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david s 10-03-2012 04:10 AM

foam concrete
OK first up have a look at this link and you"ll get the idea of how this stuff works. There is plenty about it on the net.

Light Weight Concrete

I should think it should be possible to use it as a replacement of vermicrete. or perlcrete as under floor insulation. I have an idea that it would dry out better than vermicrete or perlite because it would contain way less water. it should also be less of a problem of acting like a sponge, but we shall see. As the stuff only costs around $15 a litre (conc) it is also way cheaper than perlite or vermiculite. one litre is diluted 30 times with water which expands another 22 times in the foam generator.That is 660 litres. A lot easier to store and freight one litre of concentrate than store bags and bags of vermiculite.
Perlite and vermiculite alone are both OK up to 1100 C by the way.

Spinal 10-03-2012 06:30 AM

Re: foam concrete
I don't think it'll work...

What type of cement is appropriate for lightweight concrete ?
Lightweight concrete may be produce with any type of portland cement or portland cement & fly ash mixture. The performance characteristics of type II, type III and specialty cements carries forward into the performance of the lightweight concrete.

Portland cement spalls (violently) at 600c or so...

Gulf 10-03-2012 06:55 AM

Re: foam concrete
Keep up the resarch David.
If it can be used as a cheap replacement for V/Pcrete, that would be great. That stuff is getting more and more expensive every day. I'm looking forward to when you get into the testing stage.

Tscarborough 10-03-2012 07:17 AM

Re: foam concrete
Spinal, cement does not spall at any temperature, it simply degrades. The AGGREGATE in concrete can spall and at a lot lower temp than 600 degrees centigrade. The lightweight/foamed concrete David is talking about does not contain large aggregate that is subject to spalling and as underfloor insulation will not see extremely high temps.

david s 10-03-2012 01:31 PM

Re: foam concrete
It would be like vermicrete, but the grains of vermiculite are substituted with air.So instead of having a mini sponge in the space you'd have an air space. Apparently the stuff does not absorb water, so that would be a huge advantage.

Laurentius 10-03-2012 02:26 PM

Re: foam concrete
Hi David,

Does this product have an insulation R-value, if so what is it?

david s 10-03-2012 02:44 PM

Re: foam concrete
That would depend on the ratio of cement to air that you decide to use. I would imagine it would be the same as vermicrete or's all about the density you choose.
eg. A 1:4 vermicrete has a thermal conductivity W/(mK) of 0.16,
1:8 is 0.09
The R value is a reciprocal of the K value.
Wiki puts air entrained concrete at R 3.9, standard concrete at R 0.08 and loose vermiculite at R 2.13- R 2.4
Sounds almost too good to be true.

TropicalCoasting 10-03-2012 03:53 PM

Re: foam concrete
Sounds good,can you just get it from any concrete supplier?
Im not too far away from building one for the Community Garden and wouldnt mind using it under floor and over dome.

david s 10-03-2012 03:59 PM

Re: foam concrete
You can try them, but my local "expert" concrete additive supplier had never heard of it. You may have to search the net and get it online.

wotavidone 10-03-2012 06:46 PM

Re: foam concrete
This looks really good. I would expect you could also trowel/screed it flat, which is hard to do with vermicrete.

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