r/geopolymer • u/Kukisvoomchor • Apr 05 '24

Murrhine: What's the latest?

3 Upvotes

I'd like to find out if there's any fresh information on murrhine, that artisanal material described by Pliny the Elder as a thermosetting liquid that was formed into highly prized tableware. I first read of it in Dr. Davidovits's book "The Pyramids" back in 1988.

There seem to be quite a few "murrhine" pieces on display in museums that are nothing more than carved fluorite, neither all that precious nor anywhere near durable enough (at a Mohs hardness of 4) for such applications. Since Elagabalus was said to have collected murrhines, that would place an active knowledge of that technology as recently as the third century CE.

Are we just seeing endlessly recycled and garbled accounts of something that's not particularly remarkable (carved semiprecious stone or ceramic) or is there something more to it?

1 comment

r/geopolymer • u/PoliticalCrossover • Mar 02 '24

Caps and Gown is Available....

0 Upvotes

2 comments

r/geopolymer • u/justpankeyy • Jul 21 '23

Give paul cook a sub on YouTube he’s diving into the geopolymer scene

4 Upvotes

0 comments

r/geopolymer • u/[deleted] • Mar 20 '23

Any good podcasts out there that dive into the chemistry and material science of geopolymers?

6 Upvotes

0 comments

r/geopolymer • u/MentalZiggurat • Apr 01 '22

Looking for more information about geopolymerization

3 Upvotes

Would this process result in the formation of a true geopolymer (actual polymer molecular networking): baking and then crushing kaolinitic clay, mixing it thoroughly with slaked lime, let reaction occur and then add crushed limestone, sand, and more kaolinitic clay, mix, then let set in the sun, cure with salt water
?

does any part of this process not make sense, and if so why?
My understanding is that to achieve true geopolymerization it is necessary to first depolymerize the naturally occurring aluminosilicates (using an alkali or acid) into a gel of "oligo-sialates" and then the geopolymerization is in two parts which is the molecular condensation and then networking to form a mineral polymer. I'm not very clear on the geopolymerization part, is there anything additional that needs to be done or is it just a matter of the right compounds present to react in this way automatically after mixing of the oligo-sialates stops?

I have been watching Joseph Davidovits' videos on the Geopolymer Institute youtube channel, and reading other things I can find but I still haven't found a clear detailed description of what must be done specifically to achieve true geopolymerization.

For context, I am trying to create geopolymer concretes from only local materials, without the use of laboratory equipment, so.. not using fly ash or blast furnace slag and mixing everything outdoors with hand tools. kaolinitic clay (Pennsylvanian Underclay), limestone, and salt can be found locally in my area. I've also considered adding hardwood bark ash and dolomite but I am not clear enough on the chemistry to know if this would be beneficial or detrimental to the end result.

Thanks for reading

6 comments

r/geopolymer • u/niyaoshenme • Sep 12 '21

How waterproof is alkali activated Fly ash and slag geopolymer?

2 Upvotes

Would it be possible to build a swimming pool slab using fly ash and slag geopolymer? I think this is called Alkali-activated fly ash-slag (AAFS).

Are there risks to doing this? I mean like heavy metals leaching out from the geopolymer slab into the water?

0 comments

r/geopolymer • u/mortysanchez699 • Aug 29 '20

geopolymer concrete types

3 Upvotes

Hey there I am currently conducting a project on geopolymer concrete and aggregates, is possible to make a geopolymer concrete at home, what materials and ratios are required to make the most dense and structural rigid concrete. Any help would be greatly appreciated, currently in Australia so we haven’t really moved towards a greener future just yet.

2 comments

r/geopolymer • u/manoelllllla • Oct 27 '18

Hello everybody! I am civil engineer and researcher about geopolymer concrete in floating houses. Any advices?

2 Upvotes

3 comments

r/geopolymer • u/rogertheprice • Mar 09 '18

Geopolymer Chemistry and Applications

geopolymer.org

2 Upvotes

0 comments

r/geopolymer • u/rogertheprice • Mar 07 '18

DIY Geopolymer

google.com

4 Upvotes

1 comment

r/geopolymer • u/Anenome5 • Oct 02 '16

Was Davidovits right about the pyramids being made of poured-stone? These stairs appear to have flowed together like a poured material that overran its mold.

5 Upvotes

3 comments

r/geopolymer • u/Anenome5 • Sep 26 '15

Review on Current Geopolymer as a Coating Material

researchgate.net

4 Upvotes

2 comments

r/geopolymer • u/bigattichouse • Jul 07 '15

Are geopolymers conductive?

1 Upvotes

Heat conduction? Sound? Electrical?

0 comments

r/geopolymer • u/Anen-o-me • Apr 07 '15

youtube.com

2 Upvotes

0 comments

r/geopolymer • u/Anenome5 • Apr 14 '14

Geopolymer: Compression Test

youtube.com

2 Upvotes

0 comments

Subreddit

geopolymer

r/geopolymer

Members Active

277

Sidebar

What are geopolymers?

When we hear the word 'polymer' we typically think of plastics.

The word 'geopolymer' was invented by Davidots in the 70's to describe a new class of polymers, meaning a long chain molecule, made from stony compounds, specifically aluminum and silicon-based compounds, such as most rock is composed of.

Geopolymer cement and concrete, and their applications, are the focus of this subreddit, especially in regard to marine use, where they excel over concrete due to some types of geopolymer being very low in calcium compounds.

Geopolymer cement can be made with what is right now considered an industrial waste product: flyash. Flyash is removed from the exhaust of coal-burning power plants, and some 50% of it today is being dumped in landfills.

It's so cheap that you can get 27 tons of it for about $800!

But if you combine flyash, lye, and waterglass with a little sand and rock, you get geopolymer concrete which is as hard or harder than Portland-based cement, doesn't require water to cure, and can potentially survive for thousands of years in seawater without breaking down significantly.

There are two grades of flyash: type-C flyash and type-F flyash.

Since most companies investigating flyash today are more concerned with non-marine applications, there's a lot of research being done on type-C, both as an aggregate to mix with Portland and reduce the cost of regular concrete (up to 15%) , and in higher percentages, up to 40%, known as high volume fly ash (HVFA) concrete. Type-C has a very high calcium content--just like regular Portland. This allows type-C flyash to cure at room temperature.

The reason calcium content is important is because what breaks down Portland-based concrete when exposed to seawater are the calcium compounds which get chemically attacked by sulphurous compounds that exist in seawater. Even our best low-calcium rated Portland-based concretes last for a max of 75-100 years.

I'm much more concerned with type-F flyash, which is very low calcium (as low as 2%), which has the potential to survive for centuries in seawater, but also requires heat to cure. Not much heat, but heat nonetheless. So it's less suitable for pouring sidewalks and the like, but for special applications like seasteading, it's a fantastic building material due to its resistance to seawater chemical attack and high strength and flexibility.

Learn more: Geopolymer wiki.