SCI Ancient Roman Concrete Is About to Revolutionize Modern Architecture By Bernhard Warner

Ancient Roman Concrete Is About to Revolutionize Modern Architecture
By Bernhard Warner

June 14, 2013 Facebook Tweet LinkedIn Google Plus Email
Ancient Rome construction green architecture green construction Portland Cement Roman concrete University of California-Berkeley
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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 by an international team of scientists, and it may have a significant impact on how we build cities of the future.

As anyone who’s ever visited Italy knows, the ancient Romans were master engineers. Their roads, aqueducts, and temples are still holding up remarkably well despite coming under siege over the centuries by waves of sacking marauders, mobs of tourists, and the occasional earthquake. One such structure that has fascinated geologists and engineers throughout the ages is the Roman harbor. Over the past decade, researchers from Italy and the U.S. have analyzed 11 harbors in the Mediterranean basin where, 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.

The most common blend of modern concrete, known as Portland cement, a formulation in use for nearly 200 years, can’t come close to matching that track record, says Marie Jackson, a research engineer at the University of California at Berkeley who was part of the Roman concrete research team. “The maritime environment, in particular, is not good for Portland concrete. In seawater, it has a service life of less than 50 years. After that, it begins to erode,” Jackson says.

The researchers now know why ancient Roman concrete is so superior. They extracted from the floor of Italy’s Pozzuoili Bay, in the northern tip of the Bay of Naples, a sample of concrete breakwater that dates back to 37 B.C. and analyzed its mineral components at research labs in Europe and the U.S., including at Berkeley Lab’s Advanced Light Source. The analysis, the scientists believe, reveals the lost recipe of Roman concrete, and it also points to how much more stable and less environmentally damaging it is than today’s blend.

That’s why the findings, which were published earlier this month in the Journal of the American Ceramic Society and American Mineralogist, are considered so important for today’s industrial engineers and the future of the world’s cities and ports. “The building industry has been searching for a way to make more durable concretes,” Jackson points out.

Another remarkable quality of Roman concrete is that its production was exceptionally green, a far cry from modern techniques. “It’s not that modern concrete isn’t good—it’s so good we use 19 billion tons of it a year,” says Paulo Monteiro, a research collaborator and professor of civil and environmental engineering at the University of California, Berkeley. “The problem is that manufacturing Portland cement accounts for 7 percent of the carbon dioxide that industry puts into the air.”

The secret to Roman concrete lies in its unique mineral formulation and production technique. As the researchers explain in a press release outlining their findings, “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.”

The Portland cement formula crucially lacks the lyme and volcanic ash mixture. As a result, it doesn’t bind quite as well when compared with the Roman concrete, researchers found. It is this inferior binding property that explains why structures made of Portland cement tend to weaken and crack after a few decades of use, Jackson says.

Adopting the materials (more volcanic ash) and production techniques of ancient Roman could revolutionize today’s building industry with a sturdier, less CO2-intensive concrete. “The question remains, can we translate the principles from ancient Rome to the production of modern concrete? I think that is what is so exciting about this new area of research,” Jackson says.

Of course, if you are no fan of concrete architecture, you’re out of luck. It could be with us for a few millenia more.

http://www.businessweek.com/article...t-to-revolutionize-modern-architecture#r=read

To improve today’s concrete, do as the Romans did
By Sarah Yang, Media Relations | June 4, 2013

BERKELEY —
In a quest to make concrete more durable and sustainable, an international team of geologists and engineers has found inspiration in the ancient Romans, whose massive concrete structures have withstood the elements for more than 2,000 years.


Sample of ancient Roman maritime concrete from Pozzuoli Bay near Naples, Italy. Its diameter is 9 centimeters, and it is composed of mortar formulated from lime, volcanic ash and chunks of volcanic tuff. (Carol Hagen photo)
Using the Advanced Light Source at Lawrence Berkeley National Laboratory (Berkeley Lab), a research team from the University of California, Berkeley, examined the fine-scale structure of Roman concrete. It described for the first time how the extraordinarily stable compound – calcium-aluminum-silicate-hydrate (C-A-S-H) – binds the material used to build some of the most enduring structures in Western civilization.

