Ratios And What they Affect

  • I have my foamer down well and have numerous blocks, planters etc made. To me they are fragile, not brittle really, just fragile. I am using .64 gal water and 9.4lbs cement in 5 gallon bucket and fill it till full with 88g / qt foam made w Drexel and water. I see that stucco, when applied to the outside, makes a tremendous difference.

    My question is in the ratios.

    1. what does heavier foam density (100 or 120) vs lighter foam density (with all other ratios the same) affect? Does heavier foam / qt create stronger or less strong bricks?

    2. what does water ratio affect? Going to 5 gal water per 94lb bag or going to 9 gallon per 94lb bag. Is the 5gal stronger or the 9 gal stronger?

    This site (https://naturalbuildingcollective.wordpress.com/tag/compressive-strength/) provides field tests to identify MPa for compression and tensile on adobe bricks. I would guess these field tests would work on these block types too!? They say 1.3Mpa or 190psi compession and 1.8 tensile is strong enough to build with.

    I realize I could keep doing tests to figure out my answers above as to what affects what but thought I would ask and see if someone has already done that.


  • I have tied batches with less water and found them to create weaker blocks. I do not remember the exact measurements of those tests. I have not tried testing more water yet though. I would imagine that after you dissolve out the cement you would only dilute the cement solution thus leaving more water to evaporate out and maybe even a weaker brick.

  • Water/cement ratio has a HUGE effect on strength - the higher the ratio (the more water), the weaker the concrete. Your .64 gallons of water = 5.34# , so your water/cement ratio is 5.34/9.4 which, if Siri did the math right, is a w/c ratio of .568 = pretty high in the world of regular concrete. You can read all about water/cement ratio at various civil engineering sites on the internet. Here's what is on Wikipedia - it is accurate info:

    The water–cement ratio is the ratio of the weight of water to the weight of cement used in a concrete mix. A lower ratio leads to higher strength and durability, but may make the mix difficult to work with and form. Workability can be resolved with the use of plasticizers or super-plasticizers.
    Often, the ratio refers to the ratio of water to cement plus pozzolan ratio, w/(c+p). The pozzolan is typically a fly ash, or blast furnace slag. It can include a number of other materials, such as silica fume, rice husk ash or natural pozzolans. Pozzolans can be added to strengthen concrete.
    The notion of water–cement ratio was first developed by Duff A. Abrams and published in 1918. Refer to concrete slump test.
    Concrete hardens as a result of the chemical reaction between cement and water (known as hydration, this produces heat and is called the heat of hydration). For every pound (or kilogram or any unit of weight) of cement, about 0.35 pounds (or 0.35 kg or corresponding unit) of water is needed to fully complete hydration reactions.[1]
    However, a mix with a ratio of 0.35 may not mix thoroughly, and may not flow well enough to be placed. More water is therefore used than is technically necessary to react with cement. Water–cement ratios of 0.45 to 0.60 are more typically used. For higher-strength concrete, lower ratios are used, along with a plasticizer to increase flowability.
    Too much water will result in segregation of the sand and aggregate components from the cement paste. Also, water that is not consumed by the hydration reaction may leave concrete as it hardens, resulting in microscopic pores (bleeding) that will reduce final strength of concrete. A mix with too much water will experience more shrinkage as excess water leaves, resulting in internal cracks and visible fractures (particularly around inside corners), which again will reduce the final strength.
    The 1997 Uniform Building Code specifies a maximum of 0.5 ratio when concrete is exposed to freezing and thawing in a moist condition or to de-icing chemicals, and a maximum of 0.45 ratio for concrete in a severe or very severe sulfate condition.

  • Anyone tested with foam density?

  • Major Contributor

    Sorry to revive an oldish thread.. I have been really experimenting with the foam density and water ratios.. I’m finding that foam density is more a function of water required for a specific volume of foam.. at the specified density I have been using 4-4.5 gallons of water per 47 gallons of aircrete.. This with 7gallons to begin makes for a very thin and runny mix that cures very slow. I have much better early strength by reducing the initial water content to 5 gallons. I don’t have scientific measurements, but the 2 day cure strength is noticeably better than batches with more water after a week. Your mileage may very with water, concrete quality and weather :)

  • has anyone tried to mix foam, cemet, water and sand? in what proportions? i live in chihuahua mexico and will try to reduce water, because the slurry is very wateryy...

  • @jrtorsa
    I’d watch the videos this site has on YouTube. They go by a tested formula to water concrete 7th generation dish soap it may weight it down the sand make brick crumble in Videos these brick aircrete are are brittle to alter formula will get poor results. You have to follow the formula or you will not get best results; soap foam / concrete with water. Is the formula even people cutting back on dish soap assuming it doesn’t matter their a pacific reason why 7th generation is used a chemical in dish soap that most dish soaps don’t have people are coming up with messed up airctete bricks. Their are classes you can take . They building this domes around the world so that have to be right on formulas etc

  • @susan i just wanted to know if some has used sand. We don’t have 7th generation here in Mexico.so I’ve been looking for a dish soap that works. Since my tests have failed. Bricks are brittle, although after a few days they get harder and harder. I feel that I’m about to hit the ball out of the park haha... but i need to ask.

