foam concrete

[david s]

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]

Re: foam concrete

I don't think it'll work...

Quote:
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]

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]

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]

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]

Re: foam concrete

Hi David,

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

[david s]

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 perlcrete.it'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]

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]

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]

Re: foam concrete

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

[RogerQ]

Re: foam concrete

There is a product generically called Autoclaved aerated Concrete. Here is a link for their site in Georgia: SafeCrete.com - AAC Internet Sales / AAC Products / AAC Information / AAC Construction The company recommends the product for firewalls.

I stacked up some of the block for a hot smoker. When I add wood, the firebox is glowing red hot, while the exterior is just warm to the touch. After several firings, the block facing the fire seems slightly chalky on the surface. This material can be cut with a handsaw. Here is another link:
http://extension.ucdavis.edu/unit/gr...d_concrete.pdf

[david s]

Re: foam concrete

Foam concrete is quite different to Hebel or AAC. They use Aluminium powder to react with lime producing hydrogen which creates the bubbles. Foam concrete relies on generating the foam first then mixing it into the cement slurry, a far simper process by the sounds of it and should be a workable solution for the small operator.

[wotavidone]

Re: foam concrete

I reckon the hardest part about making concrete with the aluminium powder and lime method would be getting the aluminium powder.

Our local explosives manufacturer used aluminium powder to boost the heat, and therefore the power, coming from his mining explosives.
That'd be the only largeish scale of industrial consumption other than Hebel that I've ever heard of.
So has your foamer turned up yet?

[david s]

Re: foam concrete

Mick,

No the foamer has not turned up yet. They are trying to sell me a $1000 machine to generate the foam, but I think I can build my own. At around $20 per litre incl. freight that's not too bad (even though it's 85% water) since they claim it will make 1000 L of foam. Only problem is that it's a min. order of 10L that's then 10000 L foam. Slight problem if you only wanted to generate enough to make one insulating slab.
Here is the chemical composition of the stuff. I told you the name would be long. Let me know what you think as you are the chemist man.

Dave

WATER 7732-18-5 81.0 - 85.0%
DIETHYLENE GLYCOL BUTYL ETHER CAS number 112-34-5 8.0 - 9.0%
ALKYL SULFATE AMINE SALT +(6076P) --- 3.0 - 4.0%
SODIUM ALKYL SULFATE +(6079P) --- 1.0 - 2.0%
SURFACTANTS +(6082P, 6058P) --- 3.0 - 4.0%
TOLYL TRIAZOLE CAS number 29385-43-1 < 0.5%

[TropicalCoasting]

Re: foam concrete

Can you make it foam without the machine ?
and if you can Im sure there are people who would gladly buy some of the litres required of you.... me included. (and possibly a few more here in town)
Im about 8 hours south of you.