Episode 541 Carbon, Concrete and Climate

Karen Scrivener is a professor in Switzerland who specializes in concrete research. Peter Fiekowsky is an entrepreneur and writer about climate restoration. Martin Halliwell advises builders on the use of innovative concrete with low carbon footprint. They agree that too much concrete is used by designers who are overly conservative, and that the rebar is a disadvantage for sustainability. They do not agree on the possible costs and feasibility of producing carbon-negative concrete. Karen thinks the extraction of calcium from seawater is far too expensive. For the video, audio podcast, transcript and public comments: https://tosavetheworld.ca/episode-541-carbon-concrete-and-climate. Guests:

Karen Scrivener

Martin Halliwell

Peter Fiekowsky



concrete, co2, rebar, Toronto, cement, people, Martin, materials, Metta, design, carbon, problem, patents, limestone, product, precast, long, building, cost, silica


Peter Fiekowsky, Adele Buckley, Adam Wynne, Tariq Rauf, Martin Halliwell, Metta Spencer, Karen Scrivener


Concrete is an essential building material that contributes about 8% of global carbon emissions. There is a debate about how to reduce the carbon emissions associated with concrete, and one possible solution is to use less of it or find ways to capture carbon dioxide and embed it in concrete.    

Karen Scrivener, a materials chemist, said that concrete can be made more environmentally friendly, but that it is not realistic to create totally carbon-negative concrete. It is inherently an environmentally friendly material. It’s just because we use such huge amounts that it all adds up to a problem. There is very little calcium available to be re-carbonated. She is publishing a paper estimating that the amount of CO2 that can be reabsorbed by carbonating calcium and concrete and other things is only about 1% of annual CO2 emissions. That is a significant amount and we should be doing something with it, but we are never going to have a concrete that is totally carbon-negative.


On the other hand, Martin Halliwell, a construction expert, believes that concrete can be made more sustainable by adjusting mix designs – using basaltic fibers, and nano colloidal silica admixture. He thinks that crack control is a big problem with floors and slabs, and overdesign is a common issue in infrastructure projects. There is excessive use of rebar – steel bars that are put into the concrete, mainly to reduce cracking.

Crack control is a big issue with floors and slabs, but it leads to over-design. For example, in the 1970s we built subway walls at Yonge and Finch that were 16 inches thick. It has been fifty years and the tiles are still on those walls. Nowadays. however, we see subways with one-meter walls, one-meter slabs, and 265 kilograns of rebar per cubic meter of concrete. Our budgets are twice what they need to be.

Adam Wynne says he had heard that, instead of mitigating cracking, rebar actually exacerbates it over time, especially in climates with severe swings between hot and cold temperature. Halliwell replies that there is some truth in that, but rebar is often used, not in sidewalks, but in interior situations that don’t freeze.

Karen says that steel is even more over-used in design. She says that people are brainwashed to be safer than safe. The building codes already have huge safety margins but engineers go beyond that because concrete is such a cheap material that, if in doubt, it’s easy for them to put in some extra.

Peter Fiekowsky argues that a company called Blue Planet creates calcium carbonate rock that can be engineered for porosity and density, which can be a good substitute for natural aggregates. However, Karen Scrivener is skeptical because she says the cost of making synthetic aggregates from seawater and CO2 would be roughly 100 times more than natural aggregates, making it far from the cheapest way to capture CO2. (In fact, Blue Planet does not now get its carbon from seawater but from demolished concrete.)

The panelists also discuss companies that claim to lower the carbon footprint of concrete by injecting CO2 into the curing process. Scrivener argues that recycled demolished concrete is the most cost-effective way to capture CO2, and it can be used to make new cement or as an addition to cement. The panelists highlight the need for cost-benefit analysis and independent verification when it comes to reducing the carbon footprint of concrete production.

Karen Scrivener mentions that aggregate made of recycled demolished concrete can only recapture about 1% of emissions and it’s a very expensive aggregate, not of high quality.

However, Peter Fiekowsky disagrees and shows pictures of Blue Planet’s carbon capture plant, which has been used in high-quality, carbon-negative concrete at San Francisco airport. The plant’s investors are power, cement, and equipment manufacturing companies, and it has been profitable.

Karen mentions a company called Solidia, which makes concrete blocks and hardens them by injecting CO2 into the enclosure where they are curing. They absorb the CO2. Yes, that product does have somewhat lower CO2, but not all countries of the world have curing chambers for making concrete blocks. Structural concrete is still the best option available because it combines steel and concrete, which actually work together very well, even where the temperature does go up and down. That’s not true of other kinds of reinforcement. Things like basalt fibres can be very good for crack control, but you would have to redo all the structural designs to be able to build a skyscraper out of that material. So these products do lower co2, and they can be used in a limited sense. Some people are squirting CO2 into the concrete, but the amount of actual CO2 that it captures is really tiny – almost negligible. At a maximum we can only offset about 1% of emissions by recapturing CO2 in concrete with any of these measures.

Peter Fiekowsky disagrees with Karen and shows several slides of the Blue Plane factory, which he says is profitable. They are just taking the CO2 away from a nearby power plant as a free resource. As regards Karen’s skepticism about the price and profitability, Peter is sure they sell high quality concrete at a competitive price in San Francisco, but then all concrete there is expensive because there are no quarries near San Francisco. Blue Planet concrete might not be competitive everywhere already, but it is getting there.     

Martin Halliwell argues that improving the use of concrete should tale priority over its capacity for carbon capture, citing examples of overuse of rebar and porous precast concrete. He emphasizes the need for a better mix design to create long-lasting and waterproof concrete. Adele Buckley questions whether companies are actually reducing CO2 in their products, and Martin suggests that improving the mix design can reduce CO2 emissions. He favors the use of pozzolans and basaltic fibers to improve concrete quality.

