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We have to build differently with concrete

114 点作者 andrewl超过 2 年前

12 条评论

wonder_er超过 2 年前
Rammed Earth.<p>I&#x27;d long been part of the camp that says &quot;on the whole, concrete&#x27;s not that great of a material to build with, for a bunch of reasons, but it&#x27;s also got some significant upsides.&quot;<p>Then, I stumbled backwards into this crazy building technique that solves _some_ problems really well.<p>It&#x27;s this traditional building technique called &quot;rammed earth&quot;.<p>It&#x27;s updated a smidge for modernity, but it&#x27;s basically the same today as how buildings were built 1000 years ago.<p>Mega beautiful, practical, interesting constraints and opportunities, anyone can build them, etc.<p>Wikipedia: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Rammed_earth" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Rammed_earth</a><p>Video from a skilled modern-day rammed earth structure builder: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=jijU-4A8jAk" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=jijU-4A8jAk</a>
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XorNot超过 2 年前
I don&#x27;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.<p>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).<p>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.<p>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]<p>This is certainly not a process we couldn&#x27;t manage by CO2 scrubbing or sequestration activities during the manufacture of cement, or you know, probably could offset with forestation projects.<p>All the rest of contributions are not cement industry problems, they&#x27;re technology problems which if solved would change things positively for <i>every</i> industry (i.e. electric&#x2F;microwave kilns, electric mining and transport vehicles).<p>[1] <a href="https:&#x2F;&#x2F;www.carbonbrief.org&#x2F;qa-why-cement-emissions-matter-for-climate-change&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.carbonbrief.org&#x2F;qa-why-cement-emissions-matter-f...</a><p>[2] <a href="https:&#x2F;&#x2F;www.abc.net.au&#x2F;news&#x2F;science&#x2F;2016-11-22&#x2F;concrete-is-a-carbon-sink&#x2F;8043174" rel="nofollow">https:&#x2F;&#x2F;www.abc.net.au&#x2F;news&#x2F;science&#x2F;2016-11-22&#x2F;concrete-is-a...</a>
horseAMcharlie超过 2 年前
I recently read Construction Physics&#x27; post on concrete use:<p><a href="https:&#x2F;&#x2F;constructionphysics.substack.com&#x2F;p&#x2F;so-you-want-to-use-less-concrete" rel="nofollow">https:&#x2F;&#x2F;constructionphysics.substack.com&#x2F;p&#x2F;so-you-want-to-us...</a><p>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.<p>I&#x27;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&#x27;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.
rob74超过 2 年前
On &quot;we have to build differently with concrete&quot;: one promising development is carbon fibre reinforced concrete (<a href="https:&#x2F;&#x2F;www.compositesworld.com&#x2F;news&#x2F;carbon-fiber-reinforced-concrete-accelerates-in-germany" rel="nofollow">https:&#x2F;&#x2F;www.compositesworld.com&#x2F;news&#x2F;carbon-fiber-reinforced...</a>). 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.<p>But the &quot;...or abandon it altogether&quot; which <i>someone</i> left out of the title should be considered too.
zahllos超过 2 年前
Interesting article. Since the article focuses on Switzerland and I live there I have another angle to present that I find very interesting.<p>In our local region one problem is that the &#x27;city&#x27; is heavily concreted. There&#x27;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.<p>See the sibling comment about whether the CO2 numbers make sense, but I also think with warming environs locally we&#x27;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&#x27;re having cooling it... The Swiss build a lot with concrete in their cities and there&#x27;s going to be a corresponding difficulty of keeping them cool.
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brigandish超过 2 年前
Why has the title been changed from the article&#x27;s actual title of &quot;Concrete Built The Modern World. Now It’s Destroying It.&quot; to part of the summary?<p>Aside from that, interesting, and with the odd funny line, if not completely from the author themself:<p>&gt; One booklet described it as a “concrete temple enthroned in a mineral universe,” another as akin to the great pyramids of Egypt, except “useful.”
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zug_zug超过 2 年前
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.
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nonick超过 2 年前
There&#x27;s a Romanian startup that tries to address part of the issue. They estimate that their technology can decrease concrete use by 30%: <a href="https:&#x2F;&#x2F;svelte.eu&#x2F;" rel="nofollow">https:&#x2F;&#x2F;svelte.eu&#x2F;</a>
