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Thread: How can concrete repair itself?

  1. #1

    Default How can concrete repair itself?

    Maybe useful in our freeze heave world...

    http://www.economist.com/blogs/econo...omist-explains

    "Dr Chung tested his idea by taking small blocks of concrete, both treated and untreated, cracking them and placing them in water for a day. He found that his untreated concrete blocks accumulated 11.3 grams of water. Concrete coated with capsule-free polymer took in 3.9 grams. But the concrete covered with a polymer layer containing his capsules absorbed... "
    Last edited by KC; 05-06-2013 at 07:45 AM.

  2. #2

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    Most roads in edmonton are an asphalt like material not concrete

  3. #3

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    ^Sidewalks, bridge columns, etc, etc....

  4. #4

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    And the Hendaybahn.

  5. #5

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    Quote Originally Posted by Legacy View Post
    And the Hendaybahn.
    LOL, it does seem like the Autobahn sometimes. It scary how some people pass me going at the speed limit as if I was standing still, especially on the north leg.

  6. #6

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    Quote Originally Posted by barhonda View Post
    ^Sidewalks, bridge columns, etc, etc....
    And parkades, and ornamental walkway walls along the LRT where they stick metal posts in concrete ensuring it will crack and split... And...

    But you know the first thing I thought... Maybe a similar idea could be developed for asphalt. Add diaper powder or powdered paint or something. (Except everything gets coated in oil.). Maybe solvent capsules that degrade when exposed to air or water.

  7. #7

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    Apparently good for the environment too... ( Years ago I read where rice flour allowed Chinese mortar to outlast bricks on the Great Wall and where volcanic rock strengthened Roman concrete. Now this discovery. Maybe they can combine all these things to create far better mixes.)


    Ancient Roman Concrete Is About to Revolutionize Modern Architecture

    by: Bernhard Warner on June 14, 2013
    http://www.businessweek.com/articles...n-architecture
    Excerpt

    "After 2,000 years, a long-lost secret behind the creation of one of the world’s most durable man-made creations ever—Roman concrete—has finally been discovered ..."

    "... One such structure that has fascinated geologists and engineers throughout the ages is the Roman harbor. ... in many cases, 2,000-year-old (and sometimes older) breakwaters constructed out of Roman concrete stand perfectly intact despite constant pounding by the sea."

    "... Portland cement... can’t come close to matching that track record, says Marie Jackson, a ... In seawater, it has a service life of less than 50 years. After that, it begins to erode,” Jackson says."...
    Last edited by KC; 20-06-2013 at 06:32 PM.

  8. #8

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    Our way creates 7% of the atmosphic carbon. The old, and better way:

    Back to the future with Roman architectural concrete: Advanced light source reveals key to longevity of imperial Roman monuments
    December 15, 2014, Lawrence Berkeley National Laboratory

    "The dense intergrowths of the platy crystals obstruct crack propagation and preserve cohesion at the micron scale, which in turn enables the concrete to maintain its chemical resilience and structural integrity in a seismically active environment at the millennial scale."

    "... structures of Imperial Rome are of keen scientific interest not just because of their unmatched resilience and durability, but also for the environmental advantages they offer. Most modern concretes are bound by limestone-based Portland cement. Manufacturing Portland cement requires heating a mix of limestone and clay to 1,450 degrees Celsius (2,642 degrees Fahrenheit), a process that releases enough carbon -- given the 19 billion tons of Portland cement used annually -- to account for about seven-percent of the total amount of carbon emitted into the atmosphere each year."


    http://www.sciencedaily.com/releases...1215185026.htm
    Last edited by KC; 16-12-2014 at 10:19 PM.

  9. #9

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    Quote Originally Posted by KC View Post
    Apparently good for the environment too... ( Years ago I read where rice flour allowed Chinese mortar to outlast bricks on the Great Wall and where volcanic rock strengthened Roman concrete. Now this discovery. Maybe they can combine all these things to create far better mixes.)


    Ancient Roman Concrete Is About to Revolutionize Modern Architecture

    by: Bernhard Warner on June 14, 2013
    http://www.businessweek.com/articles...n-architecture
    Excerpt

    "After 2,000 years, a long-lost secret behind the creation of one of the world’s most durable man-made creations ever—Roman concrete—has finally been discovered ..."

