foamed cement

[eugenesargent]

The giant earthworm (approx 45 feet long) is in a public park (Wilson park, Fayetteville, Arkansas). The train is in the Botanical Garden of the Ozarks. I have a project coming up at  an elementary school (a big butterfly).

the chemicals used in making foam are generally called surfactants. The litebuilt foam concentrate is a deep reddish brown protienatious liquid containing some ox blood. There are formulas that use palm protiens, and there are completely synthetic liquids that look more like soap. 40 to 1 is a common ratio to mix with water, but my foam contact is trying to acquire some 200 to 1 concentrate. I have most experience with the litebuilt foam, wihch works quite well.

The procedure for mixing is to get the portland, sand, fibers and water mixed in the paddle mixer until they are a fairly thick mix (not too much water). I like to mix 5 or 10 minutes if I have other things to do in the shop. Then the foam is shot into the mixer in a timed burst. Then I mix until everything is nice and even and then a little more. Then I pour it into a wheelbarrow and use. The foamed cement moves very easily and trowels very easily. I would not call it sculptable as it slumps, although one can shape the backs of castings reasonably well.

Chris, I think steel rebar and the basalt fiber mesh would make an excellent hybrid. I have used so much stucco lath in my life and torn it out and watched it corrode that I am always looking for alternatives these days.

[Chris Glasspool]

Hi Eugene,

I appreciate you posting the drawing. It looks very simple. For a stationary version: couldn't the mix needle valve be one of those spray bottle needle valves used for plant fertilizer spraying. Mine is adjustable for differing ratios, and the source be the garden hose? Same idea with the air supply: Isn't the needle valve in this case a regulator, and couldn't the system regulator be adjusted down to where needed instead of adding one in-line?

I noticed the cure time with perlite mixes is also retarded (can I use that word?). With a mix ratio of 1.5 times the volume in perlite to fibered mix, the density reaches a point of neutral buoyancy, and it will hold a screw very well. sort of the traits ofa hard wood. The long term cure is very good however. A good additive might be acrylic (Acryl 60) as it likes to foam anyways. It might make the bubbles stronger along with the cured strength.

Side note: Women with guns is now my screen saver! Thanks, chris

[eugenesargent]

Hi Chris,

You are correct in all your observations on the foam generator. You can even go simpler by premixing your water and surfactant (after all, a gallon of mix will make a big pile of foam).  One point on the air, though. Turning down your air pressure will have the effect of regulating the flow, but it will not be as stable and predictable as a true flow regulator such as a needle valve (assuming regulated pressure applied to the valve). The solenoid valve for the air is essential to keep from wasting your mix.

Retarded set is a fine term, in fact I think it is the standard term, however one riscs scarring one's cement for life, giving it a poor self image. The politically correct term might should be "punctually challenged." 

[pewellman]

Ringo,
I have recently stumbled onto cellular concrete and it fascinates me.
I have been organizing what I find here:
http://www.greenearthstructures.com/aac.html
You might find some interesting stuff in here.
I really like the folks at Richway
http://www.richwayind.com/index.html?page=CreteFoamer
I am working on a building system using a steel post and beam frame with MgO board sheathing that will be poured full of cellular concrete. The steel frame will take most of the load and that way the cellular concrete can be less dense providing better thermal efficiency.
I am interested in the idea of a double wall ferrocement structure filled with Air Krete
http://www.airkrete.com/
Keep being curious!
So many building products so little time!

[upston]

Hi Paul,

Welcome to the forum. I took a look at your site and you have a bunch of great stuff assembled.

In your travels in the light weight foam world have you found a material, foam, aggregate,? that will NOT absorb water. Some of us are looking for a mix for the cream in the Oreo

IE outer layer of LFC separated by a lighter core but dense enough to be  helpful in transferring loads from face to face.

Any ideas ?

Brad
ps
My wife's from Ponca City so I'll come and annoy you  on the next visit to OK

[pewellman]

Upston,
Thanks for the kind words.
Forgive my ignorance but what is LFC? Lightweight Ferrocement?
I highly recommend you contact Steve Brenna. In my research his name has come up several times as the Guru of cellular concrete. He designs equipment for using cellular concrete  neopoli@gmail.com 505.603.5660.
Steve told me there were additives that acted as waterproofers. Don't remember what they were. You can pour a roof using cellular concrete so waterproof would be good.
Like I said I am very interested in doing something like you are suggesting here.
I am working with GLOW Ministries International http://www.glowmi.org/ on ideas for housing in poor parts of the world. You can download a current .pdf  file of drawings done to GLOWs standards at: http://www.greenearthstructures.com/rebuildinghaitigreen.html Look for GLOW Ministries on the page and click the link for the plans. I tried to attach them to this but they were to big.
These drawings have been engineered to use 20psf cellular concrete in the walls. The actual size of the structural members will be determined when we have the design load information for the place they will be built.
The FC looks interesting as a substitute for the MgO board in this design. Mike Ehrlich (the engineer) will love me when I hit him with yet another idea. The earthquake factor makes Haiti a bit more challenging for him. He is graciously donating his time to do the engineering for GLOW Ministries and I am donating the drafting.
GLOW Ministries wants to minimize the materials that have to be imported for a building. Chicken wire would be much cheaper and more compact to ship than MgO board. GLOW says labor is no issue so substituting the FC would be a win win to them.
I will be interested in what the FC would do compared to MgO board as a skin.
I LOVE all the information here!

[pewellman]

P.S.
Please do get in touch when you are in OK.
I spent many summers north of Lamont (just west of Ponca City).
I have spent some time in Ponca City and have family all around there.

[upston]

Hi Paul,

LFC is laminated ferro cement a method invented by Martin Irons in the late 60. When you get into the forum info you will find a lot of details, it's the backbone of this forum / network.

I old school FC the armature is finished first and then the mix is pressed in, hard to do with out voids, voids are very bad. Irons found that expanded metal lath could easily be pushed into a thin layer of mix IE laminated. repeat as needed for the thickness required.

It's is very similar to fiberglass lay up, finished product is like basalt if done well and the job goes very fast, they were laying up a 58ft sail boat in one good day with 4 men. nice boat at that.

Paul ,our fearless leader, is giving a class on the matter this summer, I attended last year and I just get more excited about the possibilities all the time. I would encourage you to make time if you can.

LFC could certainly replace the panel on the exterior  of you project and can be a very attractive finish as specified by SWMBO
she who must be obeyed

have a good one brad