Ancient Roman Concrete Is About To Revolutionize Modern Architecture

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.'"

Comments

Prior art

[advantis]

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"...?

Re:Prior art

[PPH]

Make out your royalty checks to "The Pope, Vatican City".

Re:Prior art

[Anonymous Coward]

I was also thinking the same thing. If roman concrete is robust as the blurb claims, it seems to me it has too much monetary value for the funders of research team to release into the public domain. (I'm going to read the article now)

Re:Prior art

[geekmux]

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.

Re:Prior art

[dpilot]

> 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:Prior art

[MightyYar]

It won't be worth patenting, if they even found anything new recipe-wise. Most concrete is steel-reinforced, and most of the failure you see is the rebar corroding. It's not hard to imagine how a lime-volcanic ash mixture would make this unsuitable for steel-reinforced concrete.

Re:Prior art

[Dekker3D]

Even if so, it could be worth building things without rebar, imitating this recipe, if you want something that'll stand for thousands of years instead of 50. Sure, it may not have the same structural strengths to begin with, but it'll keep its strength much longer.

Good for art and such, or any building meant to be impressive or to be used for a long time.

Re:Prior art

[stymy]

I'm no engineer, but why couldn't this recipe be used with rebar? Corrosion from the water that needs to be absorbed, or what?

Re:Prior art

[acroyear]

What can be patented isn't the invention, but the process for making it en masse for modern needs. The quantity involved will far exceed the Roman usage.

The complications is that most volcanic rock today is protected by national or regional parks (partly to protect people from being too close for a long time). Etna, Vesuvius, Hawaii, Iceland - many of those aren't going to just let corporations come in with the same giant trucks they use for coal mines today and rip away 3/4s of the mountainside or lava flows to get the stuff.

Re:Prior art

[Immerman]

Honestly, I would have absolutely NO problem with granting someone a patent if they were able to recreate Roman concrete. What's twenty years compared to the value of concrete that can survive 2000 years of coast-water abuse? This is in fact *exactly* the sort of thing patents were designed for - to promote the development of technologies for the good of mankind. What difference does it really make whether the technology is completely new or something that had been lost to the ages?

Re:Prior art

[Immerman]

The problem is that it's the rebar itself that often destroys the structure. Concrete is porous, and so water finds it's way into the structure and gradually corrodes the rebar. The problem is that rust (iron+oxygen) is considerably larger than the original iron, and since concrete can't stretch to accommadate the expansion it eventually gets torn apart.

Re:Prior art

[Anonymous Coward]

Not to mention there's things like paint and galvanic coatings that can be applied to rebar. No good reason why it couldn't.

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.

Re:Prior art

[Immerman]

Steel reinforcement would negate the longevity of Roman concrete anyway. The rebar will eventually rust out and crack the concrete as it expands. That's fine if your concrete won't last nearly as long as the rebar anyway, but with Roman concrete the rebar would completely rust away while the concrete itself was still just fine.

There are other benefits though, mainly the reduced carbon footprint of production, and the near-total immunity to spalling which all modern concretes suffer from.

Re:Prior art

[Miamicanes]

AFAIK, yes, it can be patented. And that's perfectly OK. Roman concrete wasn't a useful art, it was a lost art. At least under the official theory of American patent law, patents exist to promote advances in useful arts, not to merely grant a monopoly over some abstract artistic right. "Prior Art" isn't just something that EXISTED... it's something that existed, with documentation that would have allowed somebody ELSE to re-create it. Without that documentation, Roman Concrete was little more than a mere idea... maybe a half-step better since it was more like a "proof of concept", but the fact that substantial effort was required to re-discover and document it IMHO does make it patent-worthy.

Now, if Cemex (or some other company that makes concrete) gets sued for infringement 14 years from now, and shows up in court with some ancient, long-lost and recently-rediscovered Greco-Roman document with the formula, they'd have a solid case for overturning a modern patent on it.

Before somebody brings up "first to file", I should point out that if I invent and document something, but someone else beats me to the patent office, I might not be able to get the patent transferred to ME, but I can certainly show up late and spoil the party for THEM. In a way, "First to File" opens the door to trolling trolls... if you invent something, but don't necessarily think it's worth patenting (or have the resources to secure that patent), you can abundantly document it (possibly via digital notarization), then just sit on your notes. If somebody ELSE gets a patent, you can demand that they give you a cut of the royalties they collect, and threaten to go public with your own prior art and spoil their party (after they've spent hundreds of thousands of dollars securing the patent) if they don't.

Re:Prior art

[Runaway1956]

Question is - why is it necessary for concrete to be reinforced? Obviously, the Romans didn't have steel or iron rebar. They formed and poured their structures without any rebar, and they've lasted a couple thousand years. It seems more than obvious that our architects and engineers can learn a few things from the Romans.

Supposing that all their study concludes that reinforced concrete is essential in some cases, does that mean Roman concrete is never to be preferred? Slabs of parking lot, sidewalk, and highway pavement would likely be better for using Roman, rather than Portland cement. If the concrete tolerates the weather better, and resists chipping and cracking better, that would mean all that reinforcement is wasted.

I've seen nothing to indicate that Roman concrete tolerates the cold better than Portland. Maybe parts of the world with annual freezing cycles wouldn't benefit. It's equally likely that we'll find that Roman concrete tolerates freezing conditions better than Portland.

Further - we could learn that hybrid structures are preferable. Build a core out of reinforced Portland, then bond a facade of Roman concrete to exterior faces to resist the elements.

Why does rebar corrode, anyway? Most Portland concrete is porous, of course. For this reason, the Hoover Dam has interior channels built into it to siphon the water away. The water just continously percolates through the concrete, and it has to be disposed of some way. Along with the water, you get salts, acids, or whatever from the environment. Apparently, the Roman concrete doesn't suffer from this infiltration.

By all means - we need to study the old recipes, and/or any new recipes, and see how they can be used to our benefit.

Re:Prior art

[Nerdfest]

Perhaps a really clever person could come up with a way of coating the rebar in a waterproof or non-reactive coating. Maybe it's not cost effective, but it seems like a simple problem to solve.

Re:Prior art

[Nerdfest]

So if I reverse engineer a product that is not patented and relies on trade secrets to function I can get a patent as well? That's effectively what was done here, with the addition of the secret being lost.

Re:Prior art

[Anonymous Coward]

They already do this for rebar used in highways.

Re:Prior art

[Artifakt]

If you really want to check facts, the Vatican was first recognized as a separate nation in 1929 a.d. by the Lateran Treaty, signed by representitives of the then current pope on one hand and Benito Mussolini on the other. 1929 is just a tad later than the end of the Roman empire.* Maybe you are thinking of 'the' Holy See,** or some of the Papal Estates that went back to at least Medieval times.

* Watch someone post "citation needed".

**Technically, any Bishop's diocese is a See, and presumably at least some Bishops in some eras have been not particularly unholy, so what the Pope, as Bishop of Rome, has, is merely a holy see, even though a lot of lay people seem to use the term like he has a lock on it.

Re:Prior art

[Anonymous Coward]

Or replacing it with something else that serves the same purpose. I recently read that Roman Concrete is pretty tough.

Re:Prior art

[Anonymous Coward]

The biggest problem in todays concrete production is cost effectiveness. We can produce hundreds of concretes with widely varying properties. We can mix concretes with negligible carbon footprint or extreme durability or very steep viscoelasticity, but pumping tons of these into a foundation would cost more than simply using pure steel for all of it.

Source: I've just passed a polymer physics course, and the professors primary research area is concretes.

captcha: unfold

Re:Prior art

[TubeSteak]

This article doesn't talk about it, but the volcanic ash (AOL Keyword: pozzolan ash) can be found in deposits all over the world.

It's already mined commercially and it will be trivial to increase that mining capacity in locations that are far away from anywhere environmentally sensitive.

Re:Prior art

[MightyYar]

I hear ya, but if I'm an artist that is going to build a 5000-year building, I'll go with big blocks of attractive stone. This stuff would likely be super-pricey.

Re:Prior art

[Immerman]

Sure, why not? If they have neither published or patented the invention then it doesn't exist as far as the rest of the world is concerned. The original creator decided they preffered the indefinite advantage of trade secret versus the short-term monopoly of patents in exchange for sharing the technology. So basically you have created something that's new to the rest of the world, and shared it with everyone in exchange for a limited monopoly. In fact I'm willing to bet you could even sue the original inventor for infringement, especially now that we've switched to a first-to-file system.

Of course you couldn't do this for some widget being sold at the store - shipping the widget is a form of publishing, and anyone can trivially "reverse-engineer" it. But for something like the method of creating Roman concrete (not just the ingredients, we've known those for a while), or a Google-class search algorithm (actual patentability aside), it's a completely different question.

Re:Prior art

[Anonymous Coward]

This seems like such a stupid problem when they could use rebar made of stainless steel or spray a protective coating on it.

Re:Prior art

[acroyear]

Thanks for the clarification. :)

Re:Prior art

[Dekker3D]

The romans did it on a pretty big scale, as far as I understand. So industrializing it with current technology would probably be fairly easy. There's no real reason it should be pricey after it catches on, if it does so at all.

Re:Prior art

[Dekker3D]

Seems fairly simple to me. Find the average mineral ratio of this ash, pour together readily-available types of material to get the same mineral ratio, see if that works. If it does, yay. If it doesn't, grind it up. If that doesn't work, find out of there's small structures in the ash that are important. If the latter, we could still use the recipe for special projects by using real volcanic ash.

Re:Prior art

[Nerdfest]

Sure they can copy it, but they can't patent it. Patents are for *inventions*.

Re:Prior art

[MightyYar]

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, which has much better detail than TFA.

Re:Prior art

[MightyYar]

If the ingredients are more expensive, the cement will be more expensive. For instance, the Roman variety calls for more aluminum and less sand. They also mention unspecified "minerals" as being present in Roman cement that are not normally present in Portland cement.

Re:Prior art

[Baloroth]

The real issue is that we simply don't want or need anything to last for a thousand years anymore. It's just not effective: buildings, roads, and other structures are usually replaced well before that, simply because of shifting demographics and economy.

Re:Prior art

[Sarius64]

Actually, I was waiting on Al Gore to comment on whether the science was settled. Maybe if we had a consensus we could believe this scientific finding. What oil company did the Romans work for?

Re:Prior art

[Immerman]

Stainless steel isn't rust proof - it just "stains less" (and is a *lot* more expensive, something like 10-20x IRC). And once rust does get established it still spreads pretty quickly. And sure a protective coating helps but still isn't fool proof. The biggest issue though is simply that in most situations modern concrete will have degraded to the point that it really needs to be replaced anyway before the rebar expands enough to crack it, so there just isn't really any point in adding expensive protections.

Re:Prior art

[Anonymous Coward]

I was wondering and found a reference to aluminum-bronze rebar formulated to meet steel rebar strength
http://pubsindex.trb.org/view.aspx?id=481483

Re:Prior art

[Immerman]

Tell that to the Patent Office.

But basically it's a pretty contrived example - if reverse engineering is likely to be substantially easier than inventing it from scratch then a company has good incentive to patent rather than rely on trade secrets. And if it's not easier, well then you've worked just as hard and are willing to share your knowledge with the world, so why shouldn't you get the benefit? Even then probably the only reason to reverse engineer rather than reinvent would be for some sort of intercompatibility, or because you're much better at REing than at creative work.

Re:Prior art

[beelsebob]

stainless steel is not 100% immune to such problems, and has much lower tensile strength than normal steel, and I'm unaware of any protective coating that would be up to the job.

Re:Prior art

[ebno-10db]

Christianity was part of the cause of the downfall.

So sayeth some (e.g. Gibbons), but I think that's more about the agenda of the writer/historian than a dispassionate look at the facts. I'd argue the Crisis of the Third Century was the real beginning of the end (and started the path to the early middle ages) , yet it happened before Christianity became the official religion of the empire in the fourth century.

Re:Prior art

[beelsebob]

But still has extremely low tensile strength, which is what they're after when adding rebar to concrete.

Re:Prior art

[anagama]

Anyone with a boat kept in saltwater can attest to the fact that stainless rusts, and rather quickly. Saltwater is hard on everything except the things evolved to live in it.

Re:Prior art

[BradleyUffner]

Question is - why is it necessary for concrete to be reinforced? Obviously, the Romans didn't have steel or iron rebar. They formed and poured their structures without any rebar, and they've lasted a couple thousand years. It seems more than obvious that our architects and engineers can learn a few things from the Romans.

The Romans didn't build 8 lane bridges spanning highways with trucks carrying hundreds of tons of cargo at 70 mph. They also didn't build 150 story skyscrapers.

Re:Prior art

[ebno-10db]

why is it necessary for concrete to be reinforced

Because straight concrete has good strength in compression, but very little in tension (and hence little in bending). If you use unreinforced concrete you're limited to structures where almost all the stresses are in compression, like arches and short columns.

Re: Prior art

[smitty97]

Problem is, it barely lasts 80 years and that's why you see so many news stories of bridges failing since they're not bothering to replace them

Re:Prior art

[GLMDesigns]

Absolutely, the patchwork put together by Diocletian (separating the Empire into the East and West) was evidence that the empire was falling apart. The argument for and against different reasons would take too long to go into but, among them are, the collapse of the Republic into a police-state/Empire; crazy laws to keep the status quo (your father was a brick layer means that you must be a bricklayer); people fleeing the taxes and the ever present civil wars; climate change (became wet and cool) meaning that less land was available for agriculture plus the rise of diseases. Plagues swept Europe from 200-700 in the cool period; the plagues disappeared from 700-1350 in the medieval warm period and then returned every generation from 1350-1700.

