It doesn't matter that there's not enough waste to replace all of the concrete use in the world. We just need to replace enough to make an environmental difference. If we use up all of the waste products available to make this stuff, we will not only drastically reduce concrete, we will have cleaned up all of those other messes! What's not to love?

I work at a steel plant. The slag is heavy. So much so that we smoked a cement truck trying to use it to make some of this stuff. We had a hose spraying the radiator to try to keep it cool. Not an insurmountable problem just need more powerful better cooled equipment.

Great presentation. I have worked on Fly ash based geopolymers and found interesting results. Every advantage you discussed is observed in the geopolymer. Now I am working on waste glass geopolymer, where we don't need Sodium silicate and also a low concentration of NaOH is required. Once standards and rules are established, I think geopolymers will be the future of building materials

Would you consider doing a video on cost/benefits of historical preservation versus tear-down/new building construction? At what point is a building too far gone, or it’s purpose too inefficient to preserve? What are other ways of preserving buildings while also accommodating contemporary community needs? I remember a sky scraper on Sansome Street in San Francisco that preserved pieces of the street-level facade, while replacing the entire original building with a new skyscraper. Love your videos!

There are almost no more available Fly ash or slag (GBFS) in the European market, as it is already in use in cement and concrete. In many ways we already have a semi-geopolymer concrete in the market. For instance, in the Norwegian market the standard cement has 20 % fly ash, and another has 70 % slag. Yes, Geopolymerconcrete will be more common, at least in some more specific applications, but it is still much more important to reduce environmental footprint from the ordinary portland cement production.

Greatly explained :), And also the scanty supply of source materials for Geopolymer concrete synthesis you talked about is a major Impediment to its large scale applications... Thats exactly what we addressed in our research here at National University of Sciences and Technology, Pakistan, We replaced fly ash with newer source materials i.e. agricultural waste ashes (they are also rich in alumina and silica and thus conducive to Geopolymer synthesis) We found that strength remained intact for upto 15-20% replacement level

I suspect a more significant barrier to replacing Portland cement than manufacturers is that architects and engineers want to work with proven materials.

Hi, geopolymer fan here. I would like to add that one of the most common raw material for geopolymer is ferro-kaolin (an aluminosilicate source). They could be used to make ferro-sialate geopolymer. They basically exist everywhere. It's not the aluminosilicate that is rare, but the alkali metal that is crucial for the chemical reaction. There's only so much salt in the world and producing sodium hydroxide in the scale required to make geopolymer as common as ordinary Portland cement is just too expensive. But researches have shown calcium in ggbs form can substitute some of the sodium/potassium in the reaction, and 1 atom of calcium can replace 2 of them. So it IS possible for geopolymer to replace Portland cement. And sodium hydroxide is rarely used directly on site if you are talking about commercial products. Any geopolymer mix designer that is aware of the danger of NaOH should have design safe and ready to use solution of sodium silicate or potassium silicate

As someone who had permanent eye damage from sodium hydroxide burns, yeah, the liquid component of geopolymers is nasty stuff. That the activator is a corrosive liquid that requires separate packaging is a logistical hassle, too. Caveats aside it's a useful engineering material that can be applied in certain niches. As a spray-on foam fire barrier it's hard to beat, and combined with construction methods like monolithic domes and non-metallic tensile reinforcement like basalt rebar, can make long-life low maintenance structures. A monolithic-geopolymer-basalt dome could probably last longer than the Pantheon.

The biggest drawback is that fly ash is radioactive, you would be building structures that produced massive amounts of radon gas. My company looked at using fly ash back in 2007, we went with other geopolymer mixtures, steer clear of fly ash.

Thanks for the heads-up! 🙏🏽 💪 Maybe Geopolymer cement can also make infrastructure (e.g. bridges and skate parks) more affordable.

