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Concrete is the stuff civilization is made of. But for all its blessings, there are huge environmental costs

Concrete is the stuff civilization is made of. But for all its blessings, there are huge environmental costs thumbnail

You may not realize it, but as you read this you are probably surrounded by the most important artificial material ever invented. Is there a floor beneath you, walls around, a roof overhead? Chances are excellent they are made at least partly out of this astonishingly underappreciated material: concrete.

To most people, concrete is just the ugly stuff used to pave paradise and put up a parking lot. But concrete is an invention as transformative as fire or electricity. Since it came into widespread use around the turn of the 20th century, this man-made stone has changed where and how billions of people live, work and move around. It is the skeleton of almost every apartment block and shopping mall and of most of the roads connecting them. It gives us the power to dam enormous rivers, erect buildings of Olympian height, and travel the world with an ease that would astonish our ancestors.

For all its blessings, however, concrete incurs serious costs to people and the planet — and those costs are mounting exponentially.

Concrete is essentially just sand and gravel glued together with cement. It is also by far the most widely used building material on Earth. We consume twice as much of it every year as steel, aluminum, plastic and wood combined. That’s because cities are exploding, especially in the developing world, as people leave the countryside for a shot at a better life in the metropolis. The number of urban dwellers is rising by about 65 million people annually according to the United Nation’s Population Division. That’s the equivalent of adding eight New York Cities to the planet every single year.

There’s no way cities could grow this fast without concrete. It’s an almost magically cheap, easy way to quickly create roads, bridges, dams and housing for huge numbers of people. An estimated 70% of the world’s population now lives in structures made at least partly out of concrete.

Making all that concrete, however, takes a heavy toll on the atmosphere. The cement industry produces 5-10% of total carbon dioxide emissions worldwide, putting it behind only coal-fueled power plants and automobiles as a source of global warming gases.

Concrete also soaks up the sun’s heat, and cities’ countless miles of warmed-up streets and sidewalks create a phenomenon known as urban heat islands. When combined with the heat from motor vehicle engines, paved areas can boost the temperature in some cities by as much as 19 degrees Fahrenheit, according to the California Environmental Protection Agency. That kind of heat also boosts the formation of air pollutants, especially ground-level ozone, better known as smog.

The most frightening aspect of our dependence on concrete might be that the structures we build with it won’t last. The vast majority of them will need to be replaced — and relatively soon.

We tend to assume concrete is as permanent as the stone it mimics. It isn’t. Concrete fails and fractures in dozens of ways. Heat, cold, chemicals, salt and moisture all attack that seemingly solid artificial rock, working to weaken and shatter it from within. You could say our cities are like castles made of sand, except that they almost literally are castles made of sand.

Many of the world’s concrete structures are already slowly disintegrating. The most recent report on the nation’s infrastructure by the American Society of Civil Engineers declared that one-fifth of our highways and one-third of our urban roads are in “poor” condition. According to the Federal Highway Administration, nearly one-quarter of all the United States’ bridges are structurally deficient or functionally obsolete. Our dams are in similarly dismal shape. Worldwide, as much as 100 billion tons of poorly manufactured concrete structures — buildings, roads, bridges, dams, everything — may need to be replaced in the coming decades, at a collective cost of trillions of dollars.

To make matters worse, we’re running out of one of concrete’s essential ingredients: sand.

Our planet contains enormous amounts of sand, of course, but the usable type — found mostly in riverbeds, floodplains and beaches — is a finite resource like any other. (Desert sand, eroded by wind rather than water, is generally too round to use for construction.) Humans consume nearly 50 billion tons of sand and gravel every year, enough to blanket the entire state of California. Most of that is used to make concrete.

We tend to assume concrete is as permanent as the stone it mimics. It isn’t. Concrete fails and fractures in dozens of ways.

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Mining sand is its own colossal industry with its own litany of environmental devastations. In the United States, countless tons are dredged up every day in almost every state, from the San Francisco Bay to rural Florida. The most accessible sources are increasingly tapped out. A 2012 report by California’s Department of Conservation warns that the state has access to only about one-third of the sand and gravel it will require over the next 50 years.

All around the world, sand mining is slaughtering river-dwelling fish and birds, damaging coral reefs, undermining bridges and causing riverbanks to collapse. There is so much money to be made that in some countries, organized criminal gangs have moved into the sand business. In India, Kenya, Vietnam and elsewhere, hundreds of people have been beaten, tortured and murdered in recent years — all over sand.

