Geopolymer Concrete, the perfect seasteading material


I disagree, considering that the term ‘seastead’ is an adaptation of the term ‘homestead’, or ‘farmstead’, both of which are smaller than the cities they help supply. The more appropriate term for the massive, condo-laden conglomeration of floating structures should be floating city, while ‘stead’ would indicate some level of self-sufficiecy plus marketable food production.


Or how loose :smile:

I am not arguing, just commenting. The distinction is worth mentioning in order to properly define what we are trying to achieve here.


May I ask what the latest exchange has to do with geopolymer concrete…?


LOL, I can ask the same question…


Anyway, back to the subject at hand, in the opening of this thread Anenome said:

Therefore I say that years of research should be done on the material, and that’s about it. As for, would I use it to build a 1000 people seastead today, the answer is HELL NO. I would use ferrocement or steel reinforced concrete, period. You cannot risk the lives of 1000 with a material that you don’t know nothing about, period.

I can see hundreds of ferrocement boats built in the mid 70s still sailing the World’s oceans, therefore proof the material works.

Are there any things built of geopolymer concrete out there in the water? How long have they been there? How many oceans have they crossed? How many storms they’ve been through?



Ferrocement has a limited life-span, unless extra care is taken. Even stainless steel is capable of corrosion. Another drawback is that normal cement blocks x-ray inspection methods. Geopolymer cement/concrete allows x-ray examination and prevents corrosion. The next step is composite rebar, in place of steel, since it is significantly lighter, for the same strength, noncorrosive, and tends to return to shape, in case of deformation. Along with the weight savings of composite rebar, we can use thinner cross-sections of either cement, or geopolymer cement, further reducing weight.

One thing about geopolymer that I don’t see being taken into consideration, is its’ resemblance to fired pottery. A smooth surface texture reduces biofouling, reduces abrasion and geopolymer cement has more abrasion resistance.

(Jonas Smith) #108

Another thing to take into consideration is if there are any large-scale marine concrete construction firms that are capable or willing to use this material. Nobody is going to build a 1000-person floating city in their backyard…it’s going to require a construction firm with plenty of experience building large floating marine structures.

Are there any construction firms using this material, or who offer it in their project portfolio? It can be the most incredible material in the world but if nobody will use it then you are out of luck.

(.) #109

Just go ahead and buid.


Well, everything has a limited life-span, no matter what…There are just different degrees of life-span for different materials.

This is a 43 year old ferrocement boat that to me looks good for another 43 years.

[quote=“JL_Frusha, post:107, topic:240”]
Along with the weight savings of composite rebar
[/quote]On a seastead (therefore permanently in the water) being heavy it’s an asset not a drawback, unless you want to race that seastead…If you are light, your life will be very uncomfortable since you will be “all over the place” even in a light breeze.

[quote=“JL_Frusha, post:107, topic:240”]
A smooth surface texture reduces biofouling
[/quote]Without bottom paint on and 1 year in the water you’ll have growth on the smoothest material know to man.

[quote=“i_is_j_smith, post:108, topic:240”]
Are there any construction firms using this material, or who offer it in their project portfolio? It can be the most incredible material in the world but if nobody will use it then you are out of luck.
[/quote]True. Because anybody can pour concrete since the infrastructure is there. But forming geopolymer concrete it’s quite a different process. It will take extra money to build that new infrastructure, therefore more expensive.


You’ll notice I said “reduces”… Put a glass container of air in the water and you get biofouling, which will eventually affect the inherent buoyancy of the enclosed chamber but it’s a lot easier to clean than a piece of sandstone. That analogy is further applicaple due to the unique characteristics of geopolymers, which, like glass and ceramics, are heat cured.

You must not understand the mechanics of buoyancy, or you are baiting the conversation for the sake of arguing.


“Looks” is the operative word. A visual inspection, unless the corrosion is nearing failure and creates additional thickness, prior to spalling, is useless in ferrocement structures. That is one of the inherent problems of the material.

With the ability to use X-ray examination, the actual condition within geopolymer cement can be determined. That inspection technology is already available in the large overland oil pipeline construction.


Octavian thinks in terms of brute force (weight) opposing the wave forces. You and i think it’s not necessary to engage the waves in the first place.

(.) #114

He knows sailing. He has experience.


I am not debating that. But a seastead does not need to be a boat, and does not need to perform like a boat, or be built like a boat. A seastead is a house, or a farm, but it’s not a means of transportation. Different rules apply, just like different rules for trucks and skates.


Sailing and understanding buoyancy vs mass are different subjects. Point is, he’s baiting for an argument. Easier to win an argument by running off the people with differing opinions, than it is to admit there are multiple ways to achieve the different needs of seasteading, when you are wholy committed to something that is impractical.


Guess that depends on what a seastead is, along with the purpose of the design… As floating architecture, it can be stationary, or mobile. In my concept, it is free to move, for any number of reasons, with no notice. To move a city takes a level of preparation.

Increasing the mass of a structure unnecessarily, is wasted material and unnecessary expense for those wasted materials. In addition, those wasted materials decrease the buoyancy of the structure, further limiting the capacity, whether that requires a different design parameter, or reduces freeboard is up to the builder. Steel has more than triple the mass of an equivalent Basalt rebar, requiring triple the displacement, for an otherwise identical design, or reducing the carrying capacity.

Geopolymers and Basalt reinforcement have the potential to increase the buoyancy AND margin of safety, as well as the inherent ability to do a complete structural examination, rather than a visual inspection for obvious points of pending failure due to the inherent corrosion of steel within ferrocement and the inability to perform such structural examination. That lack of inspection and inherent corrosion is exactly why ferrocement has no realistic resale value, indicating an immediate loss of value and investment.

If you were buying such a composite structure and paying for the survey, would you want a simple visual inspection that cannot reveal anything about the structural integrity until it has reached the point of failure, or an identical appearing structure that has had a complete structural re-certification?


A mobile home is also free to move, and with no notice (depending on the size and each state’s laws about moving). But it’s still not a means of transportation (compared to a car). The distinction has bearing on certification, insurance, right-of-way rules, capacity, parking locations, etc etc… But that’s a different topic and has been discussed to death already.


Guess that makes mine the motorhome of seasteading vs the semi-mobilehome.

Either way, if you were buying a used seastead, would you rather have a visual inspection, or complete structural re-certification? Would you want ferrocement, knowing that it can fail due to corrosion at any time, regardless of how recent the inspection, or reinforced geopolymer that was completely re-certified?


I am planning on going with all steel construction, and replacing what’s in the water as soon as possible with cement i pour while afloat. Getting out there frees me from land-based interference, and allows me some other possible benefits. I think i am leaning towards basalt in a seaworthy common cement, assuming i can get the basalt, and assuming i cannot get and cannot process the geopolymer while at sea. Besides, i haveto figure if it lasts 20 years, it will likely outlast me, so it’s longevity isn’t the primary concern.

(.) #121

I do not debate thet eithe. I would just like to say the the word seasteading
starts with word sea.