Hey Belinda, Your videos are really informative. Yes Geopolymers are really versatile material. I am an architect doing research in the subject. I've been to the Geopolymer Institute in France to attend GP camp in 2018 and had interacted with Prof. Daviodovits. The potential in India is immense as we still have coal power plants, but I think suitable thermally activated Aluminous and Silicious materials can be found anywhere in the world. Some of my friends who attended the camp in 2018 are experimenting with bottom ash of incerinators. Portland cement has been, over the centuries, standardized. GPC is still very new in that respect. But I am sure that standardization will happen. I recently came across a paper from Arizona University which explored the total replacement of virgin aggregates in GPC. The developments happening all over the world in this field is really exciting. I think you should do a video on other uses of GP like LTGS for making stabilized soil blocks and high strength ceramics using GP - both lesser explored possibilities, especially the ceramics.

Interesting presenation Belinda! What is the cost of geopolymer concrete compared to conventional concrete?

The long term durability of roman concrete apparently involves the use of volcanic ash which reacts with salt water creating a harder material. The fact that this sort of chemistry isn't used to reinforce the concrete that we use is kind of silly. Granted volcanic ash is hard to come by unless you're near a former volcano, the fact that simple and basic chemistry isn't used more often is interesting. Simply because we'll do stuff like taking steel rebar and dipping it in plastic in attempt to prevent galvanic corrosion, but ultimately end up exacerbating the issue even further by focusing all the corrosion in specific points.

Definitely sounds like it would be best used in the applications it most excels in, to the extent that the relevant waste streams can support, rather than as a general purpose concrete. Perhaps some of the businesses already in the industries that manage those waste streams could be given tax incentives to make partnering with the businesses that utilize those byproducts more lucrative and cost effective than just letting it sit there. Sometimes it just takes a little grease to get the wheels spinning in a new industry, especially when it encroaches a bit on the territory of an old industry. Great topic, editing, and presentation - really like your shirt, too!

There is no question that humanity will have to manage their resources better if we expect to remain on this planet. What a nice summary and introduction in the pros and cons of geopolymer's. Last year I discovered Polymeric paver sand and just loved what you can do with it. By framing my paver patter, adding colored stone, brushing the sand between the gaps, sweeping off the surface and adding water, can create some artistic designs, such as walkways, that are not only lovely to look at but are waterproof and will last for years. Thank you Ms. Carr for your presentation and insights in this emerging technology. Nice job!

I wouldn't worry much about sodium hydroxide. Portland cement is plenty caustic as it is. While using SH to dissolve silica into sodium silicate happens at very high pH, the product is not. I definitely understand that as we (hopefully) move away from coal/palm oil and toward more sustainable renewables the raw materials for geopolymer will also decline. I'm not an engineer, so I never factor concrete for tensile strength. I'd be interested to know just how different geopolymer is in this regard. Fly ash is nasty stuff, but I can see it being used for applications you mentioned like sea walls and road beds. Thanks for bringing up the topic. 🙂

I firmly believe it's not the materials, it's how we've chosen to use them and our lack of adaptability or willingness to change. Your videos are fascinating and I always learn something. Thank you. :)

Fly Ash is usually used in northern climates instead of salt during the winter. Fly Ash was used in IL. in the 1970' & 1980's. Using Portland cement & aggregate ( sand & rock) can be poured in all the types of weather. I have poured concrete in the middle of winter in northern IL with no adverse effects. Concrete is a better way to pour highways, bridges, & over passes than asphalt.

It is an intriguing concept, and does seem like an opportunity to mitigate the environmental impact of concrete somewhat, but the availability problem definitely limits how much we could invest in it as the future of concrete, particularly since one of the sources of waste material are coal power plants, which are just another environmental issue that we want to scale down rather than up.

Thank you so much for the expertly crafted content! You're brilliant at conveying complex topics and I appreciate above all your commitment to earth-conscious engineering.

I really appreciate your time and effort to objectively talk about the pros and cons of various building materials. Very informative. Thank you.

I've also thought about the blocks on the pyramids being poured-in-place as opposed to mined from a quarry. It makes sense, considering the weight of each block.

When adding waste materials to concrete mix, is there any concern about volatile chemical off gassing that would endanger inhabitants? And how much of these specific waste materials do we actually produce in the associated industries? How much concrete could we make with our existing production, as compared to avail cement?

