How to make concrete green!

[@wigglewiggle3789]

Interesting. Having worked in the concrete industry for twelve years and I am also technically trained in concrete there is a concern I have here. Concrete only has compressive strength, it does not have any shear or flexural strength. In order to get compressive strength any air has to be worked out of it when it is being placed. So if CO2 is being injected into the mix I just wonder how much of that is retained in the mix when it cures. Also, believe it or not (in Australia anyway), there is no money in concrete. With competition etc there is no money in concrete. However big concrete companies own their quarries as well. This is how they make their money through what is known as the quarry pull through. The quarry side of the business makes the money the concrete side of the business doesn't and they act as separate entities. So for the concrete to make changes to existing infrastructure when they run at a loss, that will cost a lot of money is not going to happen. Concrete is ridiculously technical. There are 14000 different types of basic concrete. The technicalities are truly unlimited. Everything that goes into concrete effects they way it performs, different types of sand, stone, fresh water or recycled water even type of stone and the size and shape of the stone affects how it performs. Changing or adding anything to the mix and its ultimate long term performance would be on the minds of concrete companies and construction workers when it comes to building any sort of infrastructure. Fly ash is amazing for concrete, it truly is. When this stops getting used it will unfortunate. Fly ash behaves like cement when in the presence of cement but being a finer particle adds strength to concrete over the life of the slab. Essentially mixes with fly ash will just keep getting stronger essentially forever.

[@howardmoon1234]

Sounds like these startups are going to need to set up their own quarries if they expect to get off the ground? Thanks for the detail. Always important to understand the encumbered position to best assess path to change (if we even can…)

[@miavaughn2393]

At least from what ive seen, and this is mentioned in the video as well, co2 strengthens concrete. It chemically reacts with the concrete like concrete normally does over hundreds of years except all at once instead. Oxygen or nitrogen (atmospheric air) would create bubbles as the mostly nitrogen air we breathe is relatively non reactive so would by its very nature create bubbles instead of reacting/bonding. But how fast this process is and are there bubbles? Dont know. Only these companies know, but if their strength estimates are accurate I assume that means bubbles or air pockets aren't a problem. But massive amounts of testing needs to be done for any alternative to standard concrete as lives literally depend on exact specifications in the case of large buildings, dams, skyscrapers. Or just large amounts of money lost in the case of smaller buildings.

[@hanneskannes8209]

I see some problems with the CO2 injection as well. The reaction with CO2 reduces the pH level of concrete, so the reinforcing steel can start to rust. The bubbles might or might not be a problem depending on the planed properties of the concrete. It would depend on the size of the bubbles. If they are to small, the might get soked full of water and crack the concrete in the first winter. If they are just the right size, they allow the water to expand as it freezes. As you said, every new recipe for concrete needs to be tested before it is used.

[@rongo59]

@@hanneskannes8209 I would respectfully suggest that the major step that's missing is the testing of the new compositions. It's all very well to say "hey, I have a new formulation" but the existing formulation has been extensively tested (VERY VERY extensively). So I agree: it's not clear that we can just inject CO2 (or use a different kind of rock or any of the other things he mentioned) but it's certainly worth testing!

[@J4Zonian]

@Wiggle Wiggle Nationalization.

[@zzbloop]

It's important that we ask for these products when we build. Even if they are not available yet or too expensive it communicates the need.

[@johnorenick9026]

YES!

[@edlyop]

Nice update Dave. Once again the difficulty lies not just in invention of efficient/environmentally friendly processes. But also in the encouraging governments/manufacturers/consumers to invest/utilize these processes. Even if in the long run it benefits them and us.

[@GroberWeisenstein]

No . Better technologies move quickly especially if they are superior in practical ways. The last thing needed is incentivized technologies dependent on government's support and approval.

[@b_uppy]

It offers little utility for the cost whereas sequestering carbon into soil adds to water retention, fertility, food productivity, reduces water pollution, flooding as well as drought and heat wave effects. Adding carbon to concrete fails to add to its utility while possibly increasing its rate of degradation. Where is the benefit in that???

[@0525tharindu]

I think there needs to be shift in focus in the marketing of these products, that is specifically targeted to potential customer segments.

[@TheLosamatic]

It’s actually quite obvious with no country even willing to stop paying the subsidies to fossil fuels industry, the status quo insisting that no single weather event is caused by climate change, that’s BS! Since 2019 brought, to the arctic circle precipitation that more rain than snow, all weather events are caused by climate change to be worse! Words matter, all fossil fuels subsidies only to executives willing to live on barrier islands, in tents!🎉

[@dlorien7306]

@@GroberWeisenstein ok, goober, let's stop subsidizing fossil fuels then

[@philipbangerter1923]

Concrete & Cement are in everybody's supply chain. Pressure to de-carbonise by the customer (industrial & domestic) is the powerful force to move the conservative actors along the path. The codes/specs are a barrier, but only because the "forces" haven't pressurised this enough. It's a seriously big sector along with steel-making, so it deserves more attention from everyone. Thanks for the spotlight Dave.

