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Earth Science

Can We Live Without Concrete? (cnn.com) 407

A combination of cement, water and ground rock or sand, on the surface concrete might seem crushingly mundane. Yet it has defined construction in recent centuries and with it, in part, modernity. From a report: But do we need to re-evaluate our concrete habit for our sakes and the planet's? Production of cement is disastrous for our biosphere, while the degradation of many concrete buildings has some construction experts predicting a colossal headache in the future. There are myriad proposed solutions, such as changing the way we make concrete, creating sustainable alternatives or doing away with it altogether. But would we want to live in a world without concrete? And what would that world look like?

"We make more concrete than anything else, any other product, apart from clean water," says Paul Fennell, professor of clean energy at Imperial College London. One 2015 report estimates that each year approximately three tons of concrete are used for every person on Earth -- roughly, 22 billion tons. To put that in context, a recent study estimated that 8.3 billion metric tons of plastic have been produced, ever. Manufacturing cement, concrete's binding agent, is energy-intensive, Fennell says. Ordinary Portland cement -- the most common form in concrete -- is produced by baking lime in a kiln and emits approximately one ton of carbon dioxide for every ton of cement. Concrete production is responsible for approximately 5% of global man-made CO2 emissions, according to the World Business Council for Sustainable Development.

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Can We Live Without Concrete?

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  • by olsmeister ( 1488789 ) on Friday May 04, 2018 @09:46AM (#56553764)
    Can't live with it, can't live inside it.
  • by aaronb1138 ( 2035478 ) on Friday May 04, 2018 @09:47AM (#56553772)
    Almost as much bullshit and low quality in the premise of this posting as asphalt and the whole asphalt lobbying and astroturfing.
  • by 110010001000 ( 697113 ) on Friday May 04, 2018 @09:59AM (#56553822) Homepage Journal
    Hemp is a good alternative to concrete. In addition it is renewable and extracts Co2. Plus it makes other useful things like clothing. Unfortunately the cotton industry is preventing the world from growing it. It is those people that are preventing us from having buildings made from hemp today.
  • by account_deleted ( 4530225 ) on Friday May 04, 2018 @10:04AM (#56553868)
    Comment removed based on user account deletion
  • by Kohath ( 38547 ) on Friday May 04, 2018 @10:04AM (#56553876)

    Why do you propose changes to make everyone's life worse?

    Figure out a way for life to actually be better. That's what you did in the 1970s when there was air pollution and water pollution. Air pollution was a problem, not a fear about a possible problem.

    Fund some research to create something better than concrete if you want something better than concrete.

    Don't ask us to give up living modern lives and mire ourselves in artificial poverty. That's not something Americans or Asians will do. Europeans might.

  • by Chas ( 5144 ) on Friday May 04, 2018 @10:06AM (#56553884) Homepage Journal

    Sorry. We're too dependent on it as a building material.

    Now, this doesn't mean we can't modify concrete to reduce/eliminate some of it's deleterious effects on the environment.

    But, in the end, we still need concrete in whatever forms it eventually takes.

    • Comment removed based on user account deletion
      • by Chas ( 5144 )

        No. If we want water and food, we pretty much NEED concrete.

        Our society requires it.

        Unless you're a farm owner with a sufficient water resource on your property...

  • by baking lime in a kiln and emits approximately one ton of carbon dioxide for every ton of cement.

    If only there was some way which we could head a kiln without hydrocarbon fuel....Oh wait there are lots of ways we could do that...So Its not really cement manufacture that is the problem is it? Sounds more like an problem of how we are choosing to source the energy for it.

    • Re:If Only (Score:5, Informative)

      by Spirilis ( 3338 ) on Friday May 04, 2018 @10:24AM (#56554008)

      The lime emits CO2 as CaCO3 converts to CaO. It does not absorb back into the material in the use-case of Portland Cement.

      Lime plaster, which I posted about further down, DOES bring that CO2 back into the material (as it cures by Ca(OH)2 converting back to CaCO3+H2O with the introduction of carbonic acid, i.e. CO2 dissolved in a thin film of water).

