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posted by n1 on Wednesday July 05 2017, @08:21AM   Printer-friendly [Skip to comment(s)]
from the hard-as-nails dept.

Researchers have unlocked the chemistry of Roman concrete which has resisted the elements for thousands of years.

Ancient sea walls built by the Romans used a concrete made from lime and volcanic ash to bind with rocks.

Now scientists have discovered that elements within the volcanic material reacted with sea water to strengthen the construction.

[...] This new study says the scientists found significant amounts of tobermorite growing through the fabric of the concrete, with a related, porous mineral called phillipsite.

The researchers say that the long-term exposure to sea water helped these crystals to keep on growing over time, reinforcing the concrete and preventing cracks from developing.

Source: BBC News

American Mineralogist DOI: 10.2138/am-2017-5993CCBY


Original Submission

Related Stories

The Rock Solid History of Concrete 37 comments

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


Original Submission

Micron-Sized Calcium Silicate Spheres Can be Used to Make Stronger Concrete 15 comments

Spheres can make concrete leaner, greener: Rice's microscopic particles promise stronger building materials and more

Rice University scientists have developed micron-sized calcium silicate spheres that could lead to stronger and greener concrete, the world's most-used synthetic material.

To Rice materials scientist Rouzbeh Shahsavari and graduate student Sung Hoon Hwang, the spheres represent building blocks that can be made at low cost and promise to mitigate the energy-intensive techniques now used to make cement, the most common binder in concrete.

The researchers formed the spheres in a solution around nanoscale seeds of a common detergent-like surfactant. The spheres can be prompted to self-assemble into solids that are stronger, harder, more elastic and more durable than ubiquitous Portland cement.

[...] The work builds on a 2017 project [DOI: 10.1021/acsami.7b12532] [DX] by Shahsavari and Hwang to develop self-healing materials with porous, microscopic calcium silicate spheres. The new material is not porous, as a solid calcium silicate shell surrounds the surfactant seed.

Size- and Shape-Controlled Synthesis of Calcium Silicate Particles Enables Self-Assembly and Enhanced Mechanical and Durability Properties (DOI: 10.1021/acs.langmuir.8b00917) (DX)

Related: Biologists Create Self-Healing Concrete
Probing Ways to Turn Cement's Weakness to Strength
Roman Concrete Explained
The Rock Solid History of Concrete
Fungi Can Help Concrete Heal Its Own Cracks


Original Submission

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  • (Score: 0) by Anonymous Coward on Wednesday July 05 2017, @11:44AM (12 children)

    by Anonymous Coward on Wednesday July 05 2017, @11:44AM (#535138)

    ... did they knew sea water would have this effect at the time?

    • (Score: 2, Interesting) by Anonymous Coward on Wednesday July 05 2017, @12:05PM (10 children)

      by Anonymous Coward on Wednesday July 05 2017, @12:05PM (#535145)

      According to this earlier article, https://soylentnews.org/article.pl?sid=15/07/12/1356242 [soylentnews.org] Roman concrete was used in other places around the Mediterranean, with raw materials shipped from Italy, so it was known to be a good material.

      I also posted this story (shortly after takyon) and included that SN link. I'm slightly surprised that our editor(s) didn't pull from both submissions and/or recognize that it was posted twice?

      There have been many attempts to understand why Roman concrete is so durable. The current story talks about the chemistry in sea water, but other structures not in sea water also survive including public buildings and aqueducts. I don't think that this recent analysis is the final word on this potentially useful material.

      • (Score: 3, Interesting) by Runaway1956 on Wednesday July 05 2017, @01:41PM (3 children)

        by Runaway1956 (2926) Subscriber Badge on Wednesday July 05 2017, @01:41PM (#535166) Homepage Journal

        I don't think that Roman concrete on land grew these crystals. The claim here is that the crystals grew over time in sea water, constantly strengthening the structure. I don't see a similar claim for either dry structures, or structures surrounded by fresh water.

        Obviously, Roman concrete was damned good, and the Romans understood the importance of the volcanic ash. But, there is no reason (yet, at least) to think that they knew the concrete placed in seawater would grow stronger with time.

        --
        Taking bets: When does Biden's approval rating reach 15%?
        • (Score: 3, Informative) by Anonymous Coward on Wednesday July 05 2017, @02:27PM (2 children)

          by Anonymous Coward on Wednesday July 05 2017, @02:27PM (#535197)

          But, there is no reason (yet, at least) to think that they knew the concrete placed in seawater would grow stronger with time.