Martin aims for better-quality concrete that is sustainable and can last longer. He suggests using nano colloidal silica admixtures to make concrete more durable and resistant to cracks, thereby reducing maintenance costs. He also mentions ways of reducing the number of kilograms of cement used per cubic meter of concrete.

He believes that the government should mandate the use of the right admixtures to make sustainable concrete, and this can be done without increasing the cost of production. The use of rebar won’t go down with a carbon-captured concrete. He hopes to create awareness about better mixes. There is a need to involve decision-makers at the federal level to make concrete more sustainable. Adele Buckley asks who these decision-makers are, but no clear answer is proposed.


This is a machine-generated transcript that may contain errors. Do not cite it without checking for yourself by watching the video and catching any obvious errors.

Metta Spencer  00:00

Hi, I’m Metta Spencer, today we’re going to talk about concrete. And this is about the third or fourth, or well, at least the third conversation I’ve had about the subject. And it’s one that the more I listen to the more fascinated I get. And the not because everybody necessarily agrees, because it’s a very, very important topic, something like 8% of the carbon emissions to the atmosphere comes from concrete. So because concrete is such an important material for building, it’s the most used of any of the substances except water, or construction in the world. And therefore, we should give some thought to what it’s doing to our global warming issues. And there are people who think that we can reduce the amount of carbon that we emit in various ways. Some of them think we should use less concrete for one thing. Other people believe that there are ways of capturing carbon dioxide in the atmosphere, or in some other way, and embedding it in concrete. So this is a bit of a controversial issue. And we’re going to talk about it today with some people who know a thing or two on the subject, which I certainly don’t. Karen Scrivener is a materials chemist, and was known for her pioneering work in cementitious materials. She’s the head of the Laboratory of construction materials at the Eco politic Federal de Lausanne in Switzerland, and has served as the editor in chief of the cement and concrete research journal for 15 years. Good morning, Karen.

Karen Scrivener  01:44

Good morning.

Metta Spencer  02:20

In California is Peter Fiekowsky who is a physicist, an entepreneur, and he founded and was the chairman of the foundation for climate restoration, he is a philanthropist because he has made a bit of money by his many (inaudible) and he is the author of one of the most interesting if not the most interesting book I’ve read this year and if not the last several years called, “Climate Restoration.” I’m urging everybody to go read that book.

Peter Fiekowsky  02:20

There you go.

Metta Spencer  02:36

Okay, he is the president of footprint engineering, which constructs buildings and heavy civil, mechanical, electrical, waterproofing systems,  foundations, etc. So he has thoughts and has done innovative work with concrete. Now, the shows that we’re doing these days, we ask that some members of the Canadian Pugwash group be present, because we like to have people from the Pugwash group inquire and quick query, our expert panelists today. Tariq Rauf is nowhere near me. He’s in Vienna. And he is an expert on nuclear matters, having worked at the IAEA for some time, and is a consultant there. And in Toronto is Adele Buckley, who’s also a physicist and engineer, and a very active, both of them are very active in the Canadian Pugwash group. I know that not everybody believes that it is realistic to try to create concrete that is carbon negative. So I I’m pretty sure we have to at least two different points of view about that here. And maybe there are a dozen points of views. I don’t know, Karen, well, let me let me ask you, what do you think about the current status of all this experimentation and innovation going on? Claiming at any rate and hoping to be able to produce carbon negative concrete? There it is, very good Peter. And Martin Halliwell is a little closer to home. I believe you live in Toronto do you not Martin?

Martin Halliwell  02:36

No, in Ontario though.

Karen Scrivener  04:18

Well, I think there’s a lot of things you can do to reduce co2 emissions from concrete. And we should remember that already, it’s quite an environmentally friendly material. It’s just because of the enormous amounts we use that it all adds up. So you’re not going to make things better by replacing concrete with something else. But the idea that it can be totally carbon negative is really not realistic, because most of the emissions are coming from the breakdown of limestone. And you can’t make cement without limestone. And, you know, those people are claiming well, it combines co2 with calcium, of course it does it recarbonates afterwards, but you’ve never going to absorb more co2 afterwards than you emitted in the first place. So you know, you have to look at how much calcium is out there to be carbonated. There’s really very little. And we’ve have a paper we’re going to submit soon, which estimates the probably the amount of co2 you can result reabsorb by carbonating, you know, calcium and concrete and things like that. It’s probably roughly about 1% of annual co2 emissions. So that’s not nothing, it’s quite significant. And it’s certainly something that we should be doing. But you’re certainly not going to go to a product that’s totally carbon negative.

Metta Spencer  05:52

All right, that is planting a flag. Let’s say which of you would like to, I’m going to go the easy route and slide into this. By asking Martin, Martin Halliwell, you have long experience in construction using cement concrete, rather, and tell me what your own view about this subject is.

Peter Fiekowsky  06:16

It’s interesting Metta, I think it might be useful to clarify the issue. Because Karen said very important things about cement, which I don’t think anyone would disagree with much, I wouldn’t certainly. But there’s, of course, a big difference between cement and rock. And limestone. Concrete consists of two separate parts, the rock and this and that. So maybe Martin can talk about one or the other of those.

Metta Spencer  06:48

All right Martin. So clarify matters for us.

Martin Halliwell  06:54

So I would obviously fall on the side of doing a better job with concrete. And, you know, what’s true today is concrete is very porous. And we, we see a lot of over design with concrete. And so my objective is to try and contribute by, by, you know, a unique mix design, I’ve come up with that, that, arguably would last 1000 years instead of 25. So the 25 year stuff that we’re seeing in Toronto, you know, we see a very porous product, and so then we’re rehabbing. And you have to keep consider the rehab effort, and all the related diesel and fuels and patching bag materials that are out there. So if we can do a better job with with the original mix, you know, I just tell people how to adjust the mix. And, you know, I’ll mention two products that I that I believe in, you know, ones basaltic fibers, which is twice the stiffness of steel fiber and renders things crack free. And the other one is nano colloidal silica admixture, which is becoming a rage down in the States, and with bridge decks. But I think the overall design of rebar is a big problem, we have this idea that we have to do crack control. And that, you know, unless you need unless you need a tension or compression force, why would we put in more rebar than we need, you know, the figures show that it’s 1000 kilograms. And in metric here in Canada.

