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Post by jeff on Jan 3, 2016 9:11:51 GMT
While Geopolymer is still highly experimental and formulas are being developed that will require all sorts of testing, the basic method of construction is expected to be much like the process for Ferrocement hull construction. Build an armature and fill with cement. There are differences in matterials and methods, modern vs traditional. I recently came a cross a few products that have the potential to make the armature not only easier to make, but much better reinforced than ever before. Raw Energy Materials Corp. has a line of Basalt products that are closer to my personal ideal, based on the available online material. www.rawenergytec.com/Their Rebar features a finishing process that is highly textured and chemically reactive to OPC (Ordinary Portland Cement), creating a both a chemical bond within the cement, and a better physical bond, as well. The texture aspect will help across a range of applications. the chemical properties may, or may not be compatible with Geopolymer Cement, which is a more alkaline environment, than OPC. RockRebar: www.rawenergytec.com/default.aspx?p=13In addition, they have their RockDNA and Street Grid Basalt products, where the mesh forms a 3-dimensional lattice, within the cement, to create a 3rd bonding feature, andm the panels are made of one continuous piece, to completely prevet pull-out, which is one of the testing methods for the tradition Rebar/OPC bond. Guesstimating from the images, the trianlges, that form the basic hexagon,are about 8" on a side. These panels are made so that the points and valleys of opposite sides butt evenly together, which are them laced, or tied together, thought how is not exactly clear, from their images. For my puropses, they may not be suitable 'as-is', but they open up possibilities... First, I need to see if they have a FRTP (Fiber Reinforced ThermoPlastic) for use in the panels, then is the same texture as the Rebar available, and then, can they duplicate the pattern of the panels at a much finer grid, such as a 1" hexagonal pattern, as still have the textured surface bond. I need FRTP, for shaping purposes, so that the armature is not in tension. Otherwise, I will need a significant structure, in order to withstad the bending forces, during construction. Standard steel Rebar will bend to shape, but it also weakens the internal structure of the Rebar. FRTP Composite rebar can be heated and shaped, relieving stress and creating a structure that wants to hold and return to that shape, against forces that want to deform away from the thermo-set shape. In addition, their Street Grid may be too thick for my purposes. I need to be able to bond the finer mesh through the spaces of the Street Grid, in order to for a better laminated structure. IF, given the necessary specs, they can create a better product toward my needs, I will still need to have samples and lab testing to see if the chemical bond is appropriate for Geopolymer, and long-term application. if it reacts too much, it could actually weaken the geopolymer and lose all of the benefits, creating a situation much like the errosion of lime-crete, which was developed and withdrawn as unsuitable for the exterior application intended.
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Post by Deleted on Jan 5, 2016 18:08:19 GMT
Given the reports and data on basalt rebar and geopolymer, i believe this form of construction is crucial to seasteading. It's imperviousness to salt water makes it indespensable to use in ballast tanks, for deep hard-to-reach hull parts, and for all areas in the slash zone. Even if the structure of the seastead is not 100% geopoly, the geopoly can keep the seawater on the outside, where it belongs, by performing as the skin of the hull, the skin of tower legs, the submerged floatation pods. Or by being unitized building blocks, or separate floatation units, made in any optimal shape and size, attached to or held captive by the seastead. This construction can supposedly render the corrosive ocean water chemically inert, making floatation that can last indefinately.
And it's not only seawater which can be stored in geopoly tanks, and the thinness of the basalt fiber mesh reinforcing, it's not only structural parts that can be made of geopoly. I am thinking the general freshwater tanks, methane generator tanks, aquaponics tanks, and terrazzo floors and tables. Depending on the overall situation, perhaps even roofing tiles and stucco exteriors are feasable.
