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Are we stuck with cement?

161 points| sus_007 | 7 years ago |theoutline.com | reply

93 comments

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[+] philipkglass|7 years ago|reply
The report exposes quite the paradox: We desperately need these infrastructure projects to transition to a carbon-neutral world, but in doing so we will have to emit a massive amount of carbon.

Massive compared to what? This article highlights that a single wind turbine uses a lot of concrete. But per the latest IPCC assessment, wind power over its life cycle already has the lowest median CO2 emissions of any electricity source. Sure, look for even cleaner ways to make materials, but this rhetoric is terrible. It lets fossil shills bludgeon you with your own words later: "see, environmentalists say coal burning emits massive amounts of carbon dioxide, but they say the same about switching to wind power, so there's no rush to change things."

Here's a recent review article about curbing CO2 emissions from cement:

Global strategies and potentials to curb CO2 emissions in cement industry

https://s3.amazonaws.com/academia.edu.documents/39977040/1-s...

It provides actual numbers and suggestions. Only half of cement's CO2 emissions per ton come from the chemistry inherent in calcining calcium carbonate to produce calcium oxide and carbon dioxide. The rest comes from the fossil sources of energy used to process materials. Like most industrial processes, it can cut emissions significantly just by switching input energy sources. Also, as someone else mentioned, concrete absorbs atmospheric CO2 as it cures. It's mostly the fossil combustion embedded in its production that drives emissions over its full life cycle.

[+] philipkglass|7 years ago|reply
As mchannon comments, concrete does not absorb a significant amount of CO2 as it cures. I was mistaken. The calcium in lime forms silicates.

However, it remains true that half of the life cycle emissions of concrete come from fossil combustion. Replacing fossil combustion with other energy sources can cut concrete's CO2 footprint in half without any major changes in concrete's composition or use.

[+] quotemstr|7 years ago|reply
Agreed. It's foolishly short-sighted to worry about the one-time construction emissions of a facility that can go on to produce power for decades. It's frustrating to see a segment of climate advocacy motivated not by quantitative concerns regarding radiative forcing, but by an aesthetic opposition to industrial civilization itself no matter what form it might take.
[+] pstuart|7 years ago|reply
If that CO2 is going up a flue it should be possible to capture (yes, more energy required).
[+] madaxe_again|7 years ago|reply
This article talks as though Portland cement is the only cement. It isn’t.

I’ve spent the past few years working in my free time on the restoration of several old buildings, under the guidance of my wife, who is a conservation mason, much of which has comprised removing cement and gypsum plaster and replacing them with lime mortar, lime plaster, and other lime products as appropriate.

While it’s true that most lime products aren’t as strong as cement, and are permeable to water vapour, their CO2 impact is much, much smaller - and many applications which currently see the use of Portland could as easily use appropriate lime-based products. Breathability is a good thing in most structures - most damp that you see in buildings arises from impermeable materials and condensation.

As to strength, lime-Portland blends exist which can create impermeable and strong concrete with less environmental footprint, and I’ve been experimenting with mixing lime with various different aggregates and plasticising agents - resulting in some interesting materials - ground pumice and slate in varying proportions produce very strong (high tensile and compressive properties) and impermeable materials - I was inspired by Roman concrete.

Here’s a tiny bit of further info on CO2 footprints, from a company I’ve bought several tonnes of NHL from:

http://ecolime.co.uk/c02-quick-facts/

[+] NeedMoreTea|7 years ago|reply
Roman concrete also has loads of advantages over modern concrete. Cracks don't spread, better salt resistance, and better earthquake resistance.

Modern concrete will not survive like Roman examples have. With the environmental advantages too I'm surprised it hasn't had a resurgence.

[+] coryrc|7 years ago|reply
Using a naturally hydraulic lime is important for creating weaker joints, but it doesn't save that much CO2. You only heat the limestone a few hundred degrees cooler (though for longer) and you don't pulverize it as much, but hydraulic lime is using the minerals mixed with it to harden just like OPC (which is why it can harden in such thick pieces like the base of the Pantheon), not pull CO2 from the atmosphere like a non-hydraulic lime.
[+] sgc|7 years ago|reply
As someone outside your immediate target market:

1) what do you mean by single skin and double skin exterior walls?

2) are there any simple/quick and fast mixes to DIY a stronger lime mix?

[+] Pxtl|7 years ago|reply
> The turbine will produce about three megawatts of energy on average which, when working at full capacity, is enough to power 2,400 U.S. homes for one month.

Seriously, how does this kind of basic unit bungling happen in every report that involves Watts?

[+] rdiddly|7 years ago|reply
Unfortunately that's not the only blunder in that sentence. Are we talking "on average" or are we talking "at full capacity?"

