10 ms·

We have to build differently with concrete

114 points by andrewl 4y ago

brigandish 4y ago
Why has the title been changed from the article's actual title of "Concrete Built The Modern World. Now It’s Destroying It." to part of the summary? Aside from that, interesting, and with the odd funny line, if not completely from the author themself: > One booklet described it as a “concrete temple enthroned in a mineral universe,” another as akin to the great pyramids of Egypt, except “useful.”
- brigandish 4y ago
  I'll add, there's some fascinating stuff towards the end, like this: > Block went for a walk on top of the vaults [Kings College Chapel in Cambridge]. “In thickness-to-span ratio, they were proportionally as thin as an eggshell. They were so thin I could feel them vibrating. When I jumped, I felt them bounce. And yet they were still strong and standing. When you have an experience like this, and really feel how exceptionally thin this totally unreinforced structure is, it really motivates you. You realize: Damn, we have forgotten something. We have forgotten this knowledge.”
  - mwint 4y ago
    We’ve not forgotten it - we’ve just chosen to optimize for a different point in the (longevity, cost, time, material) space.
    - mitthrowaway2 4y ago
      What makes you think that it hasn't been forgotten?
      - rawling 4y ago
        Well, Wikipedia lists an example built in 1958. https://en.wikipedia.org/wiki/Fan_vault https://en.wikipedia.org/wiki/Fan_vault
        mitthrowaway2 4y ago
        That's a retirement-age ago. Wikipedia also says that particular vault is made of concrete and steel, while being faced with stone.
XorNot 4y ago
I don't like this trend of piling up unrelated green house gas contributions, particularly for a relatively small (8%) of the total of anthropogenic climate emissions. For example, of that 8% figure 40% is fuel used to heat the kilns which make cement - i.e. a substituteable energy usage not unique to the cement industry. 10% is the fuel used to mine and transport the raw materials (also substituteable and not unique to the industry). About 50% of emissions overall are from the actual calcination reaction of limestone[1], but plugged into that number it would then be that 4% of global emissions are from a non-replaceable operation in making cement. That itself is also a bit a misnomer of course - aging concrete structures re-absorb CO2, up to about 40+% of that released during their manufacture over their lifetime.[2] This is certainly not a process we couldn't manage by CO2 scrubbing or sequestration activities during the manufacture of cement, or you know, probably could offset with forestation projects. All the rest of contributions are not cement industry problems, they're technology problems which if solved would change things positively for every industry (i.e. electric/microwave kilns, electric mining and transport vehicles). [1] https://www.carbonbrief.org/qa-why-cement-emissions-matter-for-climate-change/ https://www.carbonbrief.org/qa-why-cement-emissions-matter-f... [2] https://www.abc.net.au/news/science/2016-11-22/concrete-is-a-carbon-sink/8043174 https://www.abc.net.au/news/science/2016-11-22/concrete-is-a...
User23 4y ago
Are these the same architects who have inflicted a shitscape of low priced high rent cookie cutter 1+5 block projects on us? If so, then why should we care what they think?
- Spooky23 4y ago
  Lol. Architects have little do do with those, that’s builder grade dreck all the way.
zug_zug 4y ago
Not to be that guy, but the most efficient solution to this is a carbon tax. Once there is a carbon tax the market will be incentivized to pick the most environmental solution (keeping in mind we can pull this carbon back out of the air if we really need to). It would make a huge economic incentive to invent low-carbon concrete, for example.
- brigandish 4y ago
  The article does address that somewhat: > There won’t be a single perfect solution to the problem of concrete. One potential advancement is green concrete, which is decarbonized by changing the recipe, production process or longevity. Another is to capture emitted carbon at cement plants and store or reuse it. Scroll down to the bit about ETH Zürich's research and there's some interesting stuff beyond the long opening about history. > Block’s early research was focused on heritage architecture — vaulted cathedrals and other historic structures. “Our modern engineering tools are quite inadequate in explaining how safe these buildings are,” he said. Sometimes, he went on, digital engineering models of old buildings concluded that there should be no way they could still be standing, that they should’ve collapsed centuries ago. But there they were, solid, unmoving. Maybe, Block thought, there was something wrong with the models.
  - adrian_b 4y ago