          Are you just making stuff up? Here is the second sentence of TFA:

          Pliny the Elder, however, in first century CE emphasized rock-like cementitious processes involving volcanic ash (pulvis) “that as soon as it comes into contact with the waves of the sea and is submerged becomes a single stone mass (fierem unum lapidem), impregnable to the waves and every day stronger” (Naturalis Historia 35.166).

          http://ammin.geoscienceworld.org/content/102/7/1435 [geoscienceworld.org]

          • (Score: 2) by Runaway1956 on Wednesday July 05 2017, @02:38PM

            by Runaway1956 (2926) Subscriber Badge on Wednesday July 05 2017, @02:38PM (#535203) Homepage Journal

            My bad. I read TFS, and went with various articles I've read in the past. I've not read Pliny's quote before.

            --
            Taking bets: When does Biden's approval rating reach 15%?
          • (Score: 0) by Anonymous Coward on Wednesday July 05 2017, @07:57PM

            by Anonymous Coward on Wednesday July 05 2017, @07:57PM (#535389)

            Are you just making stuff up?

            He is Runaway1956, the answer is, "yes". And he does not even know who Pliny was, which is why he has to make stuff up, because he "thinks" without reading.

      • (Score: 2) by takyon on Wednesday July 05 2017, @03:06PM (5 children)

        by takyon (881) <takyonNO@SPAMsoylentnews.org> on Wednesday July 05 2017, @03:06PM (#535217) Journal

        My guess is that an ed was confused by us using the exact same headline. I glanced at your sub and it did look better.

        Maybe this concrete will revive the "seasteading" concept.

        --
        [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
        • (Score: 0) by Anonymous Coward on Wednesday July 05 2017, @06:44PM (4 children)

          by Anonymous Coward on Wednesday July 05 2017, @06:44PM (#535332)

          https://seasteading.org [seasteading.org] or https://forum.seasteading.org [seasteading.org] - Apparently Thiel himself no longer believes in the org/site, forums still have lots of dreamers though!

          vivalarevolucion.i2p/#arc @ IRC2P - Less ambitious project that has been hovering around the darknet for a few years now.

          There are three big problems involved:
          1. All the seasteading.org stuff is VERY libertarian leaning, in the sense of a 'land-building ponzi scheme' (not altogether different from Liberland, if it was treated as more than a publicity stunt for a mediocre Czech politician.)
          2. Financing. The ideas being promoted on seasteading.org all center around luxury housing, rather than starting with a solid, but relatively cheap floating foundation and low cost infrastructure and building to luxury housing as infrastructure and financing allows.
          3. Legal issues surrounding territoriality, international trade laws/bans, laws regarding flagless/stateless vessels (see UNICLOS), and other requirements to be considered an independent political entity.

          All of which are resolvable, but only if enough serious people band together to do the financing, politicking, engineering, and boots on the ground work to make it happen. It has been almost 5 years since I started following all of this, and basically nothing new has happening in all that time. Between Geo-polymer formulas, Bio-rock accretion, and moderately cheap and ubiquitous renewable energy equipment, it is entirely possible today to reach the needed level of mechanical and electrical resilience to live 24/7 on the high seas, given selection of location(s) with a low probability of dangerous tropical weather patterns.

          The real question is: Who will get everything together to do it first? And will it be a singular wealthy person's effort, a cabal no better than what we already have, or a collective group effort that makes it happen?

          • (Score: 2) by takyon on Wednesday July 05 2017, @06:53PM (1 child)

            by takyon (881) <takyonNO@SPAMsoylentnews.org> on Wednesday July 05 2017, @06:53PM (#535340) Journal

            Do I have to eat fish on the sustainable seastead?

            --
            [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
            • (Score: 1, Interesting) by Anonymous Coward on Wednesday July 05 2017, @07:33PM

              by Anonymous Coward on Wednesday July 05 2017, @07:33PM (#535377)

              Between aeroponics, hydroponics, greenhouse growing (needed for salt intolerant plants to avoid salt spray/sea mist, unless you either have a shore buffer, or are 100+ feet above sealevel), and salt tolerant crop species, you can grow pretty much anything you want without relying on seafood. However, if you want meat products that are not from the sea, you would need to grow enough grain crop to support them, plus any necessary supplemental minerals needed for their long term health. For instance, calcium for chickens and the production of sturdy egg shells. From there it is just a matter of how much of the year you can grow plants and the preservation techniques employed to ensure sufficient year round supplies.