    • The heat input is one part of the problem, but you are calcining the limestone, which emits significant CO2 as well. Not sure about the overall reactions and what else comes into play.

      As for the heat input, it would be a challenge to make a solar kiln for 1300C, but you still have the thermodynamic limitations of needing to heat something up really hot and then cooling it back down to ambient temperature.

  • Concrete also causes us to use less wood. While on the one hand that's a good thing since even older forests are a great carbon sink, on the other hand it wooden houses are a really great way of removing carbon from the biosphere for quite a long time; the average wooden house stores the equivalent of 20 tonnes of CO2. Building 400 million wooden houses would compensate for the entire CO2 surplus in the biosphere (or at least in the atmosphere). In theory ;)

  • by Spirilis ( 3338 ) on Friday May 04, 2018 @10:16AM (#56553938)

    The crux of the article was Rammed Earth, which I think is a great replacement for concrete for certain applications (some load-bearing vertical walls mainly). Dirt cheap, clay & sand.

    Some applications of concrete are frivolous and I think can be replaced. The reason is mostly cost and availability, and the current labor force is skilled with using it. The wall-facade material of choice before concrete, and before gypsum drywall, was Lime plaster. For wet or exterior applications I am in favor of using lime as it is less carbon-intensive than concrete and produces a beautiful lighting effect from birefringence (https://en.wikipedia.org/wiki/Birefringence), owing to the tiny calcite crystals that form when it cures back into limestone. See http://www.sapphireelmtravel.com/travel-journal/chefchaouen-morocco-blue-city for an example.

    There's also benefits to the water vapor breathability of lime vs. concrete (which doesn't breathe, unless it's cracked).

    Producing Lime plaster is less carbon-intensive than cement as it requires lower temperatures, and the CO2 driven off by the limestone during calcining (which happens in Ordinary Portland Cement production as well) is mostly re-absorbed by the slaked lime as it cures back into limestone (leaving the net CO2 footprint coming from the fuel used to calcine the lime, if coal or natural gas or wood is used, although perhaps decades into the future someone comes up with a nuclear-fueled kiln, electric or high temp gas or whatever).

    The big downside to lime plaster is the time it takes to cure, and what that does for timelines and labor costs. It usually requires multiple thin coats (with a week or more between =3/8 inch coats - need time for CO2 to reabsorb as carbonic acid which also requires the material be damp, but not covered in water) which blows up the labor costs.

    https://johnspeweik.com/2011/10/27/the-lime-cycle/

    The upside to using lime plaster is there's a wealth of historical information on what to do with it... much of the "bling" of the pre-1800's architecture can be traced to the use of lime or limestone.
    E.g. the Moroccan process of Tadelakt - https://en.wikipedia.org/wiki/Tadelakt
    Venetian plaster - https://www.architecturaldigest.com/story/venetian-plaster-trend-guide

    • by ColaMan ( 37550 )

      Whilst lime plaster is a nice facade, you still need a means of structural support behind it.

      So how do you build ten storey buildings, shopping centres, car parks, railway sleepers, bridges, stormwater pipes and a million other little bits of modern life without concrete? Are steel and other structural alternatives more resource-intensive than concrete over the whole lifecycle? That's the kind of questions I want to see answered, not a laser-focused hit piece on concrete.

  • 5% (Score:4, Insightful)

    by wbr1 ( 2538558 ) on Friday May 04, 2018 @10:19AM (#56553968)
    FIVE PERCENT of global CO2 emissions for cement production. Reinforced is one of the most useful, versatile, and inexpensive construction materials we have devised. I wish to reduce co2 emissions - targeting something that far down the stack seems stupid to me given its utility. Much better gains in CO2 reduction can be made elsewhere (power generation and transportation).
    • FIVE PERCENT of global CO2 emissions for cement production.

      Captain pedantic here but it is NOT cement. It is concrete and they are not the same thing. Every time you conflate the two terms a civil engineer looses his wings. Cement is an ingredient [ccagc.org] in concrete but concrete is not cement.