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

[Anonymous Coward]

So then they are like SCO Group. They think they inherited all the IP of the empire and they are still trying to cash in on it.

Re:Prior art

[Hognoxious]

For instance, the Roman variety calls for more aluminum and less sand.

They could electrolyze bauxite in 100 AD?

Re:Prior art

[PPH]

yet it happened before Christianity became the official religion of the empire in the fourth century.

You don't have to give them control. Christians can bring down an empire just by getting a foot in the door and instigating internal conflict.

When did they slip "under God" into the Pledge of Allegiance?

Re:Prior art

[geoskd]

Question is - why is it necessary for concrete to be reinforced? Obviously, the Romans didn't have steel or iron rebar. They formed and poured their structures without any rebar, and they've lasted a couple thousand years. It seems more than obvious that our architects and engineers can learn a few things from the Romans.

You'll notice a distinct lack of concrete roofs on roman structures. That is because: even if they were built with them (unlikely), they have long since collapsed. Concrete has very little tensile strength. In order to get tensile strength, you have to add rebar. Were a pretty fussy breed, and for some reason we like roofs. Additionally, making a floor span out of reinforced concrete is a hell of a lot cheaper than almost any alternative. The Romans used wood...

it should also be noted that the Romans didn't build things terribly tall. a dozen or so stories was about their limit. It goes back to lack of rebar. Concrete without rebar doesn't stand up to a lateral load very well.

Where this stuff really shines is in a salt water environment. The concrete we have today doesn't stand up to salt water punishment well at all. We don't have *any* good formulations for this application. Rebar or not, concrete in salt water has to be replaced pretty often. The roman concrete is immensely valuable if for no other use than bridges.

Re:Prior art

[MightyYar]

LOL, I'm presuming it's some bound form of Al. :)

Re:Prior art

[Anonymous Coward]

There are clearly better and more suitable stainless steels to use in salty, warm and harsh sea conditions also in reinforced concrete than ordinary Austenitic stainless steels which usually people think of and refer as "stainless steel."

Re:Prior art

[justthinkit]

Not quite. Rust is iron oxide(s), yes. But it is the oxygen being smaller than the iron that allows access to lower levels of iron. The goal is for the oxide to be the same size as what was there. Too small and you don't have a barrier, so the oxygen penetrates, the rust flakes off and the cycle repeats. Atom size is related to molecular weight with Oxygen's is 16, Iron is 55.8 (periodic table) so oxygen is a much smaller atom.

Re:Prior art

[Anonymous Coward]

Does everything made out of concrete really need tensile strength? Why not change our building methods to make use of this discovery to make structures that rely more on compressive strength and that will stand the test of time? Wouldn't that be much more efficient than having to rebuild everything after a few decades?

Why not combine rigid concrete like this with steel pillars to get the best of both approaches?

Re:Prior art

[jedidiah]

> If you really want to check facts, the Vatican was first recognized as a separate nation

I think you are quibbling over syntax and trying to claim that has any significance.

Re:Prior art

[K. S. Kyosuke]

Why would they have to do that? Aluminium is an important compound in many rock types of the Earth's crust - does sial ring a bell to you?

Re:Prior art

[jedidiah]

Yes but did build modern scale coliseums. Some of those are still being used today.

Re:Prior art

[icebike]

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

[NemoinSpace]

Well eggs and beach balls, not so much. Why not change your understanding of structural engineering before assuming your hand waving opinion even comes remotely close to fact.

Re:Prior art

[icebike]

Turns out its not the ash that mattered.

Its just the composition of the particular variety of ash they had on hand. Volcanic ash differs in various volcanic regions. Further, seawater was also key. You don't find much of that in the middle of continents.

This wasn't ancient knowledge at work at all. It was simply an accident of geography.

Re:Prior art

[jbengt]

Stainless steel would be prohibitively expensive, and might very well corrode, depending on the environment and the composition of the stainless steel. (stainless steel does not do well with chlorine, e.g.)
And rebar is already often epoxy coated.
The practical problem I read about this concrete discovery is that it cures very slowly. Until they figure out how to speed that up, it won't be too popular in construction.

Re:Prior art

[ChrisMaple]

I've heard from builders that rebar with a little rust on it is actually preferred: the roughness gives the concrete a better grip on the rebar. Stainless would be pointless.

Re:Prior art

[ChrisMaple]

Choose your stone well; not all of them are good for your 5000 year building. Limestone is attacked by acid. Granite contains radioactive material.

Re:Prior art

[ebno-10db]

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:Prior art

[SeaFox]

Even if so, it could be worth building things without rebar, imitating this recipe, if you want something that'll stand for thousands of years instead of 50. ...

Good for art and such, or any building meant to be impressive or to be used for a long time.

Why would a modern construction company want to make a building that lasts for a long time? There's no repeat business in that.

People's tastes are too fickle now to want to use a building with the same appearance that long anyway. Have you ever watched the landcaping of business parks? They plant trees that are a joke for the first three years because they're still tiny plantings, and by the time they really start to branch out and get some girth on the trunk they're ripping them out because they want to redo the appearance of the property.

Re:Prior art

[ebno-10db]

Plagues swept Europe from 200-700 in the cool period; the plagues disappeared from 700-1350 in the medieval warm period and then returned every generation from 1350-1700.

Interesting correlation between climate and plagues. Do you have any links on that, or did you see that in one of those "book" things that are rumored to still exist?

Re:Prior art

[__aaltlg1547]

That's not the only problem. The root of the problem is that iron wants to react with the concrete. Nice article on it here: http://www.cticonsultants.com.au/CTI%20Technical%20Note%20C1.pdf and an article about preventing it is here: http://www.concretecorrosion.net/html_en/maitrise/contenu.htm

Re:Prior art

[cusco]

It also goes back to the lack of elevators. Think about walking up to your office on the 42nd floor in the morning . . .

The invention of the modern safety elevator revolutionized construction in the major cities of the world. Prior to them becoming affordable almost no buildings in New York City were higher than six stories, and the top floors were always the cheapest. It made no financial sense to build higher, no one wanted to carry groceries up to the 27th floor.

Re:Prior art

[colinrichardday]

Assuming that the concrete was the intellectual property of the Pontifex Maximus, that might be correct.

Re:Prior art

[colinrichardday]

When did they slip "under God" into the Pledge of Allegiance?

June 14, 1954

http://en.wikipedia.org/wiki/Pledge_of_Allegiance#Addition_of_.22under_God.22

Re:Prior art

[muon-catalyzed]

Nope, we have lost the Roman concrete precisely thanks to the Christian led purges of the 4th century. Constantine and Theodosius did it and the dark age quickly followed. They burned libraries, melted artworks dating back to the Etruscan era, history been rewritten so they are the saints now..

Re:Prior art

[colinrichardday]

What counts as filing under first to file?

Re:Prior art

[Anonymous Coward]

Where this stuff really shines is in a salt water environment. The concrete we have today doesn't stand up to salt water punishment well at all. We don't have *any* good formulations for this application. Rebar or not, concrete in salt water has to be replaced pretty often. The roman concrete is immensely valuable if for no other use than bridges.

Oh, we have plenty of good building materials that work well in salt water.
We never use them because it is cheaper to rebuild things every 50 years or so.

Re:Prior art

[Anonymous Coward]

Sounds like a perfect foundation for starting a revolution.

Re:Prior art

[theguyfromsaturn]

Roman works relied strictly on compression (arches and domes are good examples). There is no doubt that compression works can be more durable than tension structures because by the nature of the beast they require much more material to build. Because of this, they have much more material to wear off (redundancy) and so they can better resist the passage of time (and erosion).

Of course, as in everything, there are tradeoffs. One of them being the shear mass of materials required for construction. Engineering is about efficiency, and so for a structure of a lifespan of 50 years (typical design lifespan) roman-style strucures would be way over-engineered. Not only in terms of cost to build but in terms of energy consumption of the process. You are also limited in the freespan of a bridge you can build this way. Imagine the size of the arch that would be required to match modern suspended bridges spans... and the corresponding amount of rock and/or concrete needed and you start getting an idea of what efficiency means in those terms. Some things would just be impossible to build the roman way.

Of course, if one of your key requirement is 2000+ years design lifespan, then using a compression design the roman way does make sense for many things. It's all about the design objectives.

Re:Prior art

[Anonymous Coward]

What patents were designed for and what patents are used for are two very different things these days.

Re:Prior art

[Anonymous Coward]

Seawater is particularly problematic because it makes stainless steel (even 316L) corrode in cracks instead of on its surface. Gradually making initial cracks deeper and deeper, until something breaks or starts leaking, often without any visible warning. In sea water, hot-dip galvanised steel can last longer than 316L stainless steel.
It is now common practice to install electronics that keep steel structures near seawater at a pre-set voltage, relative to a few copper anodes installed in the water. About 1 Volt is enough to drastically reduce corrosion. This is especially common for steel inside concrete structures, since the concrete prevents other solutions like paint or zinc anodes.

Re:Prior art

[Anonymous Coward]

Anytime you think something's a stupid problem because the answer is so simple, it is a fair bet that you don't know much about the subject. I don't know much about the subject either but I know it's unlikely you've solved the problem. Should we Google it and see if no one has ever thought of your idea or if there are other solutions?

Re:Prior art

[Anonymous Coward]

In regards to rebar necessity, it is in order to achieve sufficient tensile strength in lesser thicknesses of concrete pours. It is absolutely possible to build a bridge with no rebar, just make the bridge one big slab that extends from the road to the river bed. Rebar corrosion has been an issue in older structures as the oxidizing rebar expands and explodes the concrete (look under just about any bridge over salt water that is more than 30 years old for a good scare). Newer technologies include cathodic protection for the rebar (applying low voltage to it to halt oxidation), epoxy coated rebar (note that the epoxy almost always gets damaged during placement), basalt rebar (my favorite choice as it cannot corrode and has a higher tensile strength than steel), and helical steel fibers (good for slabs).

Re:Prior art

[Tyler Durden]

* Watch someone post "citation needed".

Yeah, I think you need one. If you're thinking of the Holy Roman Empire then that's something quite different than what is referred to as just the Roman Empire.

I believe the Roman Empire ended with the Byzantine Empire in the 1400s.

Re:Prior art

[Immerman]

It may not be possible to speed it up, or at least not cost-effectively. It sounds like a lot of the extra durability may come from the much larger, better aligned crystaline structures, and crystal growth can require significant time. Still, if we can make concrete structures that can survive brutal environments for millenia instead of decades it might be worth the extra curing time, at least in some situations. Harbors, aqueducts, etc. all seem like projects where a forward-looking engineer could see great advantage in not needing significant maintenance.

Re:Prior art

[Immerman]

Yikes, and I thought stainless steel would be expensive... Still, if you need the tension-strength for a project that then wouldn't need significant maintenance for a few centuries it might be worth it.

Re:Prior art

[Anonymous Coward]

This reminds me of the time when the U. S. government wouldn't allow native Americans to build adobe buildings, claiming that they weren't safe and wouldn't last. They argued and argued. Finally the government relented as long as they build using steel rebar throughout the adobe bricks.

As they were leaving the meeting, the chief said to the Indian agent, "It's gonna drive the archeologists crazy in 3,000 years trying to figure out how and why we put all those little red circles in the middle of our adobe bricks!".

Re:Prior art

[Immerman]

Actually atom size is only very loosley related to atomic weight - size does increase as you move down the periodic table in a single column (more electron shells), but it actually shrinks as you move to the right (tighter bonding between electrons and the nucleus). Basically the discrepancy is because atomic mass is determined almost entirely by the nucleus, which is several orders of magnitude smaller than the entire atom. Size on the other hand is determined by the arrangement of the electron cloud.

For a quick visual reference: http://www.crystalmaker.com/support/tutorials/crystalmaker/atomicradii/
Notice that a lithium atom, with an atomic mass of only 7, is actually about the same size as bismuth, which has an atomic mass of 209

And the basic fact is that the oxide can't possibly be the same size as the original material. Common rust has the chemical formula Fe2O3, which means that where you used to have only two iron atoms, you now have two iron atoms PLUS three oxygen atoms. But you are right that the basic strategy is to prevent flaking, if we could somehow "convince" the oxide to form hematite crystals instead of flaking away corrosion would be a non-issue. That's why highly reactive aluminum appears to be so stable, the oxide readily forms a thin crystaline layer bonded to the metal which prevents further oxidation (basically corundum, the base gemstone of rubies and saphires). Disrupt the oxide layer and the aluminum will *very* rapidly rust away, as in you can actually see a beam "dissolving" in front of you - that's why they don't allow mercury thermometers on airplanes, mercury is one such disrupting agent and a spill could cause the aircraft to come apart in the air.

Re:Prior art

[Sique]

I don't think, "quickly" is the right word. Constantine made Christianity the state religion in 324 AD, and the (West) Roman Empire ceased to exist in 476. That's 150 years apart. Or to put in in perspective, it's so far apart like the Civil War from us today.

Re:Prior art

[SavvyPlayer]

It will catch on, if not become the new building code standard for moorings -- even if mariners and structural engineers ignore it, insurance companies will insist upon it.

Re:Prior art

[r1348]

If you're referring to the Edict of Milan, it happened in 313 AD and it just declared freedom of religion in the Empire.

