What have the Romans ever done for us?
July 6, 2017 11:52 AM   Subscribe

Back in 2014, a research team led by Marie D. Jackson of the University of California at Berkeley showed how the recipe for Roman concrete—a mixture of volcanic ash, lime, and seawater combined with a volcanic rock aggregate—produced a chemical reaction that resulted in super-strong concrete. Trouble is, Jackson’s team wasn’t entirely sure how the Romans managed to facilitate this complex reaction.

In a follow-up study, published this week in American Mineralogist, the researchers have learned that it wasn’t the Romans who facilitated this chemical reaction—at least not directly. Rather, the strengthening process was caused by the steady filtering of corrosive seawater through the concrete over time, which triggered the growth of rare, interlocking minerals that made the material even tougher.
posted by Chrysostom (23 comments total) 70 users marked this as a favorite
 
It's incredible to think of how much information we've lost. A 2000-year old recipe for concrete that's better than anything we make today, just gone. The Antikythera mechanism, gone. Greek fire, Damascus steel, gone.
posted by mhoye at 12:29 PM on July 6 [18 favorites]


Solid post.
posted by the man of twists and turns at 12:44 PM on July 6 [29 favorites]


The irritating thing is that the Romans were just using local materials and noting what worked. No fancy engineering or chemistry.
And, yes, making cement produces a lot of CO2, but when you use it to make concrete the CO2 is reabsorbed.
posted by Bee'sWing at 12:55 PM on July 6 [3 favorites]


Solid post.

Give it another month.
posted by curious nu at 12:56 PM on July 6 [44 favorites]


It's incredible to think of how much information we've lost. A 2000-year old recipe for concrete that's better than anything we make today, just gone. The Antikythera mechanism, gone. Greek fire, Damascus steel, gone.

Woah, there. Information may have been lost, but the idea that there's a lot that's better than anything we make today that's gone isn't really true. Most of what you mention was amazing for the time it was made. For instance, the Antikythera mechanism may have been advanced in the Bronze Age, but we've had mechanical timekeeping engines for several centuries now, and computing machines for going on 300 years. As for Greek fire, napalm is at least as effective, and besides, much of the impact and influence it had on warfare at the time was waaaay overblown. And Damascus steel? Awesome for the time it was made, but most modern steel manufacturing methods can produce superior results on a large scale, and there are a wide variety of materials that are much better.
posted by zombieflanders at 1:01 PM on July 6 [26 favorites]


Huh...I heard that it was catalyzed with blood (most likely cow blood), but maybe that's just the pink stuff...
posted by sexyrobot at 1:06 PM on July 6


MetaFilter: catalyzed with blood
posted by It's Raining Florence Henderson at 1:23 PM on July 6 [6 favorites]


too hard; didn't read
posted by ZenMasterThis at 2:02 PM on July 6 [3 favorites]


In the late eighties, a local news show aired a segment offering a possible breakthrough in concrete technology. The material scientist interviewed said that the Roman concrete may have resisted decay because the volcanic ash used in its construction was so fine that it prevented water from entering into the concrete. The segment then went on to say that modern trash incinerators could supply fine ash to add to concrete, thereby possibly making it far more resistant to moisture. This stuck in my head for decades, popping up every once in a great while. ("Whatever happened to that 'incinerator ash improving concrete' idea? Made sense. Would have been a big win for everyone. Must not have worked. Wonder why...")

So many thanks, Chrysostom, for providing the answer to one of those Stupid Ass Questions that won't go away yet also won't stay in my mind long enough for me to look up the answer.

Also, re: the discussion on lost technologies, "Greek Fire" would be my stripper name. I'm not Greek, but come on. That's a great stripper name. You can imagine the DJ hyping the crowd for me, can't you. "LADIES, HERE COMES THE MAN TO IGNITE YOUR PERSIAN GALLEONS OF LUST WITH HIS INCENDIARY DAAAANCING...GREEEEEK FIYAAAAAAH!"