There might actually be cause for some concern with geopolymer cement, the long life span might mean the particulate formed from the natural erosion gpc might become a breathing hazard and impossible to clean up if adoption reach the level of Portland cemen. Just a conjecture on my end though

Looks like these waste products come from processes which also need to be heavily reduced or eliminated. 1. Burning coal is maniacally bad. 2. The process to get metakaolin are very energy intensive itself. 3. Slag has the same problem, though steel production seems unavoidable. One barrier is that it has many other useful applications. 4. The environmental problems of palm oil production are well documented. I also hope that we learned from biofuels that competing with food is not such a great idea.

Great presentation. I have worked with Geopolymers and I know that material have many advantage versus Portland Cement, I think geopolymers will be the future of building materials

I'd like to know how to make and use geopolymer cement at home!

Thank you for showing the negatives along with the positives excellent video I appreciate the hard work very educational

Definitely would like to have a better understanding of costs (knowing that economies of scale would control or reduce cost eventually). Seems like there are enough current applications where it could continue to prove itself as a great way to use waste materials. Thanks.

Thank you for sparing us from the surprisingly complex chemical details and using a quick summary instead. I’m particularly interested in the fire resistance and insulating qualities of the air containing formulations. We really need non-flammable alternatives to traditional construction materials like wood and pvc lumber. Fire danger is increasing ever year and it’s become a surburban issue, not just a wildland-urban interface problem. Blowing embers can go anywhere.

I find the subjets and the manner in which you present them to be very interesting and pleasant to watch. All the best to you and thank you. Dave & The Girls

Magnesium Oxide is the most significant cement in history. It should be mentioned as a geopolymer. There is more than enough of it to replace Portland cement. It is non-toxic. It has fabulous properties. It probably deserves a month's worth of episodes.

This video really cemented the point

This is the single most important topic on the table today, with relevancy to every human on earth. Thank you for posing such a concise explanation, of the technical aspects. So I must interject, that while Potassium (K) is usable in these equations, this is not a wise use of Potassium. Sodium based Geopolymer is just as good as Potassium laced GP, and conserves potassium for use in Agriculture. The use of Geopolymers is predicted to grow exponentially over the next decade. If we do not, there are going to be some serious short term and long term health issues for all humans. Over the last two decades, the worldwide average Oxygenation level (expressed as an overall percentage) has dipped over 1%. This is due in large part to the release of CO2 during the creation of Portland Cement. I propose a mandatory moratorium on construction projects which require Concrete. if we take a break, and then limit the total amount of Concrete which can lawfully be produced worldwide, we will have a solution. This requires a massive international effort, drastic steps, and severe economic and legal consequences for individuals and organizations whom will inevitably skirt the laws. Personally I can tell you without batting an eye that China is out. They will likely never fully modernize, until long after it is too late. But the rest of us can use this GP as an intended Gift from above. People need to begin to think in more sustainable context. The widespread new construction wave that has spread worldwide is choking the air, polluting the water, and causing material shortages in every market. Next year over 20 Million people will die prematurely due to chronic lung conditions caused and exacerbated by poor air quality, smoke, contaminants, and low Oxygenation levels. This could have been prevented if Davidowitz's theories had been properly pursued in 1979. It is a truly shameful state of affair, that corporations are permitted to shape the course of humanity. Even worse that they choose to ignore their responsibility and pursue deadly policies of using toxic garbage to manufacture the fake reality we have become trapped by. As a Construction Inspector and Energy Consultant in Southern California, I spend half my workday on construction sites. This week alone I have been out to over 40 sites. I am witnessing the use of GP in decorative and non weight bearing applications already. In fact many builders are using "GP mix kits" purchased online to make Fake Granite, Faux Marble, even Synthetic Diorite. My suggestion is that Builders mix fly ash, slag and waste ash together to make a contiguous mixture which may be easily replicated in the field. Fly ash can be added to conventional Portland cement to stretch the recipe. This was common practice until more research was done. So, it turns out Fly Ash and slag benefits the overall mixture considerably. The addition of ash to cement increases strength while also adding moisture resistance, it lowers the heat of set, increases plasticity and decreases the water need. The result is a concrete that is harder, stronger, more water tight, and requires less to create. In Southern California we use 13% Fly Ash by weight. This mixture is a level which was agreed to by many parties, regarding many factors including cost, time, and usability. However this is just a drop in the bucket. Lowering demand is the long term solution to the concrete problems. No matter what certain products will have to be made from scratch, even with GP. So we have to change our thinking about what is and is not necessary to build. If we do absolutely have to build something, maybe we can scale it down a bit. DO we really need more lanes on the freeway? How about going to work from 10 to 7 instead of 8 to 5? Little things add up...

