What concrete things the Romans have ever done for us
June 21, 2013 8:53 AM   Subscribe

"Portland cement is the source of the “glue” that holds most modern concrete together. But making it releases carbon from burning fuel, needed to heat a mix of limestone and clays to 1,450 degrees Celsius (2,642 degrees Fahrenheit) – and from the heated limestone (calcium carbonate) itself. Monteiro’s team found that the Romans, by contrast, used much less lime and made it from limestone baked at 900˚ C (1,652˚ F) or lower, requiring far less fuel than Portland cement." -- How Berkeley Lab scientists discovered the secret of Roman concrete's durability and how it could help make modern concrete more environmentally friendly.
posted by MartinWisse (39 comments total) 44 users marked this as a favorite

 
Thank you for using "concrete" and "cement" correctly.
posted by the man of twists and turns at 8:57 AM on June 21, 2013 [19 favorites]


I wonder how many other technologies we've lost.
posted by dreamling at 9:00 AM on June 21, 2013 [4 favorites]


Greek fire!
posted by zombieflanders at 9:00 AM on June 21, 2013 [3 favorites]


I wish I could take credit for it, but that's all from the original articles.
posted by MartinWisse at 9:01 AM on June 21, 2013 [2 favorites]


There was an interesting 99% Invisible episode recently about the origins of reinforced concrete -- "Rebar and the Alvord Lake Bridge" -- without which we would not have much of our modern world's structures.
posted by Celsius1414 at 9:03 AM on June 21, 2013 [5 favorites]


This is pretty awesome! The only downside is how mind-numbinglynugly a lot of modern architecture is. I'd like to see people of our times build as strongly AND as beautifully as the Romans did.
posted by Katjusa Roquette at 9:05 AM on June 21, 2013 [3 favorites]


Thank you for using "concrete" and "cement" correctly.

It's concrete comments like this that cement our society together!

Anyway, Roman engineering was pretty fantastic. When they did things, the Romans did them! Of course, the is as true for "making deserts and calling them peace" as building aqueducts and breakwaters.....
posted by GenjiandProust at 9:06 AM on June 21, 2013 [5 favorites]


Does this mean construction workers are going to have to start blood-letting into the mixers again?
posted by The 10th Regiment of Foot at 9:07 AM on June 21, 2013 [3 favorites]


I wonder how many other technologies we've lost.

Lost? Or not use for other reasons, such as time or cost? If low lime fly ash concrete takes twice as long to set, it may be worth replacing it in 50 years. Note that most places don't have tons of volcanic ash lying around, unlike Italy with a few active volcanos nearby, and coal fly-ash wasn't really around in any real amount until recently. Also note the cost of shipping such -- it's very much in the class of materials where the cost to ship it is vastly more than the cost to acquire it.

So, for most places, knowing that adding volcanic ash would make the concrete better was useless, because they had none to add.

One of the reasons for concrete's seeming lack of durability in modern times is that it's not concrete, it's reinforced concrete, and if the steel rebar rusts, the expansion shatters the concrete. And, of course, the reason there's a lot of rust in roads and bridges is that we use salt to quickly melt snow and ice on the roads in winter.

However, we use reinforced concrete, because pure concrete is very weak in tension. Steel is very strong in tension, but the thin rods don't offer much strength in compression. Handily enough, though, concrete is very strong in compression.

A full steel bridge would probably be stronger, but would need much more steel, and cost much more money, and would probably require more skilled labor to erect. Pouring modern concretes is quite easy, and the workers in charge of pouring and setting are, in the trades, not responsible for dealing with actually making the mixture, which is quite touchy about proportions. Instead, it's either delivered premixed, or by a truck that correctly mixes it onsite -- and, of course has a guy who knows how to keep it correctly mixing in the truck.

And, of course, most of the Roman Empire had something we in the Northern US don't. They had remarkably mild winters. Roman roads in areas where strong winters are more common fared badly -- just as our modern highways do. The worst thing you can do to a road is dump a bunch of water on it, and then drop it below freezing. The water seeps into the cracks, freezes, expands, and widens the crack further.

Keeping roads in southern Italy in good shape is much easier than keeping roads in the Northern US in good shape.
posted by eriko at 9:11 AM on June 21, 2013 [39 favorites]


I've seen assertions in various places that the Romans had all of the components for steam power, they just never put them together.