The discovery could help improve the durability of modern concrete, which within 50 years often shows signs of degradation, particularly in ocean environments.

The manufacturing of Roman concrete also leaves a smaller carbon footprint than does its modern counterpart. The process for creating Portland cement, a key ingredient in modern concrete, requires fossil fuels to burn calcium carbonate (limestone) and clays at about 1,450 degrees Celsius (2,642 degrees Fahrenheit). Seven percent of global carbon dioxide emissions every year comes from this activity. The production of lime for Roman concrete, however, is much cleaner, requiring temperatures that are two-thirds of that required for making Portland cement.

The researchers’ findings are described in two papers, one that was posted online May 28 in the Journal of the American Ceramic Society, and the other scheduled to appear in the October issue of the journal American Mineralogist.

“Roman concrete has remained coherent and well-consolidated for 2,000 years in aggressive maritime environments,” said Marie Jackson, lead author of both papers. “It is one of the most durable construction materials on the planet, and that was no accident. Shipping was the lifeline of political, economic and military stability for the Roman Empire, so constructing harbors that would last was critical.”


Marie Jackson holds a 2,000-year-old sample of maritime concrete from the first century B.C. Santa Liberata harbor site in Tuscany. (Sarah Yang photo)
The research team was led by Paulo Monteiro, a UC Berkeley professor of civil and environmental engineering and a faculty scientist at Berkeley Lab, and Jackson, a UC Berkeley research engineer in civil and environmental engineering. They characterized samples of Roman concrete taken from a breakwater in Pozzuoli Bay, near Naples, Italy.

Building the Empire

Concrete was the Roman Empire’s construction material of choice. It was used in monuments such as the Pantheon in Rome as well as in wharves, breakwaters and other harbor structures. Of particular interest to the research team was how Roman’s underwater concrete endured the unforgiving saltwater environment.

The recipe for Roman concrete was described around 30 B.C. by Marcus Vitruvius Pollio, an engineer for Octavian, who became Emperor Augustus. The not-so-secret ingredient is volcanic ash, which Romans combined with lime to form mortar. They packed this mortar and rock chunks into wooden molds immersed in seawater. Rather than battle the marine elements, Romans harnessed saltwater and made it an integral part of the concrete.

The researchers also described a very rare hydrothermal mineral called aluminum tobermorite (Al-tobermorite) that formed in the concrete. “Our study provided the first experimental determination of the mechanical properties of the mineral,” said Jackson.


This scanning electron microscope image shows crystals of a rare mineral, Al-tobermorite, magnified about 25,000 times. UC Berkeley researchers characterized Al-tobermorite in samples of Roman concrete. (Image courtesy of UC Berkeley)
So why did the use of Roman concrete decrease? “As the Roman Empire declined, and shipping declined, the need for the seawater concrete declined,” said Jackson. “You could also argue that the original structures were built so well that, once they were in place, they didn’t need to be replaced.”

An earth-friendly alternative

While Roman concrete is durable, Monteiro said it is unlikely to replace modern concrete because it is not ideal for construction where faster hardening is needed.

But the researchers are now finding ways to apply their discoveries about Roman concrete to the development of more earth-friendly and durable modern concrete. They are investigating whether volcanic ash would be a good, large-volume substitute in countries without easy access to fly ash, an industrial waste product from the burning of coal that is commonly used to produce modern, green concrete.

“There is not enough fly ash in this world to replace half of the Portland cement being used,” said Monteiro. “Many countries don’t have fly ash, so the idea is to find alternative, local materials that will work, including the kind of volcanic ash that Romans used. Using these alternatives could replace 40 percent of the world’s demand for Portland cement.”

The research began with initial funding from King Abdullah University of Science and Technology in Saudi Arabia (KAUST), which launched a research partnership with UC Berkeley in 2008. Monteiro noted that Saudi Arabia has “mountains of volcanic ash” that could potentially be used in concrete.