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Post by jeff on Jan 29, 2016 17:30:50 GMT
Copied from my post in another forum: The greatest expense was the Sodium Carbonate... The Caustic/Reactive portion of the formula... Not sure which one, but one city was paying $64 per ton to haul off SSA... so $256 back into pocket, vs $1040 outlay... $156 3 tons of Fullers Earth $300 3 tons of Diatomaceous Earth $456 -$256 $200 Potential cost of 10 tons of Geopolymer raw ingredients... On land... (IF the formula holds) Addendum: Influence of aggregate content on the behavior of fly ash based geopolymer concrete Benny, Joseph A.; George, Mathew B. www.sciencedirect.com/science/article/pii/S102630981200168XGuesstimate: 4:6 Geopolymer : Sand... ~$200 for 10 tons geopolymer, ~$285 for 15 tons Beach Sand ($19/ton according to- www.delta-sand.com/docs/DeltaPriceList.pdf ) Now we have 25 tons of dry geopolymer cement mix, for roughly $500... :neutral_face: Basalt Rhyolite construction? 3d printing your own island Geopolymer Concrete, the perfect seasteading material Brainstorming Approaches to making Big, Modular
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Post by jeff on Jan 29, 2016 17:52:59 GMT
JL_Frusha Nov '15
Geopolymer experimentation continues...
Tonight, I mixed Charcoal Briquette ash in a 70/30 ratio with Diatomaceous Earth, with that mixed 40/60 ratio to general purpose sand. When mixed with water, to activate the process, this became mildly exothermic. It's at roughly 78*F, in a 73*F room... Reached about 80*F, before I got it packed into the cup and packed down.
The purpose of Briquette ash is easy access to a source of metakaolin clay and wood ash as a source of lye.
Also mixed a batch of 3/3/4 Fullers' Earth/Diatomaceous Earth/Wood ash, in a 40/60 ratio with sand. It's holding at room temp. _______________________________________________________________________________________________________________________________________
JL_Frusha Nov '15
Addendum:
The Charcoal Briquette formula is a starting point for using common waste products. Metakaolinite is also commonly referred to as fly-ash, clay is to most common binder in charcoal briquettes, here, in the US; while wood ash is a common source for homemade lye (Sodium Hydroxide).
Metakaolin is a reactive clay, caused by high-temperature heat. the clay binder slows the overall burn rate for the carbon particles, but gets treated, so a cheap diy source of both is the briquettes... _________________________________________________________________________________________________________________________________
JL_Frusha Nov '15
In and amongst, I have a sample that turned-out well... Had to figure out the off-beat side reaction, but all in all, a nice, strong batch.
Used Charcoal briquette ash, in a 70/30 mix with Diatomaceous Earth (quickie substitute for Fly Ash and Wood ash)
That was mixed 40/60 with Lowe's General Purpose Sand (all measurements by weight, using digital kitchen scale)
Added enough water to make a roughly mortar-thickness mud, and packed it into a 5oz plastic cup.
Mildly exothermic (~80*F, in a 73*F room). some mild off-gassing, primarily CO2, from the Potassium Carbonate, with water coming out, in dissolution, and evaporating, leaving behind what I presume is Potassium Nitrate, as a precipitate. unscientific, but mildly salty white powder, less salty that table-salt.
