Concrete Chairs

[lilranch2001]

I took one a little bit ago as well!

 

[RjCorazza]

Funny. There is a somewhat local (?) trucking company I have seen that the owner's name on the trailer (giant letters) is :
A. Duie Pyle
Sorry Mr Pyle, but I find that hilarious.

To stay on topic, I like concrete chairs.

 

[lilranch2001]

I’m starting to get the feeling that there’s a personal conflict between ole Moss and two bit……..

Come on guys get along. Have a good time!

 

[MossRoad]

I’m starting to get the feeling that there’s a personal conflict between ole Moss and two bit……..

Come on guys get along. Have a good time!

I'd love to. I've made it a point to not comment on his posts over the past year or so, yet he keeps commenting on me. Not my posts, me. So there you go. If he stopped commenting about me, you'd never hear a peep out of me about him.

Add to that, every time he tries to make a comment about me, my 2nd amendment, religious, family, political, social beliefs, etc., he's 100% wrong. Not sure what he's trying to accomplish other than stalking.

 

[two_bit_score]

Don't flatter yourself.

 

[KennyG]

Is there any evidence for the wire chairs, which are sitting either on dirt or visqueen, rusting out and lowing moisture to get to the rwbar and corrode them? The plastic chairs, typically used for wire wouldn't so that.
The reason I ask, is rebar should be, correct be if wrong, no less than 2.5x the diameter of the bar, from the closest edge of concrete. That wire rebar chair, the feet are touching the subgrade surface.

To get back on topic, the chairs are not a problem. You want to maintain coverage on the rebar because if it corrodes it will expand and potential accelerate cracking. The wire is so small that even if it rusts, it won't expand enough to cause a problem. As an interesting trivia point, the chemistry in concrete "passivates" the steel so it won't rust, even if there is moisture in the concrete. Rust only happens if the steel is exposed to air.

 

[two_bit_score]

To get back on topic, the chairs are not a problem. You want to maintain coverage on the rebar because if it corrodes it will expand and potential accelerate cracking. The wire is so small that even if it rusts, it won't expand enough to cause a problem. As an interesting trivia point, the chemistry in concrete "passivates" the steel so it won't rust, even if there is moisture in the concrete. Rust only happens if the steel is exposed to air.

It always concerned me that all the wire I saw going under the concrete was significantly rusty. Maybe it was just surface rust but it looked like more than that to me. I also saw a lot of wire in broken up concrete that had been pulled up which looked like it must have continued to rust after it was in the 'crete. So what you are saying sounds true because oxygen is needed for rust to continue but it goes against what I think I saw. I can accept the premise that the rust won't expand enough to accelerate cracking but if the rust could continue enough to corrode the wire that much it would also not have any ability to hold the concrete together and would become worthless at doing the job it was put there to do.

 

[lilranch2001]

And why is roadbed steel epoxied?

 

[jjeff]

Interesting thing I learned about putting poly or visqueen under concrete high density foam board does the same thing in terms of a vapor barrier and once the slab is heated by the structure it radiates to slab and maintains heat much better cuz it works like a thermal break I guess? I'm curious if the concrete experts on here use foam? Or recommend it's use? What are some of the problems using it besides added cost? it is much cheaper than doing in floor heating I'm sure of. I'm going on 10 yrs with two slabs I put foam under no cracks, no control joints, or apparent noticeable problems yet. Knocking on wood lol.

 

[ponytug]

Is there any evidence for the wire chairs, which are sitting either on dirt or visqueen, rusting out and lowing moisture to get to the rwbar and corrode them? The plastic chairs, typically used for wire wouldn't so that.
The reason I ask, is rebar should be, correct be if wrong, no less than 2.5x the diameter of the bar, from the closest edge of concrete. That wire rebar chair, the feet are touching the subgrade surface.

Both plastic chairs and concrete chairs ("dobies"?) are superior to plain wire supports, for corrosion and water leakage reasons. I believe that you can obtain epoxy coated wire versions, e.g. Meadow Burke, but I haven't used them or seen them used.

https://meadowburke.com/wp-content/uploads/2021/06/meadow-burke-technical-manual-reinforcing.pdf

The American Concrete Institute has numerous publications, but they get fairly technical...
https://www.concrete.org/topicsinconcrete/topicdetail/rebar Placement#webpages?search=rebar Placement ...

I like the concept of foam under concrete. In certain other countries, it is the norm, both for vapor barrier and insulation. Given the cost of a slab, it isn't pricey, at least from what I know.

All the best,

Peter