Metta Spencer  08:33

People will need to know more about what rebar is, I assume it’s the metal bars that they use for reinforced concrete, and you say it’s to protect, prevent cracks is could you explain what rebar is a little?

Martin Halliwell  08:49

Yeah, so it’s, it’s, it’s usually a steel bar. It’s got a big footprint, you know, the 1000 kilograms of steel is 6000 kilograms of co2, whereas you know, 1000 kilograms cement is 1000 kilograms of co2. So I go after, you know, the 80:20 rule. I’m, I’m a big advocate, I’m not overdesigning things. And then I’m, and then I went after that mix design. But my patents are all below grade because I’m a foundation specialist. And that’s where I seen the most waste from the, from the 1980s to now. We’ve seen tremendous over design, which I have opinions on why that’s caused but the you know, we just tried to do something in the way of Value Engineering. I don’t design those buildings. I don’t do detailed design that I do value engineering. So I tell people which systems to pick. I’m, I believe that crack control is a big problem with floors and slabs and you know, this whole thing with over design. Can I comment about our Toronto subways do we have time? And so in the 1970s, we built subway walls at Yonge and Finch that were 16 inches thick. And, and there’s no tile that’s off those walls. And that’s, you know, 50 years. And now we see subways that are one meter walls, one meter slabs, and 265 kilograms per cubic meter of concrete in rebar design. So those things in front of certain excavation support systems are causing our p3 budgets to be twice what they need to be. And I think for the taxpayer, and for the good of society, you know that we need to point these things out. And it might be hard to change. But I do have a meeting with city hall in Toronto on February 6, than I hoped to make some changes in the way the underground (inaudible) laws work. So in Toronto, Metta, they thought they had a problem with water going to Ashbridges Bay. So they said, We don’t want any combined storm and sanitary in this anymore. So they created a practice of pouring five foot thick raft slabs in the bottom of every parking garage, new park garage in Toronto. And that’s something I’d like to change. Because in that, in that in that five foot raft slab in the bottom of Toronto, which we never did in the 80s. There’s 265 kilograms per cubic meter of rebar.

Adam Wynne  11:35

I was hoping you could speak a bit more about the role of rebar, within crack control, I thought Metta mentioned you saying that rebar mitigates cracking, but I had heard that it actually results in more cracking over time, especially in climates where you have significant temperature swings of cold, hot, cold, hot, and that the expansion and contraction of the rebars was causing a lot of structural failure in concrete materials. Is that true? Or is it a myth in regards to these materials?

Martin Halliwell  12:01

I think there’s some truth to that. But generally, you know, these things are, are not in sidewalks, they’re in interior situations that aren’t freezing. You know, we we have a porous concrete cover on top of rebar. So what happens is the, the, the inch and a half or two inches of concrete cover that they think is protecting this rebar is leaking in the salts. And our infrastructure falls apart because of it. And so you know, they can put bituminous waterproofing on top of that, and they can do all these things. But when people it’s a common thing that rebars crack control. And you know, so they put lots of rebar in. And the other thing I’ll mention is in our infrastructure projects, the engineering industry is consolidated. And they charge 8% of hard cost. And they use the same details all the time. So there’s no incentive to reduce the thickness of subway walls in Toronto.

Karen Scrivener  13:07

And I think over design is certainly part of the issue. And, you know, there’s many aspects to this, I mean, Martin’s come up with some of them. But I mean, it can be as simple in buildings, as you know, rethinking the layout, you know, many high storey buildings, just because they want to have big areas open on the ground floor, and then transfer to housing, they have incredibly complicated structural loading systems, which you lead to very wasteful use of all materials, concrete, and of course, steel. And I would like to point out to Martin that, you know, emissions of cement may be close to 900 kilos per tonne, but that’s not the end material we use, the material we use is concrete, and that’s got much, much lower emissions, again, that’s can be down at around 200 kilos per meter cube, which is two tonnes, so 100 kilos per meter cube. So you know, I mean, it really is very good material compared to steel, we’re overusing steel, and the long and short of  overdesign. I think there’s two factors here that really need pointing out. The first one is that people are just so brainwashed that they’ve got to be safer than safe, you know, we have building codes, which already have huge safety margins put put in, but then people think, Oh, well, you know, we can’t design up to the code. We shouldn’t only design to about 80% of what we can do in the code, which is nonsense, because these codes have been very carefully worked out. And most people will already agree they’re over conservative. The other thing is that the longer short of it is that the time we pay engineers to make designs and to optimize things is far less than what it costs to put in some extra concrete because concrete is a very cheap material. So you know If people are not sure, they say, well, let’s let’s put in a bit more. And I think there are now coming out new tools, which can help people to use concrete better. You know, I think all of these are very positive trends. And I think we can really imagine that by passing down over design, we have possibility to save 30 40% of the co2 in concrete. And, you know, my philosophy is, you know, we have to work with all the different levels, we have to work at the design level, but then we have to work at the concrete level where again, we can make savings of in the order of 30% or so. And then we need to work at the cement level. And if we combine all these together, we really can make very substantial reductions, we can do these with existing technologies, we can do them fast, we can do them at large scale. But you know, we have a lot of effort being diverted by people who think they can come up with miracles, which can just sort of make this all go away. That’s why I have to say, we have to face the fact we can’t have zero carbon concrete without stopping.