In addition to KAUST, funding from the Loeb Classical Library Foundation, Harvard University and the Department of Energy’s Office of Science helped support this research. Samples were provided by Marie Jackson and the Roman Maritime Concrete Study (ROMACONS), sponsored by CTG Italcementi, a research center based in Bergamo, Italy. The researchers also used the Berlin Electron Storage Ring Society for Synchrotron Radiation, or BESSY, for their analyses.

http://newscenter.berkeley.edu/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@lbl.gov 576
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.)
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 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@ce.berkeley.edu, 510-643-8251; Marie Jackson, mdjackson@berkeley.edu, 928-853-7967

For more information, read the UC Berkeley press release at 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.

http://newscenter.lbl.gov/news-releases/2013/06/04/roman-concrete/

thanks. very interesting. the future of the colonization of the oceans will likely be closely tied to this development.

you pulled together enough for me to comprehend quite well the compositions and percentages that are critical.

In a period where most of the news is pretty dismal, that was an interesting read.

Thanks CC


BTW...I wonder why the aliens gave them the recipe?

I don't see the Roman stuff replacing modern cements in concrete, as today's production schedules are on very tight deadlines, as well as there simply isn't enough natural pozzulans (the stuff that helps to make the concrete bind chemically and set) available to mine.

I have concrete patients so I know a bit on the subject. Probably part portland and part Roman would work better.

China Connection said:

I have concrete patients so I know a bit on the subject. Probably part portland and part Roman would work better.

Click to expand...

Good post and a good read, CC

The Romans were pretty advanced for a 2,000 year old society with plumbing systems, sewers, indoor toilets that were flushed, mechanical design and building construction, 50,000 miles of engineered roads, aqueducts that ran for hundreds of miles and many other things that weren't duplicated for almost two thousand years.
Their society last longer than our seems destined to.

The truth about the Roman Empire is they "fell" several times. The original Roman Republic was created around 500 BC when they kicked the kings out. The Roman Republic fell after 100 years of civil war, 130 BC to 30 BC and was replaced with the Roman Empire. The Julius Caesar line of Emperors lasted 100 years to the death of Nero in 68 AD. That was followed by the year with four Caesars and chaos for 25 years until you had the golden age of the Roman Empire from 95 AD to the death of Marcus Aurielus in 180 AD. You then had another 30 years of semi chaos until another dynasty was founded by Septimus Severus. That lasted about 30 years. After that you had a new Caesar until Diocletican in 280 AD, followed by Constantine in 300 AD. After that you had decline until 409 AD and the physical sack of Rome. the historical date for the fall of Rome 476 AD relates to when the final Roman Caesar was openly replaced by a Barbarian Caesar. The reality is large parts of the Roman Empire fell as early as 167 AD. Other parts like southern Italy and France lasted until 600 AD.
The eastern roman empire lasted until the 1453 sack of Constantinoble by the way.
There is an aqueduct in Spain that has been in continuous use since Caesar Augustus.

Millwright said:

In a period where most of the news is pretty dismal, that was an interesting read.

Thanks CC


BTW...I wonder why the aliens gave them the recipe?

Click to expand...

I suppose that giving us superior concrete wouldn't make us a threat to their home planets.

we have the fixins right here. A shield volcano. lime deposits and a valley with silica hardpan. They can come experiment all they want.

Thanks China Connection! Very interesting read.

"Fascinating."
/eyebrow-raise
/Lenny-Spock

Well, now I am having visions of breaking out wood forms and slip forming a rock house using this if I could manage the recipe and ingredients.

Also assuming that there is a reasonable cost for them.

Ah well another project to contemplate: 10 foot high rock walls around a 9 acre fortified homestead such as was built in feudal times in Europe.

My DH told me that the oil companies were using a form of this cement which they called "Foam Cement" with fly ash, to set casing in the wells. It was quite light and foamed when mixed with water. When it was pumped into the well it came in contact with the salt water down there and set, like what the Romans were doing.

Link to patent for this same stuff in 2007 - http://www.google.com/patents/US7867954

Even mentions the Romans and Greeks using it.......

This has been known for a long time, and there's no energy saving making lime over Portland cement (which if correctly mixed, and without damaging additives, hardens over 112 years before starting to fail).