I've been toying with the idea of the Adventures of XXth Steam Legion ever since.
posted by Happy Dave at 9:12 AM on June 21, 2013 [11 favorites]


Steam power is limited if your machining and metallurgy aren't up for the job. The Romans could make steam artifacts, but didn't have a ready supply of high quality metal to make pressure boilers nor the machinists capable of making parts of fine tolerances on large scales.

Hand smithy and craftwork can produce wonders, but master craftsman don't scale as well as reproducible machines.
posted by bonehead at 9:15 AM on June 21, 2013 [3 favorites]


To add onto eriko's point - if concrete construction seems to have problems it may be due to the fact that reinforced concrete was an immature technology when it was first being applied after ww2. 60 years is not a very long time to work out the kinks in a new construction method - the Romans, on the other hand, were doing this for what, 300 years? More?

Personally I want to see rammed earth construction on a larger scale. I would love to have a home with 2 foot thick walls that look like the grand canyon.
posted by Teakettle at 9:15 AM on June 21, 2013 [2 favorites]


Don't think of this as a lost technology so much as a replaced technology. The reason we don't use Roman concrete in our construction now isn't because we don't know how, it's because it's not strong enough. Some Roman concrete in Libya compression tested at 200kg/cm2, or 19.6MPa. The strongest stuff we make now is over 70MPa. Compression is the main strength that matters, since no concrete has very much tensile strength unless it's reinforced with steel or something else.

Not to say that there's nothing useful here - it seems the addition of aluminum in concrete helps it resist seawater. Not sure if we're doing that already. Anyway, cool stuff!
posted by echo target at 9:22 AM on June 21, 2013 [4 favorites]


I've seen assertions in various places that the Romans had all of the components for steam power, they just never put them together.

Romans, schmomans. Check out the awesomely named Hero of Alexandria, who invented a steam engine and wind power, amongst other things.
posted by Celsius1414 at 9:25 AM on June 21, 2013 [3 favorites]


I've seen Roman walls in England and Germany that have been standing for 2000 freakin' years. We can't manage to create a concrete sidewalk that lasts two winters without cracking. We suck.
posted by tommasz at 9:29 AM on June 21, 2013 [2 favorites]


Perhaps Edison should have used this mix.
posted by plinth at 9:29 AM on June 21, 2013 [1 favorite]


Instead, it's either delivered premixed, or by a truck that correctly mixes it onsite

Or delivered on trucks as pre-cast, cured pieces.

And, yeah, I thought that Romans pretty much just used pozzolanic concrete and didn't realy get into the portland cement stuff, so that's actually news to me.

A similar thing is being used currently by incorporating fly ash, a byproduct of coal-fired electrical generation, in much the same way as Romans used pozzolanic materials. The fly ash can take the place of some portion of the cement that would be used otherwise, generally improves the workability of the concrete, and actually strengthens it further because the byproducts of typical cement reactions end up feeding the pozzolanic reaction. Plus, you can earn some ground toward a LEED credit for using recycled post-industrial materials.
posted by LionIndex at 9:31 AM on June 21, 2013


And that's what I get for not getting to the end of the article before posting.
posted by LionIndex at 9:34 AM on June 21, 2013 [1 favorite]


tommasz, walls are subject to a lot less wear, environmental or mechanical, than roads and pavements.
posted by forgetful snow at 9:40 AM on June 21, 2013


Stone walls can also be easily repaired, piece by piece, as they crumble. I don't know for sure, but I always assumed that so many Roman city walls are still standing because people continued to maintain them for most of the time between Roman times and today. There's a pretty small gap between the time city walls become obsolete and the time historical preservation societies start springing up.
posted by Sara C. at 9:57 AM on June 21, 2013 [1 favorite]


I've seen Roman walls in England and Germany that have been standing for 2000 freakin' years. We can't manage to create a concrete sidewalk that lasts two winters without cracking. We suck.

In addition to the other caveats people have mentioned about this kind of perception it's worth remembering the enormously distorting survivor effects involved. By definition you don't see all the crappy, shoddily constructed Roman buildings because they've all fallen down long since. Juvenal talks about the shoddy construction of the Roman apartment buildings in his Satires, for example, and how prone they were to collapse.

The Romans had a long, long time to build an awful lot of stuff all over Europe and the near East; some of that is inevitably going to survive down to the present, but that doesn't say all that much, necessarily, about the average quality of Roman construction.
posted by yoink at 10:09 AM on June 21, 2013 [9 favorites]


I wonder how many other technologies we've lost.