Not to mention the stylistic blunder by which a mathematical average, or a bunch of energy (or hey possibly even a turbine), is said to be "working at full capacity." I guess this is a dangling clause? Not sure if that's the right term for it.

Shave off all the fur and you're left with a pretty good sentence:

The turbine will produce about three megawatts of energy on average, which is enough to power 2,400 U.S. homes. (Assuming that figure is right.)

It's shorter too.

[+] jacquesm|7 years ago|reply
I spent a couple of years on a forum with renewable energy enthusiasts. In spite of endless corrections even there the posters kept messing that up so I have absolutely no confidence in journalism ever getting this right.
[+] ramchip|7 years ago|reply
> The turbine will produce about three megawatts of energy on average which, when working at full capacity, is enough to power 2,400 U.S. homes for one month.

The "for one month" makes no sense here, but if you drop it the math checks out.

[+] dredmorbius|7 years ago|reply
Clarifying further:

Megawatts are a unit of power. Think of the size of the engine in a car.

Megawatt-hours are a unit of energy. Think of the size of a fuel tank.

Both units are useful: if you run a 1 MW load (a synonym, mostly, for power) for an hour, you'll use one MWh of energy, and have to fuel or pay equivalently.

But increasing the size of your gas tank won't make your car more powerful, and increasing the engine size won't let you drive further between fuel stops.[1]

That serious information outlets still confuse the terms is a bit sad really.

_______________________________

Notes:

1. Pedants, I love you, welcome to Costco. But I'm excluding second-order effects, which tend regardless to be in the opposite directions.

[+] Agathos|7 years ago|reply
Maybe it's poorly made and the blades will fall off after a month?
[+] amluto|7 years ago|reply
It’s a thing. The article also talks about water pipes, “which leaks enough drinking water a day to serve 15 million households”.
[+] rini17|7 years ago|reply
I expected some estimate when the turbine generates enough energy to make the concrete instead...perhaps I have too high expectations.
[+] xyzzyz|7 years ago|reply
Additionally, it won’t work at full capacity all of the time. The capacity factors as seen in actual existing commercial installations usually range betweeen 40% and 60%, so the average power output here will be rather 1-1.7 MW instead of 3 MW
[+] cup-of-tea|7 years ago|reply
Or three times that many homes in Europe. US power usage shouldn't be used as a benchmark.
[+] Koshkin|7 years ago|reply
Actually, it's "megawatts of energy" that doesn't make sense; home per month, on the other hand, is a valid unit of power.
[+] Lazare|7 years ago|reply
I found the article odd, because it talked a lot about the different dynamics and the emissions of different things, but never netted them out.

If you're going to talk about the CO2 emissions of the concrete needed for a wind turbine, the obvious next step would be to net them all out and figure out if building wind turbines is a net reduction in CO2 or not.

The author seemed to go out of their way to imply that as long as we use Portland cement, it would not be a net reduction, but they never actually came out and said that.

Not quite sure what to make of it. It's like reading an article that talks about electric cars and how high electricity can make them more expensive than you think, but then...never actually calculates their operating cost and compares it to a conventional ICE powertrain.

[+] mabbo|7 years ago|reply
There's a difference between a one-time cost and a variable cost. "Spending" carbon (via concrete) in order to reduce society's "spending" of carbon (via infrastructure improvements) should usually come out to a net gain.

It's an investment.

While I agree we need to include all costs in the accounting and improve the concrete industry as well, we shouldn't let the fact that carbon is emitted by concrete creation stop us from making these investments.

[+] _jal|7 years ago|reply
Sure. Many things are. The question is not whether concrete is a marvelously useful material; the question is whether other materials might have fewer negative externalities without compromising function.

Note that you can rewrite that notion to discourage thinking about replacements for lots of things in the modern economy. Oil is a major input into nearly all other investments, so "spending" dino-juice carbon to enable everything else should usually come out a net gain, right?

[+] dmurray|7 years ago|reply
> Cement is the second-most consumed material in the world, after water.

This is repeated in the article but it doesn't sound right to me. Concrete is mostly stone and sand, with cement only making up 10-20% of the mixture. So both of those should be consumed more than cement is.

[+] realandreskytt|7 years ago|reply
Afaik the way cement works is you separate carbon from stone during its production and it binds co2 from air during setting. So wheres the big impact?
[+] mchannon|7 years ago|reply
It doesn't bind CO2 from air during setting- that's the disconnect.

By converting the carbonate to oxide, the calcium in cement is free to bond with silicates (and to a lesser extent other compounds).

That CO2 released during manufacture is now looking for a new home, which could either be a plant, or a weathering deposit of limestone which could use the CO2 in the air to convert its own carbonate to stable bicarbonate.

