Strawbale-stucco spraying

Orthorock:

Ordinarily I would say yes to C fly ash and no to F but the lime makes me hesitate on class C. Since class C fly ash usually contains a good proportion of lime you would want to cut down on that, but I'm not sure how much. The perlite seems ok.

Class F fly ash usually requires the addition of a foaming agent when added to concrete, and is not used that often.

Since C is normally obtained through cement suppliers, they would seem to be a logical source of information, especially regarding the lime content.

In any case you would want to test it first if there was any question.

Sorry I wasn't of more help.

Thank you N.Y.,

You were of help!

OK. C fly ash would replace adding lime? That would cut costs and toxicity exposure in the stucco mixing process. How would the mixing ratios compare in your estimate? Does C ash have the silicates that perlite does...so ...would a savings be accomplished there as well?

In your opinion what would be an ideal mix with Portland cement in combination with C ash for a stucco spray-on application?

Thank you...

The amount of lime in class C fly ash is "high" but it varies (each source has a different composition) so the supplier would have to be consulted and then you can leave out an equivalent amount of lime. As to replacing perlite, and recommending a specific mix I am not experienced in your particular application and there are too many variables, so I don't want to overstep my knowledge and/or mislead you.

These details are best worked out with your supplier and some testing on your part.

Good Luck!

Greg

It is a lightning made 25 years ago for popcorn ceilings...but big heavy duty...5 large hydraulic pumps, a new twin german diesel and a giant compressor.

I need to know about the chemistry of how these components bond...the silica, the lime, the Ca, the Carbon in these mixes...I like peralite because when trowled...it turns slick like glass and is very water resistant...which is important for sealing straw...it is all a recycling thing...using these materials..ash..straw..etc.

Try this web sight... http://www.tfhrc.gov/hnr20/recycle/waste/cfa51.htm This sight has helped me to mix stucco for strength. Using peralite you might have a strength issue.

I use perlite because sand does not pump with my auger.

What would you use in ratio for a suitable stucco mix without sand?

Will a GRACO President air driven drum pump work for any products suitable for straw stucco?

Sorry,

I only know what a bin mixer with hydraulic auger pump will do with a non-compressing mix of cement, perlite and lime.

85%cement,!5% c fly ash, 3 to 6 cubic ft. of perlite,1.2% fibers ,and water.....you will have to experiment with ratios....you might be able to put a little sand in if the auger will do it. Other things to add in helping it to pump would be easy spred or maybe a little lime. The more perlite in mix will make weaker stucco. I would probably do a three-coat operation ....first coat more cement/fly ash less perlite....next coat cement/flyash with desired perlite for insulation.....last coat cement/fly ash with less perlite. Your strenghth will come from fibers, in your case a good natural fiber. A message also has been sent to your mailbox. Thanks

LOI below 6 is legally required. Some locations require LOE of 3 or less.

Consider class "C" cenospheres for less weight and improved R value.

Some low LOI class "C" cenospheres require no additives except high humidity - each batch must be tested. Each plant operator produces different LOI flyash.

Thank all.

I discovered coal sand for $5 a 50lb bag.

The reason of perlite is volume. You need something to

give the mix some volume to fill the rough texture of

straw bales. I have not tried it yet..but I think that it will

move through the auger line ok. Sand compresses. I think the c-fly ash and coal sand may make a good mix. Chemistry wise? Carbon?

We built a straw bale constructed home over 20 years ago and ran into the same problems when blowing stocco. After many test products to use we opted for salt base instead of sand, then used a wire mesh laid directly on surface of the staw to increase the strength. this worked out great the home is the strongest wall we have ever built, it applied very well using the salt base because it could actually be thin a little more and the dry time along with adhesion saturation acually increased the strength. When test bore sample were performed through the walls we found the hay content would not burn after several hour of exposure to fire and we actually Have a video of this along with a track loader trying to push through a wall, it never moved the wall only dug out large trenches under the tracks. My brother still lives in this house today, it has been through 3 tornadoes which caused roof damage but nothing to the structure. kdking2469@wildblue.net