[@jonbetts21]

25 years ago I was using pulverised blast furnace slag as a opcode replacement at a rate of 70% in ready mixed concrete. It was producing stronger concrete as the maximum strength was not being reached until after 28 days (concrete is sold bu 28 day strength) it could also be used to withstand class 4 sulphates ( heavy ground contamination by previous industrys) and was more resistant to chloride ion cream ( the concrete rot that allows steel reinfcing to rust) so saving 70% co2 is achievable today. Ps it would also be possible to completely replace OPC (ordinary portland cement) with a suitable alcoline liquid. Hence 0 co2

[@johnorenick9026]

Alkaline liquid? Sodium hydroxide is used to activate some geopolymer cements, which have no water in them, and admit none, after they set, set and cure faster--far faster, if you run a little shot of electricity through them at the right time--and can have (Blue World Crete) twice the compressive and three times the tensile strength. They're always alkaline inside, so they passivate rebar--no rust. And they just might last 1,000 years instead of 60.

[@PascalHartig]

You make 48 page marketing material so exciting. No sarcasm there! I would love to see a video where you show us how you create these amazing 3D zooms and highlights of what I assume are PDFs.

[@twotone3070]

I do a bit of video editing and I've assumed he uses some expensive software, something I cannot justify, to achieve the amazing results. These videos are just technically superb.

[@Johnrich395]

It’s interesting to see my work referenced in one of your videos. I’m working with Lafarge to use alternative waste material fuels, which reduce CO2 output by 20%.

[@J4Zonian]

@Adam Flannigan 20% of some small part of 8% is not enough for civilization & nature to survive.

[@Johnrich395]

@@J4Zonian I never said that it did, just that it’s interesting to see my work referenced.

[@J4Zonian]

@@Johnrich395 I understand. But perhaps I understated my case. I would have been more specific if I knew 20% of what? (call the what “x") All concrete emissions? Then it would be 8% of global emissions, divided by .2 = 1.6% of global emissions. If it’s only reduction of a part of concrete’s bill, divide by x & it’s some fraction of 1.6% of global emissions. We need to reduce global emissions by more than 90% in the next 9 years; that means reducing every sector by >90%. If any sector is reduced by less than more than 90%, other sectors have to be reduced by more than more than 90%. That’s extremely hard in 9 years. So enough of this crap (& I don’t mean yours, I mean the concrete & associated industries’ crap, which is typical of every corporation’s, industry’s, & government’s crap) about 20% reductions & imaginary 36% reductions... we need to reduce concrete emissions by >90% in 9 years. “There are no non-radical solutions left.” Naomi Klein

[@manninggrinnan621]

​@@J4Zonian Perfect is the enemy of good, everything helps

[@J4Zonian]

@@manninggrinnan621 The reassuring distraction is the enemy of everything, & that’s exactly what industry & the lunatic right wing offer. It’s ALL they offer. Everything helps if everything added up adds up to 100% of the change that’s enough to matter; if everything proposed adds up to 8% of that then everything proposed is not only utterly useless, but criminal, psychotic, & psychopathic. “There are no non-radical solutions left.” Naomi Klein

[@peterbaxter8151]

An excellent update on the new technologies Dave. Thank you.

[@alantupper4106]

An alternative that I've been poking at the napkin math for is utilizing magnesium combustion for the clinker kiln process. Magnesium burns incredibly hot, and will happily use the carbon dioxide emitted from a clinker kiln as its oxygen source. The remaining soot and magnesium oxide can be captured, separated, and the magnesium can be restored using renewables-driven electrolysis. Need to dive into the concept deeper, to be sure!

[@johnbash-on-ger]

Dude why not use electric heating directly? Direct electric heating is more efficient. Electric heating has no temperature limit, it's even used to heat plasmas to a hundred million degrees Kelvin in experimental nuclear fusion reactors. Why the extra, energy-losing steps with magnesium?

[@alantupper4106]

In this case, because the process of heating up cement precursors (like clinker) *emits* CO2 from the precursors. Using a exothermic process that eliminates the CO2 before it leaves the facility is a two-birds-one-stone option.

[@johnbash-on-ger]

@@alantupper4106 But magnesium minerals occur in the form of magnesium carbonate. The carbon dioxide emissions from the process to produce the magnesium metal means it's extra steps and less efficient. It's also possible to produce high-purity carbon dioxide gas with electrical heating and a separate pipe for capturing the emitted gases. Or are you planning to regenerate the magnesium at your facility? What process will you use?

[@alantupper4106]

@@johnbash-on-ger So, here's the potential path I see: There are several methods for regenerating metallic magnesium via electrolysis from magnesium oxide, which is the primary combustion product. These processes could be powered by renewables, creating a energy sink for excess renewables production. This allows for a circular fuel cycle, where the same magnesium can be regenerated an indefinite number of times. You are right that the processes for extracting natural magnesium resources do release carbon dioxide. However, using the same combustion process we're discussing here you could mitigate those emissions as well. The value I personally see with this process is it both works well with electrical systems, and it has self-reinforcing emissions reduction potential.

[@johnbash-on-ger]

@@alantupper4106 Okay using renewable energy to create a circular fuel cycle like that does make a lot of sense.

[@drdehailey]

It is only a small thing, but a person can capture CO2 using an aquarium and calcium hydroxide. They can let it harden and send it to the dump or mix it with cement to make decorative pavers. Like I said, it is only a small thing, but I need a couple of tons of decorative, cement blocks, so that's what I'm doing.

[@HansLemurson]

Where do you think the Calcium Hydroxide comes from? Generally Limestone.

[@walterrutherford8321]

I didn't notice any reference to polymer concrete which is stronger than Portland concrete, doesn't require limestone but can incorporate waste material like fly ash, and is more resistant to water, heat, and corrosive substances.