Re:Prior art

[Anonymous Coward]

Not quite. Rust is iron oxide(s), yes. But it is the oxygen being smaller than the iron that allows access to lower levels of iron. The goal is for the oxide to be the same size as what was there. Too small and you don't have a barrier, so the oxygen penetrates, the rust flakes off and the cycle repeats. Atom size is related to molecular weight with Oxygen's is 16, Iron is 55.8 (periodic table) so oxygen is a much smaller atom.

Atomic radius IS a function of ATOMIC weight... (That's what you meant, right? You didn't mean that atomic radius is affected in any way by the size of the molecule it finds itself in, did you?) But this is so only within any given row on the table. From left to right, as atomic number increases, atomic radius decreases, (due to more powerful attractive force from the nucleus given more protons, and successively larger atoms' electrons are in the same orbital when the elements are in the same period,) but then at the outset of the next row, the radius jumps to a much higher value, and begins decreasing right again. In picometers, the atomic radii are:

H: 37,
Li: 152, Be: 112, ... B: 83, C: 77 ... and so on, decreasing. Then the next row begins with sodium -
Na:186, Mg:160, etc.

"The increase in radius going down a group of the periodic table occurs because successively larger valence-shell orbitals are occupied" (176). (All taken from "Chemistry," McMurry Fay, 5th Ed., 2008, Pearson/Prentice Hall.) This is right under figure 5.19, which has explicitly written comments around a modified periodic table, that radius increases down, and decreases as you move right.

From pg. 770, under the heading "A Review of General Properties and Periodic Trends," it states in Figure 19.2 that Atomic radius and metallic character INCREASE as an element is found further DOWN the table, and that these two traits DECREASE the further one is to the RIGHT.

One other thing, internet friends... remember when you quote Wikipedia, that Wikipedia is NOT necessarily correct or up to date, (since it can be edited by nearly anyone, and quality control is, well... distributed. As researchers have shown, (and no, I can't site the study, I don't have my psych textbook anymore...) when you have a sufficiently large group of people, it is possible that something can need to be done, but NO ONE will do it because everyone will assume someone else will. This very phenomenon is why in training people to give CPR, that when a crowd gathers around an apparent heart-attack victim, they tell people to grab someone specific and tell THAT PERSON to go get an AED (Automated External Defibrillator), rather than just exclaiming "someone go get the AED!" because everyone will assume someone else will go get it, and they want to stay and watch 'the show,' by which I mean, watch the poor schmuck die. (We're sick bastards, aren't we?)

Case in point, your post's periodic table link - I navigated to it, and noticed almost right off the bat that Flerovium (element 114) and Livermorium (element 116) are not listed. Oddly, there is a link on the page you indicated to an SVG version of the table, (that is more up-to-date)

In case anyone is wondering, IUPAC added Fl and Lv on May 30th, 2012.

Re:Prior art

[ae1294]

stainless steel is not 100% immune to such problems, and has much lower tensile strength than normal steel, and I'm unaware of any protective coating that would be up to the job.

I'm thinking some kind of plastic coating would work well.

Re:Prior art

[careysub]

Turns out its not the ash that mattered.

Its just the composition of the particular variety of ash they had on hand. Volcanic ash differs in various volcanic regions. Further, seawater was also key. You don't find much of that in the middle of continents.

This wasn't ancient knowledge at work at all. It was simply an accident of geography.

Is it really any different from the fact that availability of raw materials in any region is an accident of geography?

If you read TFA you will see that:

A) the Romans were well aware which ashes were the best for this purpose. Vitruvius and Pliny wrote about it. It is not as if they were mystified why this hydraulic cement was turning out so well. Sure they didn't understand the chemistry, but they tried many ashes and knew the ones that had special properties.

B) The researchers found this concrete in 11 harbors around the Mediterranean. This means the Roman were exporting their special ash to where it was needed for harbor construction.

Sounds like ancient knowledge to me. (Otherwise you are going to have to hold that none of the material production skills before modern times were really ancient knowledge.)

Re:Prior art

[drinkypoo]

The answer is that you might be able to make some non-reinforced structures out of it, especially for use in marine environments, which would have much better longevity than what we're using now. Also, you can use other reinforcements inside of concrete, for example fiberglass or, I imagine eventually carbon fiber as the cost continues to fall.

Re:Prior art

[mc6809e]

Nope, we have lost the Roman concrete precisely thanks to the Christian led purges of the 4th century. Constantine and Theodosius did it and the dark age quickly followed. They burned libraries, melted artworks dating back to the Etruscan era, history been rewritten so they are the saints now..

Total bullcrap.

After the Christianizing of Rome, much classical knowledge still remained available. Literacy was high and papyrus from Egypt was available for writing. The library at Alexandria was restocked several times after fires with works held in private collections. And the families of Germanic invaders actually had their children educated by Romans and many old Roman cities kept their Roman character.

Then suddenly old Roman cities failed and were quickly covered by a layer of soil called the "Younger fill". Literacy declined and papyrus was no longer available because trade with Egypt was no longer possible as the Mediterranean was controlled by pirates. Many classical works were lost and the library at Alexandria could not be restocked. Christian monks were forced to write on animal skins instead of paper.

This all began long after Christianity -- around the middle of the 7th century. I'll leave it to you to figure out what other events of the 7th century might be responsible.

Re:Prior art

[kwbauer]

Oh surely you jest. It is impossible for there to have been any climate change happening that long ago. The Industrial revolution had not yet happened to cause it.

Re:Prior art

[Immerman]

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

[budgenator]

The historic Roman concrete is 10% or less lime (CaO), the Portland cement we use today is 61-67% lime, I assume that lime is a significant catalyst in re-bar corrosion so Roman style cement should be more forgiving towards re-bar.

Re:Prior art

[Deadstick]

In regards to rebar necessity, it is in order to achieve sufficient tensile strength in lesser thicknesses of concrete pours. It is absolutely possible to build a bridge with no rebar, just make the bridge one big slab that extends from the road to the river bed.

Ummm, I believe that would be called a dam.

Re:Prior art

[icebike]

Its doubtful that they were transporting the ash very far because they didn't have the means to do so, nor the need. Much of the Mediterranean is of the same volcanic origin. Ash seems to be everywhere. And the harbors they checked weren't all that gat apart geographically.

Sure they knew ash worked better than gravel, but in that region ash is far easier to come by. And and trial and error led them to the proper quantities of lime (which was much harder to find).

So again, not science, not wisdom, simply geographic good luck.

Re:Prior art

[theguyfromsaturn]

To answer your question as to "rebar corrodes", I should point out that cement is generally basic. Actually, Portland Cement can be quite basic which tengs to cause some unwanted reactions with the silicate aggregates. Still, a high PH will generally tend to protect the steel from corrosion. The salts used in de-icing salts will tend to have a low pH which will foster corrosion of the reinforcement make it expand, which causes cracking of the concrete and accelerates the influx of water to the steel which accelerates corrosion etc.

Recipes such as those used by Romans are already known (the contribution of t he paper is more as to why that is, than that it is the case as various types of ashes are used in different mixes). Replacing cement by addititives can give some properties that are good in some cases, but may make it take longer to cure, and/or reduce its ultimate strength (depending on the additives). Choosing the peroper mix depends on the usage and the cost.

As to why reinforce at all, it's because we need reinforcement for tensile strength. Concrete has a fraction of the tensile strength than compressive strength (think of a chalk) . As mentionned in a previous post, Roman works relied more on compressive strength than tensile strength. There are advantages to that approach, but definitely many practical disadvantages.

Re:Prior art

[cbhacking]

Speaking as somebody whose family has lived on the ocean for over 18 years, marine-grade stainlees is pretty near impervious to seawater. You need to check it periodically, of course, but if you use the right stuff (which is closer to the "20x cost of mild steel" end of the range) it will happily endure for a very long time without even significant discoloration. Of course, it helps there the boat also has zincs and that we're careful about dissimilar metals and so forth. Nonetheless, a really good grade of stainless (one way to tell is to check with a powerful magnet; good stainless is not noticeably magnetic) is able to endure seawater much better than you imply. You just can't be cheap about it... which makes it impractical as a building material in most cases.

Re:Prior art

[MightyYar]

I'm not sure that steel rebar would care much, but the lime makes concrete so alkaline that glass fiber breaks down - so there might be an opportunity to go with composite rebar. On the other hand, I'm betting that even with "only" 10% lime, it is still really alkaline. The pictures from the news release linked in TFA show a lot of lime.

Re:Prior art

[MightyYar]

Non-reinforced structures can also be made out of things like huge blocks of solid rock, which tend to also last a long, long time :)

Re:Prior art

[MightyYar]

I'm betting that using random volcanic ash is probably just as risky as hunks of granite or marble.

I'm typing this on a marble countertop in my kitchen that is probably pumping me full of radiation, but then I worked out in the sun all day and I KNOW I got a lot of radiation :)

Re:Prior art

[Anonymous Coward]

Big yep. better concrete mix + better reinforcement + time and we can leave some monuments for future rodent archeologists to ponder.
And if we would start replacing asphalt highway construction with that concrete here in the US, they will have good roads to get to the dig.

Re:Prior art

[Livius]

The decline of the Western Rome Empire spanned generations - there is simply no way to piece together cause and effect relationships with everything happening at the same time over the course of that time period.

Personally, my guess is that after a thousand years of wars, revolutions, dictatorships, military coups, invasions, and civil wars, their luck just finally ran out.

Re:Prior art

[Anonymous Coward]

why the fuck do people insist on posting their captchas? Do you really think I care? has it added value to my day? or just wasted 0.5 seconds of my life on usless trivia? /rant

Re:Prior art

[adolf]

For this reason, the Hoover Dam has interior channels built into it to siphon the water away.

I'm not going to suggest that Portland cement-based concrete is not porous, because it plainly is, but:

Those aren't drains. Those are cooling pipes. The water in them is introduced intentionally to cool the concrete as it cures (which is a process that is still occurring today).

Re:Prior art

[MightyYar]

Gah... concrete roads. I'm from NJ originally, you are giving me flashbacks! Bu-bump-bu-bump-bu-bump-bu-bump...

Re:Prior art

[Anonymous Coward]

There is something called stainless steel. I'm not sure the Romans had it, but it is the only way to go today. Hard plastics might work too. Or just making shapes out of it like is done today would let it connect together securely. I also have seen fiberglass shreds used to bind concrete together a little.

This has a lot of potential for ocean side projects I think.

Re:Prior art

[wisesifu]

It seems to me that while they did not have the insight to know what was happening at the chemical level of today, Trial and Error plays a large part in science, as in you experiment to test the world around you, and it seems that its used in quite a bit in modern science still [url]http://en.wikipedia.org/wiki/Trial_and_error#Examples[/url], specially with the advent of computers.

To say they used no science, no wisdom and that it was good luck is just wrong. By simply looking up the word Wisdom I find "The soundness of an action or decision with regard to the application of such experience, knowledge, and good judgment." It seems they did exactly this.

Re:Prior art

[garyebickford]

Indeed. I've learned more about metallurgy and corrosion (of several types) in the few years since I started messing about in boats and salt water than I ever dreamed possible. Short answer - in salt water, nothing lasts. Stainless steel resists rusting (oxidation) only as long as it is exposed to oxygen! (enquiring readers can look up "crevice corrosion"). Fiberglass is not waterproof, and in fact the water molecules that get inside some types of fiberglass can cause blistering as the water catalyzes the plastic to break down.

Re:Prior art

[garyebickford]

Especially since it hasn't been duplicated, despite at least a century or two of trying, until now (maybe, we'll see if they're right...) And they used different kinds in different applications.

Re: Prior art

[garyebickford]

I think in fairness this is more due to the method of using steel reinforcing, without putting an electrical charge on the structure that would prevent the oxidation of the steel - and especially where they salt the roads.

Re:Prior art

[garyebickford]

Actually it can be done electrically. I forget which way the charge should go, but if done right the calcium and aluminum is attracted to the metal, instead of rusting. Entire boats have been made by immersing a hull shape made of steel mesh into sea water and then putting a couple of volts onto it. It's much like a shellfish making its shell. It's been done to bridge abutments as well.

Re:Prior art

[icebike]

The tendency to attribute great wisdom to the ancients, lost to modern man, and unknown to modern science, has a never ending allure.

This is just one more example of being in the right place at the right time, and being careful enough to remember what you did different when something falls down, and not do that again.

Sort of like your grand mother learned not to be rough with an angle food cake made from scratch because it would fall before it cooled. I'm not sure that counts either as science or great wisdom. Seems simply the school of hard knocks, if you ask me.

Our bridges and buildings do tend to last a long time, albeit with more maintenance. But then, we build differently these days. The Roman and Greek empires built always with stone and cement under compression, and virtually never under tension. Stone and un-reinforced concrete do well in this mode.

Re:Prior art

[gravious]

And (at least according to one program I saw on TV a while back) the silting up of key mediterranean harbors due to upstream deforestation for crop production leading to soil erosion which also led to poorer soil conditions on top of silted up harbors.

Re:Prior art

[Anonymous Coward]

Seeing as all this research was done by a public institution most likely mostly with public funds (UC Berkeley and Larwence Labs) I would have strong objection to a patent granted to any individual or corporation.

Re:Prior art

[wezelboy]

I believe that patents in this area have been held by a French chemist for quite some time. (So long ago, they have probably expired) If you do a google search on "Geopolymer" you will find some fascinating stuff. One of his theories is that the blocks of the Great Pyramids were not quarried, but rather cast like concrete.

