Mixing and Pouring Concrete when just above zero, and maybe below on first night
Anonymous user 23/02/2024 - 3.51 PM
I'm all prepped (8ft x 8ft shed base) for mixing 1:5 concrete tomorrow - just a bit worred that it's cold. forecase is to start day about 0 degrees, get to about 5, and maybe fall to -1 first night. My plan was keep it all covered until pour (as I've done all week), and tonight, stick a fan heater under tarp, to keep it warm all night. to use hot water for mixing, and then cover it with plastic, then 4 king size duvets and then the tarp above. maybe put fan heater in again, to keep it a bit warmer. is this a good plan or am I being mad - and should put up with having 2 tons of aggregate on my drive, and hire a cement mixer in a few weeks or a months time when its not as cold?
Are you a tradesperson and able to answer this question?
That's a solution as you plan to do, mix with warm water rather then hot water, and pour when the temperature is above 3*C. Ideal would be, cover it with frost blankets after pouring as they are tested and proven to resist frost. And to minimise the weight on the freshly poured concrete and potential deforming the finish shape.
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Answered20 January 2023
3
Anonymous user
Yeah the second option is more reasonable and and honestly saying you’re only not wasting money option
Answered20 January 2023
0
Anonymous user
Defiantly don't mix unless 3 degrees and rising and keep the water content to a minimum but still achieving a workable mix , try to pour as quickly as possible and cover with frost blankets if your able to tent the pour the heaters will help prevent latent frosting. or if your able to hold on until the temperature is a constant 3 degrees and rising even better for the quality of the concrete.
cheers
Regarding your concern about freeze temperature from my point of view your plan will not help to much,maybe at all because the impact of hot water will be canceled when will be mixt with balast which is cold to. The second point with covering the slab will not guaratee the expected result as the cold will come from the sides and below the slab cooling the concrete.
My advice will be adding in the mix the frostproofer which make the concrete setting quicker and keeps his properties and reactions by -10° as producers says. On top of that, for your peace of mind can help as you planned whith heater and other staff. Good luck!