The mix hardened really well. Waiting for remaining off-gassing to end, before doing any testing. ___________________________________________________________________________________________________________________________
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Post by jeff on Jan 31, 2016 22:27:39 GMT
Crunching numbers... Aluminum weighs in at ~168 lbs per ft^3 Ferrocement hull construction come in at ~150 lbs per ft^3 Replace Steel mesh and rebar in ferrocement, with Basalt and the weight drops to ~117 lbs per ft^3 _____________________________________________________________________________ The basalt is stronger, lighter, and non-corrosive, but that is only reducing the weight of the steel, by 2/3, not reducing the weight of the hull by 2/3. Most of the hull is actually cement, not mesh and rebar. The cement bonds everything together and solidifies. Over 65% is cement, and that portion remains the same. ............................................................................................ The density of reinforced concrete is taken to be 150 lbs/ft^3 The density of carbon structural steel is 490 lbs/ft^3 Source(s): structural engineer minorchord2000 ................................................................................................ Of that 150 lbs/ft^3.. 1/3 of that (50 lbs) is steel. replace the steel with basalt @ 1/3 X 50 lbs ~ 17 lbs. Now add that 17 lbs back to the 100 lbs of cement (or subtract 33 lbs from 150). The cubic foot now weights 117 lbs. 117 divided by 150 is still 78% of the original weight. Meanwhile the Basalt, being easier to handle and easier to tie together reduces the labor and time involved significantly. (I'm tired, so my numbers may still be a tad off, but the steel weight is no more than half of the total weight, so even if it's 75 lbs, it would only reduce the total by 50 lbs, so still weighs 100 lbs per cubic foot. In your example, it would still weigh 1000 tons, or more.) _____________________________________________________________________________________________ Ballparking: If a 55 ft Aluminum yacht hull with decks weighs 4900 kg / 10,780 lbs (per www.berckemeyer-yacht.de/tex_cost.html)Then I add 1/3 for the extra width of a Ramform hull type, I get ~6500 kg / 14,500 lbs in aluminum By switching to ferrocement construction, using Basalt rebar and mesh, I get the hull back down by a factor of 70%, and below the weight of Aluminum ~4,550 kg / 10,150 lbs Now, since Basalt is roughly twice as strong as steel, I can reduce that even further, and even reduce the overall thickness, as well, making it considerably lighter than the equivalent Aluminum hull with decks. Suppose I save another 15%, the Basalt / cement comes in at ~2,640 kg / 8,630 lbs. At nearly twice the volume, I have less mass in the hull and decks, than if I built a standard hull with decks, using Aluminum. Cost Generalization: Basalt reinforcement costs roughly twice what steel does, for the same size. However, reducing to the same strength, puts costs aligned with steel, so it will break-even, there. ~65% of the mass of ferrocement is in the cement, so I would need ~1700 kg / 5,600 lbs of cement. Round up, and say 6 tons. Using the costs I calculated for DIY Geopolymer, that 6 tons should cost in the neighborhood of $120.
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Post by jeff on Mar 22, 2016 14:59:00 GMT
One thing that recently came to mind is that, with Basalt Rebar being lighter and more flexible, the armature for a ferrocement-like structure could be woven together, during the build process, making for an inherently stronger, more durable final product.
Further, if an FRTP version is/becomes available, end-splicing, for more continual runs of reinforcement become possible, by simply using the telegraph splice, which also retains the strength of the line. I've used the telegraph splice on barbed-wire fencing and used fence-stretcher, to make the fence tight, w/o it failing.
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Post by thebastidge on Apr 26, 2017 23:31:17 GMT
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Post by thebastidge on May 1, 2017 16:23:36 GMT
If one were looking to really reduce hull weight of a floating platform while increasing surface area usability, I think I might consider an open-bottom solution and EPS. That's how many boat houses and floating homes stay afloat for decades. We have boathouses in our yacht club that have been floating since the 1950s. That's as good as many home construction techniques. These structures float on logs with expanded polystyrene foam (styrofoam) blocks under the logs, beam "stringers" across the logs, and a more or less standard floor joist system above that.
Many of the newer public docks are concrete caissons with closed or open bottoms and EPS flotation. the current code requires that it is sealed blocks, with plastic sheathing. Protect the EPS from mechanical action and sunlight, and they last a REALLY long time. Algae grows on them (on almost anything) but at least in the freshwater environment, I haven't seen anything else growing on them.
Picture the concrete structure with a surface deck, and bulwarks (walls) extending down from that, then another deck/roof above the surface deck as in the diagram (concrete in black, flotation blocks in blue, lighter superstructure materials in green).
The flotation is trapped/entrained by the walls extending down even in a tilting scenario. Friction and buoyancy usually keeps these things tight anyway, but plan for the worst. Some place like the Cay Sal bank never gets waves high enough to even expose the flotation, much less drop it out of place.
