unreinforced SOG with no sawcuts
unreinforced SOG with no sawcuts
(OP)
I am working on a project that has a 4" Slab-on-grade with embedded in-floor heating tubes. The slab is 4000 psi concrete with fibre (the type that only reduces plastic shrinkage cracking). The tubes floated to the top of the slab (near the top of the slab) because the contractor was careless. The architect wants to eliminate the sawcuts for the slab to avoid cutting the in-floor heating tubes. They don't want to replace the sla because of the project schedule. What are the potential consequences of not providing sawcuts. I realize that the cracking will not be controlled and would occur at random. Anything else we should be concerned with?
Any input would be appreciated!
Any input would be appreciated!






RE: unreinforced SOG with no sawcuts
Even if the tubes don't leak immediately but the randomly broken concrete moves because of loads applied to it, leaks could start later.
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RE: unreinforced SOG with no sawcuts
I would also want to make sure the current conditions are acceptable to the designer of the floor heating system. I've used these a few times in the past and if memory serves they depend on having a certain amount of concrete above the heating tubes to radiate the heat. If the tubes are at the surface it could potentially create localized hot spots that might be a problem.
RE: unreinforced SOG with no sawcuts
RE: unreinforced SOG with no sawcuts
I've never seen heating tubes placed in the wearing slab... seems like they would unduly weaken the slab.
RE: unreinforced SOG with no sawcuts
RE: unreinforced SOG with no sawcuts
RE: unreinforced SOG with no sawcuts
In others words, the tube, directly at a crack, doesn't know or care whether the crack was initiated by a sawed joint or simply occurred at random. Either way the tube is pulled "x" distance apart.
RE: unreinforced SOG with no sawcuts
RE: unreinforced SOG with no sawcuts
RE: unreinforced SOG with no sawcuts
I may be reading too much "between the lines" of the original post... but in my experience, when anything literally "floats" to to the surface of fresh concrete it is a sure indication that the concrete was so severely watered down during placement (probably by the "careless" contractor). If that is the case, then the size of the cracks and the pattern could really be random and excessive.
Also, with the tubes at the surface, there are likely planes of weakness in the slab that are dependent on the tube layout pattern. IMHO, how that slab will "behave" over time will be very unpredictable.
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RE: unreinforced SOG with no sawcuts
Ciao.
RE: unreinforced SOG with no sawcuts
DaveAtkins
RE: unreinforced SOG with no sawcuts
I have seen a proprietary system designed on this exact basis.
RE: unreinforced SOG with no sawcuts
Shouldn't systems like this be designed to have the fluid tubes BELOW the concrete slab? That would eliminate the problem raised by csd72. I seem to remember ice rinks, designed with the coolant tubes laid on a 4" layer of rigid insulation on the subgrade, then a sand bed, then the concrete poured.
Also, the selection of the tube material is really important. I remember an ice hockey rink built this way, with volunteer help that used black iron pipe. The leaks started at year two and eventually got so bad the floor had to be torn up to replace the piping.
RE: unreinforced SOG with no sawcuts