[@miavaughn2393]

This wasn't an alternative concrete video but ways to make concrete as we know it greener. But yeah that could be a different video with ferrock, ashcrete, timbercrete, and geopolymer concrete.

[@walterrutherford8321]

@@miavaughn2393And not that you can build with it most places but pykrete is an interesting building material.

[@Y.M.Cheung]

Good summary of recent developments in new cement.

[@Optimizemore]

Missed opportunity to revisit SaltX, that you talked about before. In designing their reactor to charge the salt battery they realized it can also be used to produce quicklime. "The technological innovation called Electric Arc Calciner (EAC) electrifies cement production with renewable energy, and the carbon dioxide released during the manufacturing process comes out as a byproduct - ready for sequestration." I think a combination of some of the technologies you mention should be able to drastically reduce the greenhouse gas emissions from cement needed in large scale applications.

[@pontswe85]

I was waiting the whole video for him to talk about saltx technique. Because I would really like to hear his thoughts about that 😁.

[@williamclark6466]

Thanks again for making such very informative videos! I truly enjoy watching everyone. I've missed quite a few and look forward to catching up on all the amazing subjects that you cover. Thank you! Thank you! Thank you!

[@JustHaveaThink]

Thanks William. Glad you like them!

[@PhiTonics]

Yeah, they call them bricks, a wonderful invention, thousands of years old. Seriously though, the oldest buildings in all the world are brick and stone.

[@chrismullin8304]

As a small time Contractor, I would and do, happily pay more for a more sustainable product!

[@robincross4625]

It is NOT the contractors! It is the Architects who write the specifications.

[@edward9674]

Thank you for this channel. It gives me hope for the future.

[@ramblerandy2397]

Superb video. I've long worried about the CO2 release in concrete. I'm beginning to realise that my environmental peace of mind is being upheld by your output, along with my own reading around world environmental issues. Many years ago I was a dyed in the wool environmentalist. I believed we had to curb our way of life, not just our excesses. I still do to a certain extent. I try to make a minimal impact myself. I'm at one Earth. There are plenty of people around the world who are below that. It's no accident that they tend not to be 1st World citizens. Over the years the general reply that I've received in conversations is, "...yeah, but I'm not going to wear a hair shirt to save the Earth [meaning habitat]", even though that remains a very good idea. This means that technology has to help save us from worsening world conditions. Whether it be from helping natural processes, or direct intervention, to putting up barriers to keep the power of natural events at bay. Besides, we're already well past the point where technology would not be required. 30 years ago we may have got away with just changing our lifestyles. Now it's really a case of bringing technology on. Obviously, carbon neutral concrete would be an extremely good thing. Starting now. Look for it in your local buiders when you do your DIY projects. And if not, why not? Thanks Dave. 👍

[@JustHaveaThink]

Well said Andy. Much appreciated

[@mikestraker2180]

Thanks for the update. Always learn something from you. Question... Your take on Geopolymers?

[@cinemaipswich4636]

A local coal fired power station has huge tailings of soda ash. When it was proposed to use it in the production of light weight concrete blocks, the polluter said "pay me". Even though it was waste, they wanted to squeeze every last drop of wealth.

[@thehotcorner3337]

Why wouldn't they. It is a feedstock at that point.

[@johnorenick9026]

Dave, there is a much better solution to the concrete problem, that you didn’t mention: geopolymer cements. Our infrastructure is crumbling because we built it with Portland cement, OPC, which inevitably cracks. Cracks let water reach the rebar, which rusts, expands, and breaks the concrete apart, in as little as 40 years: the Surfside. Florida condominium collapse was predictable. If we rebuild with OPC, our grandkids will have to do it all again, and the way we leave them our debt, they’ll still be paying off this rebuild. But the OPC industry-the largest on the planet-is already responsible for 8 percent of climate change. If we rebuild, and the developing world modernizes, with OPC, that will increase exponentially-as you said, China already uses 40 times as much cement as we do-and that industry alone will make climate change unstoppable. The concrete industry needs to go carbon negative, not save dribs and drabs here and there. Now would be good. Yesterday would have been better. Geopolymer cements based on aluminosilicates, not calcium carbonates, emit far less carbon when made than OPC, and some formulas sequester carbon as they cure. GPCs are stronger, much more flexible and resilient, far more fire resistant, don’t crack, are actually waterproof (OPC is not), chemically resistant, should cost less, and should last millennia, not decades; they’re essentially glass, not chemically-vulnerable limestone that’s always full of water. And we can clean up vast stores of toxic wastes, coal fly ash and steel-mill slag, making them; when we use those up, we turn to plentiful volcanic ash. If one geopolymer cement, Blue World Crete, is the super-insulation its designer, Daniel Panitz of Pompano Beach, Florida, says it is, I see a way (I’ve studied passive solar home design) to cut the cost of the shell, at least, of a super-insulated passive house, perhaps in half, building with it and bamboo (we need to be growing lots of bamboo). That house would keep its occupants comfortable with little or no outside energy, would be mold, earthquake, and storm resistant, would be so fireproof and insulative that it would be your refuge, your shelter, in a wildfire, and it might still be sheltering families 1,000, 2,000 years from now. I can show you how to build tornado-proof homes (Hobbit houses) with Blue World Crete. And I can show you how to seismically upgrade old brick buildings, strengthen them so they might stand a thousand years, and, with no additional labor or materials, to insulate, waterproof, fireproof, and air seal them at the same time. In BWC I see a solution to both the homelessness and the affordable housing crises: the world needs Blue World Crete, and Panitz seems to need help bringing it to market. I begin discussing it on page 254 of Pumping the Brakes on Climate Change: A Review of the Technologies and Politics that Could Leave the Future a Future, the book I’ve been working on for way too long now. PTBOCC is a literature review, with copious endnotes; getting away from OPC is vital to reversing climate change, so I spent a lot of effort on the chapter discussing alternative cements. You and your viewers are welcome to download a PDF at www.ptbocc.com , leave comments, and use my research to further your own. I will expect a full report on geopolymer cements! Just kidding. But, please. And BTW, the steel with which we reinforce concrete is 9 percent of climate change. Boston Metal (and others) will commercialize carbon-free metals smelting in just a few more years. I wish Congress would specify that our infrastructure be rebuilt with geopolymer cements and American-made clean steel-and where it’s appropriate, bamboo-not OPC and rebar from China. I don’t know how to reach them with that message. Anybody?