      • From the summary, it was concrete production that was fingered as the 5% contributor, not concrete use in general. In fact, the summary even states:

        Manufacturing cement, concrete's binding agent, is energy-intensive, Fennell says. Ordinary Portland cement -- the most common form in concrete -- is produced by baking lime in a kiln and emits approximately one ton of carbon dioxide for every ton of cement.

        That sounds to me like pretty much exactly what the parent stated. They were correct to indicate cement as the big CO2 driver in concrete production, based on the article summary. Maybe read what was actually said before getting all pedantic?

      • by crunchygranola ( 1954152 ) on Friday May 04, 2018 @12:42PM (#56554986)

        Captain Pedantic gets two demerits. The source of the CO2 production in the production of concrete IS from that ingredient called "cement". Sand, aggregate and water contribute nothing to CO2 release.

    • Not necessarily; if you believe in carbon capture then a cement kiln might be a logical place to do it. The only real issue is the CO2 is quite hot and mixed with a lot of other nasty stuff-- but maybe not much of a challenge compared to a liquid CO2 plant using refinery feed gas.

    • I was thinking something similar: How much CO2 would the next best alternative to concrete emit if we replaced all concrete with it? And how much more (in terms of money and energy) would it cost? Without knowing that, you can't say if 5% of global CO2 emissions is a bad or good thing.
  • by Artagel ( 114272 ) on Friday May 04, 2018 @10:20AM (#56553978) Homepage

    The post is based on a false premise: that CO2 production is inherent in making concrete. There is already a process to not do that. Further, most of the CO2 is made from generating the heat to make the concrete. Most of that CO2 production is low-hanging fruit to eliminate.

    This is just more chicken little chicken shit.

  • Because we know you'll also object to wood, steel, aluminum, carbon fiber, plastic, bone, fiberglass, or any other structural material we can come up with. Magical unobtanium which can be produced and used at scale without any environmental effects doesn't exist and never will.

  • It is called North Dakota. Go there sometime. Then you will be getting yourself some Concrete instead!

  • Two concrete articles today! It's great.

    Talking about environmental impact is great and all, but we will use concrete until something supplants it due to economics. Right now we are seeing real interest in tall timber construction, and while the designers will tell you about potential environmental benefits the real driving force is potential dollars - it's expected to be faster and cheaper than concrete and steel. Concrete construction is energy intensive as the article points out, but it's also surprisin

  • by sjbe ( 173966 ) on Friday May 04, 2018 @10:54AM (#56554210)

    We use concrete because concrete is cheap. Really, really, cheap. You can get similar results with other materials for many applications but there are few materials that are as readily available, easy to use, and inexpensive as concrete. Come up with a material with usable performance and a similarly low price point and you can be sure we would use a lot of that.

    FYI one ton of concrete is a piece roughly 0.42m^3. So they are saying we each use a piece of concrete about the size of a desk each year.

    • by Reziac ( 43301 ) *

      We also use it because it's relatively durable and pest-resistant. Compare and contrast, frex, a wooden foundation vs a concrete foundation in an area with ground termites.

      [for the uninitiated, ground termites can live just about anywhere that doesn't both hit -40F every winter and isn't regularly treated with discouraging pesticides.]

  • Nothing beats good old wood. We should make everything out of it: parking lots, curbs, roads ... plank roads are awesome.
  • by denis-The-menace ( 471988 ) on Friday May 04, 2018 @11:00AM (#56554270)

    Believe it or not it has to do with sand.

    Sand with sharp edges.
    Sand from the desert is round and is not good for cement.

    So stop worrying about the CO2, energy, etc needed to make cement. we are running out of sand.

    https://science.slashdot.org/s... [slashdot.org]
    http://www.spiegel.de/internat... [spiegel.de]
    https://www.npr.org/2017/07/21... [npr.org]

    IOW: we are fsked. Roads, buildings, bridges, etc will have to be built with something else and nobody cares to even worry.