Re:Prior art

[GLMDesigns]

Not rumor. I was a grad student in medieval history before getting into web development. (Hows that for a career track).

The medieval warming period is well known peaking from the 11th through the 13th C. The plagues are well documented from 200-700AD and from 1350-1700. The plots of land available for farming are also known from both tax records as well as botanical records. (How far up mountains crops are being grown.) Keep in mind that this describes a gradual cycle. There is no hard and fast date where it was warm until a particular date (say 199AD) and then cold from 200AD-700AD and then warm again.

A quick search shows a list of major plagues: http://en.wikipedia.org/wiki/List_of_epidemics . Generally in cold and wet periods plagues happened every generation.

Re:Prior art

[Immerman]

I think I can understand your objection, but the fact is that ST&E (not so much M ) academics do tend to accumulate patents on the results of their publicly-funded work, at least if they're any good. And frankly considering the massive investment of time and money it takes to become an academic, and the crap salaries they mostly make (there's some plum positions, but generally speaking academia has one of the *worst* economic ROIs out there) , I think it's not unreasonable to consider such patents a sort of non-monetary performance-based compensation. Especially considering that, as a general rule, academics aren't terribly interested in making money (they went into academics after all) and are likely to license their patents at very reasonable rates.

I certainly wouldn't object if patents that came out of publicly funded research were all automatically available for royalty-free licensing for humanitarian or public-good purposes though. Well, except that that would probably reduce the amount of research done in areas where those would be the primary expected applications.

Re:Prior art

[wezelboy]

BTW, I don't mean to make Davidovits (That's his name) out to be a crackpot. I don't think he is.

Re:Prior art

[GLMDesigns]

Gibbons declaration for the end of the empire is no longer considered correct. In 476, when Romulus Augustulus was replaced by Odoacer the average Roman didn't see a difference in his life. The toll booths were still there, with the same toll booth collectors, trade wasn't disrupted, life went on. What killed the west, in my opinion, was the war started by Justinian to bring the West back into the fold. The resulting years of civil war and then rapacious tax collection following Justinian's victory led to the final collapse. When the Lombards invaded what is now Italy (c600AD) they found a decimated shell of what was there. Their invasion was the final straw.

Re:Prior art

[Anonymous Coward]

or just wasted 0.5 seconds of my life on usless trivia? /rant

It took you .5 seconds to read that?

Captcha: dictums

Re:Prior art

[GLMDesigns]

An interesting read, though a little dated, is Marc Bloch's Feudal Society.

Re:Prior art

[Anonymous Coward]

Try throwing a block of your marine grade stainless steel without a sacrificial anode and see how long it lasts.
That block of zinc is the only thing protecting it.

Re:Prior art

[GLMDesigns]

I haven't heard of any Mediterranean civilization being affected by the silting up of harbors. My grad school days go back Archie, Veronica and Mosaic, so things may very well have come up. Still - if they were major issues it would have been in the literature (ie the Romans, Greeks, Egyptians, Carthaginians would have written about it).

Re:Prior art

[anagama]

I got my first boat a few years ago, and to prevent myself from having an expensive albatross I couldn't sell in the event I didn't end up really using the boat, I bought an old cheap boat. I figured I could sink it and not cry, so if I hated having it, no big deal, no loan -- just pull it out of the marina and give it away on craigslist.

Turns out I love having a boat, but for my next one, I'm going to hire someone to do the blisters. I fixed about 150 or so on this boat --- what a nasty horrible toxic job. Never again!

Also, my next boat will have no teak on the outside, or if there is some, I'll sand off the varnish and let it weather. Boats with lots of varnished teak are beautiful, and I love looking at exterior teak on *other* people's boats. Learned that lesson too.

Re:Prior art

[Anonymous Coward]

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.

I doubt that. Roman concrete was used in the city of Rome, e.g. for the Pantheon. Rome is far enough away from the sea that you wouldn't be carrying in sea water to mix the concrete unless you knew that this was a requirement.

Re:Prior art

[anagama]

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

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.

Re:Prior art

[icebike]

Nice try.
But there is no evidence that particular concrete in Rome was of the same composition as the harbor cement which was analyzed bythe researchers . When you consider the rather degraded state of much or the Roman construction in Rome itself when compared to the harbors that were analyzed it seems highly unlikely it was of the same composition.

Re: Prior art

[rtb61]

That is down to greed and life cycle costing. There are many blends of concrete and using the right cement, additives and aggregate and you can get concrete to last well in excess of one hundred years. Increasing cover to reinforcing will increase it life, galvanising the reinforcing will increase it life (tricky because the galvanising actually breaks down due to reaction with the cement but, it alters the chemical conditions surrounding the reinforcing thus substantially extending it's life). The article is typical literary exaggeration, concrete typically lasts well in excess of one hundred years, if it was properly hydrated, compacted and the cement was of good quality.

However we live in the age of the "LOWEST BLOODY TENDER", greed being the motivating factor, it will last longer than those who did the job so they can't get sued. Hell of lot of shonky lowest tenders often shut down and re-start their companies on a regular basis to escape liabilities for their crap work, while screaming de-regulate, de-regulate- de-regulate and supporting right wing politics.

Having demolished quite a few structures, I can tell you that some concrete done well in excess of fifty years was as tough as hell and it was all done to the quality of the builder and their contractors. Today of course cheap, cheap, cheap, not my problem, bonus now, lawyers and more lawyers, right wing political ideology and no pride of workmanship just score by wealth and you have shite all around you.

Re:Prior art

[beelsebob]

The entire reason for putting rebar in concrete is that it gets you the best of both worlds –you get a composite material with the tensile strength of steel and the compressive strength of concrete.

Re:Prior art

[aXis100]

The lime actually protects the steel rebar. Lime, being alkaline, wants to perform a reducing reaction, actually reversing oxidation on the steel.

The problem comes when the concrete has suffered significant leeching - the protective alkalines get stripped away and there is nothing protecting the rebar. You can see this readily when the rebar is too close to the surface as that's the first area to leech.

Re:Prior art

[Anonymous Coward]

There was probably more research going into it than the word "accident" allows, but that it was a consequence of geography, that is correct.

(Few people remember that the Romans were active during the "Iron age", which sounds far more primitive than it was.)

Re:Prior art

[lxs]

Its doubtful that they were transporting the ash very far because they didn't have the means to do so,

Roman transportation technology was terrible! All those obelisks that are scattered all over Rome probably just swam from Egypt on their own. Good thing those Romans were so lucky. I mean they just banged some rocks together and presto! clockwork computer. No knowledge or technology at work there at all.

Re:Prior art

[roarkarchitect]

You can passivate stainless steel also to improve it's corrosion properties. But it will rust in salt water. Hard coat anodize (over aluminum) is a better choice - I don't think it will ever degrade.

Re:Prior art

[drinkypoo]

Non-reinforced structures can also be made out of things like huge blocks of solid rock, which tend to also last a long, long time :)

The Egyptians were smart enough to use concrete instead of solid rock in cases where it would take too much labor to move stone. Aren't we?

Re:Prior art

[Anonymous Coward]

But if you drive over it then it becomes a damn bridge, damn it.

Re:Prior art

[MightyYar]

We have vastly superior quarrying and transportation technology compared to the Romans (or Egyptians). If you were interesting in building something that would last 1000 years, you would probably choose stone over non-reinforced concrete, if not for aesthetics then because you would have trouble guaranteeing the mix.

Remember that there is some selection bias going on here. The Roman concrete that didn't last 1000 years is long gone.

Re:Prior art

[mrchaotica]

Does everything made out of concrete really need tensile strength? Why not change our building methods to make use of this discovery to make structures that rely more on compressive strength and that will stand the test of time?

That's exactly why Roman architecture had arches everywhere. (Since they didn't have steel, they had no choice but to rely only on compressive strength.)

Re:Prior art

[drinkypoo]

The Roman concrete that didn't last 1000 years is long gone.

Right, and we're talking about how they made the stuff that did last 1,000 years. There's no reason to believe that all the concrete they made was of the same composition; ours isn't, and for a variety of reasons including purpose and cost.

Re:Prior art

[Anonymous Coward]

I has been foretold it would spell our undoing!

Re:Prior art

[MightyYar]

My point is that a designer considering concrete would have allow for the possibility that the concrete might get mixed wrong and not last 1000 years. With stone this would not be a concern.

And that's if someone even wanted a concrete structure that lasted 1000 years. The stuff is ugly IMHO.

Re:Prior art

[redlemming]

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.

To the contrary, the history of the Eastern, or Byzantine, Empire provides a superb example, when studied in detail, to show why separation of church and state is a really good idea.

There were very serious religous divisions within the eastern empire, particularly relating to the rift between the mainstream (and state sponsored) Orthodox faith with the Monophysite versions of Christianity. Much of the success of Islam in conquering places like Egypt and Syria resulted from this rift: the persecution of Christians by other Christians (frequently state-sponsored) had gotten so bad that many people in these regions had no loyalty to the Byzantine state.

To their credit, at that time in history, the followers of Islam tolerated other faiths and permitted them to practice their beliefs within conquered regions (although at a higher tax rate). This policy, of course, made it easier for Christians to leave the Byzantine state. The current dominance of Islam over the Middle East didn't happen for centuries after the original conquests.

Also, there were endless problems arising from disputes between the western church and the eastern (or "Orthodox") church. The best known incident resulting -- at least in part -- from these problems is the sack of Constantinople during the 4th Crusade, in which Christian crusaders conquered and looted the Christian city, then placed a Venetian prelate in charge of religion in the city. This conquest essentially shattered the Byzantine state: even though the city would eventually be regained, what remained thereafter (and lingered for many years) was a very small remnant of its former glory.

While more was involved in these incidents than just religious dispute -- the human tendency towards greed, stupidity, short-sightedness, and arrogance should never be underestimated -- there is no doubt that Christianity played a role in the downfall of the Roman state, whether Eastern or Western.

It also played a role in the glory of that state, witness Hagia Sophia and the other superb art and architecture created over many centuries.

Re:Prior art

[Dynedain]

Do you really have a problem with the term "a holy see" vs. "The Holy See". We use capitals for a reason to distinguish between a president and the President.

Re:Prior art

[Dynedain]

The recipe for Portland Cement uses alumina, aka aluminum oxide, and can be extracted from bauxite without electrolyzing.

Re:Prior art

[sursurrus]

35 USC 102(a) (as recently amended by the America Invents Act) - Patent rights immediately terminate if the invention was in public use anywhere in the world prior to the date of patent filing. "Public Use" has a much broader meaning than its plain English meaning (since an underwater structure is probably not highly visible to the public) and according to Eggbert v Lippman can apply even to things the public can't even see -- the real test is if the inventor 'retained control for experimentation and testing purposes." It is clear the Romans did not. There is a separate bar, which the article doesn't give enough info to make a conclusion on, but seems very likely. If the roman concrete was ever described in a 'publication' it would have prevented anyone from patenting it more than 1 year after the date of publication. And I know the Romans loved to keep records, histories, diaries and what have you. Under this bar, the Bible has successfully used as a source of prior art rejection on patents directed to certain construction methods described therein.

Re:Prior art

[CAIMLAS]

... and yet, the only reason why anything literary survived in volume from the Roman era through the dark ages is because of Christian monastic efforts to preserve and pass on those works. This was particularly the case in Ireland.

This, at least, can be proven. As for the Christians leading the destruction? Christians were kind of a majority at that point, so any cultural surge would've naturally been "Christian" led - it was as much a political affiliation as it was a religious one. It was horrible what happened but in no way unique.

I think the cultural heritage saved through and since the fall of Rome more than makes up for it; THAT is fairly exceptional in history (as we know it).

Re:Prior art

[RockDoctor]

Can this discovery of old stuff be patented today, or is the fact that the romans did it so long ago constitute prior art?

Nope, because this general formulation has been being used for much of the last few centuries. Just for an example, the Suez canal was built in large part using concrete made this way from volcanic rock from the island of Santorini ; the mining of that volcanic ash uncovered the buried "city" of Akrotiri, and much interesting archaeology has followed on from that.

There's a good reason that "Portland" cement was invented near Leeds (England) using limestone (available nearby) and mudstone (available nearby), and not using volcanic ash (because it was not available nearby), was that the raw materials were available nearby. Where ready-ground raw materials like volcanic ash were available, they were used.

There have been lots of patents granted on "cement" formulations over the years, many of which have now expired.

Re:Prior art

[swalve]

Or to put in in perspective, it's so far apart like the Civil War from us today.

I fear the same attitudes that caused the civil war are coming back to a head again today. It may yet be the end of the empire.

Re:Prior art

[Anonymous Coward]

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.

[citation needed]

Re:Prior art

[swalve]

A funny thing happens when you google younger fill and roman cities.

Re:Prior art

[swalve]

Also, stainless steel depends on a passivation (sp?) layer of some kind of oxide that forms when the metal is exposed to oxygen. It won't get that if it is encased in concrete.

Re:Prior art

[Anonymous Coward]

Constantine, Theodosius and Justinian did not just attack non-Christians -- they took sides in Christians versus Christians, and one side won. The side that destroyed knowledge truth and history.

Re:Prior art

[swalve]

Things that seem waterproof on a 20 year scale often aren't quite so waterproof on a 200 year scale.