[@Gnefitisis]

I'm curious how much you talk is a commercial and how much is real.

[@hurrdurrmurrgurr]

While I'd like him to mention geopolymer cement vs portland cement vs hempcrete, the blue world crete you mention lists "proprietary binding agents" combined with "materials containing alumina sylicates" which means nothing. Keeping the recipe and production method secret might be good for business but it makes your product worthless for discussion.

[@itsrachelfish]

I came here to post this! I was so surprised that there was no mention of geopolymers in this video

[@erichv.300]

@John O'Recick There are some points, i would like to add to the first paragraph: The cracks caused by expanding (i.e. rusting) rebars are caused by carbonisation, an effect where invading carbon in the air gets into the top layers of concrete where it forms carbonic acid with the water in the pores or chemically bound water in the cement-matrix. This lowers the pH-values of the concrete. This is important because normal concrete has a pH of around 12. That ensures that the reinforcement bars are "passivated" - the water in the pores cannot cause any form of oxidation/rust of the iron. The carbonic acid negates the effects of this passivation, causing the rebars to expand and break concrete parts away, as you stated previously. The solution is a higher amount of concrete cover between rebars and surface. Most countries have guidelines for prevention of carbonisation induced corrosion of rebars - though i don't know about the situation in the U.S (i'm from Germany so i can mainly speak about german and european guidelines). So cracking up of outer layers of concrete because of expanding rebars is mostly a design issue. Concrete naturally cracks, that is correct. But if the cracks don't widen due to outer influences like invading and expanding water in winter or mechanical stress, the rebars are protected. Actually, some cracks sort of "heal" because of growing C-S-H (the reaction that hardens concrete actually never ends - practically it does not end for the time of usage of our concrete-buildings which is around 50-100 years) - but the margin is in the nm margin. The most critical point for the durability of concrete are the iron reinforcements - as long as they are protected from corrosion (for example, chlorine corrosion is another big topic) - the concrete is pretty durable. Corrosion, where the concrete itself is attacked [for example Alkali-silica-reaction; biogenic sulfuric acid corrosion (don't know, if this is the correct scientific term in English), or secondary forming of sulfate-compounds] can mostly be ruled out by design and composition. Another issue as mentioned before is of course mechanical stress. But this is the responsibility of structural engineers. Another point i would like to add to the second paragraph: the usage of toxic byproducts in cement is already standard. We use fly ash (from coal power plants), silica fume (production of Silicon and ferrosilicon alloys), blast furnace slag meal (iron smelting) and many other compounds that would otherwise be stored in landfills (in the most optimistic imagination of responsibility-thinking of the producers...). We actually have the problem (i again would like to mention that my report is based on the situation in the EU), that we have less and less fly ash and blast furnace slag meal due to the transformation to green energy production and the use of hydrogen-based direct reduction process in iron production (hope this is the correct English term...). Don't get my wrong, this is great for our transformation to a green future but actually bad for the environmental balance of cement and the affordability (as mentioned in the video). So to conclude: we need other materials, that have the similar properties like portlandcement based concrete (actually portlandcement, or CEM I in the EU, isn't actually the most preferred form of used cement - in the EU f.e. we mostly use CEM III, which contains around 80% of blast furnace slag). Geopolymers are a great starter, but also the better application of concrete like UHPC (Ultra high performance concrete) and better structural utilization (you would get nightmares if you knew how much concrete isn't actually necessary for a building to be structural sound...) other materials like timber, masonry, green steel or even clay are needed to get away from the concrete-heavy building industry. And the universities need to actually teach future civil engineers to use concrete in another way as a cheap filler if you don't want to calculate too much... And we need loads, loads of research in concrete, as we use it on the construction site basically the same way as 80 years ago, but with way more steel for reinforcement. Also the chemical processes of reaction of cement aren't even fully understood - giving me a chance to do research in that field. I hope i could add something helpful to your comment and extend the view of some on the issues of concrete usage. In the case my way of writing in english was some way of pleasant. Have a nice day!

[@joeblogs6598]

I think the problem with you environmentalists, is that you seem to think all these things cost nothing. " I wish Congress would specify that our infrastructure be rebuilt with geopolymer cements and American-made clean steel" Not only do you want the entirety of our infrastructure functional or not, to be rebuilt, you want it all to be made from sustainably grown unicorn horns as well. Sorry to break the news, but socialism doesn't work in real life, because it requires that people work for free.

