[FoRK] Concrete results

Damien Morton dmorton at bitfurnace.com
Sat Jun 15 15:21:40 PDT 2013


There are people innovating in this area - see geopolymers
https://en.wikipedia.org/wiki/Geopolymer which the blocks that make up the
pyramids may be made of.


On Sat, Jun 15, 2013 at 6:08 PM, Joseph S. Barrera III <joe at barrera.org>wrote:

> We could do so much better than simply bolting on a (literally) ancient
> recipe.
>
> Why aren't the concrete manufacturers trying to innovate based on modern
> experiments instead of looking back at the ancients?
>
> I guess not every industry yet is information-driven. Oil is, of course,
> but evidently concrete is not.
>
> - Joe
>
>
> On 6/15/2013 2:59 PM, Stephen Williams wrote:
>
>> Finally. I heard about this discrepancy long ago.  Odd that it took so
>> long.
>>
>> http://www.businessweek.com/**articles/2013-06-14/ancient-**
>> roman-concrete-is-about-to-**revolutionize-modern-**architecture<http://www.businessweek.com/articles/2013-06-14/ancient-roman-concrete-is-about-to-revolutionize-modern-architecture>
>> http://newscenter.lbl.gov/**news-releases/2013/06/04/**roman-concrete/<http://newscenter.lbl.gov/news-releases/2013/06/04/roman-concrete/>
>>
>> Roman Seawater Concrete Holds the Secret to Cutting Carbon Emissions
>> Berkeley Lab scientists and their colleagues have discovered the
>> properties that made ancient Roman concrete sustainable and durable
>> June 04, 2013
>> Paul Preuss 510-486-6249  paul_preuss at lbl.gov
>>    News Release
>>
>> Drill core of volcanic ash-hydrated lime mortar from the ancient port of
>> Baiae in Pozzuloi Bay. Yellowish inclusions are pumice, dark stony
>> fragments are lava, gray areas consist of other volcanic crystalline
>> materials, and white spots are lime. Inset is a scanning electron
>> microscope image of the special Al-tobermorite crystals that are key to the
>> superior quality of Roman seawater concrete. (Click on image for best
>> resolution.)
>>
>> Drill core of volcanic ash-hydrated lime mortar from the ancient port of
>> Baiae in Pozzuloi Bay. Yellowish inclusions are pumice, dark stony
>> fragments are lava, gray areas consist of other volcanic crystalline
>> materials, and white spots are lime. Inset is a scanning electron
>> microscope image of the special Al-tobermorite crystals that are key to the
>> superior quality of Roman seawater concrete. (Click on image for best
>> resolution.)
>>
>> The chemical secrets of a concrete Roman breakwater that has spent the
>> last 2,000 years submerged in the Mediterranean Sea have been uncovered by
>> an international team of researchers led by Paulo Monteiro of the U.S.
>> Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley
>> Lab), a professor of civil and environmental engineering at the University
>> of California, Berkeley.
>>
>> Analysis of samples provided by team member Marie Jackson pinpointed why
>> the best Roman concrete was superior to most modern concrete in durability,
>> why its manufacture was less environmentally damaging – and how these
>> improvements could be adopted in the modern world.
>>
>> “It’s not that modern concrete isn’t good – it’s so good we use 19
>> billion tons of it a year,” says Monteiro. “The problem is that
>> manufacturing Portland cement accounts for seven percent of the carbon
>> dioxide that industry puts into the air.”
>>
>> Portland cement is the source of the “glue” that holds most modern
>> concrete together. But making it releases carbon from burning fuel, needed
>> to heat a mix of limestone and clays to 1,450 degrees Celsius (2,642
>> degrees Fahrenheit) – and from the heated limestone (calcium carbonate)
>> itself. Monteiro’s team found that the Romans, by contrast, used much less
>> lime and made it from limestone baked at 900˚ C (1,652˚ F) or lower,
>> requiring far less fuel than Portland cement.
>>
>> Cutting greenhouse gas emissions is one powerful incentive for finding a
>> better way to provide the concrete the world needs; another is the need for
>> stronger, longer-lasting buildings, bridges, and other structures.
>>
>> “In the middle 20th century, concrete structures were designed to last 50
>> years, and a lot of them are on borrowed time,” Monteiro says. “Now we
>> design buildings to last 100 to 120 years.” Yet Roman harbor installations
>> have survived 2,000 years of chemical attack and wave action underwater.
>>
>> How the Romans did it
>>
>> 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.
>>
>> Pozzuoli Bay defines the northwestern region of the Bay of Naples. The
>> concrete sample examined at the Advanced Light Source by Berkeley
>> researchers, BAI.06.03, is from the ancient harbor of Baiae, one of many
>> ancient underwater sites in the region. Black lines indicate caldera rims,
>> and red areas are volcanic craters. (Click on image for best resolution.)
>>
>> Pozzuoli Bay defines the northwestern region of the Bay of Naples. The
>> concrete sample examined at the Advanced Light Source by Berkeley
>> researchers, BAI.06.03, is from the harbor of Baiae, one of many ancient
>> underwater sites in the region. Black lines indicate caldera rims, and red
>> areas are volcanic craters. (Click on image for best resolution.)
>>
>> 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.
>>
>> Using beamlines 5.3.2.1, 5.3.2.2, 12.2.2 and 12.3.2 at Berkeley Lab’s
>> Advanced Light Source (ALS), along with other experimental facilities at UC
>> Berkeley, the King Abdullah University of Science and Technology in Saudi
>> Arabia, and the BESSY synchrotron in Germany, Monteiro and his colleagues
>> investigated maritime concrete from Pozzuoli Bay. They found that Roman
>> concrete differs from the modern kind in several essential ways.
>>
