Ancient Roman Concrete Is About To Revolutionize Modern Architecture 322
schwit1 sends this news from Businesweek:
"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. Researchers have analyzed 11 harbors in the Mediterranean basin where, in many cases, 2,000-year-old (and sometimes older) headwaters 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. In seawater, it has a service life of less than 50 years. After that, it begins to erode. 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.'"
Re:Prior art (Score:5, Insightful)
Can this discovery of old stuff be patented today, or is the fact that the romans did it so long ago constitute prior art? Or will the argument go like "We don't have a treaty with the Roman Empire regarding Intelectual Property Rights, an nobody did this in our country yet, so sure, go ahead an patent it"...?
People are amazed by this new discovery and yet legality was the first thought here.
I know you were somewhat joking here, but this is exactly why we can't have nice things. Too many damn laws stand in the way of true innovation anymore. It will be our demise.
De Architectura (Score:5, Insightful)
I find it odd that there are claims this is new information. Didn't Vitruvius describe it in his De Architectura, written about 15 BC?
http://en.wikipedia.org/wiki/De_architectura [wikipedia.org]
Perhaps the story is confusing the known composition with some mechanism that the new study discovered.
Re:Prior art (Score:5, Insightful)
> I know you were somewhat joking here, but this is exactly why we can't have nice things.
> Too many damn laws stand in the way of true innovation anymore. It will be our demise.
And I suspect that some (specifically, the owners of that "Intellectual Property") peoples' real attitude is that they will be on top of you and me as we all sink, and the sinking will stop while they're still above water. Whether or not you and I are above water will not be relevant, as long there are enough left to do the necessary work for a pittance.
Re:WWARS (What Would Ayn Rand Say) (Score:3, Insightful)
WWARS (What Would Ayn Rand Say)
"Money should be restricted to your social betters."
Also, she'd probably write a masturbation fantasy for rich people, about how much their social inferiors would suffer after a Rapture of the Rich.
Re:Bloody Romans! (Score:5, Insightful)
Re:Ancient Roman First Post is about to revolution (Score:4, Insightful)
Admit it. You all learned Latin on the off chance that you would find yourself in the past left to survive by your own wits.
Or because it was compulsory in those days, at least at my school. And since it was taught the "old-fashioned" way (using sadistic brutality, such that the Centurion's Latin lesson in Life Of Brian was eerily familiar), I actually learned the cursed lingo.
All interesting or useful topics were forbidden. Time travel to escape your teachers and/or homework deadlines would have been one of these.
Re:Prior art (Score:3, Insightful)
I'm not pooh-poohing their efforts, I'm just skeptical that lime-ash concrete as used by the Romans will lead to breakthroughs. I think their work is very interesting, and any kind of discovery like this lets us better-understand our world. It's just that if you make concrete much more expensive, other materials start to make more sense. For instance, if I'm making a big breakwater, eventually a giant hunk of stone will be more economical than concrete. The scientists involved seem to be chasing the carbon angle, since the Roman lime was baked at a lower temperature and yet they still made decent concrete. If we could learn to do that, that would indeed be nice...
I'm pretty sure the Roman concrete is still very porous - especially given the way they say it cures by water creeping in and activating the reaction. Here is the press release [lbl.gov], which has much better detail than TFA.
Its the good stuff that lasts (Score:5, Insightful)
Re:Prior art (Score:5, Insightful)
Other things contributed to the collapse such increased border invasions from Central Asia tribes (perhaps due to Chinese expansion forcing these tribes westward). Whatever it was - the collapse of the Roman Empire was not due to the rise of Christianity.
Re:Prior art (Score:5, Insightful)
The harder part may be finding enough suitable sources of volcanic ash that can be mined, and not all ash has the same mineral ratios and such. That would still limit its use unless there's some way to make a decent enough man-made equivalent that's better than the Portland formula.
And right there you've put your finger on both the source of the mystery and why this won't work everywhere.
In ancient Rome they didn't have the huge reduction furnaces used in the creation of Portland Cement. All they had was the raw materials found laying around or easily mined. Living in a volcanic region near the sea they had both in abundance.
In other areas conquered by Rome they never found the same mix of volcanic materials, lime, and seawater, and the structures they built there did not hold up as well. The aluminum-rich pozzolan ash isn't exactly something you find in the British isles or France. And away from the sea, any available water would be used. Its entirely possible the Romans had no no idea that sea water was essential to this mixture.
The whole thing was an accident of geography, and apparently one which no one cared to look into too closely, or those that did were unable to replicate due to raw material availability, because analysis of the composition of roman cement was well withing the scientific capabilities of even the 1800s and probably even the 1600s.
Re:Prior art (Score:5, Insightful)
Christianity was part of the cause of the downfall.
Another argument against that idea is that while the Western Empire fell in the 5th century, the Eastern Empire, which was just as Christian, continued for another 1000 years.
Re:NEWSFLASH (Score:4, Insightful)
The headline focuses on the wrong thing. (Score:4, Insightful)
From the headline one would think that this is the "secret ingredient" to the Roman concrete: "The lime was hydrated — incorporating water molecules into its structure — and reacted with the ash to cement the whole mixture together"
However, this is pretty much how portland cement (the modern binder in concrete) reacts with water to form the concrete with the agregate. Reading the article, however this is what matters:
"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."
So basically, there is alimunium in the crystaline structure of Roman cement that contributes to the differences in performance over time (not raw strength). Another factor that may impact durability that is not covered here but that civil engineers will know well is the fact that modern cements are more alkaline than even early Portland Cement productions. As a result, they tend to react with the silicates in the aggregates of the cement (phenomenon known as alkali-aggregate reaction). If you see concrete with cracks that look wet even when it's not raining, that's a symptom of this effect. The reaction with the aggregates causes an expansion within the concrete which builds ups stresses locally and result in those cracks, with obviously unfortunate effects on the longevity of concrete structures.
Re:Prior art (Score:5, Insightful)
For all the bashing on Wikipedia I remember seeing several studies that showed that, excepting controversial topics (which can suffer from orchestrated edit wars and astroturfing), the accuracy was generally on-par or better than The Encyclopedia Britanica and other "gold standard" sources. It may not always be completely accurate and up to date, but will typically be as reliable as any other single reference source, and the information will often far more detailed and accessible than most.
So how about instead of bashing one of the most reliable and comprehensive encyclopedias in the world, you instead go ahead and update the page that links to the obsolete periodic table image. You don't even have to understand the markup, just search for the link and make the minor tweak. Or do you really prefer to be one of the gawking bystanders?
Re:Prior art (Score:4, Insightful)
Fiberglass reinforced plastic hulls, the most ubiquitous type, commonly experience what are called blisters. Even the epoxies (the plastic part) are not totally impervious to salt water and over the years, it seeps in and can cause a chemical reaction -- this expands and leaves a blister. Examples: https://www.google.com/images?q=fiberglass+blisters [google.com]
You have to grind them away, fill with new epoxy, fair your work, and then you can put on new bottom paint. Every aspect is toxic.
Other kinds of plastic degrade as well. For example, it only takes a couple years for 5 gal plastic pail to become brittle -- I had to replace a couple this year that had only seen three seasons holding shrimp and crabs because the rims shattered just with light handling.
It really doesn't matter what you put in or near sea water -- it will destroy it. Which makes this Roman Concrete pretty astounding.