Metta Spencer  16:07

Now we’re getting back to the where the controversy really exists. And I have held off Peter Fiekowsky, as long as I can. I can’t I can’t hold him off anymore. Peter. Take the mic.

Peter Fiekowsky  16:20

Right, Thanks, yeah, yeah. So Karen, as I said, your point about cement is excellent. There are a lot of attempts to reduce the carbon emitted in cement production. And they’re nice, but they’re not huge. As you said, the key thing that you’re perhaps overlooking is the rock, the most of it not 80 to 90% of concrete is actually rock. And if you imagine the an oyster shell, you’re on your dinner plate, that little that, that rock that out calcium carbonate rock is is essentially manufactured by a small animal. And there’s a company here in Silicon Valley Blue Planet, which does similar chemistry, creating calcium carbonate rock, but they can actually engineer it for the porosity desired. And the density,

Karen Scrivener  17:25

Well, I think, I think that’s probably you know, where you and me seek to differ? Yes, of course, limestone was created by lots of little animals, sequestering co2, over millions and millions of years. The problem is, they need also need calcium to do that. And if you calculate the amount of calcium in seawater, and you work out the volumes of seawater, you’d have to process to meaningful amounts of limestone, you just find out it’s colossal. And the cost of that would cost you roughly 100 times what it costs us to produce cement today. In fact, the person who has this Blue Planet company, he previously for about 30 years, had this company called Calera, which tried to do this and I think over 30 years, he failed to deliver on his promises. Now he’s born this Blue Planet. And if you calculate the kind of cost he needs to make these synthetic aggregates, it’s roughly about 100 times the cost of natural aggregates. You know, I mean, how are we going to? You mean, you’ve got to increase the cost of concrete by 100 times which I think, even though it’s very cheap product, I don’t think most people could afford to pay 100, 100 times that. And, you know, we have to benchmark these carbon ways of sequestering carbon against, you know, other technologies, and there are other technologies, which can do this a lot more cheaply. You know, I think I, you know, I think we are going to have to get co2 out of the atmosphere. But we need to say this is going to be a very costly operation. And we need to see how we can get rid of most co2 for the lowest price. And, you know, certainly making synthetic limestone from seawater and co2 is not going to be the cheapest way to do it, it’s going to be about 100 times more than other off the shelf technologies.

Peter Fiekowsky  19:27

The source of calcium, that there are many sources of calcium, you know, in terms of cost, you know, it the all the experts thinks it’s a profitable business. They’re raising money from cement makers, from concrete makers who understand the process soup to nuts. And again, I understand your academic expertise is probably better than that of the corporate leaders. But there’s a difference of opinion there.

Metta Spencer  19:58

Adele Buckley.

Adele Buckley  20:00

Yes, well, excuse me, I have heard Martin tell us that something like garage floors in buildings in, in Ontario are incredibly over designed with respect to concrete, and rebar and so on. How can we reduce this overkill with the rebar? So that’s one question. And the second is, where do building codes come in? Because I think everything is built according to building codes, but they must, they could be modified to better support the co2 situation. On the other hand, all I hear from Martin is that instead of adhering to the building code, which is conservative, most buildings are built way over necessity.

Martin Halliwell  21:04

The building code is a guide, but the regulation in Toronto is ill conceived based on a treatment plant downtown, and a number of tower cranes that exceeds any other city in North America. So I know Toronto very well, I’ve been doing below grade work there a long time. And the fact is that those were pre consolidated soils, and nobody tells you how to design it by the building code. They tell you at the City of Toronto, and that’s why the city Toronto, which requires a hydrogeology report and really just said you have to keep all water off site, when that’s not realistic. So I designed a system called fvh tool lock, which is a patent now, and that that will drain behind and reduce footprint. So I work on things like that, but the I’m not here to market my patents, but you know that that will become the norm in Toronto again, because developers need a break. You know, we have developers that have land, it’s gone down. And we’re going to see a lot of problems with housing in Toronto, if they can’t get that thing figured out. And they say that the city limit requires a water management system. So this is an alternate water management system. And it’s based on my experience, it’ll work and…

Adam Wynne  21:04

South of Front Street in Toronto is reclaimed land with significant groundwater and some of those buildings were having a significant development boom, had a pumps running in the basement 24/7 Because the leak (sic) is coming up to the foundations that reclaimed land is less than 150 years old. There’s also buried rivers throughout the downtown core. So the hydrogeology plans I think are attempts to mitigate the existing groundwater situation. And I can’t imagine pumping the water from standard groundwater on reclaimed land out the back, you’re going to have it go directly back into the foundation.

Martin Halliwell  23:01

So I’m familiar with south of Front, and north of Front, I did the foundation on the Skydome in 86′, which is south of Front that excavation was dry. Now if you get down to Queen’s Quay and whatnot, you know, I wouldn’t recommend the use of an alternate water management system. But the it’s really a case of 80% of the sites in Toronto are vastly over designed. And including our subways, like our subways. It’s when when you’ve seen it before, it’s it’s it’s hard to watch, it’s hard to watch the waste. You know, I I appreciate what you’re saying south of Front though. And you know, I don’t think that’s the best space for a target project. I’m going to do one at  Three Hundred Bloor West, which is virtually dry.

Metta Spencer  23:53

How much it is possible to lower the carbon footprint of concrete by injecting carbon, co2 in some form. There are some I know you, Karen are pretty adamant about you don’t trust the blue planet approach. But there are a number of different other companies doing other things. And I don’t know why they’re so secretive, but they they don’t like to be interviewed when I’ve tried to reach them and ask them to be part of the conversation they never join us. But there are companies that do things like put the concrete make concrete blocks and put them in some sort of enclosure for curing and then inject co2 into the into the air in that, in that enclosure so they presumably absorb co2 while curing. And there are others that just squirt co2 into the mix of The liquid concrete as they’re pouring it, etc. So I don’t have any, any awareness, really, the details about how effective this is they are not claiming to be carbon negative, but they are claiming to be low carbon concrete, because of this procedure.

