foam concrete

[waikato pizza]

Re: foam concrete

Hi all - I'm a newbie so hopefully will not be re running old info

I have stumbled across another version of the lightweight concrete. Cellcrete (apologies if this is a brand name only) is a concrete sheet like a giant honeycombe bar of aerated concrete. I have been told that it is made by mixing alumium swarf into the concrete. The whole thing is then heated to a point where the aluminium burns and vaporises leaving gas bubbles behind it. Hence it is already hardened and can be cut using a hand saw.

I will be giving this a try and will let everyone know how I get on - watch for the saga - I aim to eat pizza by christmas!!

[Tscarborough]

Re: foam concrete

250F is no problem, degradation does not begin until +/- 500 degrees F. I have used AAC for doors and it fails rapidly.

[david s]

Re: foam concrete

I am sure the vermicrete slab or AAC if used for underfloor insulation would exceed 500 F. Anyone removed floor bricks and inspected the vermicrete for signs of degradation?

[Tscarborough]

Re: foam concrete

AAC is non combustible, but heat does degrade it. If you can keep it below 500F it will work fine, but above that it goes brittle then crumbles.

[david s]

Re: foam concrete

I used AAC (Hebel) for the supporting slab under my mobile oven. I used what they call Power Panel which is 75mm thick reinforced with 4mm steel rod. I was hoping this would be strong enough and insulate at the same time. Unfortunately it has cracked, although I'm not sure if this was due to inadequate strength, heat, or going over a speed bump way too fast. Fortunately it sits in a steel cradle which holds it all together so is still operational.

[RogerQ]

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.

Sorry, I was not suggesting you make your own aac concrete. If you can find a source for this block, it is non combustible, insulating materiel that can be easily worked with hand tools. I think it would be a great material for the insulating layer, depending on availability.

[david s]

Re: foam concrete

I'm hoping to use the outlet tap on the jerrycan to release the foam. Compressor to do the agitation then use a bicycle floor pump to push the foam out via the tap in a controlled way. Should be fun.

[wotavidone]

Re: foam concrete

That'll work. The foam will probably climb out of the top of your jerry can.
It's obviously carefully formulated to give you very strong bubbles of a small and uniform size. Very keen to see how this works out.

[david s]

Re: foam concrete

Thanks Mick, very interesting.
I plan on using a compresser, car tyre valve, some stainless tubing and a plastic jerry can with a tap to generate the foam. I think it should work. We shall see, still haven't got the foam yet.

[wotavidone]

Re: foam concrete

Mick,

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%

Hmm, two solvents (the water and the butyl ether), three soaps/detergents, and a corrosion inhibitor (the tolyltriazole)
Interesting. Its essentially some concentrated detergent, though the organic solvent and corrosion inhibitor must play some part.
Foaming it should really only require bubbling lots of compressed air through it, I reckon. If their foaming machine is "only" $1000, it's not going to be very complicated.

[david s]

Re: foam concrete

Why would they not sell it without the water, to be added at the site?

No, that is the % water in the concentrate. you have to dilute it to make the foam.

[david s]

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.

Sorry, but it is against the forum rules. I could be accused of touting for business.

[Tscarborough]

Re: foam concrete

Why would they not sell it without the water, to be added at the site?

[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.

[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%