Re:Prior art

[swalve]

For two reasons: one, things built purely or mostly compressive become massive very quickly. Think pyramids and pre-skyscraper era buildings. Two, because the world isn't stable. Driveways and roads don't crack because they get over compressed, they crack because the ground under them shifts and what was a nice solid base turns into a highly brittle plank spanning some void underneath. Blam. Nature has transformed your nice solid thing into a crumbly mess. Bonus third reason: you can't have spans without tensile strength. Beams don't fail because their edges crush out, they fail because their middles crack open. That's why old buildings were mostly columns. There is almost no use for structures that require that much overhead.

Re:Prior art

[Anonymous Coward]

Romans had a more advanced cement technology than XXth Century, DC??!

Re:Prior art

[Anonymous Coward]

Alumina != Alumin[i]um.

Or in general

Compound containing element != element.

Re:Prior art

[Anonymous Coward]

The problem is chrome refining is super fuel and greenhouse gas unfriendly.

Re:Prior art

[mattack2]

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.

So why shouldn't the scientists who figured this out be the ones to benefit? (...or license their newfound-through-studying-old-things knowledge)

I do think it's kind of strange to be able to patent it, but I also think that they should be compensated for its widespread use (if it is), beyond their presumed salary they got while figuring it out.

Re:Prior art

[alexo]

The biggest problem in todays concrete production is cost effectiveness. We can produce hundreds of concretes with widely varying properties. We can mix concretes with negligible carbon footprint or extreme durability or very steep viscoelasticity, but pumping tons of these into a foundation would cost more than simply using pure steel for all of it.

I would like to expand on it a little. As the AC said, the problem lies in economics, not engineering.

1) The project goes to the lowest bidder. Price tag (short-term costs) trumps quality (long-term costs) every time.

2) Planned obsolesce. There is less profit in just selling the product than in selling the product, plus a maintenance contract, plus another product when the first one breaks down. Lather, rinse, repeat.

Re:Prior art

[Anonymous Coward]

The stainless steels which are not magnetic have a different crystal structure--- they are austenitic, which is Face Centered Cubic. These steels have more Nickel, which is expensive.

Normal steel is cheap. Normal rebar is cheap for steel. And normal concrete is really cheap.

Austenitic steels have a larger coefficent of thermal expansion than normal (Ferritic, Body Centered Cubic) steels. This is a problem for use as rebar. Because concrete is so brittle, the coefficents need to match closely.

Re:Prior art

[mrmeval]

It's only a problem where road salt is heavily used and is mitigated by active electrical systems. In Indiana the iron girders in bridges and rebar in concrete roads are protected by such systems. We've migrated several roads to asphalt because concrete has a higher initial cost though even with the extra protection it's long term cost is lower. The short sightedness of bureaucrats at work. Our road maintenance costs are higher than states that do not need to use road salts. Tennessee has beautiful interstates that have seen little repair since their creation in some areas.

Re:Prior art

[Anonymous Coward]

Really? The Romans? What makes you westerlings confuse Greece and Rome?

Such a bullshit title

[Anonymous Coward]

The sensationalized title and article end with this:

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 priciniples 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.

Basically: Never mind. We probably can't use this millennia old "tech" anyway.

Re:Such a bullshit title

[__aaltlg1547]

So there's no such thing as lime and tuff? Of course we can use this method today, if they really have the formula now. I think Portland cement has been used for the last 200 years because it is cheap. This will not be as cheap, but in applications where corrosion is a particular issue, e.g. dams and in particular in salt and brackish water, it might likely be used.

Re: Such a bullshit title

[seanthegeek9306]

He didn't say we can't use it, just that further study is needed. That's how science works.

Re: Such a bullshit title

[seanthegeek9306]

The mobile site double posted. Sorry about that.

Ancient Romans

[AliasMarlowe]

Digitus impudicus ad hodierna effercio. MM anni? Mirum dictu!

Re:Ancient Romans

[worf_mo]

In high school - a couple decades ago - our teacher asked each student to think of a sentence, translate it into Latin and speak it out loud in front of the class. The guy next to me came up with: "Penis bonus pax in domus". He passed the test.

Re:Ancient Romans

[EdZ]

The people called Roman, they go the the house?

Re:Ancient Romans

[Anonymous Coward]

For some reason I want to cut your balls off for posting that.

Re:Ancient Romans

[interval1066]

Nope. It translates "A penis in hand saves nine."

Re:Ancient Romans

[Culture20]

Please rewatch Life of Brian.

Re:Ancient Romans

[balise]

Like the NSA

Re:Ancient Romans

[tedgyz]

Now write that 100 times

Highways

[Anonymous Coward]

They should test out this Pozzolan cement stuff on some highways, see if it survives the annual frost heave cycle. Although the unions wouldn't approve - they seem to like tearing up each heavily used roadway on an annual basis.

Re:Highways

[__aaltlg1547]

Ha. That's not dictated by unions. It's dictated by contractors that don't have any incentive to finish the job in a reasonable amount of time. When incentives are built into the contract, they finish on time.

Re:Highways

[Miamicanes]

I doubt whether it would help. Since Roman concrete can't be steel-reinforced, it would just crumble if ice heaved it upwards because it wouldn't have steel inside to hold it together. It wouldn't help with cracks, because even concrete roads are still surfaced with a few inches of asphalt (at least, in Florida... maybe things are different "up north"). AFAIK, the endless annual resurfacing would still be necessary, because 99% of the potholes and cracks are in the top layer of asphalt, not the structural concrete roadbed below.

Where the Roman concrete might be MORE useful is environments like causeways, by providing a hard shell around the structural foundation that protects it from erosion. Where it might become a bit dangerous is if it ends up protecting the structural reinforced concrete from VISIBLE damage, but doesn't prevent the steel from rusting away on the inside until its tensile strength gets reduced to the point of being dangerous even though it "looks fine" on the outside.(*)

(*)For those who don't know, reinforced steel consists of steel bars + concrete because concrete has tremendous compressive strength, but terrible tensile strength. Apply force in any direction besides straight down, and concrete just breaks away or crumbles. In contrast, steel has a lot of tensile strength (it tends to stretch and bend rather than snap), but terrible compressive strength. As a matter of good luck, steel & concrete have mostly identical expansion rates when heated & cooled, and form a very strong chemical bond to each other (get concrete splattered on your car, and once it dissolves the paint and makes contact with the steel body it's NEVER coming off). The combination allows concrete to provide the compressive strength, and the steel to provide the tensile strength. Without steel, an elevated freeway would have to be built from arched vaults. With steel, you can support it with flat beams. Of course, if you approximate a "classical" form like an arch, you'll be working WITH the concrete and adding strength, but steel is what allows us to build things like a 40 foot road deck cantilevered from a single support column, or support a skyscraper like Citigroup's midtown headquarters from support columns that are located in the middle of each wall instead of at the corners.

Re:Highways

[ebno-10db]

Roman concrete can't be steel-reinforced

Why?

Re:Highways

[Imrik]

It can be, but then it loses it's main advantage as the steel (and the concrete containing it) needs to be replaced after a while.

Re:Highways

[jbengt]

steel has a lot of tensile strength

true

but terrible compressive strength.

Not true

Re:Highways

[ChrisMaple]

Steel has no problem with compressive strength, it's just a lot more expensive than concrete.

Re:Highways

[Miamicanes]

Steel has no problem with compressive strength, it's just a lot more expensive than concrete.

It's not just cost. If you formed a freeway support column from a solid block of steel having dimensions of 5x10x40 feet, it would be impossible to transport to the site or place into position, and even more impossible to join to anything comparably large. You simply couldn't get the middle part of the contact points hot enough to weld, without damaging the structural integrity of the remainder of the beam/column while doing it.

In the real world, steel beams have to be some variant of a tube, box, I-beam, or C-channel/stud to enable them to be placed. The problem THEN is that many steel arrangements can't even support their own weight until they're all fastened together, and if something pushes them far enough to kink or bend, they fail rapidly and completely. For example, a futon made from steel tubes might be very strong, but if someone heavy falls into it, the whole thing can collapse the moment the first tube gets even slightly bent. However, there's no rule that necessarily says the steel HAS to be on the inside. For example, you can mount a hollow pole, then fill it with very runny concrete grout to give it compressive strength and minimize things like buckling.

Re:Highways

[adolf]

It's not just cost. If you formed a freeway support column from a solid block of steel having dimensions of 5x10x40 feet, it would be impossible to transport to the site or place into position, and even more impossible to join to anything comparably large. You simply couldn't get the middle part of the contact points hot enough to weld, without damaging the structural integrity of the remainder of the beam/column while doing it.

Yeah, and the pyramids were impossible to build, too. And thermite does not exist, and liquid nitrogen cannot keep things cold, and steel is a perfect conductor of heat so it would be impossible anyway. Right?

Sarcasm aside:

Why must it be 5x10x40 feet?

And why must it be welded, anyway? There are lots of other ways to join steel.

In the real world, steel beams have to be some variant of a tube, box, I-beam, or C-channel/stud to enable them to be placed.

Have to be? You sound mighty certain of yourself.

Rather, it's just that these shapes constitute tend a more efficient use (in terms of strength vs. weight) of material. Transportability is way down on the list: You can almost always get a bigger truck/crane/whatever.

In broader strokes, just because one thing is easier to transport or place, does not mean that some other thing is impossible to manage. (Give me a lever and a place to stand....)

And in one specific case: PiRod towers are made from solid (not tubular) round steel bars, with off-the-shelf self-supporting designs going up as high as 600 feet.

(And to be clear: Building big things out of solid steel is a often stupid idea. But being a stupid idea does not mean that it cannot be done: People do stupid, absurdly difficult things all of the time, sometimes even quite successfully.)

De Architectura

[the eric conspiracy]

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

Perhaps the story is confusing the known composition with some mechanism that the new study discovered.

Re:De Architectura

[Stickmaker]

When I was working on my BSCE in the mid-Seventies I had a course on concrete additives. Pozzolanic ash was definitely mentioned. I have also seen this mentioned many other places since then, including the fact that some of the Roman concrete mixes would cure under water. So, no, this isn't some revolutionary new discovery. Those claiming so are either ignorant of previous art - and that's *recent* previous art - or are deliberately trying to build up their own claims.

Re:De Architectura

[Jmc23]

Natural builders also discuss it all the time. It's also discussed in old ceramic texts, ~1800s. Probably the only actual new knowledge here is the role aluminum plays in the structure.

Re:De Architectura

[AthanasiusKircher]

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?

Umm, care to RTFA? From the press release:

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 ... especially from sites near todayâ(TM)s seaside town of Pozzuoli.

I'm not sure exactly all that is new here, but in the press release you can read about the role of aluminum, the effect of lower temperatures in the manufacturing process, the production of certain end products in curing that are not found in modern concrete (due to the things already mentioned), etc.

Perhaps the story is confusing the known composition with some mechanism that the new study discovered.

Or perhaps you just didn't read the link to find out that's exactly what the press release is about.

Roman concrete produces a significantly different compound [from modern concrete], with added aluminum and less silicon. The resulting calcium-aluminum-silicate-hydrate (C-A-S-H) is an exceptionally stable binder.... 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.

Etc.

(The article also, by the way, seems to be about streamlining manufacturing to produce a better product with less energy and heat, thereby reducing carbon emissions, etc.)

Re:De Architectura

[Trepidity]

As is common, the university press release (and the news story that cribs from it) is considerably over the top compared to the actual publications (and the actual findings). The research is interesting, but not some kind of groundbreaking discovery of Roman marine concrete, which is of course already well known. What it's actually doing is detailed investigation into the chemical properties of the concrete and how it's formed, in order to better understand the particular material-science aspects of this form of concrete.

Here's the abstract:

The material characteristics and elastic properties of aluminum-substituted 11 Å tobermorite in the relict lime clasts of 2000-year-old Roman seawater harbor concrete are described with TG-DSC and 29Si MAS NMR studies, along with nanoscale tomography, X-ray microdiffraction, and high-pressure X-ray diffraction synchrotron radiation applications. The crystals have aluminum substitution for silicon in tetrahedral bridging and branching sites and 11.49(3) Å interlayer (002) spacing. With prolonged heating to 350C, the crystals exhibit normal behavior. The experimentally measured isothermal bulk modulus at zero pressure, K0, 55 ±5 GPa, is less than ab initio and molecular dynamics models for ideal tobermorite with a double-silicate chain structure. Even so, K0, is substantially higher than calcium-aluminum-silicate-hydrate binder (C–A–S–H) in slag concrete. Based on nanoscale tomographic study, the crystal clusters form a well connected solid, despite having about 52% porosity. In the pumiceous cementitious matrix, Al-tobermorite with 11.27 Å interlayer spacing is locally associated with phillipsite, similar to geologic occurrences in basaltic tephra. The ancient concretes provide a sustainable prototype for producing Al-tobermorite in high-performance concretes with natural volcanic pozzolans.

Re:De Architectura

[AthanasiusKircher]

So, no, this isn't some revolutionary new discovery. Those claiming so are either ignorant of previous art - and that's *recent* previous art - or are deliberately trying to build up their own claims.

Or, maybe, just maybe, the Slashdot summary is merely quoting the first part of the press release that explains previously known information, but the Slashdot summary doesn't contain the actual details of the new findings, which describe some previously unknown aspects of the chemistry involved... some of which appear to be essential to the structural properties observed.

But, oops... for that you'd have to RTFA.

