Scientists Have Found The Ancient Secret Of Indestructible Concrete

For the most part, we humans are better at things than we were thousands of years ago. But there are some things the ancients had down pat. Roman concrete, for instance, is just way better than anything we can whip up today. Finally, after some 2000 years, modern-day scientists have figured it out. And it's a secret worth knowing.

Concrete, while often not exactly pretty, is a super important tool of city-building today. We've been using Portland cement (an ingredient in concrete) as a binder for nearly 200 years as a building block of modern architecture, but it just can't hold a candle to that old Roman stuff. There are concrete harbours in Italy that are still doing pretty damn well after thousands of years. Meanwhile, a modern-day Portland cement structure is lucky to last 50 years when exposed to salt water.

Now, after years of research in labs across the US and Europe, scientists have figured out that the most robust Roman concrete is a specific mixture of lime and volcanic rock, the details of which have been published in this month's issues of the Journal of the American Ceramic Society and American Mineralogist.

The researchers described it this way in a press release on the subject:

The Romans made concrete by mixing lime and volcanic rock. For underwater structures, lime and volcanic ash were mixed to form mortar, and this mortar and volcanic tuff were packed into wooden forms. The seawater instantly triggered a hot chemical reaction. The lime was hydrated — incorporating water molecules into its structure — and reacted with the ash to cement the whole mixture together.

And it gets even better. Portland cement is environmentally messy to produce, accounting for some seven per cent of the C02 modern industry produces. Roman concrete? Much, much greener. There's still a lot of work to be done in adapting traditional Roman construction techniques to today's needs. But the recipe is as good as ever. We just have to get cookin'. [Bloomberg Businessweek]

Image: Carla Tavares/Creative Commons

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    So why did we start using Portland Cement?

      because the Romans weren't around anymore to say how they made it.

      Humans forgot how to make concrete for the best part of 1000 years after the Romans were wiped out. Only in the 1700's did we start making it again. Doesn't explain why it took 200 years for us to work out exactly how the Romans did it though.

        the Romans were not wiped out, they just got mentally lazy: just like you.

      Because it didn't work for use in making concrete submarines. Trial and error my boy, trial and error.

      Last edited 16/06/13 4:01 pm

      What good is a concrete business if they cant keep selling you their concrete - built in obsolescence maybe? technology is already out there for light bulbs that don't burn out, car batteries that last 20 years, etc etc, but you think the big corporations are gonna allow us to access these one or 2 in a lifetime purchases. stoopid money ruining everything.

        That's a silly theory! It makes no sense what so ever. By the time the concrete starts to degrade very few of the original builders are still around to make money by providing replacements.
        and if you don't want your bulb to burn out just buy an old incandescent and use it on an extremely low power- that's ALL there is too it. Produces hardly any light and is amazingly inefficient for the electricity it uses but it will last for decades.

        And no batteries last 20 years unless it's some sort of unsafe nuclear reactor and there's obvious reasons we don't use those.

          i used to work in a battery store.
          had a battery come in that was out of a tank - a lead acid battery that was 22 years old.
          also for power stations they have lead acid batteries in 2 volt cells that allow you to pull the plates out and clean them and refill them with acid. from new they last 15 years, after the first clean, they then last 10 years, after the third clean they then last 5 years.
          and it also wasnt un-common to see Century batteries that were made 15 years ago for normal cars come in after 10 years of service.

          as for the light bulb, sounds like you need to do some reading up.

          and if you are naive enough to think that its a silly theory that companies dont build things with built in obsolescence, then you sir need to open your eyes to the world around you and see that things dont last like they used to, because if they did - companies would be going bust. think back to the fridge that your parents had growing up and how long they lasted, or the tv they owned for 20 years. and now that technology is better, things arent lasting as long? thats not a smart advance is it?

            i just found this also - i dont agree with everything written in the article, but they guy makes some valid points that make sense if you think about money hungry corporations.


            I assumed you were talking about the lithium batteries commonly in use. Lead acid batteries are a much simpler technology though and the efficiency isn't that great, aaaand they will degrade over time. But you could make your own easily enough. There's definitely nothing special in that technology.
            The lightbulb thing is very simple too. That is how the longest continuously burning lightbulb today has been working- simply using lower power than it's specced for. There's no conspiracy there, no planned ideas or grand unproven claims to get funding, just an actual bulb that really has been burning for decades.

            Of course there is planned obsolescence in modern products, this is why iphones have their batteries sealedin and why Windows stops supporting older versions of its OS and so on, but there isn't a grand conspiracy about it. It's just that the life cycle of products is shorter because technology develops faster. If we continually want the best new stuff then we have to continually buy it and replace the older stuff, so for that reason some things generally aren't made to last as long.
            (your link didn't work for me)

            Last edited 18/06/13 2:41 pm

              although i dont have any concrete proof, one theory ive also heard about conventional light bulbs is they amount of gas mixed with air inside the bulb. the more oxygen mixed in with the gas, the shorter the life. would be interesting to see if anyone has actually tested this though.

            No, most things don't have built in obsolescence. They are built crappier than before because it is cheaper and people will buy something cheap that will fail quicker over something that was built like your parent's first fridge that will last longer.

            The intense competition in some areas has also reduced profit margins to very low levels so they simply build panels thinner or use plastic etc because it is cheaper and gives them a price advantage.

            Also, look at how complex a TV that you buy today is compared to one back in the day. The more complex a system is, the more likely it is to fail.

    Its just the same with Damascus steel, or the rust proofing put on the Iron Pillars of Delhi, we just forgot. Remember after the Romans we went into the Dark Ages. A period of huge religious belief, where science was seen as heresy. Like the story of Columbus proving the world was round not flat. The ancient Greeks had figured out the world was round 500 year before Columbus. Columbus believed the world was a third smaller, and that if he set sail south west from Spain he would find the east side of India, to open it up to the Spanish Empire. But as we all know he discovered America, and the New World as it was call. Spain colonised the majority of modern day South and Central America, as parts of the States like Texas, New Mexico, and California. That's why they are big Spanish speaking.