One of the interesting ideas Bucky Fuller came up with was prestressed concrete for highways. Bolted together on substrate. It provided better performance and easier repair/replacement. I’m wondering how geopolymers would work in this environment?

I just saw you featured on Vox channel, so proud your channel now hits 200k subs! On your way to a million soon. Go strong girl!

You have an amazing channel! Keep up the good work! And yes the Pyramids are always interesting.

Production of the waste materials currently used for making Geopolymer cement is in rapid decline for good reasons. Has any work been done on finding an alternative primary source of silicates and a process that is scalable and environmentally sound?

You provide such great material to your viewers. I appreciate all the hard work you put into it. It's a truly wonderful channel!

a video on historical geopolymers used in south and center america would be lovely

Just like Belinda mentioned, it does sound good, but it's made of ingredients which all come from industrial waste, which means the suppy of it is limited by how much can you get. However you can get cement anywhere, just do a little digging, do a little burning, and a little mixing! I can't imagine my country getting Metakaolin, and we don't have coal power plants here to get the fly ash.

I like the idea of light-weight concrete for a residential roofing alternative rather than asphalt/petroleum, as asphalt roofing has a limited 15-25 year life-span before it needs replacement. I know there is metal and ceramic roofing but I like to know we have other options.

What is worth to consider it that cement manufactureres such a CEMEX are incorporating more and more waste materials into their mixes, the concrete then still fits into standard regulations and behaves similarly. Meanwhile it still gains some of the advantages geopolymers have. The content of portland cement in cement is therefore sinking. I think in europe we have seen a supplementation of 25% in the last 15 years, at somepoint as Belinda mentioned the supply of flyash etc will be exhausted.

Maybe lobby large retailers like Menards and Home Depot to carry it for small scale residential use. As an engineer the concept is very interesting. Anything to reduce landfill usage. On that matter I believe we should burn our garbage to extract the energy as opposed to landfilling it.

Love what you Belinda. Don't stop. I only see quality on your channel.

The Romans are probably scoffing in their graves seeing us still trying to figure out concrete that can last 1000s of years

I love the idea that the pyramids were made ingeniously and not just out of impossibly hard work.

Excellent presentation! I always learn so much from watching Belinda Carr's videos. I think the Canadian company Plaex is using this type of product in their composite block system.

I would love to hear more about the geopolymer theory of pyramid production - it sounds really cool!

Your speculation that Portland Cement manufacturers will fight this move to a more environmentally responsible product is 100% correct.

Great feature as always Belinda... thanks for this!

excellent presentation Belinda......very informative ...well done young lady!!! bravo!

Really great video. Had never heard of geopolymer cement before. Sounds like a really enticing material.

I have done my research in MUET, Jamshoro Pakistan on geopolymer concrete by using local NaOH as alkali activator instead of using laboratory grade NaOH since it is very costly and less market supply as you discussed in this video. The results i got from this research were seem very good as compared to conventional concrete.

Yes please, A video on geopolymer pyramid building.

Your voice over work is EXCELLENT!

Perhaps Govt incentivised initiatives under waste reduction/recycling could require that this material be exclusively used in Govt only projects where tax breaks can also be given to raw material producers within reasonable proximity to projects. That way, the Govt is playing the role that it should really play; doing the right thing in the interest of the future and its people.