Despite all that, we’ll need to keep ripping billions of tons of sand from the earth to replace our failing concrete structures, and to keep building new ones. That cycle can’t continue indefinitely — any more than we can continue indefinitely sucking oil out of the ground to fuel an ever-growing armada of automobiles. We’ve started to think twice about how much oil we can burn, how many forests we can cut down, how many fish we can harvest from the sea. It’s time to start thinking about how much concrete we can afford.

LA Times

15 Comments on "Concrete is the stuff civilization is made of. But for all its blessings, there are huge environmental costs"

  1. onlooker on Sun, 17th Jun 2018 1:49 pm 

    Humanity is in a world of hurt
    “A study led by the University of Leeds has found that NO country currently meets its citizens’ BASIC NEEDS at a globally sustainable level of resource use.

  2. Go Speed Racer on Sun, 17th Jun 2018 2:39 pm 

    and The Beverly Hillbillies
    and granny will need
    another Cement Pond !!

  3. Go Speed Racer on Sun, 17th Jun 2018 2:45 pm 

    This article looks like dumb journalism,
    Fake News for Trump to laugh at.

    Concrete can fail in dozens of ways?
    It can but that doesn’t mean it will.

    If the concrete isn’t being abused
    I will wager it is indefinitely stable.
    That means it could stay put for
    the full 1 billion years until the Earth
    no longer holds life.

    They definitely found some concrete,
    a dock pier, from 2000 years ago
    biblical times, and it’s submerged.

    So this article should be removed,
    because it is false.

  4. Anonymouse1 on Sun, 17th Jun 2018 4:25 pm 

    Concrete decays quickly, because it is just like almost everything else humans create, temporary, cheap, and, ultimately, designed to fail. The idea of making something to actually last, and not begin to fall apart almost immediately, is anathema to our great, world of planned obsolescence. Why would concrete be any different than TVs, Ijunks, oil burning cars and so on?

    Just tear it down, don’t recover the materials, and put up a ‘new’ one, so the virtuous cycle of new-and-improved can keep on rolling into eternity.

  5. Alice Friedemann on Sun, 17th Jun 2018 5:45 pm 

    A Century from Now Concrete Will be Nothing But Rubble

    Concrete is an essential part of our infrastructure. And it’s all falling apart, as Robert Courland’s 2011 book Concrete Planet makes clear.

    Courland writes that some of our infrastructure may last even less than a century. For example, in the ocean, concrete shows signs of decay within 50 years according to Marie Jackson at Lawrence Berkeley National Laboratory.

    In a world that’s shrinking from declining energy resources, topsoil, aquifers, and minerals, it’s time to construct buildings that last and maintain the ones we have.

    The problem is the iron and steel rebar reinforcement inside. Cracks in cement can be fixed, but when air, moisture, and chemicals seep into reinforced concrete, the rebar rusts, expanding in diameter up to seven-fold, which destroys the surrounding concrete.

  6. Gary Goodson on Sun, 17th Jun 2018 8:06 pm 

    The carbon dioxide CO2 produced for the manufacture of structural concrete (using ~14% cement) is estimated at 410 kg/m3 (~180 kg/tonne @ density of 2.3 g/cm3) (reduced to 290 kg/m3 with 30% fly ash replacement of cement).

  7. Makati1 on Sun, 17th Jun 2018 9:47 pm 

    Somewhere, in the past, I read that it takes a barrel of oil to make one cubic yard of concrete, in place. If so, then our new farm home will take over 300 barrels of oil. The gravel comes from the local river bed and the sand from beach deposits. Both about five miles away from the building site. The mortar needs to be trucked in from the closest cement plant. About 100 miles from our location. But, it is only a small fraction of the concrete itself. We are building for the future, so it is worth it.

  8. Go Speed Racer on Sun, 17th Jun 2018 9:57 pm 

    Yes agree, there is high CO2 consumption because the industrial process to make the cement (and that’s the active portion of the concrete) requires heating the whole thing to red heat.

    The initial cool-down is a bunch of cement rocks, which then have to be pulverized. All are energy-consumptive activities, even separately from the heating issue.

    BUT what’s with the author, and y’all friendly fellow friendly posters, telling me that concrete naturally decays ?? Like
    a tub of cottage cheese that was left out
    on the counter, give it a few days and
    it’s just completely chemically changed?

    Just what chemical process is occurring in the inert, room-temperature concrete, that
    is rapidly converting it from one state to another? Ph.D. grad students in chemistry
    are just dying to hear about this transmutation, they can make their Ph.D.
    thesis about the spontaneous decay of concrete, OK.

    FACT: Abuse of the concrete, which is water-soaking, freezing/thawing, failure to apply the correct surface-sealers, overstress, rebar that’s not correctly chosen (either stainless steel or epoxy-coated) and especially “SPALLING” yes these things make concrete go away.

