Building Barges Using Advanced Concrete Methods?

(Nick Gencarelle) #166

AGAIN, I said magnesium phosphate NOT mag oxide.

(noboxes) #167

I guess you do not know there is a lag with online communications. I found what i found before you made clearer what you wanted us to do the research on.

Fwiw, irc is real time, and has been around since the 1960’s in one form or another. @JL_Frusha has kept at least one irc channel open for seasteading and gulfsteading discussion (or asian music, small computers, etc) for two years now.


In an email from the Geopolymer company, here in Texas, they sell buckets, bags and delivered mixed. Not including a mixing truck, one type sells for $70/cubic ft.


$9.25 for a 94 lb. bag of portland cement @Home Depot,…


1 cubic foot of OPC makes about 1 cubic yard of concrete, same for Geopolymer, using the same basic gravel and sand composition.

Unlike OPC, it is already Acid resistant, protects ordinary steel rebar from corrosion, has far higher heat tolerance, etc.

All I can do is quote what they sent.

(noboxes) #172

Ok, i was confused about the OPC bag mentioned saying on the bag “Portland cement” while the HomeDepot webpage says “concrete mix”, and you saying “they sell buckets, bags and delivered mixed”, which i interpreted as the sand/gravel was already mixed into the geopoly. The numbers i gave certainly do not apply if the buyer is mixing various stuff into the bags of cement or geopoly to produce the final product.

Is this why Nick says no one sells a ready-to-use geopoly, but that each sale is based on how and why it’s being used? Because they haven’t thought to sell a product that’s already completely mixed and ready to add only water (or other liquid) to?

This is like calling some oranges apples, and comparing them to grapes. I may never understand how HomeDepot calls a bag of Portland a “concrete mix”. Or how a bucket of geopoly isn’t ready to use. I need to buy some IQ points.


No, their site confuses the issue. Following the link, it adds the word concrete, which, to me changes the product from being cement, to ready to mix concrete. That’s the distinction I see, from the internet.

Who knows, we may both be wrong, the way they can confuse and rewrite stuff, these days…

Is Geopolymer a good, worthwhile building material, IMHO, if it will outlast OPC Concrete by generations, then it is. That’s my opinion.

(noboxes) #174

I 100% agree.

How are we to know when they sell a bucket of geopoly, just what it is meant to be mixed with, and how much, and even how mixed? Nick was talking about high pressure mixers… i gather now he was not talking about mixing the ingredients to make geopoly, but he was talking about how to go about mixing in sand or aggregate to the bucket of geopoly?

This seems important to me, because if you get your seastead support facility on the coast, and someone wants to show up and 3D print a boat with geopoly, they may have no interest at all in buying aggregate and a pricey special mixer, and (like me) be put off by the price of $70 for a single cu ft of geopoly.


I’ve responded to the email, questioning the price quoted. It seems excessive, but I do not know the ratio to aggregates, so it may still be competitive.

(Larry G) #176

The expectation seems to be that the vendor is consulted on the project and supplies expertise in determining the mix. Perhaps because the material is new enough to 1) not have the basic formula published for a given supplier’s mix 2) the vendor thinks that supplying expertise to make a custom mix is economically safer than trying for volume through widespread adoption of standard mixes 3) not have enough use cases behind it to have matrix of formula for specific purposes built and published.

Personally, I would be willing to procure special aggregates for special projects, and the mixer requirement is just part of the cost of the project. The mixer cost is partially recoverable anyway, either by resale or leasing out for other projects.

The problem with #2 above is that they probably don’t know the real answers (vs approximate estimate) on a mix for a new type of application much better than the person trying the new project for the first time could figure out from having the range of engineering data presented to them.


iirc, the high-sheer mixer was for the UHPC, which had multiple fibers mixed in, not the Geopolymer.

(noboxes) #178

Were you told that is for the A240? because i just read the 1 cu ft kit is

The A100, A200, and A300 data sheets all read about the same, “A240 COLD FUSION CONCRETE™ is a 3/8-inch nominal (or other size) aggregate (quartzite)
concrete material”, so i am assuming that a cu ft of geopoly from them has 3/8 aggregate in it already. Am i wrong again? I do not find the A210 on their website, which is strange, because the A240 sheet says that if too much water is added in mixing, to add more A210, without saying where to buy A210.


I guess I missed that. I’m still waiting for clarification. $70/ft^3 is excessive, imho





Just don’t know how it mixes, with how much aggregate. It’ll boils down to proportional costs, or even if they’ve misquoted it to me.

Hell, I don’t know how often I’ve spent an hour fixing autocorrect.

(Nick Gencarelle) #182

High shear mixers are needed for a UHPC mix to be well blended as the size of the particles is so small and yet they need to mix very well to perform well. Every place has different aggregates and sands and water so these companies take some samples from the local place and design a mix that is specified to be compatible and work best for the regions materials. Florida has lots of limestone sand-we have lots of quartz and granite-the water is different etc. so a mix that is made to order for these high and ultra high strength materials is more exacting-yes more expensive and more of a pain in the ass however if one is looking to buy a Ferrari you do not just jump in and drive without someone giving you the basics and some training. Sure you can just go get a Ford and it is fine for a while but it will not offer the performance and if people are looking to build actual floating islands that people live on in salt water they would be wise to use the best concrete solutions they can find if they expect then to last and not be spending a whole lot fixing them or damages as a result of using the wrong stuff. So it takes a little training and cost more but I think in the end for this type of project the wisest thing to do.

(noboxes) #183

Yes, $70/ft^3 is $1,890 per cubic yard. I must agree, that’s excessive, imho. I do not know what the average redi-mix sells for now, but if it’s $100/yd, that’s only $3.70 per cu ft.