In terms of things like fly ash, there are significant inclusions of radioactive and other problematic materials such as high arsenic and mercury compounds. What's the purification process for this (e.g. do they remove the toxic materials)? As well, has anyone done a material degradation test in terms of use in roads and other high-abrasion situations where geopolymers are ground down from their original construction and leach into the environment?

Waste salt for waterproof building materials by Israeili University is being worked on. Plus Eric Geboers and The Salt Project needs waterproof coating material that should be available made from algae or existing chemicals.

You're thumbnail intrigued me enough to not just scroll by. Then i realized it was you. Been loving the videos. Hello from Long Island NY 👋🏼

Ive subscribed to your channel because of the fine amazing construction information that is provided. Thank you Belinda

Sounds like similar materials to glass- this would pair well with basalt rebar. Since basalt is essentially a glass fiber stronger than steel rebar per weight (basalt is much lighter), constructed wall and deck thicknesses could be much thinner. This in turn would mean every 3 tons of cement could be displaced by just 1 ton of geopolymer. Skyscrapers, bridges, dams, large public works, should all be the ideal target projects. How about desalination domes in the middle of the Sahara, and giant aquaducts linking Mauritania to Egypt. Such a project to green the Sahara could end poverty in northern Africa, providing a backbone for a linear city and ending world hunger with adjacent agriculture land watered with solar distilled seawater, despite global warming. Any potential for a translucent geopolymer?

There is always a problem with using waste products. Say we replaced all cement with any industrial waste stream. That waste stream will never be large enough. It's the same as burning waste frier oil in vehicles. It worked great for the first couple of people. But really quickly that "free" oil stream went completely dry.

Have you ever heard of volcanic mud? There's a Polish professor Janusz Mikula who led research on a different geopolymer as an ideal building material. The volcanic mud when cured, hardens to the strength of granite and is highly insulating.

I too would be interested to hear of further evidence of this approach being used in the pyramids. It would explain a lot of things but I am a solid sceptic, mainly to due the chemistry involved. That said, I am perfectly willing to have the scales fall from my eyes if the evidence supports it.

So if geopolys were used in Florida, even with the leaks etc, the base structures would likely have remained intact or would not have failed as they did because of regular concrete.

Coal ash? So the idea is to take a toxic waste product that nobody wants, sitting in special landfills around the country, loaded with radio active elements, heavy metals, and add that to my foundation or slab? Why don't we insulate with some asbestos residues for good measure, can't wait to invite the grandkids over. PS: I do like your videos.

Would love to see more tests on geopolymers. Maybe talk to a few manufacturers, see current projects, etc.

1. You may wish to explore Basaltic Fiber rebar, reinforcement bars made from fused bundled fibers drawn from melted basalt. This type of rebar does not corrode, so when water penetrates the concrete the rebar does not expand from rusting, thus eliminating or greatly diminishing one cause of failure of modern concrete. 2. Yes, a video on the theory of cast geopolymer stone in construction of some of the pyramids would be interesting. However you may wish to take note of the remains of a form of windlass and of what is called Petrie's Cradle. With these devices many of the stone blocks could have been rolled into general position. Quite possible that several types of methods were used. Interesting.

Thank you for vid, i used to follow Davidikus always wondered how the limestone blocks they made a few years ago in paris are doing. Could be another part of your Egyptian themed video. Take care

Good information. Never heard of this material before now, sounds promising. But one thing you didn’t touch on, if you did I missed it, is the bottom line. What is the cost? I’m thinking about things like spray foam insulation. It’s super to almost all other insulations, except it’s cost prohibitive in most cases, so it’s not widely used. This material, how much does it cost per yard? How does it compare to regular concrete?

Yes, that would be an exciting video about the period the pyramids were built.

I’m curious if cementitious “green” wall systems like SIREWALL or other products with carbon mitigation/offset targets will pivot to using geopolymers vs Portland for their binders. Cement seems to be the big BUT when looking at the sustainability of these solutions. Plus, their goals and scale may position them in the ideal market for geopolymer cement as opposed to more commercial manufacturers focused on consistency, availability, and bottom line.