    Any kind of physical model that is computable must make huge simplifications by ignoring most characteristics of the modeled system. Therefore whoever creates the model must choose a priori which features should be included in the model, because it is believed that they influence the results. and which features should be ignored, because it is believed that they have negligible influence. Any kind of physical model must be validated by comparison with experiments. It is extremely frequent to discover that the model does not match the experiments, which means that the a priori judgments about what can be neglected have been wrong. In such cases, the assumptions on which the model is based must be reviewed and some of the decisions about what features should be included in the model should be reversed. This is the normal way of working with any models, so the fact that the first attempt of modeling the ancient vaults has failed, does not say much, except that those who had made that initial attempt either did not understand well the behavior of certain rocks under compressive stresses, or they did not understand well how the building techniques used by the old masters redistributed the stresses in the rocks composing the vaults. The article does not explain which was the problem with those wrong models, but then it mentions that the team of Block has applied the traditional method of stone masonry, of making structures which are under compressive stresses, instead of bending stresses, like in a flat floor or ceiling, to design floors that need much less concrete than the conventional floors. This seems like a very obvious method, which should have already been used if good, so I wonder if the comparison about the concrete consumption was made at equal usable interior spaces. The main reason why flat floors and ceilings have been preferred in modern multi-level buildings was to provide interior spaces that can be completely used, without being partially blocked by structural elements (e.g. if the ceiling is a vault, you cannot put at a wall a cabinet raising up to the ceiling, but only up to the height where the curved part of the vault joins the vertical walls; if the vault has ribs, those impose additional constraints).
zahllos 4y ago
Interesting article. Since the article focuses on Switzerland and I live there I have another angle to present that I find very interesting. In our local region one problem is that the 'city' is heavily concreted. There's a distinct lack of green in many areas. In the summer and in particular this year, but other heatwaves as well, this becomes punishing in the city: concrete absorbs the heat during the day and radiates it at night, making the city even hotter. See the sibling comment about whether the CO2 numbers make sense, but I also think with warming environs locally we're going to have to get a lot smarter about how we build to manage heat as well. There was a fascinating article on HN a while ago about the London Underground and the troubles they're having cooling it... The Swiss build a lot with concrete in their cities and there's going to be a corresponding difficulty of keeping them cool.
- ouchjars 4y ago
  Traditional masonry construction has the same results in terms of thermal mass. More so, if it's denser and thicker. With the right shading and ventilation it's useful for both temperature extremes. See vernacular architecture in warmer/more extreme climates, or what Federation Square in Melbourne achieves with concrete: https://blogs.unimelb.edu.au/sciencecommunication/2013/09/22/federation-square-a-thermal-labyrinth/ https://blogs.unimelb.edu.au/sciencecommunication/2013/09/22... https://www.youtube.com/watch?v=vBWYe99ERqM https://www.youtube.com/watch?v=vBWYe99ERqM Considering active heating/cooling as well as passive, the more thermal mass we have in buildings, the better they can act as thermal batteries for surplus renewable energy.
wonder_er 4y ago
Rammed Earth. I'd long been part of the camp that says "on the whole, concrete's not that great of a material to build with, for a bunch of reasons, but it's also got some significant upsides." Then, I stumbled backwards into this crazy building technique that solves _some_ problems really well. It's this traditional building technique called "rammed earth". It's updated a smidge for modernity, but it's basically the same today as how buildings were built 1000 years ago. Mega beautiful, practical, interesting constraints and opportunities, anyone can build them, etc. Wikipedia: https://en.wikipedia.org/wiki/Rammed_earth https://en.wikipedia.org/wiki/Rammed_earth Video from a skilled modern-day rammed earth structure builder: https://www.youtube.com/watch?v=jijU-4A8jAk https://www.youtube.com/watch?v=jijU-4A8jAk
- SECProto 4y ago
