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  • RE: cracking of bricks

    Perhaps part of the problem is language -
    Since the article is in the UK the article is probably discussing Autoclaved aerated concrete (AAC), rather than Domegaia's form of AirCrete.

    The article mainly discusses the problems with using the wrong mix for mud and poor application techniques. Both problems are usually taken care of in a Domegaia type build.

    posted in AirCrete
  • RE: concept by Isosceles.

    the finished dome might not be perfectly rounded

    Perhaps perfectly round is over rated. Well defined geodesic domes can be very artistic. I suppose the rounder it is the stronger it is though.

    posted in General Discussion
  • RE: cracking of bricks

    Welcome to the forum for aircrete pioneers. Thanks for your interest and your post. Thanks for questioning the norm.

    One of the articles I found advised that due to the brittle nature of aircrete it is not advisable to use as a building material

    For the average do-what-everybody-else-does builder, this information is perfectly correct. For them it is the correct answer for several reasons on several levels. For others, the statement is humorous.

    Brittle is a relative term. The concept of brittle is relative to other materials, and/or what you are intending to build. Giving advice based on a completely relative aspect without stating what it's relative to, leaves a lot to assume.

    Concrete is quite brittle in comparison to certain other building materials such as granite and solid steel. Due to the brittle nature of concrete it is not advisable to use it as a building material without incorporating vast amounts of steel to keep it from cracking apart. I've worked with plenty of concrete and enough aircrete to say that concrete is more brittle than aircrete. Pour two walkways 4-6 inches deep, one pure aircrete and the other pure concrete (no rebar, thanks) and I'm pretty sure the concrete will crack up more.

    Comparing building materials can be fun, but mostly pointless banter unless we know what we are trying to build. For those intending to build a square house with straight walls, I don't advise using aircrete because flat walls set at 90 degrees to each other tend to make incredibly weak structures compared to say, domes. For those interested in making inherently strong geometric structures such as domes, aircrete looms as a seriously viable, affordable, insulative, easy to use, building material.

    I suggest reading this post about fibers. There are others on this forum - try the search function and see what comes up.

    posted in AirCrete
  • concept by Isosceles.

    Hello Domies! As I was tossing about on the roiling seas of thought and imagination. It came clear that one might possibly make clever use of his or her (Aircrete) by building a dome working with forms that were built with (formed) isosceles triangles. It certainly would be easy to pour into such a form. And I am willing to bet that the mortar milk would hold well because the construct can be accomplished by layers from the bottom up. Of course the finished dome might not be perfectly rounded the same as when done in block. But it would definitely reduce the time involved in construct so far as producing block. Think tall Triangle and Small :) I imagine you could cut in doors Arches and windows or ports after the mortar set because aircrete cuts like wood. the fabric could still be applied.

    Definitely something a builder might consider. (triangle man doing the things a triangle man can) Happy construct folks...

    posted in General Discussion
  • RE: cracking of bricks

    funny thing but I wonder if sawdust is viable....

    posted in AirCrete
  • RE: Block thickness, dome diameter, Fabric Reinforement

    @brian-spooner

    Does the fabric re enforcement increase the structural strength?

    Absolutely

    posted in AirCrete
  • RE: Block thickness, dome diameter, Fabric Reinforement

    @anthonydjones The dome complex I spoke of in aircrete-vs-ferrocement regarding the minor effects of major earthquake activity is based on a 21 foot internal diameter dome and it is made with 3.5" block wrapped (exterior only) with a APOC 483/Fabric Cement shell and painted with Behr Exterior Latex Paint. I don't heartily recommend using latex paint, however, Gabe just now confirmed to me that he distinctly recalls walking around and working on that dome with two other grown adults simultaneously. His memory of the situation is that he would not have hesitated to work with a fourth adult if the need or whimsy had arose. I don't know of a table or formula for determining block thickness per dome diameter, but I can say 3.5 inches is plenty for a 21 foot dome.

    posted in AirCrete
  • RE: Block thickness, dome diameter, Fabric Reinforement

    Does the fabric re enforcement increase the structural streangth?

    posted in AirCrete
  • RE: aircrete vs. ferrocement

    @claudettn said

    So I want to build a dome house (in a tropical climate), where sun, lots of rain, humidity, insects and earthquakes are to be considered.

    Regarding sun: Aircrete is very insulative, ferrocement is not insulative. Most ferrocement domes are coated with a thick layer of spray foam insulation.

    Regarding rain, humidity, and insects: Aircrete and ferrocement perform the same in this arena. Both are cementitious materials that are not affected by water, moisture, or insects and do not support the growth of molds.

    Regarding earthquakes: My personal vote goes toward aircrete, though there may be room for some debate. Aircrete is well known for it's inherent flexibility. An aircrete dome wrapped with a polyesther fabric shell has amazing resilience to seismic movement. The dome complex I am most familiar with is near the epicenter of Hawaii's recent 6.9 earthquake, which was preceded and followed by literally hundreds of smaller quakes in the surrounding few weeks. During that period 4 and 5 degree quakes were considered normal daily occurrences, with 2 and 3 degree quakes being experienced up to several times per hour. As a result, some cracks (up to 1mm wide and up to 24 inches long) can be observed in the dome structure above the raw cutouts for the planned windows and doors. To be precise, I observed one such crack above each of these raw cutouts. The one window that was finished has no cracks whatsoever. Regardless of how earthquake proof a structure may be, there are no rules on how strong an earthquake may be. In a catastrophic event where a structure is overcome by an earthquake, I'd rather be in an aircrete structure because chunks of falling aircrete will hurt, like ouch!, but falling chunks of concrete sever, crush, and splatter.

    posted in AirCrete
  • RE: aircrete vs. ferrocement

    @claudettn We walk on our domes frequently. We've not attempted to add a roof structure like Steve's. Depending on the mass of the roof structure, the dome needs to be made with appropriately thick walls and shape (see catenary dome) to accommodate. Our typical domes use 3.5" thick blocks. I think for now our focus is on creating affordable, practical, reasonable living spaces. But there is lots of room out there for exploring even more artistic, creative endeavors. I would suggest building a small simple dome first, then another larger one, try connecting them, then play with more advanced concepts like roof structures and so on.

    posted in AirCrete