cover concrete while curing ?

RobAMerc

hi all,

I am building a vermiculite / cement pizza oven out doors.

I believe its a good idea to keep it fairly damp while curing.

So should I cover it with a tarp and spray daily ? Or just leave it out ( with an old bedsheet over it ) and let the April showers do their thing?

Thanks

10-10-20

If it's going to dry off quicker than it will consume the required water to cure, then it needs to be covered. That's a science all in itself.

With slabs this happens on warm & dry days where there is a wind - the top of the slab can rapidly dry out and micro-crack afterwards as the drying effect prevents full curing. As you'll be constructing on a raised structure, possibly using wood for bracing and also with large open combustion spaces, I would be throwing over a heavy tarp and spraying it down for the first 2 days. I think that beyond ~2 days the effect is limited as the curing has mostly consumed the required water. Just bear in mind that vermiculite is in itself a water absorber and will act as a reservoir for the concrete. You'd need to check whether you're supposed to wet the vermiculite first, or just add in it dry and mix and then add water.

You can also do a thing called "ponding", but that's normally for mid-summer pours in Texas.

Just be extra cautious here as you're obviously intending on having high temperatures within the structure, so having the concrete right is a significant objective to prevent cracking and failures. Are there guides on how to pour and set for pizza ovens?

Lumen

https://www.vermiculite.org/wp-content/uploads/2014/10/Vermiculite-Concrete.pdf