[@NeilHarper2001]

Great stuff. There is also a UK Graphene technology that can be added to concrete and then used in a 3D printer to make large engineered structures with much less concrete for a stronger overall product. The company is called Versarien and they have a couple of products .... including one called Cementene. Might be an interesting follow up video 😎

[@raresmircea]

Very interesting vid as usual, great channel 👌

[@Nphen]

I think a lot of folks underestimate what local building codes can do for environmental building materials. If engineering codes are not updated for new materials & new types of structures built (Earthships are illegal almost everywhere in the US) then ecobuilding is a niche at best. If, otoh, cities, counties, and states update codes to insist on sustainable materials, and work with concrete producers, and timber & lumber industry, to produce a set of materials which passes building code, then we can leverage these materials to produce better buildings, sidewalks, trails, and roads. These same local political groups of people should be getting cities & schools to stop mowing lawns, buy electric buses, add bike trails, ebike grants, and road diets to reduce car traffic.

[@Richard_McDonald_Woods]

Very interesting, as usual😀 Many thanks Dave. It will be interesting how the new and successful concrete production methods can come together to optimise production. Increasing the use of wood laminates in building and the massive reduction in the need for automobiles with the introduction of EV taxis, and we will be living in a very much greener world. The future will be exciting, but I doubt that I shall be around to see it.😒

[@bjarkih1977]

Some negative side-effects of using a new type of cement can take decades to appear. So there's no wonder the industry is slow-moving.

[@zennvirus7980]

That's what happens when you've had a rock solid industry for decades. Too much inertia makes it very difficult to shift their mentality without fracturing the whole holistic system that exists around it. But it still has to happen, since, after decades of cracks forming within the industry due to its ever increasing climate impact, we are coming onto a point in time where we cannot allow the thing to set naturally.

[@bjarkih1977]

@@zennvirus7980 Tell that to a house owner whose house starts crumbling 20-30 years after construction. Or the government that has to bear the cost of a bridge that becomes unfit for use due to some material degradation. This industry has to be slow moving and careful.

[@jtjames79]

The technology of softening stones is finally being rediscovered. There's a theory that the pyramids weren't stacked they were poured. It actually explains how the stones were so precisely laid in the simplest way possible. So the ancients had a way of making concrete that turned into literally stone. There is a bird in South America that's figured it out too. They grab a very specific twig and use it to carve out nests out of solid stone. Basically Warhammer 40K's "rockcrete" isn't just a real thing, it's superior forgotten technology.

[@davestagner]

The negative side effects of pouring CO2 into the atmosphere can take decades to appear, too. The difference is we KNOW what will happen if we keep producing it.

[@jtjames79]

@@davestagner Some things just don't turn quickly. The cement industry is like a freight train, try to turn too quickly and it's going to derail, and then you're going to have a much bigger problem.

[@mikemarley2389]

A close friend of mine owned Barstow readymix in the 90s .He made a fortune with his invention of using hot water tanks in the winter in the high desert.I've used cement all my working life as a mason.

[@michaelbindner9883]

Brimstone's use of Basalt makes it the perfect process for lunar concrete,.

[@Mar-vu9nx]

Very good that your channel, is free of advertisement !

[@craigh8390]

G'day Dave, Thanks for your take on what is very much in my 'wheelhouse', moreover an important and significant emission contributor to global construction sector. Not sure if your considering other future follow-up stories where we could take a deeper dive into non-cement systems of concrete, but feel free to reach out if your looking for sources. I note you reference lost of sources, one of which is Joseph Davidovits and his body of work in 'Geopolymers'. There is a considerable body of literature which has grown within this area -- what I call 'low carbon concretes' so as to avoid some Davidovits controversy. Having said that, mainstreaming LCC use requires the removal of systemic barriers built within such tools as; codes; standards; and specifications -- all of which are important enablers to uptake in construction. Anyway, thanks for placing a spot light on theses issues. Genuinely enjoy your casual style and your evidence based channel. Craig Heidrich for Australasian (iron & steel) Slag Association, Ash Development Association of Australia and Australasian Pozzolan Association (just to mention a few Associations we manage)

[@philipbangerter1923]

Yes. I'd add my weight to that comment. Codes etc are definately slowing the uptake of Geopolymers. Is there a GP video on the channel yet Dave?

[@LucodeHome]

What about Geopolymer, even they aren't technically cement, they are a viable replacement for many use cases of cement.

[@thomasbernecky2078]

i always feel better after seeing these. Well done and thanks.

[@b_uppy]

People gushing without considering that they may bug e doing more harm than good. There is good ROI green tech out there but this is dubious at best. It fails to look at possible long term negatives such as acidification of concrete, etc.

[@mikeaustin4138]

Can concrete be recycled? That is, ground into powder and re-used? Could recycled concrete be bound with some of these emerging technologies to improve it strength, flexibility, etc.?

[@patrickdegenaar9495]

In the 1970s novel concretes and building methods turned out to be a disaster, with flats collapsing. So I suspect part of the hesitancy is evidence of longevity before builders jump in.

[@mikenco]

Their "30 years" just secures to comfort of the current management and shareholders... It needs a TWO YEAR target instead.

[@MrPincoNico]

Love your work. Keep it up.

[@yodaiam1000]

Is the acidification of concrete (with the injection of CO2) going to promote corrosion of reinforcing bars and decrease the life expectancy of buildings?