A large part of the secret may be the amount of time components of it were aged before being finally mixed and used. I remember reading reports that for the best concrete, some components were watered and worked daily, for at least 100 years before it was used (reminiscent of Hispano Suiza cars having their engine and gearbox cases, etc., weathered outdoors for a period before being finally finished and used for production).

People have been mixing lime with Portland cement for years (it makes the resulting concrete more elastic/plastic and less susceptible to movement failures). It's good for bricklaying mortar too.

Probably the most interesting concrete, looks to be that used to skin the Bosnian pyramids - which relied on burnt clay as the elastic/plastic binder.

There's a strong possibility this has done about 35,000 years, and it is still intact.

"Under the concrete of the Pyramid of the Sun, the series of large sandstone blocks show various types of rocks (differing pebbles and cobbles), including sandy quartz limestone, when more closely analyzed. It is thought that the concrete is made from material found at a locally deposited post glacial conglomerate. Experts who examined these crystals determined that during the manufacturing process, the materials were heated to above 500 degrees. Studies done at the University of Paris discovered that the concrete material found on the Bosnian Pyramid of the Sun was five times stronger than modern day concrete. The concrete was shown to be resistant to 94 Megapascals of pressure, which means it is highly compressed and extremely rigid - concrete of this strength is only available in a few very developed countries at special request. The founder of the French Institute of Polymers, Joseph Davidovits, Ph.D. performed an electronic microscopic analysis on a sample of concrete; he concluded that the chemical composition of the old concrete’s basis is a calcium/potassium geopolymer cement. He found the cement to be five times stronger and five times more water resistant than any concrete able to be made today. Davidovits is an author of over fifty patents in the field of the science of materials, and is considered an expert in the field. He holds a French Medal of Merit and has published ten books about the construction of the Egyptian Pyramids."

http://www.bosnianpyramids.org/index.php?id=39&lang=en

It'd be right nice to have some 'modern' roads that lasted longer than a few dozen years at best - talking mostly about asphalt (no matter how well it's 'done').

Asphalt's nice and smooth when freshly laid out, but never seems to last that long - and it's a real bear to have to reroute traffic when redoing it.

Orange barrels are the bane of modern roads...necessary, but a bane nonetheless. They seem to pop up everywhere in recent decades.


Quality concrete could do the job for a lot longer (even tho' more expensive initially) - and better.
Getting the right concrete done properly is the key, of course! Especially the foundation materials.

Asphalt in this climate (hot, hi-U/V, dry) just won't last...especially with the beating they take from the heavily laden trucks from May He Ko.

jmho.

Hognutz said:

Thanks China Connection! Very interesting read.

Click to expand...

Agreed...thanks CC verrry interesting....

The biggest reason stuff doesn't last, is there's too many kickbacks for having to re-Contract work at regular (and short) intervals. Corruption costs a fortune.

The original motorway construction over here was to a very high standard. A good foundation of large scalpings to dust, a good thick sub-base course of large aggregate tarmac, a good thick base course of smaller aggregate tarmac, a good thick top course of small aggregate tarmac, then a wearing course of very fine aggregate tarmac.

That was designed so every 15 years minimum, all you had to do was burn off the thin wearing course, and apply a new one.

They actually did 17 - 20 years.

The test sections (large parts of the M1, for example) with concrete, weren't very successful.

I was site agent and QS/Surveyor on several sections of the Motorway construction, and the Company I worked for had outstanding tarmac gangs (the middle son of the owner went over to America for a couple of years to see how you guys did it there - your people were really impressive and he learned a lot).

eta: Another factor, and perhaps the most important, was quality control. Every load of tarmac was tested for compliance, and every load of concrete was tested for compliance. ALL non-compliant loads were rejected. For example there was a contractor I personally warned, that all the spacings of the streetlights in certain sections had to be at the exact distances. If they weren't, the speed limit would be illegal. The idiot didn't listen, put them in where it suited 'him' (to save costs), and he had to rip the lot out and put them in properly. At his expense.

Sadly today, quality control has people that don't even comprehend what they are looking at.

If it is even present.

I'm surprised they haven't analysed this before