    "... One such structure that has fascinated geologists and engineers throughout the ages is the Roman harbor. ... in many cases, 2,000-year-old (and sometimes older) breakwaters constructed out of Roman concrete stand perfectly intact despite constant pounding by the sea."

    "... Portland cement... can’t come close to matching that track record, says Marie Jackson, a ... In seawater, it has a service life of less than 50 years. After that, it begins to erode,” Jackson says."
    ...
    More to the secret of Roman concrete:

    Scientists explain ancient Rome's long-lasting concrete - BBC News


    "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.

    "Contrary to the principles of modern cement-based concrete," said co-author Marie Jackson from the University of Utah, US, "the Romans created a rock-like concrete that thrives in open chemical exchange with seawater." ...

    "Their technique was based on building very massive structures that are really quite environmentally sustainable and very long-lasting," she said.

    "I think Roman concrete or a type of it would be a very good choice [for Swansea]. That project is going to require 120 years of service life to amortise [pay back] the investment.
    "We know that Portland cement concretes contain steel reinforcements. Those will surely corrode in at least half of that service lifetime."

    http://www.bbc.com/news/science-environment-40494248



    Bolding was mine
    Last edited by KC; 04-07-2017 at 09:25 AM.

  10. #10

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    Cementless concrete (that's even carbon sequestering):


    Made-at-McGill technology drawing global attention
    Posted on Tuesday, November 15, 2016
    “Concrete made with our technology contains no cement,” says Mahoutian. “In addition to providing significant environmental benefits compared with conventional cement-based blocks, our blocks are less expensive to produce.”
    http://publications.mcgill.ca/report...bal-attention/

    per the company website:

    Cement-free concrete

    Conventional concrete is made using Portland cement…but cement production accounts for 5% of the world’s CO2 emissions!

    Our patented technology, which can be implemented in any concrete products plant with virtually no process flow disruption, makes it possible to produce concrete products without using cement. Products made using our technology are less expensive, more durable and more environmental than their cement-based counterparts…all while ridding the environment of harmful emissions.

    More durable...more sustainable...more cost-effective

    The primary binder in our concrete is steel slag—a by-product of steel-making, typically destined for a landfill.

    Using a process called carbonation activation, CO2 is injected into the wet concrete to give it its strength. As a result, any product made using Carbicrete technology permanently sequesters CO2, while turning industrial waste (steel slag) into a high-quality construction product.

    Products made in this fashion meet all of the same specifications as cement-based concrete products, have lower material costs, possess the same mechanical properties, and are more durable.

    Carbon-negative concrete

    Because we don’t use cement, the production of which emits a massive amount of CO2, and then sequester CO2 within the concrete, products made using our technology are carbon-negative.


    http://carbicrete.com



  11. #11

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    Their page doesn't say where the sequestered CO2 comes from. If it's produced for the purposes of making the product then that's not sequestration. Extracting and cleaning CO2 from a stream of byproduct gases is not a trivial process.
    I am in no way entitled to your opinion...

  12. #12

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    Quote Originally Posted by Spudly View Post
    Their page doesn't say where the sequestered CO2 comes from. If it's produced for the purposes of making the product then that's not sequestration. Extracting and cleaning CO2 from a stream of byproduct gases is not a trivial process.

    There's so many companies looking for ways to capture carbon from polluting sources to reduce costs and hopefully redeploy the CO2 into other uses - so the essentially hope to cut their mainstream production costs (or carbon taxes thereupon) as well as use the captured carbon as a saleable product itself, maybe even generating net profit, so I doubt there would be a need to produce it separately for concrete.

    Anyway, I came across it because I have a few shares in CO2 Solutions (a carbon capture research company) which is working with this company on some competition. It has an Alberta connection tooI suppose since the Alta Gov't has funded some of CO2 Solutions' research.
    Last edited by KC; 21-09-2017 at 01:12 PM.

  13. #13

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    Volcanic Ash Reduces the Energy Required to Manufacture Concrete

    https://scitechdaily.com/volcanic-as...ture-concrete/

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