On Monday I poured 28 yards of concrete for my shop. It has 8 loops of pex for radiant heat. After sawing in the greencuts on Tuesday, I was pressure-checking the pex (came out fine). The water running through the loops was not surprisingly hot.
I’ve been keeping the slab wet to allow a good cure. What about running cool water through the pex? I haven’t so far thinking this might be too much of a shock to the slab and would result in cracking. this is a 6 inch slab…..
Any advice? –Ken
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Seeing as your post is about to "fall off the bottom" and no one else has replied and I don't have an answer, I'll post this to bump it up where others may see it to reply.
Thanks for the bump.
No!
Do not run water through it while curing for the first week anyways. The heat you report is a by-product of the chemical reaction between the water and the portland in the mix. Crete cures strongest and best at around 90 - 97°F. by ru8nning cold water through the PEX, you will have cool spots and hot spots resulting in an uneven cure and stange shrinkage cracks with weaker cretee than you might otherwise have.
The only thing that will harm the cure is when excessive heat causes too much surface moiiusture to evaporate before it can complete the reaction. That is why some mist it and others cover it with plastic - to slow the evoporative rate, not to cool it.
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Thanks for the info. Since the ambient temperature around here is about 97 right now, I have been keeping it wet. I'll hold off on further water in the pex pipes for another couple of weeks or two. I should get around to posting some pics in a while...