    BUT if you think that concrete just naturally
    “transmutes” from one thing into another
    thing just because it’s sitting under a carpet idle at room temperature, sorry
    to disappoint — there is no chemical change
    taking place whatsoever.

    If you don’t know what spalling is,
    then you’re not ready to comment on this
    topic, the author certainly didn’t know.

    If you’re not able to enter ‘spalling’
    into Google, I understand completely,
    sympathize how difficult that would be, in
    comparison to just shooting mouth off with
    a bunch of useless gibberish.

    So here I will help U a little:

    And on that happy note, U can now get out
    your flame throwers and insults and tell me
    how stupid i am, and how smart you are.


  9. dave thompson on Mon, 18th Jun 2018 1:19 am 

    Your link is a sales pitch for some kind of BS concrete sealer. Go Speed.

  10. Go Speed Racer on Mon, 18th Jun 2018 9:26 am 

    Yes Dave, thanks for the post.
    If that page was actually read,
    it shows what is “spalling” and the sealer,
    (no doubt expensive) either repairs the concrete,
    seals the concrete, or both.

    The point is, there isn’t a magical transmutation of
    the elements slowly converting the concrete back
    into sand, while it sits there, inert.

    Decay of concrete is due to misuse, mistreatment of
    concrete, one of the most obvious examples being
    spalling. Which if we examine the photographs,
    generally involves corrosion of the rebar which
    (a) was the wrong type of rebar
    (b) was too close to the surface.


  11. dave thompson on Mon, 18th Jun 2018 9:49 am 

    Go Speed Racer, Yes spalling is a huge prob. BS concrete stories are rampant in our current and past state of affairs of industrial civ. The biggest reason for bad application of technology is capitalistic profit. The bottom line says if we can do it faster and cheaper it is better. Put a warranty up for the dummy consumer, make em think they are getting a great deal and the rest is easy. Just walk away and say, “so sue me”.

  12. Go Speed Racer on Mon, 18th Jun 2018 4:16 pm 

    The whole country is just one big scam.

  13. drwater on Mon, 18th Jun 2018 4:38 pm 

    “When combined with the heat from motor vehicle engines, paved areas can boost the temperature in some cities by as much as 19 degrees Fahrenheit, according to the California Environmental Protection Agency.”

    Ummm – that would be asphalt, not concrete.

  14. Harquebus on Mon, 18th Jun 2018 7:02 pm 

    Economy, environment, politics, society, climate and energy etc. They’re all related and dependant on each other. Diminishing returns on energy production is a phenomenon that will continue to increase stresses throughout our modern society.

    “In every single reinforced concrete structure, silently behind the smooth exterior, the concrete is breaking itself apart due to the corroding steel inside.”
    “What all this means is that literally everything you see today that’s made of concrete will need to be replaced within a hundred years of its installation. Every bridge, every building, every roadway…all of them.
    They’re just rotting away from the inside, silently and relentlessly.”

    “Of all the resources in the world, oil is top dog. All other resources depend on oil. You can get every fish in the sea, drain every drop out of non-renewable aquifers, make enough concrete to pave the planet, and convert every square mile of land to grow crops and feed barnyard animals cutting down the remaining forests. Which we are well on our way to doing. But only oil can do it, because the heavy-duty diesel engines that do the essential work of civilization run on diesel fuel.”

    “Why modern mortar crumbles, but Roman concrete lasts millennia”

    “Take for example depletion of copper ores….humanity extracts 15 million tons of copper a year from ores that are only 0.5% copper, which means there are 3 billion tons of waste ore – even more than the total mass of concrete produced a year globally. Once humanity is down to 0.1% copper it will be necessary to shift 5 times the amount of waste – with a correspondingly 5 fold increase in the energy bill to do that.”
    “In summary, the theorists of 1972 argued that growth would run out as more and more resources would have to be devoted to the work arounds and techno-fixes to deal with depletion and pollution. They did not deny that techno-fixes would be available – what they were drawing attention to was that adopting them would take resources away from growing production to fixing the problems.”

  15. autistmouse on Wed, 20th Jun 2018 8:55 pm 

    Modern concrete suffers from “concrete cancer”. It is a phrase that describes the rusting of the steel rebar which causes the concrete it is laced through to flake and weaken. Cement from 2000 year old structures is solid because they didn’t have the steel. So while it is imprecise to say that concrete decays, thanks to the steel the effect is the same. Modern concrete structures are typically rated to last 50 to 80 years instead of thousands. Also stresses from the colossal scale of structures or vehicles are far greater wear than horse hooves and leather sandals. I hope this clears some things up. Cheers!

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