concrete attack
concrete attack
(OP)
hi i am inspecting a suspended slab which has some serious degradation. the bottom steel has lost all concrete in large areas. that is to say the bars are hanging with concrete cover loss and loss behind the bars. is this repairable. im not even sure what's keeping in in place.






RE: concrete attack
Another consideration would be to make sure that whatever is causing the deterioration is repaired prior to any restoration work.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: concrete attack
RE: concrete attack
RE: concrete attack
Dik
RE: concrete attack
RE: concrete attack
Sounds like whatever repair is made, you need to protect the underside of the concrete after it is completed, otherwise it is just a matter of time until it happens again.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: concrete attack
http://www.nceng.com.au/
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
RE: concrete attack
RE: concrete attack
Or you can thicken the bottom of the slab by 4 or 6 inches. Add the reinfocing in the space. Build falsework and pour from above using access holes cut in the slab above. You can line the formwork with T-Lock. It's tricky, because you're working blind.
The second best fix is to do your structural repairs (replace reinforcing, trowel on repair material, or shotcrete or whatever)from below and line it with a high quality coating done by a qualified applicator (harder to find than it seems). We like Sauereisen's systems, but everyone (Plasite, etc.) has a system and most of them will work for a while. There are PVC liner systems that can be retrofit, but applying it to the underside of a slab seems very difficult.
Whatever you do, carry the lining down the wall. Once the gas is resisted by the liner, it moves on to the next weak link, which will be the walls.
RE: concrete attack
Listen to Jed. He has experience in sewage treatment plants, while most of us don't. Whatever you do, the chamber has to be taken out of service for the repairs. As well, there may be modifications required in the process to lessen the problem of H2S and H2SO4.
RE: concrete attack
RE: concrete attack
My chemistry is not too sharp, but I think both hydrogen sulfide and sulfuric acid are involved.
RE: concrete attack
http://www.nceng.com.au/
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
RE: concrete attack
RE: concrete attack
Richard A. Cornelius, P.E.
WWW.amlinereast.com