Aircrete experiments

AirCrete is a mixture of cement, water and foam used to make a lightweight, fire resistant, bug resistant product that can be used as insulation or filler or other applications not requiring the strength of regular concrete.  (Many of my TLUD Charcoal Making outdoor cookstoves have used fiberglass as an insulation which makes ideal homes for mice.)  There are many YouTube videos showing techniques and applications, as well as various methods of creating the foam that is mixed into the cement and water mixture.  The foaming agent can be Drexel.  Here is a link to a one gallon container:  https://www.ruralking.com/drexel-foam-concentrate-gallon-160-1?utm_medium=cpc&utm_source=google&utm_campaign=shopping&utm_content=60990286&adpos=1o2&scid=scplp60990286&sc_intid=60990286&gclid=CjwKCAjw-ZvlBRBbEiwANw9UWmiwv06qfBFe8HJPQ18TRd516MvErdi2Bq1iwzvHLA5-w2Eg9C1ZkxoCcyUQAvD_BwE
(Drexel FM160 is a foaming agent designed for use in foam generating equipment. This product is temperature stable. When dispensed, this product produces a dense, readily visible, white foam of sufficient longevity under normal conditions for many applications. Using this product in field marking systems helps eliminate costly spray gaps and harmful overlaps that can occur during the application of pesticides and fertilizers.)
Amazon also sells it and about $45 will get a gallon delivered to you.
Honey Do Carpenter says the best foaming agent is Suave Oil Control Shampoo, or Suave daily clarifying for Noral-10 oily hair (light Blue tint) mixed 32:1 (4 oz in 1 gallon water, or 20 oz. in 5 gal. bucket).  He adds household baking soda to accelerate the set-up time, and mixed J-Lube into the water to increase surface tension.  Also using S grade Hydrated Lime, with some Diatomaceous earth (a Pozzolani) to make the Lime set up faster.  (However, the Lime must be used as soon as the bag is opened, or it goes bad.   Also noted that WSR-310/Peg90M is cheaper than J-Lube and doesn't contain sugar.  1 gram is enough for 1/2 cubic meter of water.  (How many gallons in 1/2 cubic meter of water??)
According to Aircrete Harry (YT), Drexel is the best foaming agent when compared to Dawn and 7th Generation Hair Shampoo because he did some testing and the Drexel foam in a bucket did not collapse as quick as others did.   Before I knew this, I bought a bottle of Dawn Ultra Dish Soap, and that is what I am using for my experiments. I mixed it 32:1 by putting 15 ounces of water in a measuring cup, and adding enough Dawn to make 16 liquid ounces.
I copied the foam generator shown by Honey Do Carpenter (YT) using parts purchased at Harbor Freight and hardware stores.  He sells a kit on Etsy for about what it cost me to round up all the parts from various stores making multiple trips to Bastrop and Lockhart.
O.k., now that I have all the materials what should I make first?  We have multiple raised beds and planters using conventional concrete building blocks that leave holes for grass and weeds to grow in. 

  A case for VHS cassettes fits across these, so a form holding 12 of these could be poured easily.  

Using a 1 pound coffee can I mixed the following:
1 1/2 cans Portland Cement
3 cans sifted sand (The sand, charcoal, and wood ash are not normal additions.)
1 can charcoal less than 1/4" and greater than 1/8"
1/2 can wood ash mixed with fines less than 1/8"
half gallon water
(Other additives might be baking soda (accelerate set-up time),and S grade Hydrated Lime.)
Then I added the foam made from Dawn dishwashing soap as shown in these photos.

 I bought a mixer paddle, but it came with a hexagonal shaft, and none of my drills would open wide enough.  Lowes had a big hammer drill on a return table for about 1/2 price (with no key) that does accept the mixer paddle shaft, and works fine.  (I had a key that fits it.)

Finally I poured the soupy mix into the VHS Cassette forms, and expected them to set up in a few hours.  No way...soft as mush for hours.  After two days, I was able to remove them from the plastic cassette cases.  (BTW, these were brushed with used motor oil before use.)  Previously when making concrete tiles in the same plastic cases, I removed them from the mold and let them cure in a bucket of water.  Many commenters on YT videos are saying NOT to do this, and not to quench them in water, but rather to cover with plastic and leave them alone.  Haven't figured out why they are saying this...unless there is a danger of some kind of decomposition?