Re:De Architectura

[Toad-san]

What a bunch of crap! Yes, you're absolutely correct: this is all (literally) ancient history.

http://en.wikipedia.org/wiki/Roman_concrete

"Vitruvius, writing around 25 BC in his Ten Books on Architecture, distinguished types of aggregate appropriate for the preparation of lime mortars. For structural mortars, he recommended pozzolana, which were volcanic sands from the sandlike beds of Pozzuoli brownish-yellow-gray in color near Naples and reddish-brown at Rome. Vitruvius specifies a ratio of 1 part lime to 3 parts pozzolana for cements used in buildings and a 1:2 ratio of lime to pulvis Puteolanus for underwater work, essentially the same ratio mixed today for concrete used at sea.[2]"

Also, back in 1993:

http://www.romanconcrete.com/docs/spillway/spillway.htm

Re:De Architectura

[maestroX]

Check the original news at http://newscenter.berkeley.edu/2013/06/04/roman-concrete/. The businessweek article and this summary are misleading.

Re:De Architectura

[ebno-10db]

What a bunch of crap! Yes, you're absolutely correct: this is all (literally) ancient history.

RTFPR (read the f******* press release) and not just the headlines. This is about getting a better understanding of the important chemical and crystalline properties of Roman concrete. Of course the basics of Roman concrete have been known for a long time, but an ever more detailed understanding is useful for analyzing and predicting the properties of new concrete formulations.

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.

Re:De Architectura

[ebno-10db]

Didn't Vitruvius describe it in his De Architectura, written about 15 BC?

According to the terms of the Mickius Mousius copyright extension act, that means it'll soon enter the public domain.

Re:De Architectura

[theguyfromsaturn]

Yup. It's about the shashdot summary which sucks and completely misses the point. The press release focuses on the differences in the chemical composition of the hydrated cement (chiefly the presence of aluminium atoms in the Roman cement) and how those differences may affect durability.

Re:De Architectura

[Stickmaker]

Let's try this again; /. messed up my login my first attempt. We were discussing this last week on a technical e-mail list. Agreement was pretty much unanimous - with lots more evidence than I mentioned here - that this is someone blowing a valid but incremental development out of proportion.

Re:De Architectura

[Anonymous Coward]

the Slashdot summary doesn't contain the actual details of the new findings, which describe some previously unknown aspects of the chemistry involved... some of which appear to be essential to the structural properties observed.

...which makes the article scientifically innovative, producing new knowledge about Roman concrete. It still does not constitute invention of Roman concrete. Now, if someone were to take this new knowledge and design a concrete that used the same chemistry as Roman concrete, but did not require pozzolanic volcanic ash, that would be patentable.

Re:De Architectura

[kermidge]

Yeah, nine of ten posts would have been unnecessary (to say it politely) had its author read the article - even just the press release - although there's been some fun discussion anyway. And for all the talk of geography and ancient stupidity, it's the pozzolan, not a particular volcano, that's key; the Romans found out, experimented, and perfected what they did.

Use of pozzolan itself has long been known and used, although it adds cost and a bit more care in mixing. The worth of the current discovery is the particular combination of pozzolan with a particular technique for lime, and the exact chemical composition and behaviour that leads to the uniqueness of this form of Roman concrete.

(I have wee prior knowledge; when I helped a friend build his boat circa 1975 we incorporated 15% fly ash by volume into the mix.)

Re:De Architectura

[Anonymous Coward]

That would be the Michael Musculus Ius auctoris, according to the Latin Wikipedia.

WWARS (What Would Ayn Rand Say)

[jabberw0k]

I plan to build my next structure with Roman Concrete and Rearden Steel...

Re:WWARS (What Would Ayn Rand Say)

[Anonymous Coward]

Ayn Rand is dead.

Dead people don't say anything.

And in the case of Ayn Rand who was a nutcase
who wrote stuff which is embraced by fucktards with
minds which have not progressed beyond the juvenile
state, that is a good thing.

Re:WWARS (What Would Ayn Rand Say)

[Black Parrot]

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:WWARS (What Would Ayn Rand Say)

[Anonymous Coward]

There's nothing you have said that appears anywhere in the megatons of her writings. Is this the state of anti-Rand memes that filter about in your mental tribal community?

Re:WWARS (What Would Ayn Rand Say)

[ebno-10db]

how much their social inferiors would suffer after a Rapture of the Rich

That's an interesting description of the French Revolution.

Re:WWARS (What Would Ayn Rand Say)

[ebno-10db]

There's nothing you have said that appears anywhere in the megatons of her writings.

Megatons? Did she write much about nuclear weapons, or was she just using a very heavy bond paper?

There's nothing you have said that appears anywhere in the megatons of her writings. Is this the state of anti-Rand memes that filter about in your mental tribal community?

I can't speak for the GP, but in my mental tribal community (hint: I'm over 18) any discussion of Ayn Rand's writings gets reduced to endless jokes. Admittedly any attempt at a precise critique falls by the wayside, but there are some things you just can't help.

Re:WWARS (What Would Ayn Rand Say)

[Anonymous Coward]

Ayn Rand is dead.

Dead people don't say anything.

The subjunctive mood is used for hypothetical situations. In gay languages (like French) it is indicated by different endings. In English, the auxiliary "would" commonly serves a similar purpose.

Re:WWARS (What Would Ayn Rand Say)

[russotto]

Megatons? Did she write much about nuclear weapons, or was she just using a very heavy bond paper?

Evidently you've never SEEN _Atlas Shrugged_. "Megatons" is the appropriate unit for that tome, even if it's printed in 3pt type on onionskin.

Bloody Romans!

[Sponge Bath]

All right, but apart from the sanitation, medicine, education, wine, public order, irrigation, roads, the fresh water system and public health, what have the Romans ever done for us?

Re:Bloody Romans!

[Black Parrot]

On the down side, they had to change their concrete marketing slogan from "It keeps the Germans out" to "It keeps the seawater out".

Re:Bloody Romans!

[loufoque]

They taught grammar to barbarians; unfortunately English discarded most of it.

Re:Bloody Romans!

[Anonymous Coward]

Gladiators, orgies, toga parties, lions and Christians, Roman Catholicism, fiddling emperors, Byzantine Generals problem, assassinations, Latin, the Senate, demagoguery, pasta.

Re:Bloody Romans!

[kaoshin]

You left out the most important one of all. Welfare.

Re:Bloody Romans!

[Anonymous Coward]

Ah, something with concrete or other? And all those tourist traps in southern Italia, those too. Price was a bit steep though, quite a warry people, them. ROMANI ITE DOMUM indeed.

What gets me, though, is that these trick cyclists came up with this on a single sample. Surely they could've done a little comparising. But perhaps they're deliberately saving that for another paper, you know, to justify the inevitable "more research needed" ending of this one.

And also, while the Romans did have quite a bit more technology than we commonly think back then (taximeters, ...), that doesn't change that apparently we haven't even tried to figure out their concrete before. Even though it's just about everywhere and we very well knew it was superior to what we had access to. Who's the lazy bum now, eh?

Re:Bloody Romans!

[ShanghaiBill]

pasta.

The Romans ate bread, not pasta. Noodles were invented in China, and didn't reach Europe until the late middle ages. The first record of pasta being made in Italy was in 1154.

Re:Bloody Romans!

[Anonymous Coward]

Add central heating to that list.

Re:Bloody Romans!

[Em Adespoton]

... that doesn't change that apparently we haven't even tried to figure out their concrete before. Even though it's just about everywhere and we very well knew it was superior to what we had access to. Who's the lazy bum now, eh?

As mentioned in a previous thread, we haven't tried to figure out their concrete because we haven't had to... they left us the recipe, and it's been discussed through the centuries by anyone remotely interested in the stuff.

It just doesn't have all the properties (structural, cost and availability) that are desirable for most modern construction. Makes good statues / fake rocks though.

Re:Bloody Romans!

[wisnoskij]

They taught us why it is not a good idea to flavour wine with lead?

Re:Bloody Romans!

[Black Parrot]

pasta.

The Romans ate bread, not pasta. Noodles were invented in China, and didn't reach Europe until the late middle ages. The first record of pasta being made in Italy was in 1154.

So Pastafarianism is an Oriental religion?

Re:Bloody Romans!

[Hadlock]

I think the Iranians have the beat on wine beat by a couple hundred years at least

Re:Bloody Romans!

[Anonymous Coward]

i think you misspelled "fortunately". we communicate just as much
with a small fraction of the rules in english.

Re:Bloody Romans!

[Anonymous Coward]

pasta.

The Romans ate bread, not pasta. Noodles were invented in China, and didn't reach Europe until the late middle ages. The first record of pasta being made in Italy was in 1154.

That's why its called Ramen noodles instead of Roman noodles ;-)

Re:Bloody Romans!

[ebno-10db]

They taught grammar to barbarians; unfortunately English discarded most of it.

Even more unfortunately some people in the 18th century tried to impose Latin grammar on English. That's where we get nonsense like "don't end a sentence with a preposition" and absurd constructs like "he/she" instead of the neuter singular "they". Write in a dead language if you wish, but don't try to impose its absurd rules on the greatest language ever spoken: American English.

Re:Bloody Romans!

[__aaltlg1547]

They crucified Jesus and burned a lot of Christians. Does that count?

Re:Bloody Romans!

[guruevi]

They crucified lots of people, usually criminals. Jesus was therefore a criminal.

Re:Bloody Romans!

[Hognoxious]

As your post shows, you clearly don't.

Re:Bloody Romans!

[__aaltlg1547]

According to the gospels, he was convicted of being such, though they are pretty insistent on the point that he was convicted based on false and contradictory testimony and that his accusers were politically motivated.

Re:Bloody Romans!

[guruevi]

Which Paul (also according to the gospels) repealed by calling upon Caesar. The Roman justice system was quite advanced with multiple levels of courts. According to the gospels, Jesus remained quiet therefore WANTING to die a martyr and fulfilling his own prophecies. He was a criminal nutjob at best.

Re:Bloody Romans!

[Anonymous Coward]

You left out the most important one of all. Welfare.

Oh, but they did. Ever heard of panem et circenses

Re:Bloody Romans!

[onyxruby]

Yup, their right about noodles being a Chinese invention. Every time your eating Italian your eating a knock off of a Chinese original. Thus the true revelation that the Flying Spaghetti Monster is actually Chinese....

Re:Bloody Romans!

[Anonymous Coward]

The Spaghetti Monster was Chinese????

Re:Bloody Romans!

[Anonymous Coward]

That Marco Polo brought pasta to Italy is an urban legend. Pasta in Italy probably goes back to the Etruscan period and outside Italy the Greek already knew about it.
Also, the simplicity of the basic pasta recipe and that it's very different from Chinese pasta, should have given you pause and made you research the subject.

Re:Bloody Romans!

[__aaltlg1547]

That's theology speaking, not a straight reading of the stories. Yes, he remained silent to most of the charges. But was that "wanting to be martyred" or simple recognition that he was in a kangaroo court (miraculously, hundreds of years before any Jew or Roman knew of Australia) and anything he said would make no difference?

Re:Bloody Romans!

[laejoh]

Oh, Germans. I'm sorry, I THOUGHT there was something wrong with them!

Re:Bloody Romans!

[Anonymous Coward]

Rahmen

Re: Bloody Romans!

[fferreres]

Yes. But more importantly, I read 20 years ago the main reason bread was more popular....they still haven't discovered tomato...as it was a Mexican invention. They first thought it was ornamental. Not sure who did the first tomato pasta dish dough :-)

Re:Bloody Romans!

[pwizard2]

These days, ending a sentence with a proposition is grammatically correct. I was taught that using "he/she" in a sentence about a single person is correct because "they" is plural and should only be used when referring to multiple people.

Re:Bloody Romans!

[pwizard2]

Gah, I meant preposition, not proposition.

Re:Bloody Romans!

[hawk]

That "they is plural" is correct.

However, absent context otherwise, "he" does *not* indicate gender; it is the correct word for both male and for unknown gender.

Women get their own words, while men get hand-me-downs.

hawk

Re:Bloody Romans!

[MarkCollette]

An ancient Eastern knowledge, predating our modern string theory by millenia!

ok but what have the romans ever done for us?

[Anonymous Coward]

this comment left intentional blank

I find it oddly disturbing

[TheRealHocusLocus]

That the title of the article has flopped the whole topic from strength and durability to carbon emissions.

The authors fail to point out that large scale mining of tuff by Corporations will only encourage volcanism.

First to file

[rsilvergun]

didn't most countries move to a first to file system? I'm pretty sure Julius didn't get to the Patent office on time for this one.

Re:First to file

[Trepidity]

Yes, but you still can't patent something that's widespread public knowledge. First-to-file is just a way of resolving disputes over priority when two people claim the right to patent an invention. The alternative system is first-to-invent, which has more problems because it requires digging into each party's private records of when they invented the thing, and trusting that those records aren't falsified.

Re:First to file

[Goaway]

Yes, but you still can't patent something that's widespread public knowledge.

Which, of course, this isn't. It's been long since forgotten.

Re:First to file

[Anonymous Coward]

I really don't get the first to file way. Yeah, its is here to settle disputes when 2 parties try to pattent an invention at nearly the same time. But, if there are actually 2 parties, doesn't that mean that whatever is to be patented really is pretty obvious to a person specialized in the field, which would, in some countries stop it from being patent worthy?

Re:First to file

[Anonymous Coward]

Yes, but you still can't patent something that's widespread public knowledge.