parski超过 2 年前
Anyone know more about the magazine and what it&#x27;s trying to accomplish? It seems to be run by some billionaire.
mjevans超过 2 年前
Some of the suggested alternatives, glued and compressed wood, sound far more flammable than an artificial stone like concrete.<p>I&#x27;d much rather a building were as fire proof as possible, that should be a strong component of any replacement technology.
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mdip超过 2 年前
For those clicking in, seeing the length and thinking something like &quot;Pages and pages; sounds <i>really</i> alarmist&quot; and are ready to click off, he ends up doing a really thorough job also explaining what advances have been made, what&#x27;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&#x27;s a pretty good tl;dr if you want one, but it makes me sound (at best) underwhelmed or (at worst) grumpy, so ...)<p>I&#x27;m kind of reading this thinking &quot;that sounds like a bunch of crappy things to say&quot; and I can&#x27;t find a way to <i>accurately</i> explain where my head was at without kind of sounding like &quot;a dick&quot; -- it&#x27;s really not intended. I get <i>extremely</i> annoyed with alarmist articles, especially those with the words &quot;Carbon Footprint&quot; and &quot;Climate Change&quot; in the title[0]. I am not a &quot;Climate Denier&quot;-whatever-boogie-man, I&#x27;ve just noticed that articles with those words in the title are (a) almost certainly going to tell me nothing I don&#x27;t already know -- they&#x27;re very low-information, (b) they&#x27;re low-information because their audience is the general public usually for the purpose of getting them behind some government action that will &quot;move money around and help nothing&quot; or (c) no-information because the goal was to scare you into clicking.<p>I feel <i>really badly</i> 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&#x2F;in use (or near&#x2F;in research). Failing to include those components causes readers to fall into a &quot;mental trap&quot; that I&#x27;m sure has a name, but which I don&#x27;t know. It&#x27;s the &quot;5% of cars are electric vehicles, we expect that to grow to 10% but if ((really unpalatable&#x2F;expensive solution)) isn&#x27;t done, we won&#x27;t have the charging&#x2F;grid&#x2F;etc capacity to support it!&quot;, ignoring the fact that ten years ago we didn&#x27;t have the infrastructure to support the 5% that we have, today and assuming that we&#x27;ll suddenly <i>stop</i> building out new infrastructure.<p>&quot;Humanity&quot;[1] advances at an <i>accelerating</i> pace. It&#x27;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&#x27;re getting better at that, too and overall we&#x27;re ahead. By including past advances, current state of the art and where things are heading, the author reminded the reader that &quot;the world is moving around all of these problems, too.&quot;<p>It also presents the trade-offs correctly. I find it interesting that -- in my lifetime -- I&#x27;ve watched 12 miles of a 6 or 8-lane cement road get blown away and rebuilt twice (along with <i>years</i> of roving maintenance). Grumbling about &quot;it seems like they work on that same road every other year despite replacing it every 25 or so&quot; aside, the differences in <i>how</i> 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 &quot;pouring from the cement truck&quot; to &quot;cleaning everything up and smoothing the top out&quot;. In all cases the last several years, it&#x27;s some combination of &quot;prepare the foundation the surface of the road will sit&quot; then over two weekends this machine the width of the <i>entire road</i> rolls down the bed while about the same number of workers manage the machine. They finish it off with curbs&#x2F;the like and Bob&#x27;s your Uncle. If this similarly reduces the <i>cost</i> (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 &quot;price&quot; of the most expensive part and &quot;how long the voters will be furious&quot; will win out provided everything else is &quot;barely passable&quot;.<p>[0] Calm down... just read on.<p>[1] I know, what&#x27;s &quot;Humanity&quot; -- a subset of humanity, of course, but enough of us to matter.<p>[2] And similar balancing of civilian annoyance: I&#x27;m OK with an important highway being taken out for a year every 25 or so if maintenance is &quot;knocking a lane out for a few months every 5 years&quot; instead of &quot;knocking most of the highway out for most weekends every other summer&quot; for a material that goes down in a few months (or lasts for 50 years, etc).<p>[3] Extremely durable&#x2F;robust concrete is great until it&#x27;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.
User23超过 2 年前
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?
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