[@rogerkuchel193]

I'd be interested to know the comparison of concrete to hempcrete. Good vids mate. Cheers

[@gooseface2690]

For those who expected a tutorial, just add a bit green oxide powder to your concrete mix and voila! :p

[@thepeff]

My dad is an engineer and I feel like Dave does a polite version of what my dad always did: explain why things weren't ready yet XD I've always appreciated the candor

[@JustHaveaThink]

:-)

[@cameronmacdonald6525]

Why wasn't hempcrete mentioned in this. It's the perfect solution and has been around for years. It's stronger, cheaper, uses 80% less energy to be created, is a significantly better insulator, and absorbs CO2 for up to 25 years making it stronger and stronger every year. I honestly have no idea why we aren't all using hempcrete by now

[@oosconzult.8639]

Please 🙏♥️ can you do a video on geoploymer concrete production....?....

[@johnorenick9026]

Yes, please.

[@acccardone7679]

What about the concrete that the Romans used? That doesn't require heat, but how does its composition compare with other types of concrete's emissions of CO2 or other greenhouse gasses?

[@P.Ross192]

Hempcrete super interesting too

[@MichaelRada-INDUSTRY50]

Dear David, thank you very much for the next interesting thought. In the Czech Republic for a long time operated a company that provides technology to recover not activated cement from old, demolished buildings. At the same time I have to ask, why instead of investing in a reduction of consumption, all money goes only to keep it or even scale the volume of material produced. This on my opinion is a wrong direction

[@flex-cx9bi]

Can't see that SaltX have been mentioned. Their thechnology to completely decarbonize cement industry have been verified in small scale and seems to work just fine. Next step is to scale up and see if the business case also holds up... So the final solution for decarbonize the cement industry might already be here.

[@steverichmond7142]

We don't need cement/concrete or bricks. There is no need for any embodied energy in buildings or infrastructure. Build using SIPs on screw piles. Roads can be made cheaper using the original tarmac methods (compressed stones) but with a porous epoxy seal for a surface.

[@Rezac66]

Thanks for yet another video!! Have you heard about "Cemvision" in Sweden? Aiming for zero emission.

[@Leberteich]

When conventional cement sets, does it re- absorb the CO2 that was driven out when making the clinker (Ca carbonate --> CaO + CO2 reverses, Ca carbonate

[@chinookvalley]

HEMPcrete. What a great literally green product! There is very little info online about how WELL hempcrete works. There's plenty of naysayers, but let's look at how hempcrete could replace concrete!! Or we can stay on the road we are currently traveling and end the world for good. I hope Dave will cover this green product.

[@thehotcorner3337]

I don't understand the intense resistance that hemp gets.

[@matthewtalbot-paine7977]

0:55 this pie chart is important to look at electricity is 28% and transportation 29% The current solution for transportation is to make EVs but the problem with that is that while the transportation slice of the pie goes down the electricity slice of the pie goes up so realistically if we want all car, lorries etc to run on electric we need to realise that the electricity slice of the pie is 57% of the diagram and so it's importance is way more than the others and should be given appropriate levels of attention. That's not to say we shouldn't look at things like green concrete but they should come secondary to energy production.

[@J4Zonian]

@MatthewTalbot-Paine You’re right. But it’s too late to pick & choose. We have to do everything at once, as fast as humanly possible. We have less than 10 years before exponential increase in climate harm makes it much much harder to implement solutions, & the path to irreversible devastation that's more than civilization can bear becomes an inescapable rut. The endpoint doesn’t matter nearly as much as the area under the curve as we reduce emissions to zero. Emission reductions now are almost infinitely more valuable than reductions in 10 years.

[@philipandrew1626]

[9:54] Fly Ash is not harder to source. There are literal Fly Ash waste lands waiting to be utilised.

[@J4Zonian]

@Philip Andrew They’re by the sea?

[@philipandrew1626]

@@J4Zonian ha ha thanks for spotting the typo. Now edited.

[@timburn8293]

How about a programme on Hemp and its benefits?

[@MrPwnageMachine]

Construction industry will not change without regulation.

[@ChrisMorton]

You didnt mention self repairing concrete that contains bacteria that produce calcium carbonate when cracks occur. These cracks fill with water from rain in which bacteria grow, the bacteria then excrete calcium carbonate to fill the cracks and self repair.

[@EleanorPeterson]

"Concrete? Huh! What have the Romans ever done for us!" (Monty Python's 'The Life of Brian' reference.)

[@janami-dharmam]

romans used lime mortar, not concrete.

[@whatevil]

Think you made a minor mistake at 0:34 where you said that cement is made from concrete, but it's the other way around.

[@aarononeal9830]

Just have a think please talk about Ecosia they are a search engine that plants trees

[@wiezyczkowata]

what about hempcrete?

[@drpk6514]

What about using the heat from concentrated sunlight? In Australia a compony is going to use sun for heating iron ore instead of coal.

[@doncoon4154]

Please look into a product called GigaCrete. They claim to have a more long lasting product made at ambient temperatures that they use in conjunction with a foam core for a cheap earthquake/ hurricane proof structure that will last for centuries.

[@matusknives]

Very interesting, thank you for bringing this to our attention.

[@b_uppy]

This focuses on the wrong subject because it produces little benefit for energy used/carbon sequestered. It would a much better return on investment to sequester carbon into soil as this increases soil productivity, food production, increases aquifer recharge, increases soil aeration, reduces the need for irrigation, reduces flooding, drought and heat wave effects, pollution, etc. It can even reduce electrical grid strain due to the need for less water pumping/less electricity to pump water...