  > Video from a skilled modern-day rammed earth structure builder Note that the rammed earth there is being mixed with cement, making it in effect a lean concrete. Additionally, the column (?) is on top of a concrete footing, it appears from coloration to be a fairly normal concrete mix at the bottom, the top layer is also definitely a standard concrete mixture, the rebar looks like standard for something in a short building as that presumably is. Essentially the only difference between that and a standard concrete structure is that the column has to be much larger in cross section (as the lean concrete mix used would have lower compressive strength than normal concrete), the mixture uses less cement in exchange for compaction in lifts (i.e. exchanging material cost for labour cost), and the formwork has to be much heftier to sustain the pressures being placed on it from the pressure rammer. I quite like the sturdier looking columns, and the layering is quite attractive (that guy clearly puts a lot of effort into it, visible when he's fine tamping the outside edge of the layer very carefully), but I don't think it's so much different than normal concrete. Trying to do QC or QA on that mix design would be a nightmare.
- steve_adams_86 4y ago
  I've had the fortune of checking out a few rammed earth structures around BC, Canada (there is a cool fence/wall built with it within a property on Saltspring Island, a winery's sales building on Hornby Island, an amazing example in Osoyoos[1], and many more) and I agree, it's really beautiful. If I have the opportunity I'll almost certainly use it to build a home in the future. I'm always excited when I see buildings using it. Well done rammed earth walls are absolutely stunning when finished properly. 1. https://sirewall.com/portfolio/nkmip-desert-cultural-centre/ https://sirewall.com/portfolio/nkmip-desert-cultural-centre/
mdip 4y ago
For those clicking in, seeing the length and thinking something like "Pages and pages; sounds really alarmist" and are ready to click off, he ends up doing a really thorough job also explaining what advances have been made, what's being looked at for each of the various identified problems and it ends up being an interesting and informative piece on the subject ... if you find Concrete interesting. (That's a pretty good tl;dr if you want one, but it makes me sound (at best) underwhelmed or (at worst) grumpy, so ...) I'm kind of reading this thinking "that sounds like a bunch of crappy things to say" and I can't find a way to accurately explain where my head was at without kind of sounding like "a dick" -- it's really not intended. I get extremely annoyed with alarmist articles, especially those with the words "Carbon Footprint" and "Climate Change" in the title[0]. I am not a "Climate Denier"-whatever-boogie-man, I've just noticed that articles with those words in the title are (a) almost certainly going to tell me nothing I don't already know -- they're very low-information, (b) they're low-information because their audience is the general public usually for the purpose of getting them behind some government action that will "move money around and help nothing" or (c) no-information because the goal was to scare you into clicking. I feel really badly for getting annoyed at this article given that it was none of these things, but turned out to explain history, current state-of-the-art, the various problems, various approaches being looked at by industry/in use (or near/in research). Failing to include those components causes readers to fall into a "mental trap" that I'm sure has a name, but which I don't know. It's the "5% of cars are electric vehicles, we expect that to grow to 10% but if ((really unpalatable/expensive solution)) isn't done, we won't have the charging/grid/etc capacity to support it!", ignoring the fact that ten years ago we didn't have the infrastructure to support the 5% that we have, today and assuming that we'll suddenly stop building out new infrastructure. "Humanity"[1] advances at an accelerating pace. It's easy to get lost in that word. A way that helps me grasp it better was told to me in fifth grade: as time goes on, we double the amount of things we know in less and less time. Yes, we lose things, too, and even regress in places, but we're getting better at that, too and overall we're ahead. By including past advances, current state of the art and where things are heading, the author reminded the reader that "the world is moving around all of these problems, too." It also presents the trade-offs correctly. I find it interesting that -- in my lifetime -- I've watched 12 miles of a 6 or 8-lane cement road get blown away and rebuilt twice (along with years of roving maintenance). Grumbling about "it seems like they work on that same road every other year despite replacing it every 25 or so" aside, the differences in how they are built and the final product are astounding. Gone are the rusting painted iron road bridges, replaced with cement. In two cases, a 2.5-year (and I mean, in-between snowfalls on both ends of the year) job took