****I guess we can't upload on this forum?
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Post by thebastidge on May 17, 2017 16:15:28 GMT
An aspect of open-bottom positive buoyancy flotation such as EPS is that reinforcing the span of the deck only has to really account for major hog/sag forces, not for loading. It's essentially like building a flat plate on the ground, there is continuous compression across the span, as the buoyant foam presses up against the deck. As long as it is kept evenly applied against the bottom, the deck's dead load is counteracted, and with proper planning, it can counteract dead load of decks above, and even live loads to a degree, since they are generally a small percentage of dead load.
Building an open hull that extends above and below the deck, provides rigidity against hog/sag. For long straight spans of hull, internal concrete buttresses can provide reinforcement like the ribs of a traditional ship.
I'm finding costs of ~$103/yard on traditional concrete, so I'm using $115/yard as an estimate of cost of geopolymer. I'm estimating 3x cost of concrete as the residual cost of basalt reinforcement (mesh and rebar) and labor combined. So 4x $115/yard for a finished shell. These are just cocktail napkin estimates.
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Post by jeff on May 17, 2017 19:06:31 GMT
Thing about Geopolymer is the difference between what I am trying to formulate, and standard, commercialized formulas. Current commercial formulas still use slacked lime and is difficult at best to X-ray examine. My base formula eliminates the Calcium.
As for the Basalt Reinforcement, where commercially available Basalt Rebar is flexible, it is like any fiberglass composite, and has natural tendency to return to the manufactured shape, straight. My intent is to start with Basalt Roving (rope) and use a thermoplastic enamel, rather than a thermoset epoxy. Meaning I can form it, heat it, and it will 'take' the new curves, thus reinforcing the desired shape, rather than being under tension. Each additional bar further adds to the forces that have to be led within the structure. Not bad for a circle, and actually reinforcing a submerged cylinder, but it gets really difficult with compound curves.
Typically, when a curve is desired in commercial Basalt Rebar, it is either in tension, or the epoxy is burned-out, with a torch, and new epoxy applied.
One of the inherent problems with ferrocement hulls, including those with a geopolymer admixture, is the lack of X-ray inspection capability, creating an immediate loss of value. In addition, any osmosis of seawater creates corrosion in steel rebar, and spalling. Eliminate the Calcium AND the steel, and the hull can be X-ray examined, using readily available pipeline X-ray equipment, and reducing the corrosion related spalling to zero.
Further, the materials I have chosen are generally available as surface-mined deposits, and municipal waste ISSA (Incinerated Sewage Sludge Ash) that can be a profitable haul-away item, rather than a purchase, reducing net expenses.
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Post by thebastidge on Jul 28, 2017 18:40:33 GMT
What about just using the basalt cloth? Octavian says most ferro boats are only 3/4-1" thick, with wire mesh rather than rebar for the longer expanses, with rebar used in reinforcing ribs. That accords with the ferro construction methods I've seen (Navy manuals etc.)