[@matusknives]

@@b_uppy please don’t hesitate to make a well researched and explained videos on that subject. However this video was about concrete, so I think you missed the point.

[@b_uppy]

@@matusknives Think you missed the point. The concrete has only one value gained by putting carbon into concrete. It may even increase harm by killing people into thinking concrete is the way to be green and increase its use. I am also concerned about long term strength of carbon in concrete as well as its acidification/breakdown. We may be shooting ourselves in the foot. Think there are better choices elsewhere. Hydrochar is great as it serves multiple needs. Carbon concrete serves corporate conglomerate interests...

[@JustHaveaThink]

Glad you enjoyed it!

[@Gwydion67]

These CO2-reducing alternatives, plus the substitution of cement / concrete by grown fibre materials such as wood, bamboo etc. as building material would add even more to a reduction of climate gas emission, plus even recapturing CO2 within buildings. This of course isn't new or rocket science (more of rock sience, pun intended 😉), but I just wanted to mention.

[@knight_lautrec_of_carim]

Why does the relative CO² emission of cement change all the time? In this vid it's 9% of all emissions, in another one (the one about strong timber possibly being a replacement for concrete) it's 15 and I also heard 20.

[@thewatersavior]

Metal shavings as binder... strength under fire? rust?

[@Larsbor]

It is so amazing how much damage the invention of the personal car have contributed with to the world all in all.

[@richardhill4938]

Geopolymers date from the 80's at least in the modern sense however both the Egyptians and the Romans produced geopolymers.

[@janami-dharmam]

if you want to use basalt instead of limestone, you will be needing a higher temp for cooking. also the resulting cement will set slowly (not so sure).

[@lisalaughing5355]

Concrete takes up some carbon over its lifetime anyways, is the process just beeing speed up or is additional carbon stored?

[@paulhaynes8045]

Very interesting - good roundup. Normally, I feel fairly cynical about such things, but this sounded quite positive. Unfortunately, later this week I have some bricks to lay and some fence posts to concrete in - and will be using normal cement and concrete. But maybe next time (hopefully some years away!) I'll be using something greener.

[@marccracchiolo4935]

This is all great as long as the finished product meets the specs for safety and longevity. If so I hope they accelerate its adoption.

[@glike2]

This situation just adds more support for the need for Active Climate Restoration, as the cement industry will be slow to change and hard to disrupt without a carbon tax.

[@J4Zonian]

@Gilles de Brouwer Probably impossible to change without radical action at the government level: removal of those in power from power; replacing them with sane people... The social cost of carbon is the total cost it involves, including the paid price, all the subsidies & externalities now & in the future. It’s what carbon taxes, prices & trading systems are theoretically based on & must equal to have sufficient effect. The real social cost of carbon is somewhere in the neighborhood of $250/ton. Almost every carbon price passed so far, or even proposed, is in a very different neighborhood-the neighborhood of clowns & mental patients between $1 & $15/ton. One or two very limited in scope have gotten up to $50/ton. Most are passed low to make them acceptable to the lunatics on the far right; raising them is sometimes built into the law or it’s claimed they’ll be raised gradually later. They never are. At least nowhere near enough even to keep up with inflation, let alone inflation on top of carbon inflation. It’s long past time that a carbon price can have any meaningful effect in time to matter. We need stronger resolve & more courage now. Sequestering carbon through forestry & permaculture is a crucial part of the climate solution. It can never come close to being enough if we don’t stop emitting carbon for energy, & industry.

[@JonathanSwiftUK]

I thought industry was short of CO2? Isn't it required in food packaging and elsewhere?

[@piotrwojdelko1150]

always well prepared

[@extraincomesuz]

Brimstone needs to start a plant in Florida to get houses rebuilt after Hurricane Ian.

[@nigeljohnson9820]

But what are the critical properties of these new chemical formulas for cement and how do they compare with traditional 'cement? How do these new cements set hard?

[@grahamalbert3805]

Great video Dave! :)

[@castlephoenixandsculptureg6467]

I wonder how much c02 energy is needed to capture c02 in the first place? Infrastructure and such

[@rickemmet1104]

Unlike hydrogen storage or some of the other proposed systems, this looks pretty straight forward to implement. Nice video, David!

[@incognitotorpedo42]

You could simplify the formula at 1:53 to CaCO3 -> CaCO + CO2. The SiO2 is unchanged, so appears to be a catalyst.

[@janami-dharmam]

SiO2 is not a catalyst; it reacts with CaO to form Cacium silicate and when hydrated, the product is a mess of interlocking crystals.

[@HighWealder]

Let's go back to building with clunch, adobe and wattle & daub.

[@ChipsChallenge95]

The exothermic reaction in curing of 6.6 gigatons of cement would produce 1.32 trillion degrees of heat. Which is 48,888x the temperature of the sun

[@JohnsonShoreInnHermanville]

Carbon8 is a CCUS for aggregate that can help green pourable concrete. It's a UK company. Thanks for another great vid.

[@petefletcher2993]

Someone needs to explain to the American the difference between cement and concrete, I'd love to see how a cement bridge works.