under a year to do the second time. I think the biggest difference was how the road bed was put down. Before, it was methodical, a few squares at a time at various stages in the "pouring from the cement truck" to "cleaning everything up and smoothing the top out". In all cases the last several years, it's some combination of "prepare the foundation the surface of the road will sit" then over two weekends this machine the width of the entire road rolls down the bed while about the same number of workers manage the machine. They finish it off with curbs/the like and Bob's your Uncle. If this similarly reduces the cost (I have to believe it does but I have no data), an interesting equilibrium has to be reached between price, the time it takes to build[2], maintain and destroy[3]. Unfortunately, the raw "price" of the most expensive part and "how long the voters will be furious" will win out provided everything else is "barely passable". [0] Calm down... just read on. [1] I know, what's "Humanity" -- a subset of humanity, of course, but enough of us to matter. [2] And similar balancing of civilian annoyance: I'm OK with an important highway being taken out for a year every 25 or so if maintenance is "knocking a lane out for a few months every 5 years" instead of "knocking most of the highway out for most weekends every other summer" for a material that goes down in a few months (or lasts for 50 years, etc). [3] Extremely durable/robust concrete is great until it's time to build a bypass through town and some roads need to ripped up before their useful lifetime. Concrete that survives being beaten up by God, semis and all of us for hundreds of years is going to be resistant to ... a lot of stuff.
horseAMcharlie 4y ago
I recently read Construction Physics' post on concrete use: https://constructionphysics.substack.com/p/so-you-want-to-use-less-concrete https://constructionphysics.substack.com/p/so-you-want-to-us... and I consider it to be required reading for people outside of the field on the topic of concrete emissions. Globally, concrete production emits like crazy but this is largely a product of scale; other building materials emit far more GhGs by mass and volume but are used in much smaller quantities than concrete. I'm all for a broad package of carbon taxes to both reduce growth and force the development of political and financial solutions for a low-growth, steady-state or degrowth economy but don't be misled into thinking the end result is a smaller share of concrete as a building material. More likely, carbon taxes will reduce the proportions of plastics, steel, aluminum and glass in construction in favour of more concrete.
mjevans 4y ago
Some of the suggested alternatives, glued and compressed wood, sound far more flammable than an artificial stone like concrete. I'd much rather a building were as fire proof as possible, that should be a strong component of any replacement technology.
- antod 4y ago
  Large wooden structural members perform better in fire than most people expect, and concrete ones often don't perform as well as most people expect.
  - jaclaz 4y ago
    Yes and no. No doubts about "traditional" wood elements (beams and the like) made from trees, they show quite good fire resistance, basically when on fire an outer shell of carbonized material forms and acts as a insulating layer that keeps the core stable for relatively long times. But in many "modern" structures the large, structural parts tend to be made of composed materials, essentially smaller parts glued together. In these cases the weak point becomes the glue used in them that may make the element fail well before a monolithic wood one. Of course it depends on local codes and standards, but generally speaking these elements need to be protected by either anti-fire paint or gypsum panels.
rob74 4y ago
On "we have to build differently with concrete": one promising development is carbon fibre reinforced concrete (https://www.compositesworld.com/news/carbon-fiber-reinforced-concrete-accelerates-in-germany https://www.compositesworld.com/news/carbon-fiber-reinforced...). Since most of the cement in conventional concrete is actually needed to protect the steel reinforcing rods from corrosion (and parts of the structure have to be stronger to support the rest of it), structures built with carbon fibre concrete can be much lighter and therefore use less resources. And because of that, it might even become cost competitive despite the higher price of carbon fibre. But the "...or abandon it altogether" which someone left out of the title should be considered too.
nonick 4y ago
There's a Romanian startup that tries to address part of the issue. They estimate that their technology can decrease concrete use by 30%: https://svelte.eu/ https://svelte.eu/
parski 4y ago
Anyone know more about the magazine and what it's trying to accomplish? It seems to be run by some billionaire.