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Post by jeff on Aug 1, 2017 16:30:58 GMT
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Post by thebastidge on Aug 2, 2017 15:38:45 GMT
In a word? A mold. Some of the recommendations I'm seeing for geopolymer recommend molds for reasons of slump, since the viscosity of the mix is difficult to adjust (can't just add or subtract water like with concrete). In fact, that pic you show seems unusual in that most of the versions I've seen, they have the hull upside down for plastering. I mean, why would you even try to plaster something against gravity (underside of the structure) if you don't have to? Another link I will try to find again (I don't think I book-marked it at the time) talks about converting old wooden boats to ferro boats by simply applying the 'crete over the existing (inverted) hull, using it as the inner mold. I've looking back through TSI forum threads (new and archived, and here as well) and building Wiki pages. I ran across the concrete canvas link again: What the concrete canvas emergency structures have in common with the Monolithic Dome company is an airform. It looks a little sloppier and more of an expedient solution than the Monolithic guys- they seem to have very precise domes. But where it is better is that it's a consistent thickness with no massive dump truck, no massive concrete pump spraying it on, no concerns about delivering multiple truckloads back to back timed precisely enough to keep spraying all day long without a gap or without the stuff starting to set, and they don't have to worry about slump as much. (You might wanna consider this for your incubator site.) Think about a geopolymer-impregnated basalt fiber cloth (probably cloth on both sides and maybe a thicker mesh in the middle?) Maybe, there's a peel-back designed in such that you can overlay strips like ship-lap for good chemical adhesion during the cure. You lay it over a form, adjust the seams, and wet'er down. Sand/grind any imperfections just like you would in traditional ferro boat construction, only you have no iron involved. Perhaps you plaster lightly over the outer layer of basalt cloth to smooth out the fiber texture for a smooth hull. It might be more difficult to control the amount of water applied since the concrete canvas isn't mechanically mixed with water. I dunno, just thinking out loud. Trying to find ways to simplify a repeatable process.
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Post by jeff on Aug 2, 2017 17:50:06 GMT
Yes, during the curing process geopolymer goes through a very watery stage and then firms up. My thought is to use a plaster gun to shoot smaller batches as they start to set, since it will readily adhere to itself, unlike OPC.
The pic was just one I found easily. Most seem to do it inverted, as you said.
Molding means needing standoffs. They could be cast of geopolymer, then they would integrate with the added geopolymer, but I believe it would require very careful design, with both inner and outer forms. That might make for excessive air pockets.
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Post by thebastidge on Aug 2, 2017 20:06:21 GMT
Molding means needing standoffs. They could be cast of geopolymer, then they would integrate with the added geopolymer, but I believe it would require very careful design, with both inner and outer forms. That might make for excessive air pockets. I was thinking you might get away with only an inner mold, depending upon the shape of the hull. We're sort of conflating two very different concepts, so let's explicitly separate them. 1. Typical ferrocement hull construction involves plastering a mesh, which needs a 3D framework of rebar to support it during curing. If the mix is thick enough, you just trowel it smooth. Any steel that breaches the surface gets ground down and epoxied over. 2. Typical traditional construction concrete pours with molds have inner and outer forms. Stand-offs are incorporated into the rebar structure, sometimes plastered or epoxied over later. 3. This thought experiment, opposed to shaping loose sheets hanging from a line, or using removable forms on each side, you have an inner mold that provides shape and support of the concrete cloth (upside-down hull shape, perhaps even an existing hull that is not sound anymore) until it firms up and you lift the new hull off of it. It's a continuous support underneath, and the concrete cloth prevents slumping. No external form, just some light plastering to smooth the texture on the outside. No need for stand-offs. It's basalt cloth, so the geopolymer plastered outside bonds to it with 100% strength. There was a guy in Puerto Rico(?) that made himself a monolithic dome (actually it was domes and tunnels, and wooden structures in a big messy combo) with no inflatable air dam or other mold. He just piled a bunch of soil, covered it in visqueen plastic and concreted over it, then removed the dirt. You can do it with clay and no plastic. Or plywood. There's all kind of low tech ways to form a dome or hull structure, with varying degrees of quality control. Another thing about air pockets: if the Geo-Poly is truly as good at bonding to already-cured Geo-Poly substrate as claimed, then those air pockets are less of an issue than in traditional ferro-cement, which already had notable concerns about this issue. Those concerns are addressed by vibrating the curing mix, or chiseling out and filling with epoxy after the cure. If the basalt/geopoly concrete cloth rolls were wide enough, you could conceivably use one per side, with a single seam down the keel, which when righted, could be reinforced with a narrow pour of geopoly into the bilge doing double duty serving as keel reinforcement and ballast. The bow and stern are merely trimmed to shape and draped over the inner mold.
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