Karen Scrivener  25:19

It comes down to cost benefit analysis. You know, if you talk about this technology, which is actually commercialized by a company called Solidia, which hardens blocks by carbonation, yes, this is fine, this does absorb some of the co2 that was admitted in the process of making the cement. And then, you know, you have a product which has somewhat lower co2. The point is that, in the current technology, these kinds of products are not going to protect reinforcing bars, we’ve already talked about reinforced first forcing reinforcing bars. And for structural concrete, you know, this is still the best option out there, because you have a very good match in terms of properties between steel and concrete, they actually do have the same thermal expansion coefficients. So that’s actually why they do work well together even when the temperature goes up and down. And that’s not the case for other kinds of reinforcement things like basalt fibres can be very good for crack control. But you would have to redo all the structural designs to be able to build a skyscraper out of that material. So these products do lower co2, they can be used in a limited sense. But if you take this example of blocks, you have to have a block factory that already has a carbonation sorry, a chamber usually use for for curing. And this exists in, you know, some places like North America. But in the vast parts of the world where blocks are made like India and Africa, they don’t have these curing chambers, because the ambient temperature is already warm enough to not need them. So this is a good bit of reasonable technology, but has a limited application. Now as for the thing of squirting co2 into into concrete, that’s a little bit more controversial, because the actual co2 you capture in the concrete is really, really, really tiny fractions of a percent. So it’s really, almost negligible. And it’s claimed that this then improves the quality, quality, but improves the properties of the concrete. But there hasn’t really been independent verification of this. And as I said, it comes back to this quick question of how much co2 Can you capture for a given amount of money. And both of these technologies end up being fairly expensive ways to capture co2 Compared to other solutions out there, you know, just capturing co2 and stocking it underground. One of the best ways to reuse to capture co2 is to reuse demolished concrete, this is an incredibly good technology, because a lot of that cement in the concrete has not been carbonated. And if you can separate out the aggregates, reuse the aggregates, then take all the fine materials, you can use it in two ways you can use it either to make new cement or you can actually carbonate it further and use this as an addition to cement both of these are very cost effective ways to use the potential of that concrete to take back some of the co2 it gave out when it was originally produced, but they’re not carbonate and they’re not carbon negative solutions.

Metta Spencer  28:47

Okay, well, that’s interesting really is because, you know, the thing that Blue Planet does is it uses come demolished concrete, as a source of calcium. It captures and smashes old concrete and mixes it with co2 from a flue or smokestack nearby with presumably some other chemicals. I don’t know why, but that’s how it makes the aggregate that then is a substitute for the gravel or the limestone stuff that is normally used as as the aggregate in concrete, which is something like Is it 70% or so of the component of real concrete.

Karen Scrivener  29:26

But the problem again, there is it makes it very expensive aggregate which is actually not a high quality aggregate neither. So, you know, we use that demolished concrete, we also have to bear in mind that the amount of that concrete we have is quite limited. You know, we can only, at a maximum mop up about 1% of emissions by recapturing a concrete so we should certainly do these things, but it’s not going to totally solve the problem.

Peter Fiekowsky  29:58

Okay, so So obviously, Karen, I disagree on reality here. I’ll show you a few slides of the, the, of the plant. So here you can see there, the blue planet plan for power plant, they’re getting co2 from this in the background. And the one point to get here is that the investors who I said are power companies, they’re cement companies, they’re equipment, manufacturing companies, or even quarries investing. I trust them, I’ve gotten over the number of myself, but I’m a physicist, I don’t trust my personal analysis by trust the experts. And so in the background, you can see the pipes coming in, just part of the process, they’ve, they’re capturing this, this co2, I don’t have the slide handy. But the the mixture is in the tank here. And then the limestone they create, it gets filtered out in these. And then, and here’s some of the limestone they’re creating from calcium, in addition to as Karen said that they reuse the existing rock in the existing sand. But a lot of the calcium is still available in the cement, the demolished rock demolished concrete, and here’s some of their final product. And there, here’s the pipe coming in from across the street. It’s just a matter of opinion of do you believe the the people who actually manufacture it, and they’re expecting it to be zero cost. They started this before there was any forty-five Q benefit here in the United States. So this was profitable without any cost of carbon. And in fact that the the power company is not paying them to take the carbon away. They’re just taking the carbon as a free resource. And then they of course, get paid for by taking some of the the remedial remediating the concrete anyway, but it’s it’s I think it’s fine for us to disagree about the finances of it.

Metta Spencer  32:37

Do you know how much they they’re able to claim that they can do this for Peter, have you asked them about the cost?

Peter Fiekowsky  32:44

Oh, yeah. Yeah. So they’re the quality of their concrete that they’ve been using it at San Francisco airport. And of course, San Francisco airport is not going to use low quality concrete. And so they certified it that it was absolutely high quality, and they sell it at a competitive price. They’re all of their output is called for over the next several years. So, you know, there’s no cost is the point is that as actually they actually earn money selling the carbon negative concrete, it’s about 1000 pounds per cubic yard. The concrete here is expensive, right? So we don’t have quarries in San Francisco, or even very close. And so the very high quality concrete it’s light they need. They specialize in lightweight rock, which you use in skyscrapers and overpasses. And that tends to sell if I can recall, for $100 a ton or even more than that, as opposed to just go to your garden, garden. Shop sharp rock can be as little as 30 or $40 at a time. But for high quality, it’s 100 or $200 a ton. And that’s why it’s popular.

Metta Spencer  34:04

Is that good or bad? I don’t know what…

Peter Fiekowsky  34:05

It doesn’t matter. The point is is profitable. Now. If you take today’s process and you move it out to Kansas, somewhere where land is cheap, and they probably don’t mind opening up quarries. It’s not going to be profitable yet at today’s process in the future, it’s likely that the technology will improve it always does. At which point it is likely to get competitive even in in rural areas.