114 points by andrewl 4y ago

Why has the title been changed from the article's actual title of "Concrete Built The Modern World. Now It’s Destroying It." to part of the summary? Aside from that, interesting, and with the odd funny line, if not completely from the author themself: > One booklet described it as a “concrete temple enthroned in a mineral universe,” another as akin to the great pyramids of Egypt, except “useful.”

brigandish 4y ago
I'll add, there's some fascinating stuff towards the end, like this: > Block went for a walk on top of the vaults [Kings College Chapel in Cambridge]. “In thickness-to-span ratio, they were proportionally as thin as an eggshell. They were so thin I could feel them vibrating. When I jumped, I felt them bounce. And yet they were still strong and standing. When you have an experience like this, and really feel how exceptionally thin this totally unreinforced structure is, it really motivates you. You realize: Damn, we have forgotten something. We have forgotten this knowledge.”
- mwint 4y ago
  We’ve not forgotten it - we’ve just chosen to optimize for a different point in the (longevity, cost, time, material) space.
  - mitthrowaway2 4y ago
    What makes you think that it hasn't been forgotten?
    - rawling 4y ago
      Well, Wikipedia lists an example built in 1958. https://en.wikipedia.org/wiki/Fan_vault https://en.wikipedia.org/wiki/Fan_vault
      - mitthrowaway2 4y ago
        That's a retirement-age ago. Wikipedia also says that particular vault is made of concrete and steel, while being faced with stone.

XorNot 4y ago

I don't like this trend of piling up unrelated green house gas contributions, particularly for a relatively small (8%) of the total of anthropogenic climate emissions. For example, of that 8% figure 40% is fuel used to heat the kilns which make cement - i.e. a substituteable energy usage not unique to the cement industry. 10% is the fuel used to mine and transport the raw materials (also substituteable and not unique to the industry). About 50% of emissions overall are from the actual calcination reaction of limestone[1], but plugged into that number it would then be that 4% of global emissions are from a non-replaceable operation in making cement. That itself is also a bit a misnomer of course - aging concrete structures re-absorb CO2, up to about 40+% of that released during their manufacture over their lifetime.[2] This is certainly not a process we couldn't manage by CO2 scrubbing or sequestration activities during the manufacture of cement, or you know, probably could offset with forestation projects. All the rest of contributions are not cement industry problems, they're technology problems which if solved would change things positively for every industry (i.e. electric/microwave kilns, electric mining and transport vehicles). [1] https://www.carbonbrief.org/qa-why-cement-emissions-matter-for-climate-change/ https://www.carbonbrief.org/qa-why-cement-emissions-matter-f... [2] https://www.abc.net.au/news/science/2016-11-22/concrete-is-a-carbon-sink/8043174 https://www.abc.net.au/news/science/2016-11-22/concrete-is-a...

User23 4y ago

Are these the same architects who have inflicted a shitscape of low priced high rent cookie cutter 1+5 block projects on us? If so, then why should we care what they think?

Spooky23 4y ago
Lol. Architects have little do do with those, that’s builder grade dreck all the way.

zug_zug 4y ago

Not to be that guy, but the most efficient solution to this is a carbon tax. Once there is a carbon tax the market will be incentivized to pick the most environmental solution (keeping in mind we can pull this carbon back out of the air if we really need to). It would make a huge economic incentive to invent low-carbon concrete, for example.

