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posted by martyb on Tuesday October 17 2017, @09:31AM   Printer-friendly
from the Roman-concrete-lasts-2000-years...-why-not-our-roads? dept.

The story of concrete is so ancient that we don't even know when and where it begins. It is a story of discovery, experimentation, and mystery. Emperors and kings became legends for erecting great concrete structures, some of which are still a mystery to engineers today. Many of history's most skilled architects found inspiration in slabs of the gray building material. Common bricklayers advanced the technology, and a con man played a crucial role in the development of concrete recipes.

Today, the world is literally filled with concrete, from roads and sidewalks to bridges and dams. The word itself has become a synonym for something that is real and tangible. Press your handprints into the sidewalk and sign your name to history. This is the story of concrete.

[...] Let's get this out of the way right here: cement and concrete are not the same thing. Cement, a mixture of powdered limestone and clay, is an ingredient in concrete along with water, sand, and gravel.

So ubiquitous and fundamental, that nobody thinks about it. Its inventor is unknown, but that person changed history.

Related: Volcanic Rocks Resembling Roman Concrete Explain Record Uplift in Italian Caldera
Roman Concrete Explained


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  • (Score: 2, Informative) by Anonymous Coward on Tuesday October 17 2017, @12:57PM (2 children)

    by Anonymous Coward on Tuesday October 17 2017, @12:57PM (#583434)

    Please read what the GP said earlier more carefully. Modern Portland cement-based concrete can last submerged in seawater, perhaps for decades as has been stated, but not for the thousands of years that Roman concrete has been known to last. I don't think there is a ship of any construction that can still be said to be seaworthy for more than a hundred years, at least not without replacement of nearly every key component, so yes, you can probably build a ship out of modern concrete that will last for a few decades. Doesn't change the fact that some Roman concrete has lasted for more than two thousand years.

    Indeed, the Romans must have built plenty of shoddy structures back in their day too, but that doesn't make what they did build that managed to withstand the test of time any less remarkable. And any house built today that survives to 2710 will be of interest to any of the archaeologists of that future era for the same reason.

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  • (Score: 2) by rylyeh on Wednesday October 18 2017, @12:12AM

    by rylyeh (6726) <{kadath} {at} {gmail.com}> on Wednesday October 18 2017, @12:12AM (#583738)

    Yes! The secret of was only very recently understood - all should read the above about the Roman Concrete.

    --
    "a vast crenulate shell wherein rode the grey and awful form of primal Nodens, Lord of the Great Abyss."
  • (Score: 2) by VLM on Thursday October 19 2017, @12:36PM

    by VLM (445) Subscriber Badge on Thursday October 19 2017, @12:36PM (#584501)

    In all honesty you're right AC I made a low quality post.

    This concrete thing was all figured out well over half a century ago. Take for example USAR Corps of Engineers paper 6-690 "Effects of seawater on concrete" linked:

    https://www.dtic.mil/dtic/tr/fulltext/u2/739563.pdf [dtic.mil]

    (I hope dtic isn't paywall for general public. If it is, this is a 50 yr old paper, just google for it there's copies afloat out there)

    Yes its true that a century or two ago liberal arts types noticed Romans had a really nice concrete that lasted forever (or rephrased, the concrete we still see was the subset of concrete which was capable of lasting forever) and some/most cheap concrete of the "modern" era didn't last long. And that has gotten copied liberal arts style for a century or two up to today. So to todays date there's mysticism about roman concrete solely from the liberal arts side of academia.

    But the engineers figured it all out a long time ago, and for well over half a century its "easy" to spec non-bottom of the barrel concretes with specific aggregates that will last eternally in seawater.

    I guess a good /. car analogy would be something like historians going on about the Ford model T engine being about 3 liter inline four, and producing about 20 HP, as the pinnacle of technology today in 2017, meanwhile modern (post 1940s?) automotive engineers are laughing at those specs and claims.