Lost? Or not use for other reasons, such as time or cost?


No, straight up lost (#2) in the dark ages, the replacement technology not to be rediscovered for another 800 years.

I looked at the Colosseum in Rome and marveled at what it must have been like to have been part of a generation where no one in the recollection of living history had any idea how it and many of the rotting things around them had been created and how that must have been.
posted by Ogre Lawless at 10:22 AM on June 21, 2013 [5 favorites]


Because Roman concrete is SUPER AWESOME, if anyone is interested there are other studies like The Roman Maritime Concrete Study (ROMACONS): the harbour of Chersonisos in Crete and its Italian connection and on Caesarea with much more bibliographic information and context. If anyone is interested in a scan of the chapter "Technology, innovation, and trade: research into the engineering characteristics of Roman maritime concrete," from Maritime Archaeology and Ancient Trade in the Mediterranean, please let me know. There's a very brief overview of Roman building construction techniques (with really good diagrams/pictures) here. Constructions Techniques of Roman Vaults: Opus Caementicium and the Octagonal Dome of the Domus Aurea, anyone?


The Romans had a long, long time to build an awful lot of stuff all over Europe and the near East; some of that is inevitably going to survive down to the present, but that doesn't say all that much, necessarily, about the average quality of Roman construction.

While it's true that it doesn't say a lot about the average quality of Roman construction, it does say a lot about the quality of many of the larger-scale public works from the Roman period. There are still Roman sewers as well as parts of some aqueduct channels that are in use by people today, 2000 years later. Much of the Roman world is also beset by catastrophic earthquakes, and it's pretty incredible to see that some monuments and larger wall systems are still withstanding that kind of pressure. The Pantheon, even as denuded as it is now, is pretty incredible. There are still multistory apartment buildings from Roman Ostia that are partially extant. Yes, a lot of cheaper buildings were rubbish and have been lost, as have many other systems created from ephemeral materials like wood (aside from where parts of those systems have been preserved, like the amphitheater in London, or the mines in the Rio Tinto.) Juvenal wasn't writing about this kind of concrete or construction.
posted by jetlagaddict at 10:34 AM on June 21, 2013 [7 favorites]


the quality of many of the larger-scale public works from the Roman period.

I personally wonder whether any of our modern major public works will survive half as well as something like the Colosseum. Possibly some of the cathedrals, if they're tended and used the way the medieval cathedrals have been. But we're not good to our infrastructure in the United States, so the bridges and roads and things probably won't last and might not even if the building materials were intended to do so (which I'm not sure they are).
posted by immlass at 10:42 AM on June 21, 2013


I personally wonder whether any of our modern major public works will survive half as well as something like the Colosseum.

Hoover Dam.
posted by Justinian at 10:53 AM on June 21, 2013 [4 favorites]


Modern public buildings, roads and bridges are typically engineered with a specific lifespan in mind, with the expectation that as they wear out, they will be replaced. The motivation is primarily economic, but also utilitarian: why pay for a 1000-year building when your grandkids will probably want to tear down or rebuild in 100 years anyway?

Even though things don't last, the occupants get to have modern buildings rather than old refits. How many of us have cursed old buildings with bad air con and crappy hot water boilers? That's why we don't, generally, build to last now.
posted by bonehead at 11:14 AM on June 21, 2013 [1 favorite]


Yeah, the Romans were not considering planned obsolescence as part of the building process as much as architects do today. It's still shocking to me to see buildings made of concrete being torn down less than half a century after their construction, but my engineer twin sees Roman construction as being somewhat of a waste, so...
posted by jetlagaddict at 11:27 AM on June 21, 2013 [2 favorites]


Lost? Or not use for other reasons, such as time or cost?

In the category "other reasons", there's a story that a clever Roman presented Tiberius with a crystal goblet that would not break. The emperor asked if anyone else knew how this was done. When assured that no one did, Tiberius had the man killed.

Pressure from the Goblet Makers Union, I expect. (Vide Cassius Dio 57.21.7.)

On a less grim note, the Roman ability to carve porphyry was lost for centuries. Or rather, the Roman ability to temper steel hard enough to carve it was lost for centuries.