      Science was not seen as heresy, especially by religions, considering they worked to save as much knowledge (including science).

        It's great to see someone who actually knows their history (even if a Cracked article isn't the best backup source) as opposed to "RELIGION LOL". +1 to you.

          Yes the individual Monk did store works of science. But the church did demonize science. Galileo had all his work destroyed by saying the Earth and planets rotate around the sun. The general conception was the Eartg was centre of the universe. only advoided death by renouncing his work, and working in secret

            That's an over simplification - the Inquisition only accepted it as a possibility, and even other astronomers at the time disagreed with the man. Galileo was attacked by the church because they thought that an article he wrote defending his theory was attacking the Pope. The Inquisition and papacy actually permitted him to publish his book at the time. But don't let that get in the way of a good story!

        Science was definitely seen as heresy in some cases. Galileo suffered mightily from the heavy-handed oppression of the Catholic Church because he championed heliocentrism, contrary to the dogma of the church. Galileo was tried by the Inquisition, found guilty of heresy, forced to recant, and spent the rest of his life under house arrest.
        We should all be very glad that an organization built on primitive superstitions is now losing power and followers every single day.

          I wouldn't say that it losing its power or followers is a good thing, nor would I say that it ever will. The Catholic Church is still a massive religion 1.3 billion, which is growing everyday, more then any other Christian faith. I would say the Church has a lot to come to be a modern religion, but I can never seen it dying.

          Be very careful using the word 'science' for any period more that two hundred years ago.

          Natural philosophy occupied the time of most religious figures throughout the Dark Ages and and bore little resemblance to the science of today.

          Theology was the principal 'mode' of investigation, and as a result all research was framed using it, in the same way we make scientists stick to publishing papers for peer review today.

          The other requirement was an acceptance of Aristotelian Philosophy, which pretty much put a kibosh on any critical thought.

          People committed 'heresy' by performing research outside of the accepted circle of eminent academics, and by questioning Aristotelilan philosophy in any way, not by making findings the church d'did not like'. The church welcomed any new development, as long as you could wrangle it into Christian-speak.

      No-one in Columbus's era thought the world was flat. They thought (correctly) that it was further to Asia than Columbus estimated, which is why is voyage was criticized. He had the good fortune of running into the Caribbean - if America didn't exist he'd have died somewhere in the middle of the combined pacific+atlantic.

    Hey don't forget the Egyptians made the Pyramids from Concrete !
    But that's another story . . .

      I cracked my tooth on a Falafel the other day, I think they are actually made of Felafel blocks. They should last another 10,000 years or so.

    The human race is suffering amnesia.

      And we are repeating the mistakes of the past, except this time on a scale unprecedented in human history.

    How did we forget Damascus steel? The Japanese were lamenting their steel all through this period. And making much better and much more complicated pieces.

    Last edited 16/06/13 2:15 pm

      Remeber that Japan had a policy of isolation or Sakoku roughly chained country. In 1853 when Commodore Perry open Japan up with the black fleet we got modern Japan. So they had hundreds of years to no lose methods due to a fall of an empire or through foreign interference.

        I don't think that had anything to do with it to be honest. There was a fair bit of foreign steel coming through Nagasaki though the Muramachi and Edo periods to the restoration. And some smiths were working with it during the Shinto (new sword) and Shinshinto (new new sword) and after, but most found it inferior to Tamahagane and left it well enough alone.

        Some people say, there was some loss of skill during the Sengoku with so many mass produced blades being made. And the end of the Koto era with the wasting away of the 5 schools, but I think thats more because of the crap that was being produced during the Sengoku, just to get blades in peoples hands. The high end Shinto and Shinshinto bades are still amazing IMO.

        Also you want to see AMAZING Damasc type work in Japanese swords, Check out the Gassan school, very cool shit!!

        Last edited 17/06/13 9:46 am

    So now the eyesores will last forever....yay!

    Those Romans are crazy

    Old don't mean stupid.

    Last edited 16/06/13 3:51 pm

      Now my advice here would be to outline what this video is about - sadly nobody clicks on anything unless they care a bit about it. Just saying like.

    It's not just the 50 years salt water exposure that is a problem. The water used in making concrete affects the iron rebar used for reinforcement. As the iron corrodes & flakes, you lose support.

      i wonder if the romans used rebar?

    "What have the Romans ever done for us"

    Just like their roads, the reason they're so good was because they were built several feet into the ground, not like nowadays where all you get is a pooncy layer of asphalt over a little bit of compacted gravel.

    Its not a new discovery at all.. might be for these "scientists" but the constituents of roman concrete have been know for decades. Its not just volcanic ash.. its ash from a particular type of volcano, and its known as pozzolanic ash. Unlike portland cement, the stuctures formed by the chemical reaction between the ash and quick-lime continue to grow. You can actually put a lump of the mix in salt water with out any formers around them and it hardens.

    A perfect example of how the ancients could do things we can't, and without the help of any aliens.

    Not even the ancients. NASA forgot how to make something. They ran out and couldn't make it anymore.
    Quick Google search couldn't pull up the article, but it's not just the ancients (unless you call your elders ancient).

    The positive effect of producing conrete using volcano ash and lime in certain percentages is very well known to the industry for centuries. It's not something new to discover (guess another reinventing the wheel classic). It just happens that using residuals from the steel factory (slags) is much cheeper than excavating and pulverizing volcanic ash. However, special concrete types are still made using lime and volcanic ash as main ingredients.!!

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