brigandish 4y ago
The article does address that somewhat: > There won’t be a single perfect solution to the problem of concrete. One potential advancement is green concrete, which is decarbonized by changing the recipe, production process or longevity. Another is to capture emitted carbon at cement plants and store or reuse it. Scroll down to the bit about ETH Zürich's research and there's some interesting stuff beyond the long opening about history. > Block’s early research was focused on heritage architecture — vaulted cathedrals and other historic structures. “Our modern engineering tools are quite inadequate in explaining how safe these buildings are,” he said. Sometimes, he went on, digital engineering models of old buildings concluded that there should be no way they could still be standing, that they should’ve collapsed centuries ago. But there they were, solid, unmoving. Maybe, Block thought, there was something wrong with the models.
- adrian_b 4y ago
  Any kind of physical model that is computable must make huge simplifications by ignoring most characteristics of the modeled system. Therefore whoever creates the model must choose a priori which features should be included in the model, because it is believed that they influence the results. and which features should be ignored, because it is believed that they have negligible influence. Any kind of physical model must be validated by comparison with experiments. It is extremely frequent to discover that the model does not match the experiments, which means that the a priori judgments about what can be neglected have been wrong. In such cases, the assumptions on which the model is based must be reviewed and some of the decisions about what features should be included in the model should be reversed. This is the normal way of working with any models, so the fact that the first attempt of modeling the ancient vaults has failed, does not say much, except that those who had made that initial attempt either did not understand well the behavior of certain rocks under compressive stresses, or they did not understand well how the building techniques used by the old masters redistributed the stresses in the rocks composing the vaults. The article does not explain which was the problem with those wrong models, but then it mentions that the team of Block has applied the traditional method of stone masonry, of making structures which are under compressive stresses, instead of bending stresses, like in a flat floor or ceiling, to design floors that need much less concrete than the conventional floors. This seems like a very obvious method, which should have already been used if good, so I wonder if the comparison about the concrete consumption was made at equal usable interior spaces. The main reason why flat floors and ceilings have been preferred in modern multi-level buildings was to provide interior spaces that can be completely used, without being partially blocked by structural elements (e.g. if the ceiling is a vault, you cannot put at a wall a cabinet raising up to the ceiling, but only up to the height where the curved part of the vault joins the vertical walls; if the vault has ribs, those impose additional constraints).

zahllos 4y ago

Interesting article. Since the article focuses on Switzerland and I live there I have another angle to present that I find very interesting. In our local region one problem is that the 'city' is heavily concreted. There's a distinct lack of green in many areas. In the summer and in particular this year, but other heatwaves as well, this becomes punishing in the city: concrete absorbs the heat during the day and radiates it at night, making the city even hotter. See the sibling comment about whether the CO2 numbers make sense, but I also think with warming environs locally we're going to have to get a lot smarter about how we build to manage heat as well. There was a fascinating article on HN a while ago about the London Underground and the troubles they're having cooling it... The Swiss build a lot with concrete in their cities and there's going to be a corresponding difficulty of keeping them cool.

ouchjars 4y ago
Traditional masonry construction has the same results in terms of thermal mass. More so, if it's denser and thicker. With the right shading and ventilation it's useful for both temperature extremes. See vernacular architecture in warmer/more extreme climates, or what Federation Square in Melbourne achieves with concrete: https://blogs.unimelb.edu.au/sciencecommunication/2013/09/22/federation-square-a-thermal-labyrinth/ https://blogs.unimelb.edu.au/sciencecommunication/2013/09/22... https://www.youtube.com/watch?v=vBWYe99ERqM https://www.youtube.com/watch?v=vBWYe99ERqM Considering active heating/cooling as well as passive, the more thermal mass we have in buildings, the better they can act as thermal batteries for surplus renewable energy.

wonder_er 4y ago

Rammed Earth. I'd long been part of the camp that says "on the whole, concrete's not that great of a material to build with, for a bunch of reasons, but it's also got some significant upsides." Then, I stumbled backwards into this crazy building technique that solves _some_ problems really well. It's this traditional building technique called "rammed earth". It's updated a smidge for modernity, but it's basically the same today as how buildings were built 1000 years ago. Mega beautiful, practical, interesting constraints and opportunities, anyone can build them, etc. Wikipedia: https://en.wikipedia.org/wiki/Rammed_earth https://en.wikipedia.org/wiki/Rammed_earth Video from a skilled modern-day rammed earth structure builder: https://www.youtube.com/watch?v=jijU-4A8jAk https://www.youtube.com/watch?v=jijU-4A8jAk