>> One is the kind of glue that binds the concrete’s components together. In
>> concrete made with Portland cement this is a compound of calcium,
>> silicates, and hydrates (C-S-H). Roman concrete produces a significantly
>> different compound, with added aluminum and less silicon. The resulting
>> calcium-aluminum-silicate-**hydrate (C-A-S-H) is an exceptionally stable
>> binder.
>>
>> At ALS beamlines 5.3.2.1 and 5.3.2.2, x-ray spectroscopy showed that the
>> specific way the aluminum substitutes for silicon in the C-A-S-H may be the
>> key to the cohesion and stability of the seawater concrete.
>>
>> Another striking contribution of the Monteiro team concerns the hydration
>> products in concrete. In theory, C-S-H in concrete made with Portland
>> cement resembles a combination of naturally occurring layered minerals,
>> called tobermorite and jennite. Unfortunately these ideal crystalline
>> structures are nowhere to be found in conventional modern concrete.
>>
>> Tobermorite does occur in the mortar of ancient seawater concrete,
>> however. High-pressure x-ray diffraction experiments at ALS beamline 12.2.2
>> measured its mechanical properties and, for the first time, clarified the
>> role of aluminum in its crystal lattice. Al-tobermorite (Al for aluminum)
>> has a greater stiffness than poorly crystalline C-A-S-H and provides a
>> model for concrete strength and durability in the future.
>>
>> Finally, microscopic studies at ALS beamline 12.3.2 identified the other
>> minerals in the Roman samples. Integration of the results from the various
>> beamlines revealed the minerals’ potential applications for
>> high-performance concretes, including the encapsulation of hazardous wastes.
>>
>> Lessons for the future
>>
>> Environmentally friendly modern concretes already include volcanic ash or
>> fly ash from coal-burning power plants as partial substitutes for Portland
>> cement, with good results. These blended cements also produce C-A-S-H, but
>> their long-term performance could not be determined until the Monteiro team
>> analyzed Roman concrete.
>>
>> Their analyses showed that the Roman recipe needed less than 10 percent
>> lime by weight, made at two-thirds or less the temperature required by
>> Portland cement. Lime reacting with aluminum-rich pozzolan ash and seawater
>> formed highly stable C‑A-S-H and Al-tobermorite, insuring strength and
>> longevity. Both the materials and the way the Romans used them hold lessons
>> for the future.
>>
>> “For us, pozzolan is important for its practical applications,” says
>> Monteiro. “It could replace 40 percent of the world’s demand for Portland
>> cement. And there are sources of pozzolan all over the world. Saudi Arabia
>> doesn’t have any fly ash, but it has mountains of pozzolan.”
>>
>> Stronger, longer-lasting modern concrete, made with less fuel and less
>> release of carbon into the atmosphere, may be the legacy of a deeper
>> understanding of how the Romans made their incomparable concrete.
>>
>> This work was supported by King Abdullah University of Science and
>> Technology, the Loeb Classical Library Foundation at Harvard University,
>> and DOE’s Office of Science, which also supports the Advanced Light Source.
>> Samples of Roman maritime concrete were provided by Marie Jackson and by
>> the ROMACONS drilling program, sponsored by CTG Italcementi of Bergamo,
>> Italy.
>>
>> ###
>>
>> Scientific contacts: Paulo Monteiro, monteiro at ce.berkeley.edu,
>> 510-643-8251; Marie Jackson, mdjackson at berkeley.edu,  928-853-7967
>>
>> For more information, read the UC Berkeley press release at
>> http://newscenter.berkeley.**edu/2013/06/04/roman-concrete/<http://newscenter.berkeley.edu/2013/06/04/roman-concrete/>
>> **.
>>
>> “Material and elastic properties of Al-tobermorite in ancient Roman
>> seawater concrete,” by Marie D. Jackson, Juhyuk Moon, Emanuele Gotti, Rae
>> Taylor, Abdul-Hamid Emwas, Cagla Meral, Peter Guttmann, Pierre Levitz,
>> Hans-Rudolf Wenk, and Paulo J. M. Monteiro, appears in the Journal of the
>> American Ceramic Society.
>>
>> “Unlocking the secrets of Al-tobermorite in Roman seawater concrete,” by
>> Marie D. Jackson, Sejung Rosie Chae, Sean R. Mulcahy, Cagla Meral, Rae
>> Taylor, Penghui Li, Abdul-Hamid Emwas, Juhyuk Moon, Seyoon Yoon, Gabriele
>> Vola, Hans-Rudolf Wenk, and Paulo J. M. Monteiro, will appear in American
>> Mineralogist.
>>
>> The Advanced Light Source is a third-generation synchrotron light source
>> producing light in the x-ray region of the spectrum that is a billion times
>> brighter than the sun. A DOE national user facility, the ALS attracts
>> scientists from around the world and supports its users in doing
>> outstanding science in a safe environment. For more information visit
>> www-als.lbl.gov/.
>>
>> Lawrence Berkeley National Laboratory addresses the world’s most urgent
>> scientific challenges by advancing sustainable energy, protecting human
>> health, creating new materials, and revealing the origin and fate of the
>> universe. Founded in 1931, Berkeley Lab’s scientific expertise has been
>> recognized with 13 Nobel prizes. The University of California manages
>> Berkeley Lab for the U.S. Department of Energy’s Office of Science. For
>> more, visit www.lbl.gov.
>>
>> DOE’s Office of Science is the single largest supporter of basic research
>> in the physical sciences in the United States, and is working to address
>> some of the most pressing challenges of our time. For more information,
>> please visit the Office of Science website at science.energy.gov.
>>
>> TAGS: Advanced Light Source, chemistry, engineering, materials sciences
>> VIEWS: 26,974
>>
>>
>> sdw
>>
>>
>>
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>
>
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