rebar. Then cut out the old rusted rebar and replace it with epoxy coated rebar and re-pour the concrete.

I've got a good friend in the concrete business although he's branched out into wind turbines as of late. http://www.aristeo.com/ This is pretty much what he was telling me one day when I questioned him about using rusty steel to reinforce concrete.

Your driveway is one thing, a structure is another.