Metta Spencer  34:33

Martin, you had a comment.

Martin Halliwell  34:36

Yes. So I disagree with Peter and the and it’s based on science but the it’s not really opinion is experienced, you know the amount of concrete amount of kilograms per cubic meter. In a 30 MPA concrete in Toronto is 350 kilograms and with a nano colloidal silica are 450 kilograms with an anticline silica, we actually get that down to 325. And that makes the price competitive. And nano coloidal silica is an internal curing, even the concrete you’re talking about Peter could benefit from that. Because it would, it wouldn’t need any curing, removes wet curing costs. And but I go back to the rebar, you know, the idea of rebar wouldn’t go down with with a carbon captured concrete. And I don’t think on scale, you can do that technology. Basically what I’ve read about it, I mean, Bill Gates is pushing it, and I don’t really think he’s doing it for any other reason than then to create a smoke screen or whatever. He’s got lots of money, but I really believe that co2 is, is best to help with the right mix.

Metta Spencer  35:58

Tell me what Bill Gates is doing. I don’t know anything about that. I like to hear about Bill Gates’ adventures.

Martin Halliwell  36:04

Well, I think he’s backing carbon capture, as technology

Adele Buckley  36:09

Direct air carbon capture, isn’t he? You know, which is extremely expensive.

Martin Halliwell  36:16

Yeah. He doesnt know anything about concrete. But, you know, the fact is that people who are using internal cure of silica, are claiming that it will give it 1000 year life. And I go back to the idea of Peter getting rid of rehab. I mean, why, why have an expensive mix, people won’t buy it, they won’t buy an expensive mix. Everyone cares about money. So if we can get the cement down, and make it last longer. That’s the value value and functionality over costs.

Peter Fiekowsky  36:50

Martin, I think you’re making the very good point of both. And obviously, you always want to use a better cement, you always want to use a better mix, they’ll reduce the steel reduce the cracking, you want to do that. If you if your the aggregate you use happens to be carbon, sequestering, that’s good. If if it’s too expensive, then no one’s going to buy it. It’s a moot point. I don’t think any of us are going to be issuing any multimillion dollar contracts. So and it’ll be several years before the blue planet is available at large scale. It’s I think we’re all I think we’re all pretty much on the same page, as long as you instead of saying either, or you say both, and. Of course, you want to improve the use of the concrete, then they optimize it. And of course, as far as you can get synthetic limestone and capture co2 from somewhere and at a cost in a way that’s cost effective, then you should do that. But here’s what I think a big takeaway, and it’s implied in everything we’re saying is that the best way to do it is not so much with a price on carbon.

Martin Halliwell  38:11

I agree with Peter, in the sense that we shouldn’t price carbon, but go ahead. I think Adele was gonna say something. Adele.

Adele Buckley  38:18

I think I have more questions for for Martin, because he’s he taught me about concrete in the area that I live in, in Canada, whenever are companies at all conscious of trying to reduce co2 in their product? It seems to me that, you know, there’s a lot of publicity but and, you know, trying to do, but there’s a lot of greenwashing and not, no, no actual reduction. But the so that’s one, is there anybody trying to actually reduce the co2 in real life? And second, what would make anyone stop over kill and using twice as much concrete as and rebar as this as this actually needed? And is this controversial? I mean, we certainly know about collapsing buildings, you know, they come in the news when it happens. And, and everyone wants to avoid the possibility of that happening. So so how, how can you get motivation to to stop the overkill when meeting the building code apparently, is sufficient.

Martin Halliwell  39:39

It is overkill. And we do it one step at a time. You know, I try to advocate to make the problem smaller first, before you can get your arms around it before it can go away. It costs is always a factor and I think Peter recognizes that that that you know if we if we can get the best technology today into the cubic meter of concrete and turn bottles, then people are going to be able to use different systems. And so if they can pick different systems, for instance, precast is more secure. But you know, we’re testing precast, and they handle colloidal silica without any moist curing and think of all the energy involved in moist curing.

Metta Spencer  40:16

Hold on, What is precast?

Martin Halliwell  40:19

Precast is when you create certain members that are done in a plant, shipped out like a bridge girder or whatnot. And traditionally, they’re highly porous. So, you know, we can do, we can do a better job and not have the energy of the steam, they do steaming to try and get that thing cured. And when they, when they cure it, then they ship it. So they want to have a turnaround in a plant environment, and they put it on trucks and precast is a good product, they just have to change the mix design. In ready mix plants in Toronto, they have a certain amount already explained to North America, they have a certain process, they have mixed water, they have dry, they have dry and mix. So, if you can, if you can improve their use work with their existing process, and make them realize that this is a better concrete, get rid of the crack control rebar and go back to that because it’s a big problem. There’s still people doing slabs with rebar in them that they don’t need. They don’t need to put the rebar in the slab. If you don’t have to do a socket after. Why do you need the rebar? We’re seeing no cracks. The benefit of basaltic fibres is it’s inert. And it’s the same density as concrete. So it behaves better. And you can you can deal with it without any cover. So Roman concreteness was done with a pozzolan. And the pozzolan is basically.

Metta Spencer  41:51

What’s that?

Martin Halliwell  41:52

Well, we’ve got a pozzelan is a fly ash that’s very, very fine grained from volcanic events. And so that concrete’s still around. And so my goal is to try and prove that, you know, we can do 1000 year concrete. That’s my goal. And at least I can make it waterproof.

Peter Fiekowsky  42:12

Oh, Martin, hurry up.

Martin Halliwell  42:14

Yeah,I have a mix design that I can be happy to send the Pugwash group. And everybody on this. Anybody on this, on this video?

