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Concrete Mix.

Home Forums Archive Structure Designs Concrete Mix.

This topic contains 33 replies, has 11 voices, and was last updated by Profile photo of shredder7753 shredder7753 3 years, 2 months ago.

Viewing 15 posts - 1 through 15 (of 34 total)
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  • #1306
    Profile photo of elspru
    elspru
    Participant

    So what is an optimal concrete mix for making seasteads?

    From the book “Ferro-cement boats” by Colin Brookes:

    Brookes on Cement

    sulphate resisting cement

    sulphate resistant cement.

    after doing some research,

    have found that cement between 35% and 65% ash is considered highly-sulphate-resistant.

    this ash can come from industrial slag, as byproduct of cement kilning or steel milling.

    http://slagcement.org/image/123800_c_sU128801_s_i185534/No7_Mitigate_Sulfate.pdf

    Brookes on Aggregate

    sand .. ideally a mixure of 85% round particle sand and 15% irregular particle sand,

    with no particles larger than would fit through a no 8 sieve,

    this is not critical for strenght (within reasonable variations), but in achieving a high standard of finish..

    I’m wondering if Ellmer might have some variations,

    for instance perhaps using larger particles like rocks,

    the concrete submarine being made of cast concrete.

    Brookes on concrete mix proprotions

    3 buckets of sand to 2 buckets of cement

    What variations in this have you encountered?

    Brookes in terms of application

    metal floats draw water to the surface of the float and destroy the even water distribution of the mix

    best are the plastic floats with the chequered face, they will cut back and level the ‘mud’, without drawing water.

    So if anyone else has suggestions,

    would be quite interested in hearing them.

    #10951
    Profile photo of OCEANOPOLIS
    OCEANOPOLIS
    Participant

    Why would u be interested in hearing of any “suggestions” about this matter?

    “So what is an optimal concrete mix for making seasteads?” Well, the same freaking “optimal” mix for making ferrocement boats for the last 50 years will do as good for seasteads. Dahhh. The answer is just an engineering , technical matter,..

    “3 buckets of sand to 2 buckets of cement”. Whats wrong with that? Thats not good enough? How much “technical” you want to get?

    ” Ideally a mixure of 85% round particle sand and 15% irregular particle sand,…” You got to be joking…. Some f—-ing sand of any beach will do.

    Or,..wait…I got it !!!!!!!!!!!!!!

    YOU WANT TO BE IN CHARGE OF MEASURING THE PERCENTAGE OF ROUND PARTICLES VS. IRREGULAR PARTICLES. Hey, thats cool w/ me. You got my vote!

    #10954
    Profile photo of wohl1917
    wohl1917
    Participant

    I have to agree with elspru on this: Concrete mixing IS a lot more technical that just ‘3 buckets of sand to 2 buckets of cement’. There’s a link I got to once from that spent many pages explaining spalling, salt permeability, absorption rates,etc., etc., etc., and the intricacies of how and why those concrete ships are still floating. The long and short of it is you probably can do it the way you suggested but if you want it to last…

    < http://ocr.wikia.com/wiki/Oceanic_Citizens_Republic_Wiki>

    Profile photo of
    Anonymous

    Beach Sand has to be washed and screened to get consistant size and remove both organic and inorganic impurities. Any salt left in it reduces its’ resistance to water infiltration and freezing damage… Sand isn’t just sand, when it comes to making ferrocement, anymore than rice flour is readily usable as a replacement for wheat flour, or beef substitutes for chicken… (flour is flour/meat is meat)

    Later,

    J.L.F.

    Never be afraid to try something new…

    Remember, amateurs built the ark, professionals built the Titanic.

    #10958
    Profile photo of OCEANOPOLIS
    OCEANOPOLIS
    Participant

    that beach sand has to be washed and screened. So? It beats paying for sand, by far. I also agrre that are certain “intricacies” of “how to”,… But it is not rocket science.

    The ideal mortar composition it seems to be Portland cement, pozzolan (fly ash) and basalt sand in certain procentage. How hard can it be?

    But if you 2 would like to join Elspru, and now become A TEAM IN CHARGE OF MEASURING THE PERCENTAGE OF ROUND PARTICLES VS. IRREGULAR PARTICLES IN THE SAND, then you got my vote, too!

