House Build

The topic caused me to research why people would paint the rebar and there is a very extensive report here that illustrates it is just one of the ways to stop the rebar from rusting after the concrete has set. In summary, it says the concrete will maintain its compressive strength even when the rebar is rusted through but the tensile strength, such as what is desired in a concrete roof or during an earthquake, is greatly reduced by rebar that has rusted through while inside the concrete. I found it interesting but I don't imagine it is a life or death decision whether or not the rebar is painted.

Edit: The link is available if you click on the 'here' but it is not very obvious on this site so here is the link I was referring to:
http://www.contrib.andrew.cmu.edu/~neeravv/presentations/Neerav_Term paper.pdf

 

I have done a lot of construction projects here and always paint the rebar with red oxcide. I have seen so many concrete walls and posts blow apart due to rusted rebar expantion.

 

Why did the concrete blow apart? I've also seen this in the Philippines and what I saw looked like the rebar was barely covered. Maybe without the proper coverage cracks develop that let in water? Using round river stone, questionable amounts of water in the mix, and not enough cement probably all contribute in one way or another, especially to any cracks developing.

I've torn down facilities built in the 50's and the rebar looked fine (other than being mangled). I think if done properly (always a big if) then it should basically last forever.

My wife did not tell me earlier, but the workers pre-painted all the rebar currently on site...so it looks like my rebar for the columns and beams are painted

Shawn

 

Hi Shawn,

You have to consider concrete is porous, water can always seep in, even with the correct mix and crushed stones. When the rebar rusts it expands with incredible force. Then factor in the best concrete here is sub standard. I built a large 2 story boarding house with pool in Danao and now it is required to paint all rebar there.

Regarding your earlier post, Please don't make my mistake. I left a bucket containing water and a small amount of concrete outside. My dog drank it and died a horrible death. It's toxic and dogs love it.

Looks like your project it going well and I wish you all the best.

Ron

 

Ron,

I see nothing wrong with painting the rebar and there are definitely environments that I agree would be beneficial. The folks at CRSI, ASTM and ACI are much, much smarter than me and I have to follow their guidelines for my job and that also goes into my mind set with the house. The guys painted the rebar and, even though I think it is not necessary, it does not hurt anything.

Sorry to hear about your dog and I will pass that info on to the wife. I was never a pet person, but the wife loves animals and I have to say our dogs are loving, loyal characters and it would break both our hearts if they were hurt/passed.

Thanks,

Shawn

 

Sounds like your workers may be the ones I trained.. Haa Haa

 

If they spend any more of my money painting rebar you can have them back

 

Howdy Shawn , I would think that a coat of paint on the re-bar would do know harm , consider the sand used in the concrete mix , is it 100% salt free , I have actually seen epoxy coated re-bar in the past , regards Tony

 

Good point about the sand, make sure it's from inland, not near the beach.