Metta Spencer  42:25

How many things are created that anybody’s going to want to live in 1000 years from now? I mean, I don’t know how much to worry about the fact that the lifetime of concrete structures is not comparable to what the Pantheon looks like 1000 years. So I don’t know what to worry about. Because maybe people would be digging up that the the sidewalks anyway, or maybe, you know, they design a building, they’re not going to want that building much, you know, more than 50 years, and they would tear it down anyway. And so is it important that we get concrete that’s going to last a lot longer?

Martin Halliwell  43:12

Well, it is for the 25 year rehab that we’re seeing on the on the on the bridges in Toronto.

Metta Spencer  43:19

Twenty five years is that how long?

Martin Halliwell  43:21

Twenty-five years — they start to go at it again, you see them starting to chip in to do the work again, it’s pretty hard to fix the concrete when you didn’t do it right to begin with. You end up with a with with putting patching on everything in that internal structure is the mistake. So when you use an anecdote of silica admixture, it’s very, very tight, waterproof concrete, we can get away with without any waterproofing on basement walls in Toronto. So I see the multiple layer benefit to the person who’s a developer. And,…

Metta Spencer  43:58

But most of these companies…

Martin Halliwell  44:00

You don’t need 1000 years. But you know, unfortunately, if you put this mix together, that’s how long experts are saying it will last.

Peter Fiekowsky  44:07

Metta, what’s wonderful about what Martin is saying and what he’s doing. And I think we really want to encourage him and his colleagues is we’d forgotten a lot of what the Romans learned about concrete. And I, Martin correct me if I’m wrong, but the cost of doing the concrete right is probably lower than the cost, the way we’re doing it now. is that correct?

Martin Halliwell  44:33

Yeah, my goal is to is to change it out without an increasing cost. When we sell it like for instance, the nano colloidal silica admixtures from one supplier is $50 us a gallon and from another supplier is $25 us a gallon so I recommend the $25 us a gallon and I try to specify the nano size where I would say you know in my shotcrete on this system, I’d like this product And I’m gonna make you use basaltic fibers. And so we prove one job at a time in civil engineering. And for sure, we don’t need 1000 years, you know, I hope we’re all around in 100 years. We have stations and all these different things. So it’s, I’m a big sustainability guy, Peter, and I appreciate where you’re coming from as well. Because, you know, it’s, it’s, it’s multifaceted problem. But if we make every facet a little bit better tomorrow.

Peter Fiekowsky  45:31


Martin Halliwell  45:32

Then we’re doing what we can is as human beings, right?

Adele Buckley  45:38

Martin, to make it move into a common practice some of these things that you’re talking about. I mean, they’re, they’re just limited examples. And, you know, if we wait long enough, maybe everybody will do it, but we might have expired from the heat by then. So we really need to move it along. How do you do that?

Martin Halliwell  46:01

Well, I’m hoping that by being vocal by what Metta has started here, and what Pugwash is picking up.  Pugwash I think, is a group that the government may pay attention to. I don’t believe that the government wants to have rehab after five years or 10 years on on their bridges, there’s a lot of federal bridges. And, and so we get the word out, like in Indiana and Ohio, they’ve done 350 bridge deck rehabs, and I could look at their bridge deck rehabs, and I can improve it further, you know, they’re still putting green rebar on the base of the deck at quite a large, large volume. And realistically, the best bridge deck rehab is ultra high performance concrete called core tough. So that product is gone, goes on with two inches thick, and it replaces the rebar even though the product is probably $1,100. or $1200 a yard or something. It’s it’s a, it’s just going to last forever. So I it speed is important, you can pour that as a liquid. And it’s it’s a very interesting product. So the I tried to study the best products and I try to recommend something that has a value point for functionality. So so based on experience, we see a lot of below grade mistakes. If we we don’t really have the problem with a high rise a high or a high rises covered in a cladding. And it’s pretty efficiently designed, we could probably get rid of some of the the flooring problems like for instance, flooring in slab on grade is a $3 billion a year insurance problem in in the US. So we can get rid of that problem. But nano colloidal silica, you know, I, I try to hang around with the experts and I ask them good questions. So the idea would be, you know, can we get everybody’s input? And do it expeditiously? I think, you know, I

Metta Spencer  48:12

Let me ask about these concrete blocks. Because most of the companies that I’ve looked into a can’t interview anybody, they just won’t do it. But that the ones that claim to be low carbon, concrete, are making concrete blocks. Now I just don’t imagine that there’s a whole lot of use for concrete blocks. I mean, you can’t do highways that way, I don’t think you can do bridges. What can you do with concrete blocks? And how far will that go in solving the problem? Let’s assume that you could make concrete blocks that really are quite quite low it unusually low in carbon, then the carbon footprint in general, would it, would it solve much of our problem?

Martin Halliwell  49:02

Concrete blocks won’t, because you need to have an assembly that can carry the tension and compression rebar into a larger design. The concrete block is a piece of precast metal to give you an idea that’s really precast and it’s a good idea to perfect every piece of concrete if it lasts longer than we’re gonna last, you know, I mean, it’s I don’t think the Romans thought of that but the you know, there’s they did the best job they could with what they had to work with. And they didn’t use rebar. They used arches and different innovative innovation design. But the nano colloidal silica is a is an engineered (inaudible) and nanotechnology is in our world now. It’s so that benefit. It’s, It’s quite inexpensive. You know? I believe that we can, we can get this concrete right, and get rid of the tension or the crack control concrete, which is a big thing. Or we can get down the number of kilograms per cubic meter. If we can go from 450, on shotcrete, which is sprayed concrete, to 325. And we’re testing at the University of Windsor. And I believe Metta, we can give you some names for future shows and move this thing towards a value at, it doesn’t have to be me presenting, there’s other people who say what I say, I mean that you know, this is becoming common knowledge that concrete is too porous. And I think the ready mix plants, if we can give them a process that doesn’t change the way they make a concrete truck, if we can still pull up a concrete truck, the fact that they’re going to sell more of them, apparently, there’s a cement shortage anyway. I think you might be aware of that metal, there’s a cement shortage.