    #10963
    Profile photo of elspru
    elspru
    Participant

    OCEANOPOLIS wrote:

    that beach sand has to be washed and screened. So? It beats paying for sand, by far. I also agrre that are certain “intricacies” of “how to”,… But it is not rocket science.

    The ideal mortar composition it seems to be Portland cement, pozzolan (fly ash) and basalt sand in certain procentage. How hard can it be?

    But if you 2 would like to join Elspru, and now become A TEAM IN CHARGE OF MEASURING THE PERCENTAGE OF ROUND PARTICLES VS. IRREGULAR PARTICLES IN THE SAND, then you got my vote, too!

    so have you made anything out of ferrocement?

    it would be nice to see some pictures or videos.

    have you gotten floating ferrocement mixes working?

    perhaps using floating aggregate.

    calm aware desire choice love express intuit move

    #10964
    Profile photo of
    Anonymous

    OCEANOPOLIS wrote:

    that beach sand has to be washed and screened. So? It beats paying for sand, by far. I also agrre that are certain “intricacies” of “how to”,… But it is not rocket science.

    The ideal mortar composition it seems to be Portland cement, pozzolan (fly ash) and basalt sand in certain procentage. How hard can it be?

    But if you 2 would like to join Elspru, and now become A TEAM IN CHARGE OF MEASURING THE PERCENTAGE OF ROUND PARTICLES VS. IRREGULAR PARTICLES IN THE SAND, then you got my vote, too!

    Dude, I’m just saying that impurities cause unnecessary failure. Salt is bad, as are many other impurities. I’m not about to go using a microscope on tons of sand, ’round’ vs. ‘irregular’ would be a waste of effort. Good ol’ white beach sand… Basaltic sand has some unique properties, not sure it’s good for ferrocement. I’ve read about it and remember discarding the idea… Don’t remember why… Corrosive to iron, maybe?

    As for ‘floating’ ferrocement, IIRC, it has a lower strength, due to the entrained air reducing over-all strengths… Ferrocement structures are cheap because you can do it with readily available materials and not have to pay for the labor, if it’s a DIY project…

    Later,

    J.L.F.

    Never be afraid to try something new…

    Remember, amateurs built the ark, professionals built the Titanic.

    #10966
    Profile photo of OCEANOPOLIS
    OCEANOPOLIS
    Participant

    I guess not. I am withdrawing my vote!

    I would let a professional ferrocement builder deal with the construction,…

    I did own a ferrocement boat for 2 years. A 40′ Samson designed sloop. I said that “The ideal mortar composition it seems to be Portland cement, pozzolan (fly ash) and basalt sand in certain procentage.” because, back in Cali, a sailor friend of mine owned a wooden sloop (a 33′ Alden) that he ferrosheathed himself with the above mortar composition. I met him in 1992, and he did the job in 1980. His boat hull was in exellent condition after 12 years. So I guessed that mortar worked very well.

    #10969
    Profile photo of elspru
    elspru
    Participant

    Have any of you herd of Geopolymers?

    It’s potentially the material used for the pyramids and tihuanaca.

    wikipedia geopolymer

    From what I’ve been able to decipher,

    can be made from mixing a clay with 3% of a base like baking soda.

    I’ve tried it on a clay tablet,

    it seems to have worked,

    in terms of there were bubbles,

    so seems like a chemical reaction,

    also it looks quite different from my pure clay tablets,

    even having different coloration, closer to fired clay.

    calm aware desire choice love express intuit move

    #10974
    Profile photo of
    Anonymous

    OCEANOPOLIS wrote:

    I guess not. I am withdrawing my vote!

    I would let a professional ferrocement builder deal with the construction,…

    I did own a ferrocement boat for 2 years. A 40′ Samson designed sloop. I said that “The ideal mortar composition it seems to be Portland cement, pozzolan (fly ash) and basalt sand in certain procentage.” because, back in Cali, a sailor friend of mine owned a wooden sloop (a 33′ Alden) that he ferrosheathed himself with the above mortar composition. I met him in 1992, and he did the job in 1980. His boat hull was in exellent condition after 12 years. So I guessed that mortar worked very well.

