Floor slab curling
Floor slab curling
(OP)
I am investigating the cause of some uneven concrete floor slabs. The building had been used for an ice skating rink. The existing floor slab consists of a 3 1/2" slab on grade, in good condition, around what was the ice rink. The new owner of the building hired a contractor to "fill in" the area which was the ice rink with a 3 1/2" concrete slab. The slab was poured in sections approx. 85'x43' with zip strips placed creating slabs averaging 20'x 20'. The new slab has cracks at about every 10' and has apparently curled adjacent to existing slab in some areas as much as 3/4". The new slab was installed with heating tube. The new slab was placed on 3" of crush aggregate with fines which was on top of the existing 1" foam insulation. The issue is the cracking and more importantly the apparent curling which has created a tripping hazard. The Contractor is claiming that the owner turned on the heating system to soon and caused the cracking and excessive curling. The owner apparently turned on the heat 30 days after the concrete was poured. I think that some of the curling was not curling but poor workmanship. Does anybody have any experience with this or know of any references pertaining to curing slabs with heating tubes?






RE: Floor slab curling
Temperature gradient difference can also cause curling, so the heat can add to the problem. There are also numerous other things that can be done to avoid curling but it would be an article in length. Hope this helps.
www.idecharlotte.com
RE: Floor slab curling
Also - there probably isn't much you can do to "fix" the slab at this point since it is only 3 1/2" thick. You could consider grinding the slab down level, but this would reduce the thickness to 2 3/4" thickness at the 3/4" curl points and this probably isn't acceptable.
Quite the mess.
RE: Floor slab curling
Having said that, a good concrete contractor should have been aware of the outcome...
Dik
RE: Floor slab curling
I assume that you mean difference in temperature, which could resally come into play here if, having been an ice arena for many years, permafrost developed below the slab. I may be all wet here, but was a concrete core done to test for this possibility?
Actually, it's well below freezing, sunny, with four inches of snow on the ground, so I'm not all wet, just cold.
Mike McCann
MMC Engineering
RE: Floor slab curling
Thanks for all your replies.
RE: Floor slab curling
2) Who specified the curing method? Were there specfications, or was it left to the contractor? If there were not specifications, was the contractor the "expert" and supposed to know how to avoid curling with proper techniques similar to the above?
It is obvious the top of the slab cured faster than the bottom, creating the "curling" effect. The real question lies with the responsiblity of knowing how to prevent the curling.
RE: Floor slab curling