  • I’d go to the domegaig site again the chemical in 7th generation dish soap that makes bricks 🧱 not as brittle is sodium laryle sulfate .. it’s that chemical that does the trick it’s Gabe the builder of dome Crete homes at domegaia id ask domegaia why use 7th generation dish soap it’s the sulfate in soap high level of it. Use dawn other soaps won’t get same results some using dexel etc and it you don’t follow the formula on mixture cement bricks be more brittle .. 24 hours after drying bricks are brittle it’s in nature they brittle so after 24 hours let bricks dry another 29 days. Longer they cure stronger less brittle they are. You have to cover wet aircrete cement with plastic sheets clear ones adding sand weight it all down make it worse dish soap foam helps bricks rise airpockets you add extra anything mess up formula it all online videos domegaig have to follow the formula or you will be left let down . Gabe is the one to ask he’s aircrete dome professional builder at domegaig. If you can follow a cake recipe exact measurements bake at certain temp. This will be easy to do bricks it’s like cooking follow the cooking directions exactly you will get results your seeking . Once mastered brick cement formula the building in the next process .. you do well.. I’d ask domegaia what other soaps that have the high content of sodium larlye sulfate that’s the chemical that’s does the magic it’s high content of the chemical read back the bottle online 7th generation you read sulfate levels

  • @susan Sodium Lauryl Sulfate Liquid

    A Solution of Sodium Lauryl Sulfate, Also known as SLS Liquid Our 29% typical solution of Sodium Lauryl Sulfate is a widely used, top quality product creating a mild foaming surfactant. ... Combine with Cocamide DEA (high foam booster) and cocobetaine for high viscocity products.

    This why they use 7th generation high level of sulfate plus this ingredient that ruins your hands a lot of domegaia builders experience wounds on Hanna’s whole building down even with gloves it’s this sulfate it’s a decreaser is surts but a foam booster as well .. I’m certain there’s an equivalent to 7th generation domegaia is building two dome aircrete homes on Mexico 🇲🇽 this year they finishing up one in Bali this month. You be ok get help you need. Most likely you may be able to buy sodium larlye sulfate add to your dawn or dish soap . It’s not good to skin at all even with gloves.

  • @jrtorsa if you go to section general on this site domegaia go to one lists Bali March 2019.. I’m certain you will find Gabe Rafa they build aircrete domes globally face the same loss of 7th generation dish soap they can help more than i they build the downs a guy from the Bali instruction class is full information and phone numbers emails to Gabe and Rafa builders of domegaia.. you will be I’ll you will build your done sooner than you know..

  • @susan

    Buy a bag of sodium larlye sulfate at eBay $18.95 USAD add to the dish soap you have make it foam better that’s what in 7th generation dish soap high content


  • @susan thanks a lot! I already bought SLS here in Mexico. I read here on the forum that a guy has been using this in any soup and gives great results. I hope I can get what I’m seeking. Creating aircrete has been a real challenge so far. Can’t wait to test this SLS. It would be very helpful to get in touch with Gabe and Rafa. I will seek that post of Bali 2019. If you found their emails and number first please share them. Thanks a lot!

  • @susan you be ok you get to your goal one.. day by day it will happen once people see you get more help. I’d contact domegaia itself to reach Rafa or Gabe. They will build two aircrete dones in Mexico itself this year. On menu go to general then click on Bali 2019.. there is a guy went to workshop knows the Rafa and Gabe he may be alike yo located them for you they plan to build two aircrete domes Mexico this year maybe they assist you once bricks are cured 30 days you lay foundation start layering the aircrete bricks it will go up within two weeks or less depending on the size etc

  • @susan SLS
    Sodium larly sulfate you add that to water mixture to with two cups of dish soap that’s main ingredient in 7th generation dish soap that’s why domegaia supports that dish soap it’s a booster add it to dish soap you have you be ok. Can’t access 7th generation add pure sodium larly sulfate with water 5 gallons two cups of dish soap watch measurements you may only need to add 1 teaspoon to that batch I read for measurements. You can what o understand volunteer to be a builder in Mexico they help build you a dome home in return but not sure about that I’m return learn to build help them build aircrete homes Mexico 🇲🇽 I’d get a Laura if questions send them to Julian at domegaia. Aircrete be best place you all have serious earth quakes in Mexico 🇲🇽

  • @susan also it could be your foam density that’s causing your issues with aircrete bricks.. the foam needs to be between 80 to 100 grams per quart. You get a digital kitten scale weight your quart container then put foam in quart container minus weight of quart container it should be between 80 and 100 foam density.. the ideal foam density weight 94 that’s the best outcome. This why 7th generation dish liquid it’s weight of foam best results of just add SLS teaspoon to two cups of dish soap to 6 gallons goal 80 to 100 density to quart perfect is 94 on digital scale kitchen scale.

  • @susan thanks a lot for all your help on this topic! Hope it goes on. Can I ask something, have yourself helped built a dome? Are you building one right now?

    Another thing that’s critical is curing time, isn’t it?

  • @susan no not yet I study all stuff at domegaia and volunteering to help build a dome in Sedona Arizona I will be building my dome I’m in the process self education talking to community as domegaia and build myself . There’s many on site here that gave built domes offering services I can’t wait to build dome I’m mire studying as much as I can from domegaia volunteers helping others build domes

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