Using Quikrete instead of Portland?

[asudavew]

Re: Using Quikrete instead of Portland?

Ok so here is my next question...how bad is it if I already layed my insulating layer with quikrete? Is it going to hold the weight of my dome? Do I have to break it down and pour it with portland?

It's bad.
Most heat is lost through the floor.

What was your mix ratio of quikrete to vermiculite?

[Faz]

Re: Using Quikrete instead of Portland?

The concern is that the presence of aggregate in the mix (assuming that it is a dry concrete mix rather than just a fast setting cement) will greatly reduce the insulating properties of the layer. If this is the case you can either remove and relay or maybe add a further insulating layer over the top, as long as that wouldn't make your oven too high.

[JRDeMeo]

Re: Using Quikrete instead of Portland?

Ok so here is my next question...how bad is it if I already layed my insulating layer with quikrete? Is it going to hold the weight of my dome? Do I have to break it down and pour it with portland?

[dmun]

Re: Using Quikrete instead of Portland?

You will have lots of uses for your unused concrete mix (if that's what it is, they make several mixes) in this project. Vermiculite/perlite concrete needs portland.

[james]

Re: Using Quikrete instead of Portland?

Quikrete is concrete -- a mix of Portland cement, sand and gravel (and a setting accelerator). But for your vermiculite concrete you want to use pure Portland cement (not concrete). Think of it this way -- when you make insulating concrete, vermiculite replaces the sand and gravel as the aggregate that you mix with Portland cement.

You can buy Portland cement by the bag at Home Depot and it isn't expensive.
James

[JRDeMeo]

Is there a difference in using Quikrete instead of Portland? I plan on using Quikrete for all my insulating because I have a lot left over from my foundation. Will this give me enough strength?