              There is also always the possibility of trading fish for food you actually want :)

              Also as a fix to the grandparent: I2P's default addressbook doesn't link to vivalarevolucion.i2p, inr.i2p (the default addressbook for i2pd) however DOES.

          • (Score: 2) by aristarchus on Wednesday July 05 2017, @08:17PM (1 child)

            by aristarchus (2645) on Wednesday July 05 2017, @08:17PM (#535394) Journal

            2. Financing. The ideas being promoted on seasteading.org all center around luxury housing, rather than starting with a solid, but relatively cheap floating foundation and low cost infrastructure

            But on the plus side, they do allow certain pets. To be specific, white, longhair cats exclusively.

            --
            #Freearistarchus, again!!!!!1!!
            • (Score: 0) by Anonymous Coward on Wednesday July 05 2017, @09:58PM

              by Anonymous Coward on Wednesday July 05 2017, @09:58PM (#535426)

              I assumed they were white longhaired monkeys :)

    • (Score: 4, Informative) by EvilSS on Wednesday July 05 2017, @02:04PM

      by EvilSS (1456) Subscriber Badge on Wednesday July 05 2017, @02:04PM (#535182)
      Well they probably didn't know the exact chemistry, but they knew volcanic ash was a key to making marine cement structures:

      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.

      Descriptions of volcanic ash have survived from ancient times. First Vitruvius, an engineer for the Emperor Augustus, and later Pliny the Elder recorded that the best maritime concrete was made with ash from volcanic regions of the Gulf of Naples (Pliny died in the eruption of Mt. Vesuvius that buried Pompeii), especially from sites near today’s seaside town of Pozzuoli. Ash with similar mineral characteristics, called pozzolan, is found in many parts of the world.

      https://newscenter.lbl.gov/2013/06/04/roman-concrete/ [lbl.gov] (Thanks to a number6 for the link in another comment)

  • (Score: 4, Interesting) by number6 on Wednesday July 05 2017, @12:02PM

    by number6 (1831) on Wednesday July 05 2017, @12:02PM (#535142) Journal
  • (Score: 3, Interesting) by kaszz on Wednesday July 05 2017, @02:14PM (4 children)

    by kaszz (4211) on Wednesday July 05 2017, @02:14PM (#535190) Journal

    Seems concrete made without rebar is what makes structures stand the test of time. So maybe some constructions should be made this way?

    • (Score: 4, Interesting) by Immerman on Wednesday July 05 2017, @04:18PM (3 children)

      by Immerman (3985) on Wednesday July 05 2017, @04:18PM (#535249)

      That is a second factor definitely - as rebar rusts it expands and shatters the concrete. But modern concrete suffers from spalling and other degradation problems as well. It's a pretty safe to bet that nothing made in the last few centuries will still be around and structurally sound after two thousand years, even if it didn't incorporate rebar or other metal reinforcements.

      There's a somewhat related "joke" in the southwest - government officials finally decided to allow traditional adobe construction to satisfy construction code requirements, provided it was reinforced with rebar. The natives acquiesced, while commenting amongst themselves that in a few hundred years archaeologists were going to wonder how and why they had these strange red circles perfectly lined up between all the tiers of adobe brick in their walls.

  • (Score: 3, Offtopic) by leftover on Wednesday July 05 2017, @02:37PM (1 child)

    by leftover (2448) on Wednesday July 05 2017, @02:37PM (#535200)

    This "mystery" is "solved" every couple of years. As noted, it is described in ancient Roman writings. Breathless announcements probably date back only to the scramble for grant money being the driver for [scams disguised as] science. This pattern is becoming tedious. /grumble

    --
    Bent, folded, spindled, and mutilated.
    • (Score: -1, Offtopic) by Anonymous Coward on Wednesday July 05 2017, @04:20PM

      by Anonymous Coward on Wednesday July 05 2017, @04:20PM (#535250)

      Breathless announcements probably date back only to the scramble for grant money being the driver for [scams disguised as] science. This pattern is becoming tedious.

      Bullshit. Almost every time, even with the "getting paid and staying employed" incentive for seeking grants, science has jack shit to do with "breathless announcements". Lay the blame where it should be: the PR department.

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