SECProto 4y ago
> Video from a skilled modern-day rammed earth structure builder Note that the rammed earth there is being mixed with cement, making it in effect a lean concrete. Additionally, the column (?) is on top of a concrete footing, it appears from coloration to be a fairly normal concrete mix at the bottom, the top layer is also definitely a standard concrete mixture, the rebar looks like standard for something in a short building as that presumably is. Essentially the only difference between that and a standard concrete structure is that the column has to be much larger in cross section (as the lean concrete mix used would have lower compressive strength than normal concrete), the mixture uses less cement in exchange for compaction in lifts (i.e. exchanging material cost for labour cost), and the formwork has to be much heftier to sustain the pressures being placed on it from the pressure rammer. I quite like the sturdier looking columns, and the layering is quite attractive (that guy clearly puts a lot of effort into it, visible when he's fine tamping the outside edge of the layer very carefully), but I don't think it's so much different than normal concrete. Trying to do QC or QA on that mix design would be a nightmare.
steve_adams_86 4y ago
I've had the fortune of checking out a few rammed earth structures around BC, Canada (there is a cool fence/wall built with it within a property on Saltspring Island, a winery's sales building on Hornby Island, an amazing example in Osoyoos[1], and many more) and I agree, it's really beautiful. If I have the opportunity I'll almost certainly use it to build a home in the future. I'm always excited when I see buildings using it. Well done rammed earth walls are absolutely stunning when finished properly. 1. https://sirewall.com/portfolio/nkmip-desert-cultural-centre/ https://sirewall.com/portfolio/nkmip-desert-cultural-centre/

mdip 4y ago

For those clicking in, seeing the length and thinking something like "Pages and pages; sounds really alarmist" and are ready to click off, he ends up doing a really thorough job also explaining what advances have been made, what's being looked at for each of the various identified problems and it ends up being an interesting and informative piece on the subject ... if you find Concrete interesting. (That's a pretty good tl;dr if you want one, but it makes me sound (at best) underwhelmed or (at worst) grumpy, so ...) I'm kind of reading this thinking "that sounds like a bunch of crappy things to say" and I can't find a way to accurately explain where my head was at without kind of sounding like "a dick" -- it's really not intended. I get extremely annoyed with alarmist articles, especially those with the words "Carbon Footprint" and "Climate Change" in the title[0]. I am not a "Climate Denier"-whatever-boogie-man, I've just noticed that articles with those words in the title are (a) almost certainly going to tell me nothing I don't already know -- they're very low-information, (b) they're low-information because their audience is the general public usually for the purpose of getting them behind some government action that will "move money around and help nothing" or (c) no-information because the goal was to scare you into clicking. I feel really badly for getting annoyed at this article given that it was none of these things, but turned out to explain history, current state-of-the-art, the various problems, various approaches being looked at by industry/in use (or near/in research). Failing to include those components causes readers to fall into a "mental trap" that I'm sure has a name, but which I don't know. It's the "5% of cars are electric vehicles, we expect that to grow to 10% but if ((really unpalatable/expensive solution)) isn't done, we won't have the charging/grid/etc capacity to support it!", ignoring the fact that ten years ago we didn't have the infrastructure to support the 5% that we have, today and assuming that we'll suddenly stop building out new infrastructure. "Humanity"[1] advances at an accelerating pace. It's easy to get lost in that word. A way that helps me grasp it better was told to me in fifth grade: as time goes on, we double the amount of things we know in less and less time. Yes, we lose things, too, and even regress in places, but we're getting better at that, too and overall we're ahead. By including past advances, current state of the art and where things are heading, the author reminded the reader that "the world is moving around all of these problems, too." It also presents the trade-offs correctly. I find it interesting that -- in my lifetime -- I've watched 12 miles of a 6 or 8-lane cement road get blown away and rebuilt twice (along with years of roving maintenance). Grumbling about "it seems like they work on that same road every other year despite replacing it every 25 or so" aside, the differences in how they are built and the final product are astounding. Gone are the rusting painted iron road bridges, replaced with cement. In two cases, a 2.5-year (and I mean, in-between snowfalls on both ends of the year) job took under a year to do the second time. I think the biggest difference was how the road bed was put down. Before, it was methodical, a few squares at a time at various stages in the "pouring from the cement truck" to "cleaning everything up and smoothing the top out". In all cases the last several years, it's some combination of "prepare the foundation the surface of the road will sit" then over two weekends this machine the width of the entire road rolls down the bed while about the same number of workers manage the machine. They finish it off with curbs/the like and Bob's your Uncle. If this similarly reduces the cost (I have to believe it does but I have no data), an interesting equilibrium has to be reached between price, the time it takes to build[2], maintain and destroy[3]. Unfortunately, the raw "price" of the most expensive part and "how long the voters will be furious" will win out provided everything else is "barely passable". [0] Calm down... just read on. [1] I know, what's "Humanity" -- a subset of humanity, of course, but enough of us to matter. [2] And similar balancing of civilian annoyance: I'm OK with an important highway being taken out for a year every 25 or so if maintenance is "knocking a lane out for a few months every 5 years" instead of "knocking most of the highway out for most weekends every other summer" for a material that goes down in a few months (or lasts for 50 years, etc). [3] Extremely durable/robust concrete is great until it's time to build a bypass through town and some roads need to ripped up before their useful lifetime. Concrete that survives being beaten up by God, semis and all of us for hundreds of years is going to be resistant to ... a lot of stuff.