YES ! Egypt pyramids for sure , a worthy subject and an interesting one too ! ---- a big THANK YOU for all your quality work , KEEP SHINING , KEEP SMILING & KEEP SHARING THE KNOWLEDGE --- from Canada J.

Definitely make a video about the theory that Egyptian pyramids were made of geopolymers. If you touch on or go deeply into other possible sites using geopolymers so much the better. Fascinating.

really enjoy this educational video, this sounds like a no-brainer for a lot of different applications, if not all.

A brilliant use of a waste product/s, that said we should be looking at the cause, the originators of the waste and finding alternatives that don’t produce the harmful waste products.

a few years ago someone in Australia tried to source Fly Ash to manufacture Geopolymer , Within 2 months Cement Australia and Boral got wind of it and set up a new company called Fly Ash Australia , They were the biggest names in Cement and Concrete so now they control that whole market. :(

Enjoyed your presentation, thank you very much.

We had a project in engineering on geopolymer, The mixture should be balanced otherwise it will bulk.

There are huge rose granite statues in Egypt that couldn't possibly have been carved out a single block of granite and dragged to the site, lending credence to the theory that they were actually cast out of crushed granite stuck back together. But we don't have the recipe. We credit the Romans with inventing cement, but it's possible they got the technology from earlier civilizations, like the Egyptians.

It's funny because we don't really need all this concrete do we? We could just have a curb and fill it with crusher fines or dirt or wood mulch, but then you'd need a bunch of people with brooms or machines to constantly sweep roads and stuff and maintain the paths, since a lot of concrete is used for foot paths like sidewalks. Also we could make bricks and have paved paths of brick, or stone could be used if there's a way to cut it to size easily like with a water jet, but then somebody would have to create all those supply chains and production that concrete already has. I hope we see more of this geopolymer is used in the near future

Recently there is also Ferrock a mix of Steel Slag & Crushed Glass powder what I like about ferrock is it doesn't look like gray concrete it comes out many shades of iron reds and also sometimes layers turn out to be black

Belinda should do one on hemp crete. Very sustainable and can reduce not only water consumption but has a net zero carbon emissions. I would love to here your pros and cons on the matter.

Wagner's - developers of Wellcamp - have been in polymer cement for years. They also manufacture fibre reinforced plastic cross arms for power networks.

Fly ash has long been added to concrete. When Jeffrey Energy Center was build unit #1 was in service when concrete was being poured for unit #3. They mixed fly ash from #1 into the concrete for #3.

Great presentation,I would like to hear about Quantum Mechanics next 😊

Yeah, I think a video on the pyramids and geo polymers would be a good one.

What about sea-crete, made from electrically charged nets in ocean water drawing and solidifying carbonates? If it can scale, it is a huge carbon sink, itself a suggested method for carbon sequestration.

Geopolymer cement sounds like a product that can and should be integrated into construction projects instead of using portland cement for all applications.

Interesting. And very interesting theory that the pyramids are build from cast blocks and not natural blocks. Could be very interesting to dig deeper into that.

Geopolymer institute is a great resource

Why does every one forgets that geopolymers are basically aluminosilicates which apart from industrial waste, aluminosilicates makes up 80% of the earth crust. You can make geopolymers from literally anywhere. Well, even on the moon

You're a really good teacher, thanks!

im all for it, use the stuff as much as possible!

Thanks, I enjoyed the video.

It looks like it can be pumped. I wonder if it can be sprayed like gunite or shotcrete? If so, it seems like it would be far superior to gunite or shotcrete for swimming pool shells.

Additional things to think about with fly ash are the minor constituents depending upon the specific coal bed composition but may include one or more of the following elements or compounds found in trace concentrations (up to hundreds ppm): gallium, arsenic, beryllium, boron, cadmium, chromium, hexavalent chromium, cobalt, lead, manganese, mercury, molybdenum, selenium, strontium, thallium, and vanadium, along with very small concentrations of dioxins and PAH compounds.[1][2] It also has unburnt carbon.[3][4]. Source Wikipedia

Brilliant, thanks, I knew nothing about this and that's pretty rare when I've never heard of something