[@mynameisnobody5295]

What about Hempcrete? The biggest problem so far is that you need to mine Lime for binder. There are a number people looking for alternative binders and I have not seen any news on discovery. Hempcrete is not good yet for larger block but great for two floor building where large number of people live upon. Plans are carbon captures compared to releasing carbon underground. The biggest problem is that growing plants for production should not harm food supply. That where a previous video could help with tower of glass to produce building materials. You see so many high rise skyscrapers in US, but none of them are used for growing building materials. kzbin.info/www/bejne/eJ_GYqiAq7VkecU

[@shailendrajha8132]

A quick question regarding the statement at 0:34 ("cement or more accurately concrete that it's made from"): Is cement made from concrete? Or is concrete made from cement?

[@b_uppy]

Cement is the product you mix with water to create concrete structures. Hopefully that's a concrete enough answer for you.

[@janami-dharmam]

concrete is cement plus stone chips. the cement is the glue and the stone chips are the strength. If you put iron bars or rods in the structure, you get RCC (reinforced concrete cement)

[@chrisvincent8123]

It is the latter. Cement is basically the glue that holds the added sand and gravel together to make concrete.

[@firstlast-cs6eg]

So with the versions that have CO2 injected in it, how is that C02 collected and purified in the first place?

[@anneeq008]

The best replacement is hemp 👍

[@johndododoe1411]

Are any of these inventors working with the companies that supply the machinery and designs of cement factories, such as the much maligned F. L. Schmidt company? If the next generation of cement factories produce the raw cement with much less net emissions, It'll have a huge effect on global emissions compared to new experimental factories trying to break into an established industry.

[@mudandstars182]

CarbiCrete 2kg of co2 captured per concrete block - how heavy is a concrete block?

[@stephentroake7155]

I don't know much about geopolymers, but wondered if they might be worth an episode of their own. I've just seen a video from the Geopolymer Institute which I'll add as a separate comment in case KZbin thinks I'm being a naughty boy.

[@stephentroake7155]

kzbin.info/www/bejne/jabIdHirqZakg7csi=QwybS9dkwgQs6A85

[@simonpannett8810]

Problem of planned economies always overproduce until a crash as so much oversupply.

[@hemayethasan3723]

Design glitch in esp is the main reason for high carbon exhaust

[@vhulheim]

The bigger problem is the shortage of sand - and how mining sand damages the environment. For more info read: The World in a Grain: The Story of Sand and How It Transformed Civilization by Vince Beiser

[@KarryKarryKarry]

Just a clarification; Concrete is made from cement which is made from burning limestone. Just figured you’d want to sticky this considering your fumble in the beginning of the video 😊

[@davestagner]

At the end of the video, he talks about Brimstone’s technology that doesn’t involve limestone at all, instead using calcium silicate rocks. So maybe at some point, limestone will no longer be part of the process most of the time.

[@KarryKarryKarry]

@@davestagner I was pointing out that he said cement comes from concrete which doesn’t make for a very good introduction nor a factual one. Kinda thought more people would have picked that one up by now… It’s really not a good look if you want to be a science communicator.

[@RolanTheBrave]

I bet this is Daddy Pig's favourite episode of the show ..

[@theharper1]

Even back in 2004, I saw huge motorways and vast walls of 30+ storey apartment buildings all built with concrete in Guangdong. The amount of concrete being used in China was mind boggling.

[@eriktempelman2097]

Good one. Nu #1 addition to make is this. High quality concrete, line all structural materials, has become a lot stronger in the past decades. Plus, we have had incredible improvement in CAD tools. Both combined allow us to save huge amounts of weight, yet deliver the same structural functionality.

[@b_uppy]

Hempcrete has a problem in that it is made from a water-intensive, annual plant. It still uses the base product of cement which is where the problems arise. This ignores that we need to replenish carbon to soils to increase crop yields, reduce flooding, drought and heat effects, improve soils, etc.

[@macmcleod1188]

Concrete is weird. I watch the hydraulic press Channel and concrete in the past was much stronger in all directions. It was over designed a bit. Some older concrete took 20 tons of pressure to break which was ridiculously Beyond modern concrete. It seems like it was pretty close to solid rock. They also compared bricks and the bricks today we're weaker in two directions but stronger vertically. Experts in the forum said this is because modern bricks have air bubbles in them to provide insulation. However I will also put on my skeptical hat. Outside of licensed legally controlled engineering, cost cutting in modern business is relentless. Some concrete structures in China used bamboo instead of Steel rebar. This was found out when it failed.

[@b_uppy]

@@macmcleod1188 You've shared some interesting bits. Think there may be some implied incongruencies, however.

[@jims6498]

yes and wrapping old concrete with carbon fiber was obvious solution for encino bridge pulverised saturda night instead with no more safe passage over now you have to climb wall and dodge ten lanes of 80 mph traffic. this is on the 101 with claims it costs 20,000,000 to walk over the traffic but obviously pedestrians can get across for much less although the ramp for wheelchairs will b emost expensive and probalby cost over half a million to remove needlessly It's insane they can't put ladders but can put nothing now. i've seen the ban on ladders cancel other bridges but never seen a cost no object funding get shot down by ignorance There is land that is public now free for shade, drinking fountains, electric outlets powered by sun or at least usb c or induction charge plates some nonprofits needs to run a drone across for packages and help those denied a bridge stay safe on these two former ramp pads. the thickness of that 1950's walk surface was insane! How many bridges are not taller then 14.5 feet?

[@troychampion]

*"the concrete it is made from", ... cement is not made from concrete, rather the concrete is made from cement. I am just sayin', you got that one backwards.