Which, of course, this isn't. It's been long since forgotten.

OTOH, I believe it's commonly referred to as "prior art". Now IANAL but I would definitely call Roman structures prior art.

Well there's a news flash.

[interval1066]

The secret to Roman concrete lies in its unique mineral formulation and production technique.

Oh? Really? Its not becuase the Romans made sacrifices to Jupiter? They didn't make their concrete with a recipe given to them by ancients astronauts? The secret lies with thier recipe and technique? Who knew?

Re:Well there's a news flash.

[__aaltlg1547]

I thought it was because of the sacrifices to Janus, sadly a mostly-forgotten god, only commemorated these days in the month of January, the honorable job of Janitor (keeper of the keys) and the admonition to look both ways before you cross the street.

Re:Well there's a news flash.

[Anonymous Coward]

> recipe given to them by Vulcan, the god of metalworking and volcanoes

Re:Well there's a news flash.

[colinrichardday]

Well, the followers of Janus nearly made a fortune by subjecting London to an electromagnetic pulse, but that heretic Bond had to interfere.

Re:Well there's a news flash.

[Anonymous Coward]

Recipe, eh? So was the concrete beaten, whipped, or folded? Muffin or biscuit method?

Duh

[fnj]

Cement is not concrete. Concrete is made of cement plus aggregate.

Re: Duh

[Anonymous Coward]

So... concrete is abstract because the actual thing is rocks with cement between them?

Re: Duh

[gagol]

well, just like iron and steel...

Opus caementitium

[no-body]

Researched and published over 30 years ago. Known technology for decades. Could reduce the 7 % of total carbon dioxide output on planet generated by cement production.

Anything changed in 3 decades - will anything change in the near future in a billion $ industry?

BOHA!

Revolutionize or "more eco-friendly"?

[tijnbraun]

From http://newscenter.berkeley.edu/2013/06/04/roman-concrete/ 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.”

Re:Revolutionize or "more eco-friendly"?

[taharvey]

Indeed, this is nothing new.

Most concrete ready-mix suppliers cut their portland cement by around 20% with Fly Ash , another pozzolan. It makes better, cheaper concrete. This is well known. However, the more Portland Cement you replace with pozzolans, the slower the cure.

The markets skew towards high-portland content concrete is largely dictated by the desire to strip forms as soon as possible. With portland, forms are striped in 24 hours. WIth high pozzolan content concrete, the forms often need to be in place for upwards of a week.

Re:Revolutionize or "more eco-friendly"?

[Anonymous Coward]

... fly ash, an industrial waste product from the burning of coal that is commonly used to produce modern, green concrete.

I am so tired, so goddamn tired, of marketing. How the *fuck* does concrete being made out of the ashes of fossil fuel wind up as green?

All hail Bill.

Re:Revolutionize or "more eco-friendly"?

[hawguy]

... fly ash, an industrial waste product from the burning of coal that is commonly used to produce modern, green concrete.

I am so tired, so goddamn tired, of marketing. How the *fuck* does concrete being made out of the ashes of fossil fuel wind up as green?

All hail Bill.

Because it uses waste material from an industrial process (i.e. electrical production) that's completely unrelated to the production of the concrete? Reuse of waste products is "green", even if the waste product comes from a non-green industry.

It's the same reason Ethical Vegetarians can still wear leather shoes without feeling guilty because hundreds of millions of cattle will be slaughtered for meat each year yielding plenty of leather regardless of how many shoes are produced.

Re:Revolutionize or "more eco-friendly"?

[stoploss]

It's the same reason Ethical Vegetarians can still wear leather shoes without feeling guilty because hundreds of millions of cattle will be slaughtered for meat each year yielding plenty of leather regardless of how many shoes are produced.

That seems rather arbitrary, perhaps even cognitively dissonant.

Are they also okay with eating meat as long as it would otherwise go to waste (eg. meat at the grocery store that expires today, or leftover catered meat, or "pink slime" reclaimed meat)? Either way, it seems like the demand for leather further bolsters the cattle industry by making it more profitable to raise and slaughter cattle. I would even posit that buying leather shoes is in the same class as buying a hamburger: both are contributing nigh negligible material support for the farming/slaughter of cattle.

But hey, whatever they want to do is fine. I just prefer it when others' belief systems are self-consistent.

NEWSFLASH

[somepunk]

Application specific concrete that has stood up for two millenia beats our common, everyday, casual-use concrete. Compare it to the stuff used for capping deep water oil wells and I'll be more impressed. [/sarcasm]

Re:NEWSFLASH

[Anonymous Coward]

They don't build them like they used to, now get off my corona graminea.

Re:NEWSFLASH

[Rich0]

Yup - obviously the Roman stuff has essentially had the benefit of selection applied. I wouldn't be surprised if the Romans had a bunch of ways of making cement, but the stuff we notice is the stuff that is still around.

That said, nothing wrong with learning from it all. We don't really have any modern materials that have gone through 2000-year stability tests under real-world conditions. Stuff that we fortuitously have at hand to study could turn up other useful finds.

Re:NEWSFLASH

[__aaltlg1547]

They also invented the idea of Senators. Obviously not all of their long-lasting creations turned out to be useful.

Re:NEWSFLASH

[hawguy]

Application specific concrete that has stood up for two millenia beats our common, everyday, casual-use concrete. Compare it to the stuff used for capping deep water oil wells and I'll be more impressed. [/sarcasm]

What's the design life time for an oil well cap? I always figured that they only had to last for decades, maybe a century before mother nature took over and sealed the well permanently.

Re:NEWSFLASH

[DarkProphet]

They also invented the idea of Senators. Obviously not all of their long-lasting creations turned out to be useful.

Come now, it was a great idea. We just fail terribly at the execution. You can hardly blame Ikea when Joe Blow can't be bothered to read the instructions and invariably ends up with furniture that looks like it belongs in an Escher painting!

People discovered this in 86 it seems.

[Anonymous Coward]

From http://en.wikipedia.org/wiki/Pozzolana

Cook D.J. (1986) Natural pozzolanas. In: Swamy R.N., Editor (1986) Cement Replacement Materials, Surrey University Press, p. 200.
Lechtman H. and Hobbs L. (1986) "Roman Concrete and the Roman Architectural Revolution", Ceramics and Civilization Volume 3: High Technology Ceramics: Past, Present, Future, edited by W.D. Kingery and published by the American Ceramics Society, 1986; and Vitruvius, Book II:v,1; Book V:xii2.
McCann A.M. (1994) "The Roman Port of Cosa" (273 BC), Scientific American, Ancient Cities, pp. 92–99, by Anna Marguerite McCann. Covers, hydraulic concrete, of "Pozzolana mortar" and the 5 piers, of the Cosa harbor, the Lighthouse on pier 5, diagrams, and photographs. Height of Port city: 100 BC.
Mertens, G.; R. Snellings, K. Van Balen, B. Bicer-Simsir, P. Verlooy, J. Elsen (2009). "Pozzolanic reactions of common natural zeolites with lime and parameters affecting their reactivity". Cement and Concrete Research 39 (3): 233–240. doi:10.1016/j.cemconres.2008.11.008. ISSN 0008-8846. Retrieved 2009-03-23.

Re:People discovered this in 86 it seems.

[rahvin112]

Yes this article is garbage IMO. Pozzolans are the basis of concrete. That's what concrete powder is, an artificially produced pozzolan. Fly Ash is also a Pozzolan, we've been using in PCC for decades. Volcanic ash is also a Pozzolan, and in a sense it is "green" to use volcanic ash instead of modern cement powder because you don't have the input energy to make the cement powder. But Volcanic fly ash is NOT an unlimited supply and mining and transporting it may use just as much energy as cement powder.

Second, Modern Portland Cement does NOT deteriorate after 50 years. Properly placed concrete has no known lifespan. (if concrete only lasted 50 years there would be a LOT of buildings failing every year) What does fail, as has been noted, is the reinforcing steel used to give the concrete tensile strength (concrete has no tensile strength) and wear and tear. There are ways around the rusting rebar that are being used, galvanized rebar, epoxy coated and stainless steel are just a few of the techniques being used to increase the lifespan of the rebar to give equal lifespan to the steel and concrete.

Finally, we can make concrete better than the Romans, we just have to use the equivalent amount of Pozzolans they were using. When the Europeans (after the dark age) tried to duplicate the Roman mix they found it far to wet to be usable, the missing knowledge was that one of the mix ingredients was all that volcanic ash which meant the amount of pozzolan in the mix was far higher and in fact comprised a significant percentage of the mix. In fact the measurements made recently have shown that modern concrete isn't using near the equivalent amount of cement powder. Stronger concrete can easily be produced by increasing the amount of cement powder, the problem is the cost that adds. We don't use concrete of that strength generally because of two reasons, cost and failure mode. Standard reinforced portland cement concrete fails in a manner that provides warning of imminent collapse, high strength reinforced concrete does not provide that warning, it fails explosively.

So in summary that is the WORST cement article I've ever read, but what can you expect from Businessweek I guess. It reads like a scam article to get someone to invest money in an idea that isn't revolutionary. Caveat Emptor.

Re:People discovered this in 86 it seems.

[Anonymous Coward]

I've been making my concrete with an extra sack of Portland cement for my whole life.
One drawback of that is if you want to tear it out, it resists stubbornly. The current owner of a house I built a stone terrace next to forty years ago wanted to punch a hole through for some sprinklers. One of my old neighbors asked me if I had done something weird to the grout.
Long laughs, the guy had to tunnel five feet.

Judean People's Front

[Anonymous Coward]

no, we're the People's Front of Judea! bloody Romans.

Re:Ancient Roman First Post is about to revolution

[Phizzle]

in the spirit of Slashdot shouldn't it be FROSTVS PISTVS?

Re:Ancient Roman First Post is about to revolution

[newcastlejon]

Si tacuisses philosophus mansisses.

Re:Ancient Roman First Post is about to revolution

[Anonymous Coward]

Si tacuisses philosophus mansisses.

Spasibo za neumestnuju Latin i afishirovannije erzatsa intellecta, voistinnu skazano, "Obrazovanie ne portit pridurka".

Re:Ancient Roman First Post is about to revolution

[Anonymous Coward]

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.

Re:Ancient Roman First Post is about to revolution

[AliasMarlowe]

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.

Prestressed concrete performs better under tension

[stoploss]

Question is - why is it necessary for concrete to be reinforced? Obviously, the Romans didn't have steel or iron rebar. They formed and poured their structures without any rebar, and they've lasted a couple thousand years. It seems more than obvious that our architects and engineers can learn a few things from the Romans.

IANASE (structural engineer), but from my understanding one key difference that reinforced concrete confers is that it allows the concrete to be prestressed to perform better under tension. Concrete (Roman or modern) is just fine under compression, so it can support a prodigious amount of weight loading down on it. However, once you try to span an area then the concrete in the middle of the span is normally under tension. As you can imagine, this often leads to cracking and outright failure. Furthermore, it's why the Romans had such a predilection to using arches and domes, which keep the concrete predominantly under compression rather than tension.

Think about it this way: our highway bridges couldn't be built the way they are if we were using unreinforced Roman concrete; however, if the concrete is prestressed then the tensile forces are balanced by the compressive forces. This also allows us to do many other interesting things with architecture that weren't feasible before.

I have wondered about whether something like carbon fiber could be used in the future to produce prestressed concrete that wasn't as prone to corrosion as the steel rebar-based approach. Something like that might be the best of both worlds. Okay, so I just Googled and it looks like at least one carbon-fiber approach is already patented.

Just as an aside, the Romans were quite ingenious when it came to implementing their architectural application of concrete. I read that when Hadrian ordered the construction of the current version of the Pantheon, the Roman engineers were faced with difficulty designing a dome that would not collapse under its own weight (again, tensile forces and concrete are not friends). The Romans overcame this by reducing the density of the concrete in the dome by using pumice in the aggregate and reducing the thickness of the concrete as the dome progressed. The dome of the Pantheon remains the largest unreinforced concrete dome in the world—not because we can't replicate the techniques, but because reinforced concrete performs so much better under tension.

Corrupted link was corrupt.

[stoploss]

Prestressed concrete

Its the good stuff that lasts

[starkadder]

I'm sure that Roman concrete greatly varied in quality. Every batch was an experiment using local materials.The crap that didln't last for 25 year is long gone. All we have left to look at today are the results of successful experiments. And it is a wise thing to learn from it. But to consider everything the ancients built as evidence of their genius disregards the winnowing of time. Good stuff lasts, bad stuff falls apart and is discarded.

Re:Its the good stuff that lasts

[gtirloni]

I wish Roman techniques were employed in our electronics and cars.

Acid proof stainless steel

[Anonymous Coward]

Acid proof stainless steel is used quite a lot in places where it's so humid that it penetrates concrete. I've seen it used in (Arabian/Persian) Gulf region for some time already. It's expensive, but there is no alternative there if you like to build bridges and such structures that will last half a century or more.

Now that we got Roman concrete...

[olip85]

it's time to rediscover Damascus steel.

Re:Prestressed concrete performs better under tens

[ebno-10db]

Roman engineers were faced with difficulty designing a dome that would not collapse under its own weight (again, tensile forces and concrete are not friends)

IIRC in a dome all the stresses are compressive. It's like an arch rotated around an axis, is one way to look at it. Also, it's not essential to prestress the concrete in order for reinforcement to add tensile strength. Sorry for being pedantic, but a compulsion is a terrible thing to waste.