Yeah, the Romans were not considering planned obsolescence as part of the building process

Maybe not as such, but as yoink notes, there was plenty of shoddy, short term thinking going on back in the day (even Cicero was a slumlord). Big fires, like that during which Nero fiddled, were a constant source of anxiety, so you got it while you could because why bother when it could go up in an instant?

But you could argue that truly bad construction was mostly in the private sphere. When the government wanted to indulge itself (Domus Aurea) or overawe the masses (Pantheon), things were done right.

BTW, there would be more marble facing and even statuary left today were not for the fact that marble, when super heated in the absence of oxygen, creates lime, which is crucial in making cement. Which is what the medievals in need of their own cement did.
posted by BWA at 11:45 AM on June 21, 2013 [4 favorites]


Interestingly, right now I'm listening to "Thors Angels," the Dan Carlin podcast about the European Dark Ages, and the big framing he keeps returning to for understanding the time period is the end of Planet of the Apes, where Charlton Heston sees the Statue of Liberty. A LOT of technologies were lost, and the next thousand years was basically living in the ruins of a great society, without the capability of building it up again because nobody knows how.

Fascinating stuff, and a great post!
posted by Navelgazer at 11:47 AM on June 21, 2013 [4 favorites]


I've seen Roman walls in England and Germany that have been standing for 2000 freakin' years. We can't manage to create a concrete sidewalk that lasts two winters without cracking.

Even more sad; the Inca didn't even need to cheat and use mortar.
posted by The 10th Regiment of Foot at 11:51 AM on June 21, 2013 [2 favorites]


the Inca didn't even need to cheat and use mortar.

Oh, the Romans knew from mortarless construction well enough, as did the Greeks. But in the cost/benefit analysis, and for sheer versatility, cement came out on top.
posted by BWA at 12:04 PM on June 21, 2013 [1 favorite]


But you could argue that truly bad construction was mostly in the private sphere.

Oh, there was probably shoddy concrete and people yelling at Cornelius for building rubbish baths too :). And there's then there's the overlap between "private" and "public" when it comes to some larger-scale Roman works: euergetism, commercial properties...but yes, I was still speaking more to larger-scale public works, not smaller private buildings and complexes with an expectation of a shorter lifespan. Though the fires didn't spare many fine examples of higher-end public buildings too, like the Basilica Iulia.
posted by jetlagaddict at 12:09 PM on June 21, 2013 [2 favorites]


American housing and construction is generally pretty lame. European and middle eastern stuff is generally superior to what we do here. I wonder how much the higher quality over there is due to the Roman influence. Being around quality stuff that has been there forever cannot help but impact how people think about such things, both the makers and consumers. There were just a lot of little touches in Europe that were mindbogglingly user-friendly compared to here.
posted by Michele in California at 1:17 PM on June 21, 2013 [1 favorite]


Very cool.
posted by homunculus at 2:30 PM on June 21, 2013


Yes, lost the way that Ogre Lawless said.

related: things lost from the library of Alexandria. I know we can't keep everything on cuneiform anymore, but what useful technologies do we keep discovering and forgetting?
posted by dreamling at 3:55 PM on June 21, 2013 [1 favorite]


The comments in this thread are why I love Metafilter. Where else could I find so many informed people writing about ancient Roman concrete (and modern, for that matter)?

(I kind of want a rammed-earth house too, teakettle)
posted by emjaybee at 7:51 PM on June 21, 2013 [2 favorites]


I haven't enjoyed reading through a thread this much in weeks. A big hearty thank you to all who contributed - it was very much enjoyed appreciated.
posted by Davenhill at 12:32 AM on June 22, 2013


Share it like Cicero: How Roman authors used social networking
posted by homunculus at 4:53 PM on June 22, 2013 [1 favorite]


See also this article from 1993 on the secrets of Roman concrete that talks about building a dam in Colorado using a similar high pozzolan and low water-to-cementious-materials mix and a lot of manual work (with vibrating rollers in 1993) to work the low-slump concrete into place.

Volcanic ashes are currently used in concrete; there are regions where they are common/standard but they are even used in limited quantities in the United States. Fly ash actually generally has a higher alumina content than most volcanic ash.

I still want to see the actual article in JACerS to see if there actually is a story here beyond the (very interesting!) archaeological/history aspects.
posted by mountmccabe at 7:34 PM on June 23, 2013


« Older In 1985, McDonalds sued left-wing activists in the...  |  Mr Balls is a happy mascot,... Newer »


This thread has been archived and is closed to new comments