horseAMcharlie 4y ago

I recently read Construction Physics' post on concrete use: https://constructionphysics.substack.com/p/so-you-want-to-use-less-concrete https://constructionphysics.substack.com/p/so-you-want-to-us... and I consider it to be required reading for people outside of the field on the topic of concrete emissions. Globally, concrete production emits like crazy but this is largely a product of scale; other building materials emit far more GhGs by mass and volume but are used in much smaller quantities than concrete. I'm all for a broad package of carbon taxes to both reduce growth and force the development of political and financial solutions for a low-growth, steady-state or degrowth economy but don't be misled into thinking the end result is a smaller share of concrete as a building material. More likely, carbon taxes will reduce the proportions of plastics, steel, aluminum and glass in construction in favour of more concrete.

mjevans 4y ago

Some of the suggested alternatives, glued and compressed wood, sound far more flammable than an artificial stone like concrete. I'd much rather a building were as fire proof as possible, that should be a strong component of any replacement technology.

antod 4y ago
Large wooden structural members perform better in fire than most people expect, and concrete ones often don't perform as well as most people expect.
- jaclaz 4y ago
  Yes and no. No doubts about "traditional" wood elements (beams and the like) made from trees, they show quite good fire resistance, basically when on fire an outer shell of carbonized material forms and acts as a insulating layer that keeps the core stable for relatively long times. But in many "modern" structures the large, structural parts tend to be made of composed materials, essentially smaller parts glued together. In these cases the weak point becomes the glue used in them that may make the element fail well before a monolithic wood one. Of course it depends on local codes and standards, but generally speaking these elements need to be protected by either anti-fire paint or gypsum panels.

rob74 4y ago

On "we have to build differently with concrete": one promising development is carbon fibre reinforced concrete (https://www.compositesworld.com/news/carbon-fiber-reinforced-concrete-accelerates-in-germany https://www.compositesworld.com/news/carbon-fiber-reinforced...). Since most of the cement in conventional concrete is actually needed to protect the steel reinforcing rods from corrosion (and parts of the structure have to be stronger to support the rest of it), structures built with carbon fibre concrete can be much lighter and therefore use less resources. And because of that, it might even become cost competitive despite the higher price of carbon fibre. But the "...or abandon it altogether" which someone left out of the title should be considered too.

nonick 4y ago

There's a Romanian startup that tries to address part of the issue. They estimate that their technology can decrease concrete use by 30%: https://svelte.eu/ https://svelte.eu/

parski 4y ago

Anyone know more about the magazine and what it's trying to accomplish? It seems to be run by some billionaire.