Metta Spencer  50:55

No. I wasn’t

Martin Halliwell  50:56

Yeah. There is.

Metta Spencer  50:59


Martin Halliwell  51:00

My calculation is that 40% of the co2 problem is from the built environment. And 20% of that is concrete steel.

Metta Spencer  51:09

Well, let’s just sum it up by saying how much if everybody took your best advice, and we had the optimum materials to use, and everybody did the perfect thing, given the information that we have now, the state of knowledge, how much could we reduce the emissions? Presumably, you don’t believe it’s possible to be negative? But if you can’t, if you just look at reducing the emissions, how much can we take out of carbon emissions from the manufacture of concrete?

Martin Halliwell  51:49

Well, it’s cement. But the 

Metta Spencer  51:52

No, the whole thing?

Martin Halliwell  51:54

Yeah. Well, I would say, the 40% of the of the built environment percentage, I think we could get to 30. So if you, you know, chances are that that’s going to be done over the next 10 years. I think it’s unavoidable that people aren’t getting aware of these better mixes. And it’s, I’m not the only one doing it. It’s, it’s more prevalent in the States. And as Canadians we can be leaders, you know, there’s I talked to a value engineer this morning, was quite popular in Toronto, and a lot of developers use them and we’re going to, we’re going to work together, we made a deal. We’re going to try to work together. And he’s going to mentor me a bit on how to get my patents going. He’s got several patents. So the I think patents have to be priced reasonably, you know, Trudeau did a one good thing he allowed patent review in four months. And that got an examiner on. And so we took advantage of that program. And then now, most patents that are done in Canada.

Metta Spencer  52:54

But why should we care? Why should I care whether whether patents go through quickly or take a long time?

Martin Halliwell  53:01

Well, I think there’s some benefit to me moving on to things other than making patents and (inaudible) examiners perhaps, but I just want to see the see. I think I might where my heart is, is I think where Peter is, you know, I think he’s an environmentalist. And so we need we need to be more care about the environmentalism. I mean, we end up with people saying there’s no co2 problem. You know, that’s the thing you get.

Adele Buckley  53:31

A question, who are the decision makers? Because those are the people and groups that we have to get at. It doesn’t sound like it’s the province, here in Ontario. It sounds like it’s more like the city,

Peter Fiekowsky  53:44

Adele. That’s an ideal question. And when it comes to their two issues, your Martin is talking about the quality of concrete, which we just finished remodelled here, and there’s a hell of a lot of concrete used. And I wish Martin were here to redesign it. That notwithstanding, when it comes to climate, the issue Adele is, is our goal. And the UN goal has been to stabilize co2, co2 and greenhouse gas levels. And most of us really want to bring the co2 and methane back to the level that humans can’t have survived and presumably can survive. Today, co2 levels are 50%, higher 40% Higher 40 to 50% higher than humans have ever survived long term. And academics think what the academic justified they say, Listen, it could be worse. And if every bit of admission we don’t do makes it not so bad. You’re presumably we can survive a little longer. Those of us who are parents and grandparents it looks like we’re mostly grandparent here, although Tariq, your hair’s not very grey yet. What we’re really concerned about are our children and not and not emissions. And so the critical thing Adele is to get the UN and get Justin Trudeau to talk about climate restoration, that what’s really important is the survival of humanity. And that’s,

Adele Buckley  55:28

That’s, I agree with all of that. And we probably know that too. But I want to know, who are decision makers with respect to concrete?

Peter Fiekowsky  55:37

Ah, okay, that I can’t answer.

Adele Buckley  55:40

I think Martin probably has some answer to that and Metta wants to say something now.

Peter Fiekowsky  55:44

With that, I’m gonna go. Thank you.

Adele Buckley  55:46

A key question. I think.

Martin Halliwell  55:47

Thanks, Peter. Yeah, yeah, I think that decision maker who could make a difference in the somebody like Trudeau, so at a federal level, you know, they could mandate the use of the right admixtures. That’s pretty simple. I mean, people are just going to do it overnight. And I don’t need to make any money off the admixture. Somebody, will make some money off it. But, you know, you can get tanker loads into Toronto, nano colloidal silica, and you can adapt it into the existing plants without a lot of money. There’s no money really, it goes into the mix water percentage. So you’ve put about, I’m going to say it, this video, you put about 10 ounces of what’s called internal cure silica, per 100 pounds of cement, but you can reduce the amount of cement. So my goal is to try and see how this price’s out. So it doesn’t increase the cost of the concrete can’t,  why can’t, why can’t, we mandate it it’s not like they they need to put that much concrete it. It’s a start right.

Metta Spencer  56:52

Keeps us posted, Martin, if you know you’re on the on the track of solving it, well good for you. times up . It’s been interesting.

Martin Halliwell  57:00

Well thanks Metta.

Metta Spencer  57:00

Yeah, thank you very much. Appreciate it. And we’ll be back in touch with everybody, I’m sure.

Tariq Rauf  57:04

That was a very informative discussion. That’s why I kept quiet because I was listening to all of the details. It was way beyond my level of contributing anything but thank you.

Martin Halliwell  57:16

Anyway, call anytime. Thanks very much Metta.Thanks for what you did Metta.

Metta Spencer  57:23

Project save the world produces these shows and this is episode 541. You can watch them or listen to them as audio podcasts on our website to save the world.ca you can share information there about six global issues too. To find a particular talk show enter its title or episode number in the search bar, or the name of one of the guest speakers. Project say the world also produces a quarterly online publication Peace magazine. You can subscribe for $20 Canadian per year. Just go to pressreader.com on your browser. And in the search bar is or the word pace. You’ll see buttons to click to subscribe.



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