Plural intentional

[Hognoxious]

You mean roman_mir? He seems to be her biggest fans.

Let's not be silly here

[Anonymous Coward]

This isn't news - or anything remotely approaching it. We're talking about Pozzolanic reactions. Fly ash/Silica fume (and other materials) when added in the correct proportions to a concrete mix will dramatically enhance its compressive strength, prolong its lifespan, & reduce the deleterious effects of sodium ions. Google "UHPC" or "Ultra High Performance Concrete" fir further information.

Re:Prestressed concrete performs better under tens

[Anonymous Coward]

It's not easy to find a suitable replacement for steel as reinforcement, because steel and concrete just happen to have almost the same coefficient of thermal expansion. A carbon reinforced concrete structure might just tear itself apart if it gets too much colder or hotter than the temperature at which it was initially poured/erected.

Not News

[Anonymous Coward]

This is not new. Not even second time around. People have been using this for decades, at least, in modern times. I use this in my construction. This is just a spinning press release for someone hoping to make a degree or buck. These claims keep getting made every few years by nobodies that think they've reinvented or rediscovered.

Re:Not News

[drwho]

You are correct. I have known about it for some time...I think it is pozzolan or similar - nothing lost or rediscovered.

they also used to put blood in some of their cement.

Re:Prestressed concrete performs better under tens

[cusco]

Fiberglass threads are sometimes added to concrete to eliminate the need for rebar/remesh. I used that on my truck's parking spot in part because it was only slightly more expensive per yard than the price of concrete+remesh, and since it could be poured thinner without cracking slightly less material was necessary. The fiberglass makes getting a smooth finish on it pretty much impossible, which was fine since my concrete finishing skills are not really up to snuff anyway.

The Pantheon

[mendax]

If you want to see an example of Roman concrete, look at photos of or just go to Rome and visit the Pantheon, that great domed temple nearly 2000 years old. It's completely in tact and the dome is made of that marvelous concrete. No rebar, no reinforcement, just concrete. There is no way in hell that temple would have stood this long if it contained any kind of metallic rebar other than something made of gold or other material that doesn't corrode when exposed to the elements, and if it did the building would have been torn down to get to the metals inside as with the Colosseum. That's what happened to the bronze tiles that originally covered the dome.

Re:Prestressed concrete performs better under tens

[theguyfromsaturn]

Even without prestressing, (which reinforced concrete does allow) reinforcement provides additional tensile strength. Concrete's tensile strength is no more than 10% of its compressive strength which means it's nothing to write home about. You can get reinforcement from fibres (which is why the ancients would add straw to clay to make bricks).

The point is that while pretensioning does give you added tensile resistance (by converting the inital tension to a reduction of the pre-imposed compression), reinforced concrete does not require pre-tensioning to reinforce concrete in tension, and in most cases just the presence of rebar is enough to provide the required tensile resistance. Pretensioning will be used when larger spans (and therefore larger tensile stresses in some parts of the beams) are required.

It depends on the curvature

[stoploss]

IIRC in a dome all the stresses are compressive.

Eh... I am fairly certain it depends on the arch/dome curvature. Here's a HowStuffWorks cite:

"But as with beams and trusses, even the mighty arch can't outrun physics forever. The greater the degree of curvature (the larger the semicircle of the arch), the greater the effects of tension on the underside of the bridge.

It makes sense: if you have a very low curvature the arch/dome trends toward being a flat beam and is obviously is experiencing tension. You can try to counterbalance that by building more support structure to counteract the tension by compressing the low curvature beam, but then we are quickly approaching the concept that prestressed concrete accomplishes intrinsically.

I will say that it is a shame we don't see as many flying buttresses anymore (haha).

Re:It depends on the curvature

[ebno-10db]

I am fairly certain it depends on the arch/dome curvature.

Good point. I should have said that a dome can be designed so that the stresses are primarily compressive. My point was that otherwise they wouldn't have been able to build the Pantheon with unreinforced concrete. I'm always amazed at how they managed to figure out good design rules without any mathematical stress analysis. Obviously they managed, though it may have involved a few things falling down or at least having to be patched up post-construction (not that that doesn't happen nowadays). Perhaps it also had to do with only slowly evolving their design/construction techniques, rather than making big leaps.

It makes sense: if you have a very low curvature the arch/dome trends toward being a flat beam and is obviously is experiencing tension.

I thought of the same "degenerate case is flat", and there must be a point where that becomes true, but if you have a dome that's a large portion of a sphere (e.g. 180 degrees), the tensile hoop stresses occur towards the bottom, and one way of dealing that is to reduce the portion of a sphere you're using (e.g. to 140 degrees). The whole "tending towards flat" may be covered by the fact that these simple analyses apply to domes that aren't "thin", which is defined by the ratio of the thickness to the radius. IIRC thin domes are structurally called shells.

Shame it's a Saturday, otherwise we'd almost certainly have some actual structural engineers chiming in. Some interesting references:

http://masonrydesign.blogspot.com/2012/03/thickness-of-dome-walls.html

http://site.iugaza.edu.ps/marafa/files/Spherical-dome.pdf

I will say that it is a shame we don't see as many flying buttresses anymore (haha).

Why haha? Not only are those cathedrals beautiful, but they sure do last (at least if you don't bomb them). IIRC they did have a few failures while they were working things out though.

Lost Art

[Wansu]

It's amazing how advanced the Romans were and how some of their technology stayed "lost" for so long. The fall of Rome was a great societal reset. There may be another at hand.

The headline focuses on the wrong thing.

[theguyfromsaturn]

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:The headline focuses on the wrong thing.

[Anonymous Coward]

So just more cash? Greedy.

Re:The headline focuses on the wrong thing.

[iKauai]

Nothing new under the sun or maybe it's the same only different! When one reads the source article: http://newscenter.lbl.gov/news-releases/2013/06/04/roman-concrete/ "seawater formed highly stable CA-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.” We see that this amazing new discovery is not new, at least to anyone who has been in or around the Ferro-cement boat culture over the last hundred years or more that the use of pozzolan (ultra fine volcanic ash) has been used all along for it's ability to completely fill the pores in the 'cement' mix by the nature of pozzolan's small aggregate size, allowing it to be impervious to water penetration when fully cured.

Mod up OP!

[Pf0tzenpfritz]

Exactly. The hydraulic reaction described in the summary is the very same as used in today's concrete. As are the wooden casks. (Today we also use to throw a lot of iron in there to deal with tension, but that doesn't affect erosion.) The real deal is a lot deeper in TLA.

Scotty would be so happy

[theguyfromsaturn]

From the press release: "The resulting calcium-aluminum-silicate-hydrate (C-A-S-H) is an exceptionally stable binder."

Now, if they could only make it transparent...

Re:Ancient Roman First Post is about to revolution

[rcamans]

I don't understand. Why don't those fly-ash-challenged countries just burn more flies? Are flies in that short a supply?

Space Elevator!

[Pepebuho]

Finally, we have what we need to build an Space Elevator!

Are you sure?

[Anonymous Coward]

So what you're saying is that concrete made by our current 200 year old formula could stand the test of time better if only not for the rebar? That if you pour a slab of Portland cement, with and/or without aggregate, and once cured you put it in the sea, or whatevs, that it will last 2000+ years because there's no rebar?

I'm not calling you out, saying you're wrong, I'm just saying, to quote Wikipedia, [citation needed].

Are you perchance a chemist? Have you actually experimentally verified this, or is it just possibly an anally derived idea that makes sense, but is not based on any actual research into the actual, specific topic being discussed? Finally, if rebar really was the problem, couldn't the same formulation be used, but rods of some other hard, strong, non-rusting material be used instead, perhaps aluminum rods wrapped in carbon fiber? Or is carbon fiber itself stiff enough, and just use miniature, rounded in cross-section triangular beams of carbon fiber without the aluminum... Triangles composed of smaller triangles, perhaps an extruded Sierpinski of carbon fiber?

I think the deal here is that the Roman formula used materials that were chemically radically different from what we use, which is why they got different results, just as making a sword out of iron versus bronze will give you radically different results, too.

But though I did get an 'A' in a collegiate (introductory level) chemistry class, I'll admit I'm not a chemist, nor a concreteologist. Or whatever.

Re:Are you sure?

[Immerman]

No, you misunderstand me. I'm making no claims about the quality of modern concrete, everything I've heard says Roman concrete is vastly superior. What I'm saying is basically that if the Romans had used iron rebar then their structures would have long since crumbled as the expanding corrosion split apart the concrete. Roman concrete lasts. Iron doesn't. And if you encase iron in concrete then the concrete will eventually be shattered because it doesn't have the tensile strength to withstand the expansive forces (if it had the tensile strength you wouldn't need the rebar)

Re:Prestressed concrete performs better under tens

[careysub]

... I read that when Hadrian ordered the construction of the current version of the Pantheon, the Roman engineers were faced with difficulty designing a dome that would not collapse under its own weight (again, tensile forces and concrete are not friends). The Romans overcame this by reducing the density of the concrete in the dome by using pumice in the aggregate and reducing the thickness of the concrete as the dome progressed....

That is not the only interesting weight reducing methods they used. They also used a form of hollow core composite construction - embedding hollow clay pots in the wall to reduce its density, and the done itself is a ribbed structure, with vertical and horizontal ribs framing those "decorative" (but highly functional) square indentations in the inner surface.

Some speculate that scale and partial full scale engineering models were used to perfect the design and construction techniques.

Re:Geography

[gr8_phk]

The whole thing was an accident of geography

Going out on a limb here, to what extent would the accidentally superior cement in that area lead to the establishment of an empire? All those structures would be stronger than the other guys, which would have to count for something. I find it interesting to think that they dominated the time in part due to naturally occurring ash and such.

Makes you wonder what subtle things in the modern world lead to success - the US in particular. Are we strong due to our laws? Our constitution? The wide open land full of resources? Peoples attitudes toward any number of things? The diversity? Who knows, certainly some of those things could be as subtle as a different composition of volcanic ash.

Re:Prestressed concrete performs better under tens

[stoploss]

I thought I recalled the use of hollow pots in the aggregate, but I couldn't find a cite for that claim so I omitted it. It was an ingenious idea, though.

Lime mortar is wel known

[Anonymous Coward]

and was very common until Portland cement came along. Just google Portland cement vs lime and you'll get some good info. I don't think this is a new-material story, just cool that the Romans knew what to use.

Re-discovered is the word here

[Anonymous Coward]

"finally been discovered by an international team of scientists"

Shouldn't that say 're-discovered', after all it had been discovered by the romans 2000 some years ago we are just re-discovering an ancient tech.

Re:Geography

[icebike]

Actually, there is a school of thought that speculates that the US is in the position it finds itself in precisely because of the land we found ourselves living on. But the Russian Federation / USSR has more of just about everything in the way of natural resources than the north american continent. So its an interesting speculation, but still up for debate.

Re:Geography

[Kaenneth]

It's our huge tracts of land.

Re:Geography

[GerryHattrick]

In 'Economic History' we were taught that the widespread use of cheap barbed wire (to tame the prairies) was what gave the USA its biggest boost. And when that wire came to Europe, it changed WW1 from a fast war of cavalry charges to a slow war of trench attrition, and ruined several other empires as a result.

bad mod

[Psyborgue]

Posting to undo

Aluminium containing cements

[Anonymous Coward]

As the owner of serveral important patents that I have so far spent much to protect they are important but unfortunately not literally read so arguably counter productive. Having said that my original magnesium cement patent applications included the addition of aluminium in cementitious compositions. It is still there in the text even though I was, wrongly it seems, advised by my attornies to get rid of any claims for aluminium.

The researchers should note that the pier the researchers took a drill core from at Baiae in Pozzuloi Bay also contains a high level of magnesium compounds and I refer the reader to http://www.tececo.com/history.magnesium_hydraulic_cements.php written by me. I don't know why I am an anonymous coward for this post because I am to my detriment the opposite! John Harrison TecEco

Re:Aluminium containing cements

[Anonymous Coward]

Sorry about the spelling of "several" and "attorneys" It is hard to type with a stuffed finger! John Harrison TecEco

Re:Prestressed concrete performs better under tens

[Anonymous Coward]

Nothing like leaving both haunch loading and tesserae out of the discussion -- both key factors in the structural analysis...

AMEDEO MAIURI

[Anonymous Coward]

Who conducted excavations in Pompeii et super omnes in Stabiae, discovered and published the formula in 1932....

Ancient Roman Concrete

[BundyGil]

A new discovery? I've been reading about this for at least 20 years and nothing has come from it so far. Hopefully these researchers have now solved the technical problems in producing it.

Roman Rebar?

[DarthVain]

According to this Roman's didn't use rebar.

http://en.wikipedia.org/wiki/Roman_concrete

However I was in Rome a few years back and it sure seemed like they did. Perhaps it was that they didn't use concrete like we do today, i.e. entire poured structures. To increase the stability and structural strength of stone blocks iron bars were used to connect them, or at least they did in the Colosseum. Roman concrete was also used, but not as a stand alone product in the most part, but rather in conjunction with stone blocks, and bricks.

Also the primary problem with the iron bars being used, was that it was incredibly expensive at the time (which perhaps why not widely used), and looters would dig out the iron rods (destroying/ruining(literally!) the structure to sell them.

So while not rebar in totally the same sense as we use it today, it was used by Romans. You could also examine where it was dug out, and where they only got partially through, but exposed the iron to view.