[+] dzhiurgis|7 years ago|reply
At some point it must be cheaper to just cut a massive piece of rock and ship it to the construction site, isn't it?
[+] NegativeLatency|7 years ago|reply
The “separate carbon from stone” step is not 100% efficient
[+] sandworm101|7 years ago|reply
>>And due to their lack of scientific acumen, they’ve focused on using different raw material mixers for cement which are introduced after the carbon intensive portion of the process.

That someone does not share your goals says nothing of their scientific acumen. There are plenty of intelligent scientists working in the concrete industry. Their priorities may be different, but they are not bad scientists.

Concrete is also a consumer product. Real change has to come from the architects and engineers who create the demand. But finding a true low-carbon alternative, a real alternative, is exceptionally difficult. Properly designed and maintained concrete structures can last centuries.

[+] jessaustin|7 years ago|reply
Centuries? Doesn't the material lose much of its strength when the rebar rusts away, which it certainly does in a century?
[+] adrianN|7 years ago|reply
We just need a carbon tax that appropriately prices the pollution in. Just set up a market where people can trade carbon and companies can make money by sequestering carbon out of the atmosphere.
[+] skosch|7 years ago|reply
Fortunately, the political will for carbon pricing is growing. The one obstacle is that conservative politicians are scared of using the word "tax" – so the current strategy is to push for a bill that would return all of the money to citizens ("carbon dividends" are an easier sell than "carbon taxes").

Here are the biggest organizations pushing for this — support them if you can:

https://citizensclimatelobby.org/ (strictly bipartisan)

https://www.clcouncil.org/ and their PAC, https://twitter.com/afcdividends (conservative/industry-backed)

https://allianceformarketsolutions.org/ (conservative)

https://www.s4cd.org/ (campus-based)

[+] amluto|7 years ago|reply
It’s not at all clear to me why carbon trading is useful. If a ton of CO2 emission is taxed $5 and a ton of capture is credited $5, what’s the point of trading certificates?
[+] gmueckl|7 years ago|reply
Sequestration should not be part of a market for CO2 certificates. Sure, you could earn money by sequestering CO2 and selling certificates generated by the process. But you will have to buy them back when the CO2 leaks. And it should diffuse out of the atirahe over time, albeit slowly. So you might eventually have to buy back the certificates instead of earning the money required to maintain the filled up CO2 storage for, well, virtually forever.
[+] crankylinuxuser|7 years ago|reply
> “We have created the Ferrari, now we need to create the Ford,” Ulm said.

No, you put a racing stripe and a spoiler on a dumptruck, and then talked about its aerodynamic qualities.

Not all industries are happy about ecological actions. That game will have winners and losers.. The Earth as a biosphere will "win", but there's a lot of industries that lose.

Last I checked, the Earth's biosphere isn't paying the politicians. The dirty companies, well, they are.

[+] lpcam33|7 years ago|reply
It's time to question economic growth. We cannot change the whole economy with a green one, we simply don't have the resources. This is just one example of many. What we need it's to take care of what we have right now and create conditions for people to have a good live regardless the economy is growing or not.
[+] Turing_Machine|7 years ago|reply
The only possible way that the billions of people in the Third World will ever have anything approaching a "good life" is by massive economic growth.
[+] maxerickson|7 years ago|reply
First step to creating conditions for 7 or 8 billion people to have good lives is to massively grow the economy.
[+] timwaagh|7 years ago|reply
im in, where can i buy this? where can i invest?

ah thats right...nowhere.

the problem is not the industry. the problem is the people who write this and complain about it have not taken any steps to bring these more sustainable cements to market.

[+] aoner|7 years ago|reply
The problem is actually the industry. Many companies have tried, but keep failing. There is a really insightful report why innovation is stopped by huge barriers in the industry: https://www.sciencedirect.com/science/article/pii/S221042241...

The development of more sustainable cements is a challenging but urgent venture. Demand-oriented knowledge formation and the reliance on existing prescriptive standards impede progress towards more sustainable alternatives to conventional cements. None-the-less the last years saw the emergence of a number of technology based start-ups with ambitions to introduce new low-carbon cements as alternatives to traditional Ordinary Portland Cement (OPC). An overall analysis of the Technological Innovation System for cement technology is conducted. This is extended with an investigation of how three start-ups, Celitement, Novacem and Calera perform within this environment. The implementation of new materials requires new types of collaboration between R&D and market actors, a combination of synthetic with the existing analytic knowledge base and redefinition of standards and norms. Moreover, a close cooperation of incumbent actors along the construction value chain is precondition for success of disruptive innovations.