Not sure what my music would be; have to think on that.
posted by Harvey Jerkwater at 2:17 PM on July 6 [13 favorites]


I believe the song you're looking for is Greeced Lightnin'. What? You can't tell how it's spelled when you're listening to it.
posted by It's Raining Florence Henderson at 3:05 PM on July 6 [4 favorites]


I really hope someone can come up with something commercially useful based on this discovery. I live in a coastal city (New York) that's going to need some new infrastructure to deal with rising seas, even in my lifetime.
posted by Calloused_Foot at 3:48 PM on July 6 [2 favorites]


This microscopic image shows the lumpy calcium-aluminum-silicate-hydrate (C-A-S-H) binder material that forms when volcanic ash, lime and seawater mix. Platy crystals of Al-tobermorite have grown amongst the C-A-S-H in the cementing matrix.

C-A-S-H rules everything around me.
posted by fedward at 4:16 PM on July 6 [2 favorites]


But the acronym was C-R-E-A-M not C-A-S-H?
posted by Talez at 4:59 PM on July 6 [1 favorite]


See, the "C" stands for "cash," and …
posted by fedward at 6:19 PM on July 6 [2 favorites]


So the Gizmodo post notes that this process takes hundreds of years to make Roman concrete as strong as it is. So first, the thing you build has to be strong enough to last for hundreds of years, and then it will last for thousands. Talk about built to last.

But also, it's not clear that the Romans knew about this property. It takes a very long time to develop! Could it even have been developed by trial and error, if the results take centuries to be known? The Romans made the best concrete they could, based on what they had at the time. I'm sure it was decent stuff back then. But the additional property it had, that we have only come to understand recently, was probably not known to them. This is a very unusual, and amazing link from archaeologists to materials scientists.

We are only part way through the process of being able to make this into something that we can use today. We can't exactly rinse concrete with sea water for centuries before using it in an apartment building in Oklahoma City. So the fun part will be finding out if there is another path to creating these minerals within the concrete with a process or ingredient mix that doesn't take nearly as long. Given how much concrete gets used around the world in so many applications, there will probably be some significant resources applied to see if they can figure this out.

Regardless, this is a wonderful example of why history, archaeology, and pure science are worth the resources applied.
posted by thenormshow at 7:44 PM on July 6 [8 favorites]


I'm a bit confused . . . does this only refer to underwater concrete? The paper mentions "marine concrete" but the article seems to be raving about all Roman concrete having unusual strength?

And, yes, making cement produces a lot of CO2, but when you use it to make concrete the CO2 is reabsorbed.

As far as I can tell the better phrasing is "some CO2 is absorbed but not nearly as much used."

If you have a reference suggesting run of the mill concrete absorbs equal amounts as that used in the cement production (for standard industrial production techniques) I'd be curious to read it.
posted by mark k at 9:35 PM on July 6


Does roman concrete work with reinforcing rod?
posted by sebastienbailard at 2:06 AM on July 7


I think only the underwater concrete self-repairs; but Roman concrete is very good. I believe the dome of the Pantheon is still the largest non-reinforced concrete structure of its kind ever created (and my hat is certainly off to whoever could pour a perfect concrete dome that big, presumably in one go, using Roman-level technology).

Somewhere in the Claudius novels Robert Graves talks about the invention of concrete that would set under water - anyone remember?
posted by Segundus at 7:49 AM on July 7 [1 favorite]


A search on the text of the two books didn't find anything very detailed about concrete, though there were a couple of mentions in the second book. I know I read some good stuff about Roman concrete sometime in the 90s, but it looks like it wasn't from Graves.

Whatever it was, it's probably in this list of Roman concrete references somewhere. (And finding this delightful work from a retired engineer makes me really glad I did that search. So much fun!)
posted by asperity at 9:11 AM on July 7


Previously.
posted by mountmccabe at 5:43 PM on July 7


("Whatever happened to that 'incinerator ash improving concrete' idea? Made sense. Would have been a big win for everyone. Must not have worked. Wonder why...")

I don't know if this is the same thing but: silica fume, a byproduct of silicon smelting which increases the strength of concrete and is an extremely fine powder
posted by XMLicious at 4:44 AM on July 8 [1 favorite]


I've seen her talk and I love her and I love this so much.
posted by you must supply a verb at 5:09 AM on July 8


Harvey Jerkwater: "Whatever happened to that 'incinerator ash improving concrete' idea? Made sense. Would have been a big win for everyone. Must not have worked. Wonder why..."

Maybe because fly ash is cheap, consistent and pozzolan so it can actually reduce the amount of portland cement required (which also reduces the embodied energy of the concrete).
posted by Mitheral at 6:53 AM on July 8 [2 favorites]


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