  • by Dr. Spork ( 142693 ) on Friday May 04, 2018 @11:12AM (#56554372)
    If we could teach AI to quarry, transport, shape and stack rocks at least as well as humans did in the 17th century, we could literally build castles (and bridges and aquaducts) with very little energy input. Rocks are everywhere, and an army of AI powered instruments could be programmed to improve on the work of even the best stonemasons: If they scanned each available stone that comes from a quarry, algorithms could design the optimal stacking arrangements to minimize gaps and maximize structure stability. They could "solve" a construction project like it's a giant 3D puzzle, thus minimizing the number of stones that would need to be chiseled. But even chiseling stone with machines uses very little energy. The pace of construction would only be limited by the number of autonomous tools brought to bear, and they themselves could turn out to be cheap and mass-producible. Sure, you can't build skyscrapers from rocks, but I would happily live in a city of six story rowhouse blocks built from stone. The neighborhoods in Europe that are actually built in this way are beautiful, functional and pleasant to live in. With AI building tools that sink the cost of labor to almost zero, I think we should explore returning to some of these old, well-tested building methods and architectural designs.
  • Here's an example of what we're doing in Vancouver BC, to build low-cost housing for the homeless. These modular buildings use metal framing instead of concrete foundations: https://vimeo.com/208333352 [vimeo.com] No concrete needed!
  • Regular concrete for a lot of applications is way too strong (say non-load-bearing walls). So switch to aerated concrete, AAC for that.
    https://en.wikipedia.org/wiki/... [wikipedia.org]

  • Here's the problem: If you're going to call out cement production as one more thing that's going to destroy the Earth with global warming, that's fine, but you've got to come up with an alternative that doesn't set back human civilization (such as it is; I don't feel like we're very 'civilized' at all, but I diverge) 2000 years in the process. Do we start making everything out of stone again? Obligatory jokes about slaves and pyramids, I guess. Wood? Environmentalists would have a fit, also show me how you
    • Okay.. Here's an update [slashdot.org] to the above; graphene-reinforced concrete that cuts the CO2 emissions almost in half. I'd provisionally call that progress. Now, how much environmental impact does graphene production cause? Anyone? Bueller?
  • This article just appeared claiming a concrete twice as strong as existing concrete while releasing less CO2.

    https://inhabitat.com/ [inhabitat.com]

  • by pubwvj ( 1045960 ) on Friday May 04, 2018 @12:52PM (#56555068)

    There is a mythconception touted by some that concrete is bad. That is totally wrong. Concrete is almost all rock and sand. There is very little cement (the material at issue) in it. And the long term net effect is that concrete is a benefit because concrete structures last for a very long time, measured in hundreds to thousands of years as opposed to wood built structures that last mere decades.

    Additionally, if you properly design your structures you can make concrete even greener by eliminating the need to heat or cool the buildings. I have done this with both our home and our butcher shop. Concrete offers tremendous thermal mass which can store the heat from summer over to winter to keep the building warm and store the cold from winter over to summer to keep the building cool.

    I have done this with our home which masses about 100,000 lbs inside an insulated envelope. Even in our extreme cold climate in the central mountains of northern Vermont we don't have to heat or cool our house. It will stay in the mid-40's through the winter and rise to the 60's in the summers. We can optionally raise that to the mid-70's in the winter with just 0.75 cord of wood (a very small amount for those of you who don't use wood heat), which is a renewable resource from dead wood on our land.

    Our butcher shop is built along the same lines but far more massive at 1.6 million pounds of concrete built in six shells with insulation between each. We have no heating system and no refrigeration system to chill our cutting room, etc. We've been operating for three years under Vermont state inspection and on May 1st we received our USDA license. I've been told repeatedly by the USDA and other government officials that they are amazed by our facility because it is so good, requires so little maintenance, is so easily cleaned and how it naturally stays the right temperatures. All of that is about design. I love math. Math applied is even better - it solves real problems.

    Concrete is not evil and is not the cause of global warming. Properly used concrete and cement are the solution to reducing pollution and cutting energy consumption.

It was kinda like stuffing the wrong card in a computer, when you're stickin' those artificial stimulants in your arm. -- Dion, noted computer scientist

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