Another use for Aircrete is in the construction of Domes.  2 X 4's are used to construct molds about a foot wide and 8 feet long, and the resulting plank is sliced with a hand saw or knife to create blocks about 3 1/2" wide by a foot square.  A mortar is made using aircrete and this mortar is troweled on all edges of the block before it is set in place.  Later, the wall is covered with a Soft Polyester Reinforcing Fabric.   Is this then covered with a very hard concrete stucco?
The cellular structure of aircrete gives it a very high surface area. Over time, much of the material is likely to carbonate, largely offsetting the carbon dioxide produced in the manufacture of the lime and cement due to the calcining of limestone.
The structure of the blocks is similar to a sponge, and some people have poured water glass (Sodium Silicate) into the pores to make an even more heat resistant product. 
April 8 update.  These little aircrete "tiles" are very porous and extremely fragile.  I'm considering immersing them in a container of water to allow the maximum hydration of the Portland cement, which is what I have done with other tiles not made from aircrete.   A day later, I immersed all of them in buckets of water hoping to get maximum possible strength from them.  I broke one which was very "crumbly", and crushed it into a sandy material and recycled it into another concrete project.
Update June 11, 2019  Honey-do-carpenter just posted a new video on "back to basics", building a raised bed with aircrete.  https://youtu.be/MXs-tqfCSX0
June 30  https://youtu.be/i9N5Qqe2_a0
Another good video by Jim White showing his foam generator, and Drexel 160 vs Dawn. 
Here is a video showing a version of the foam generator made with garden hose hardware and a plastic drinking water tank from Wal-Mart.  https://youtu.be/jBejawsN4p4
July 4, 2019  Concrete planter forms using 3 recipes, including aircrete (made without a foam generator).  https://youtu.be/ddedMmuj7xY
July 10, 2019  4th recipe using CSA Mortar mix in thinner forms to reduce weight, rather than using Aircrete (would not stand up to a weed eater string trimmer).  Looks like this is the stuff he said he got at Home Depot:  https://www.homedepot.com/p/Rapid-Set-55-lb-Mortar-Mix-04010055/202188453
Sets really quick, and can reach 6500 psi (28 days), also cost almost $17 for a 50# bag, plus it needs the plasticizer. 
August 9, 2019
We decided to pour aircrete into the holes of the cement blocks around the raised garden beds.  First, the weeds and grass were removed by hand, and then by using a propane weed burner.  Then about 3 1/2" of aircrete was poured into each block.  The mix was 2 full large tin coffee cans (17 and 1/2 pounds) of Portland Cement, added to 6# (3/4 gallon milk jug) of water, and then foam made with Dawn dish washing detergent to fill the remainder of a 5 gallon plastic bucket.  A bag of Portland Cement would then make about 5.3 batches or roughly 25 gallons of aircrete. 

Now that we have started this project and the first bed is done, and the second is half done, the $64 question is whether or not the 25 gallon yield to a bag of Portland Cement is too rich, or too strong.  Back to YouTube to see what other people are doing.
August 11, 2019  Just watched Littlepigstore,LLC's aircrete video on YouTube where he was making some panels using a ten gallon trashcan for mixing.  I wanted to see how his mixture compared to mine in the 5 gallon bucket for the garden bed blocks.  His video:  https://youtu.be/la-2eVoi9Bg
He put 29 -30# of Portland cement in the ten gallon can containing a mix of 19.2 ounces of hydrated lime and 1.9 gallons of water. After mixing that he filled the can with foam and mixed it all together.
Looks like my 5 gallon mix was a little rich on the Portland Cement, and I did not use any hydrated lime.  I'm thinking I should buy some S grade Hydrated Lime and store it in a large plastic bucket with a screw-on lid.  Last time I bought Portland Cement, I got two bags, and immediately placed the contents of one is a sealed plastic bucket, and left the other sealed bag in a wheelbarrow in the garage.  When we were pouring these garden bed blocks (holes) the cement in the wheelbarrow was in perfect condition, whereas the sealed bag in the wheelbarrow was starting to set up for the first inch or so in contact with the paper (plastic lined) bag.  Note:  Don't buy too much Portland Cement unless it can be stored in a sealed plastic container!
September 24, 2019
Aircrete Harry is excited about what he calls "EPIC" mix.  Using shredded styrofoam in big bags, and then mixing that with Portland cement and showing that the compressive strength is much higher than regular aircrete with soap bubbles.
The next question I had is how to grind up the junk styrofoam pieces into the little pieces or balls.  Found it all here, in a Russian video (turn off the lousy music).  https://youtu.be/YdJujE2wNvA