Zero Emissions Cement is Closer Than You Think

Concrete is the second-most-used substance in the world after water, and it's responsible for 8% of global CO2 emissions.

But, what makes concrete so indispensable and strong? The secret ingredient is cement. Cement is what binds everything together and gives concrete its strength – and also where most of the emissions come from. In 202, more than two and a half billion tons of CO2 were released from cement production. While cement in concrete can be recycled, the demand far outstrips the amount recycled each year, which means we have to produce a lot of fresh cement.

There are things we can do to limit how much we use, but because developing countries are using increasing amounts of cement to build housing and infrastructure to improve living standards of their booming populations we’re going to need more and more each year for a while yet. That means we need to find a way of producing it without the emissions, and unfortunately cement-making is likely to be one of the most difficult sectors to decarbonize.

But though it’s difficult, it’s by no means impossible. In this video we’re going to take a look at how traditional cement production works, where the CO2 comes from in that process, why it’s so hard to get rid of, and how we can make cement without CO2 emissions. I’m going to try and make the abstract concepts a bit more… concrete.

Bookmarks:
00:00 Intro
01:29 Laying the foundations - Cement vs Concrete
02:35 How is cement produced?
03:55 Methods of reducing emissions in cement production
06:48 Can we avoid using lime altogether?
07:56 Carbon Capture and Storage using Cement
09:40 Removing emissions from heat
10:33 Outro

Sources:
(coming soon)

The Engineering with Rosie team is:
Rosemary Barnes: presenter, producer, writer
Kevin Irman: research, calculations, assistant editor
David Hodgson: writing and research

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[Aermydach]

Many thanks for such a concise summary of the state of low-emission concrete.
Keep up the great work!

[roidroid]

IIRC the --Brisbane International Airport-- runway (HUGE amount of concrete) used a carbon negative geopolymer, developed by a local university.
Edit: oh it wasn't Brisbane's Airport, it was a Toowoomba airport (a town 130km inland of Brisbane.

*"BWWA is built with approximately 40, 000 m3 of geopolymer concrete making it the largest application of this new class of concrete in the world" [2015]* Nice

[BillMSmith]

That was a lot of information in less than 11 minutes. So much so that I'll forgive your pun to close your intro. 😎 Having had 4 decades of time in and around the building industry I think the initial low hanging fruit is use reduction. As you pointed out there are areas that could benefit from thoughtful engineering to reduce concrete use, and there are opportunities to eliminate concrete in some areas as well. Concrete free "slabs" for on or below grade construction are viable and within the ability and skill set of almost all builders. They merely need to rethink a few steps in the process.

[astrotrav]

Great stuff! I always learn something from your videos.

[ferdyhengeveld]

Excellent video, condensing loads of info in a structured way in just a few minutes. Hats off!

[OilBaron]

Loved the video Rosie, learned so much about the cement making process.

[keeblebrox]

An excellent summary of the progress towards net zero cement and cement alternatives. Thanks, Rosie et al.

[oshimia]

Love your videos Rosie. I can see lots of improvement in them since you first started as well. You speak more naturally and the transitions between points are much more confident and fluid. I don't know if you're editing them yourself, but there's also definitely a higher quality of editing since you started. It's really nice to see you growing into something you've obviously put so much effort into.

Your videos are fantastic, and very informative, thank you.

[Dr.Gehrig]

Great and thorough video. Glad to see that CCS is actually being used in the industry already.

[NaumRusomarov]

outstanding video. well explained, infromative and clear. 👍

[happyman]

Really informative summary of the production process, emissions sources and potential mitigation solutions. Would be great to see more 'overview' videos like this for other hard-to-abate sectors like shipping, chemicals, aluminium, heavy-duty vehicles etc 🙂

[k-labgaming]

Very good summary, one thing that was, however, overlooked is the recent research on replacing the cement precursors with glass.

For those unfamiliar, glass has an amorphous structure which suggests it may be able to be dissolved and reorganised to form a geopolymer cement. However the big road block is that glass is extremely unreactive which is why it is typically used as an additive rather than the sole precursor.

Recently I was involved in research on this area for my thesis where we used a glass derived from a martian simulant material (fake martian soil). In the experiment, we demonstrated that using a strong sodium hydroxide solution the glass could be dissolved and activated to create a cement which uses (aluminosilicate) glass as a sole precursor. The cement was then analysed using xray diffractometry (XRF wasn't available at the time) which showed that the cement had clearly absorbed CO2 from the atmosphere as the glass itself could not contain any carbon due to the glass making process.

While we were not able to test its material properties the experiment did show a potential route to a carbon neutral cement (only carbon neutral as glass making releases CO2). The use of a varied composition martian simulants also seemed to suggest a strong dependence between reaction time and iron content in the sample. Where iron assisted the reaction and dominated the reaction products.

[Patrick-jjnh]

the video you include about MCi international isn't linked, just to let you know! great content as usual, well done

[davidmartin]

Many thanks for your comprehensive analysis, which certainly does include as a major factor avoidiing concrete use, which some commentators seem to not have taken on board!
But there is no way it will reduce to zero, so you also cover techniques for reduction, some of which I was previously unaware of.

Kudos.

[kingdimitrieclips]

the video quality and production really went up. congrats!

[spitfireresearchinc.]

An excellent review. One point that seems to have been missed: much of the CO2 driven off in lime production (calcination) is re-absorbed by the cement, just over the ~ 100 yr timeframe, so not fast enough., but carbon neutral over the long term- so the real issue is the energy, not really the calcining..Alternative cementitious materials, wiser use of cement, alternatives TO concrete for above-grade construction, electric heating in calcination, biofuels for clinkering, and CCS...they're all needed. Note one thing missing here: hydrogen. I don't think there's really a role for hydrogen in cement production because the clinkering kilns need a radiant flame- they don't even like burning gas, they'd prefer coal. Hydrogen is definitely capable of generating the required heat (at tremendous cost) but isn't a perfect fit. Biogas methane with the addition of biochar is a better fit there.

[sebastianmonroe]

Thanks for the great video. Love your channel, I watch it regularly. Mass timber can replace concrete in so many. applications from buildings to bridges. It is great to get to zero emissions concrete but that doesn't solve the problem that it is a finite resource. Keep up the great videos!!

[SocialDownclimber]

Sublime has the best name. Until someone gets a viable, scaled manufactory, I'll stick with the best name ^.^

[mikeklein]

Thank you for this comprehensive yet succinct review.

[Haffa]

Loving the set. And cool to see the progress made in production. And as always informative and good content