Frozen Concrete Slab
Frozen Concrete Slab
(OP)
According to our materials consultant, a large concrete floor slab that was poured last week partially froze before it had a chance to cure properly. Apparently the top 1.5 inch or so has been frozen. There are numerous concerns that we have here:
1) With the expaned ice trapped in the concrete, will there be voids, even after the ice melts?
2) With the obvious stratification that will be present in the slab, will we be able to justify treating the full slab depth as composite, as we assumed in design.
If anybody has any experience in this arena, please let me know your thoughts. What other things should we be concerned about? Any ideas for a solution?
Thanks,
Adam
1) With the expaned ice trapped in the concrete, will there be voids, even after the ice melts?
2) With the obvious stratification that will be present in the slab, will we be able to justify treating the full slab depth as composite, as we assumed in design.
If anybody has any experience in this arena, please let me know your thoughts. What other things should we be concerned about? Any ideas for a solution?
Thanks,
Adam






RE: Frozen Concrete Slab
How thick is the slab? If it is only 4" or 5", I would tear it out.
Is it reinforced with bar or mesh?
If this is a thick slab and has bar reionforcing, you might consider removing down to solid concrete and then scarifying that surface and then pouring a bonded topping.
RE: Frozen Concrete Slab
RE: Frozen Concrete Slab
RE: Frozen Concrete Slab
RE: Frozen Concrete Slab
RE: Frozen Concrete Slab
2. Breakout and repour the slab when the weather is not freezing.
Mike McCann
MMC Engineering
RE: Frozen Concrete Slab
RE: Frozen Concrete Slab
out of curiousity, what was the lowest air temp and lowest wind chill and how soon after placement did these temps occur? was there an admix used? is the slab "on grade" or elevated? why the heck didn't the contractor follow the appropriate steps to protect the slab per aci?
RE: Frozen Concrete Slab
Definitely take the advice of cvg and msucog, before insisting on ripping out the entire slab. Find out the level of damage for sure. If you don't have good evidence that the level of damage requires complete replacement, then it could get messy with the contractor, if it does not turn out to be so. He'd probably hit the engineer and owner with delay claims if you're wrong.
RE: Frozen Concrete Slab
The simplest solution is to tear it out...
Dik
RE: Frozen Concrete Slab
Don Phillips
http://worthingtonengineering.com
RE: Frozen Concrete Slab
if the slab itself did not freeze, you may have damage due to that up layer freezing during the finishing process.
RE: Frozen Concrete Slab
How did the consultant determine the depth and if the concrete was frozen. He may have the information to proceed.
If it is fresh concrete a windsor hammer would be meaningless regarding the future condition.
Cores sliced and run through a microscopic exam would be a very good method to determine any destruction or disturbance that will not heal. The location of the cores can be important depending on the curing, protection and exposure.
A good testing lab frequently works with other in the analysis and it frequently done here on projects or by concrete suppliers.
Dick
RE: Frozen Concrete Slab
this may not be the ideal way of evaluating the overall condition, anticipated long term performance, etc of the slab but it is definitely a good, practical place to start in my opinion. if the damage is there and near the top, it should be evidenced by what i describe above. for that matter, you could probably split cores in to layers and perform testing on those layers to help identify where/how deep the damage occurred, if at all.