    No font for ‘humor’ so it doesn’t show intent, as a joking post…

    As for mixes, I’d be a lot more likely to use the same one they used in the ferro-hull from WW1, that’s part of a floating break-water… along with the mixes used in the WW2 hulls that are also part of that breakwater… after a close-up view, to see how they are weathering…

    Later,

    J.L.F.

    Never be afraid to try something new…

    Remember, amateurs built the ark, professionals built the Titanic.

    #10995
    Profile photo of Farmer
    Farmer
    Participant

    elspru wrote:

    From what I’ve been able to decipher,

    can be made from mixing a clay with 3% of a base like baking soda.

    I believe the alkali formed when the ash in cement gets wet is providing a base in the standard cements.

    I think it is worth loking into not only making a better cement than portland and the other standards but looking at other fillers than sand. I have been chewing on using polymers as fillers because they are lighter, stronger and more flexable than silicates. I would just feel better about very large structures if they could flex just a little.

    #10996

    The perception that concrete structures do not flex and there is a need for inventing a “better” concrete than the one that is in use in general engineering is probably not very acertive. In fact concrete highrise buildings flex so much that they move with the wind like trees and one of the the design challenges is to avoid that people in the upper floors get seasick and that water does not spill out of the toilets. Prestressing is mostly a measure to avoid excessive flexing in long thin structures.

    #11002
    Profile photo of elspru
    elspru
    Participant

    Farmer wrote:

    elspru wrote:

    From what I’ve been able to decipher,

    can be made from mixing a clay with 3% of a base like baking soda.

    I believe the alkali formed when the ash in cement gets wet is providing a base in the standard cements.

    I think it is worth loking into not only making a better cement than portland and the other standards

    [/quote]

    Yes, so what do properties do we want to see in this cement?

    100% all natural, environmentally friendly, easy to get materials, and easy to make.

    2 unsoluble in water, for underwater application (perhaps using a vegetable or animal oil).

    high sulphate resistance, or immunity to sulphate attack.

    also we could look into seashells,

    perhaps learning from them,

    how to make steel-free concrete,

    as most shells don’t have reinforcing,

    yet they seem to get by quite well.

    but looking at other fillers than sand. I have been chewing on using polymers as fillers because they are lighter, stronger and more flexable than silicates. I would just feel better about very large structures if they could flex just a little.

    well I was thinking it would be great to use floating plastic,

    finding a home for it in floating islands would be environmentally friendly,

    turning waste into food.

    calm aware desire choice love express intuit move

    #11004
    Profile photo of
    Anonymous

    Ferrocement has better structural integrity, compared to fibercement(fiber reinforced cement), over long spans. Tested in small-scale, fibercement looks better, but doesn’t have the structure to resist forces that affect large-scale stuctures. Adding a fiber reinforcement to the cement also gives finishing problems, since it fuzzes when the surface is worked on. Under paint/sealant, it shouldn’t be a problem. If the surface needs to be ground/sanded/sand-blasted, it will get the fuzz…

    For painted surfaces, fiber reinforced cement would add strength to a ferrocement design.

    The biggie is worrying about the re-bar. Best possible way to keep it from becoming electrolytically active is to coat it with an epoxy, after tieing it into the shape you need. Lead seems to be the most reactive around steel and iron. If lead was used to ballast a ferrocement hull, it would cause elecrolytic action (like the plates in a car battery) when exposed to water (especially sea water). Copper reacts with iron, too. That’s why they sell di-electric unions for plumbing, where newer iron meets the copper pipes of older homes…

    I learned that, while looking into using ferrocement and the possibilities of a ferrocement sub…

    Later,

    J.L.F.

    Never be afraid to try something new…

    Remember, amateurs built the ark, professionals built the Titanic.

    #11005
    Profile photo of Farmer
    Farmer
    Participant

    Naturally I believe Elmer when he says this is all unnecessary (Of course we all knew skyscrapers sway in the wind) but for the sake of argument. ..

    elspru; all of those. also, good point about the sea shells (and other natural designs) of course pure calcium carbonate is free out there if you can wait for it to form but the structure rather than the materials is something we might learn from.

    The most frustrating thing about this forum is that there is really no engineering left to do. the only job remaining to make seasteading real is financial.

Viewing 15 posts - 1 through 15 (of 34 total)

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