Study confirms Romans used “hot mixing“ to make concrete

Latest results from a recently discovered ancient Roman construction site confirm earlier findings.

See full article...

 

[DCStone]

Let's not forget that they knew lead was bad for them, but used it in cosmetics and water supply anyway.

That probably effected the wealthy morethan the poor.

And food, as a sweetener... and likewise affecting the wealthy more.

 

[S-T-R]

A lot of it is rubble because of many wars over the centuries.

Earthquakes are a bigger issue. Most of the Roman forums fell in the 8th century in a series of quakes. Hagia Sophia probably would have fallen already if not for interventions by the Byzantine, Latin, and Ottoman states after numerous quakes.

It's not a coincidence that most extant, intact Roman buildings spent most of the last millennia as churches. People repair things that still have use and the fora and secular basilicas simply outlived the state that built them. The Pantheon and the Curia Julia (Senate house on the Roman forum) survived precisely because of late antique conversions.

It gets even more complicated than that. For example, Mary Beard's docuseries on the Romans showcased a cemetery in Rome containing many graves of those who'd been slaves and ended up as citizens. But she also highlighted that life expectancy in Rome (particularly the outskirts) was brutally short because living conditions led to widespread and frequent infectious disease outbreaks, particularly of the respiratory kind. In short, Rome needed those people to become citizens just to keep the wheels of commerce in the city running.

By the time the empire fell, slavery had all but vanished. End result of both Christianization and (more practically) the fact that the empire hadn't conquered anyone in centuries. No prisoners of war = nothing on the intake side.

 

[ranthog]

It gets even more complicated than that. For example, Mary Beard's docuseries on the Romans showcased a cemetery in Rome containing many graves of those who'd been slaves and ended up as citizens. But she also highlighted that life expectancy in Rome (particularly the outskirts) was brutally short because living conditions led to widespread and frequent infectious disease outbreaks, particularly of the respiratory kind. In short, Rome needed those people to become citizens just to keep the wheels of commerce in the city running.

Keep in mind it is a pretty recent change in Europe the towns and cities aren't a negative demographic sink.

 

[CarrerCrytharis]

Good to know they’ve found concrete evidence…

 

[TauCeti]

Well she cant be crucified because her owner is displeased. Nor can her children be sold to a brothel.

Only non-roman citizens were crucified, fwiw.

 

[Anonymous Chicken]

Remember that up to 40% of people in the Roman Republic/Empire were enslaved. It's great to talk about all the wonders of the Roman world, and they did do a lot, but don't romanticize them too much.

Holy crap man, is slavery even in the top 5 ways the Romans do not meet modern standards? Off the top of my head, they were permanently on unprovoked conquest of everything they could reach, entertainment was having people kill each other in public, army discipline gave us the word "decimated", they burned cities, salted fields, slaughtered people as collective punishment, and carried out every possible version and feature of genocide.

 

[zeroplusone]

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


"Brought peace?"


Umm self healing concrete?

They started the globalization of domesticated cats. That's enough for me.

 

[Veritas super omens]

'It is the duty of a good shepherd to shear his sheep, not to skin them.' Tiberius

"Shear his sheep"? Is that the eupemism he used to describe his activities with young boys on Capri?

 

[Gandoron]

I thought one of the key aspects in the recipe was using "sea water", eg. salt water instead of fresh water.

 

[rochefort]

We almost never get original copies from antiquity. The Dead Sea Scrolls being perhaps the most famous exception, but there are others. They're rarely intact. Even what we do have rarely predate Constantine. Preserving writing is an active process. Copies of crumbling, aging texts had to be continuously made for posterity. If a work fell out of vogue for even a generation, it was usually lost forever.

Extant copies start becoming a lot more common as you exit late antiquity and enter the early medieval (~9th c) Most of the Latin classics come to us via medieval monks. Greek works largely survived via the Romans themselves in Constantinople. The empire lasted just long enough for early Renaissance writers to come east looking for classics.

It's why the Library of Herculaneum is so exciting. Hundreds of original antique scrolls, potentially including works quoted in surviving texts, but lost in their entirety. Unfortunately, so far we've only uncovered uninteresting philosophical commentary. Still, one can still hope to (e.g.) find the missing books of Livy, or even better, the writers he used to construct his history.

I'm holding out hope for the rest of Polybius' Histories, as well as his other works.

 

[rochefort]

It's not just "quicklime" which you can get today, but is fine and has none of the aggregate.

That's why they're doing research; people would like to know which key(s) would unlock 2000 year concrete that survives constant sea waves. And it's not just that somebody has found the key. There are multiple teams following multiple lines of research reporting success. So it could be the lime clasts in the quicklime... or something else. I'm unfortunately struggling to find the primary other strain of promising research.

This is one place to look: Unlocking the secrets of Al-tobermorite in Roman seawater concrete

 

[rochefort]

And not just political disagreements. Those elites were subject to the same lack of sanitation, poor medical care, high infant and maternal mortality, parasites and pestilence as was the rest of the population. And they couldn't even put tomato sauce on their pizza!

Don't forget the lead poisoning!

Edit: Ninja'd

 

[Albino_Boo]

Only non-roman citizens were crucified, fwiw.

Oh for god sake, slaves were not citizens. They had no rights.

 

[Albino_Boo]

It gets even more complicated than that. For example, Mary Beard's docuseries on the Romans showcased a cemetery in Rome containing many graves of those who'd been slaves and ended up as citizens. But she also highlighted that life expectancy in Rome (particularly the outskirts) was brutally short because living conditions led to widespread and frequent infectious disease outbreaks, particularly of the respiratory kind. In short, Rome needed those people to become citizens just to keep the wheels of commerce in the city running.

There was a different market for slaves with administrative and literary skills than the ones with manual labour. Tyro, Cicero's secretary had all the skills needed to work as a secretary when he was sold by his parents. The 1 million slaves sold by Caesar end up in the mines, agricultural estates or in the galleys. There was no freedom for them and their life expectancy was terrible. Even house slaves suffered from the fact they had no rights. They could be are were raped and faced the risk of arbitrary death. Servilia, the mother of Brutus, killed her chef be forcing him to eat hot coals. You also crucified all the men women and children who worked in one of her villas.

 

[AlexisR200X]

One thing I have wondered about is whether standardization was such a widespread concept at all for ancient civilizations in terms of formulas for construction. The likelihood of a single exacting formula for concrete being used across an entire civilization kinda hinges on the concept. It required widespread disemination of information that more or less was equivalent to modern trade secrets. More importantly, strict adherence by crews all across the Roman empire. I think its reasonable to think that there could have been at least several variations of the formula in use. (Materials availability being an easy reason to imagine for adapting the formula to use different and more readily available resources on different areas.)

 

[dragoninnaMINI]

Well she cant be crucified because her owner is displeased. Nor can her children be sold to a brothel.

Or used by the owner for their own sexual pleasure, whether mom or kids.

 

[SixDegrees]

One thing I have wondered about is whether standardization was such a widespread concept at all for ancient civilizations in terms of formulas for construction. The likelihood of a single exacting formula for concrete being used across an entire civilization kinda hinges on the concept. It required widespread disemination of information that more or less was equivalent to modern trade secrets. More importantly, strict adherence by crews all across the Roman empire. I think its reasonable to think that there could have been at least several variations of the formula in use. (Materials availability being an easy reason to imagine for adapting the formula to use different and more readily available resources on different areas.)

As others have mentioned, survivor bias is also likely. We're astounded by the buildings that have survived, but not so much by the probably much larger number of buildings that didn't and have collapsed into rubble over the years. It's likely, as you suggest, that actual formulations and practices varied widely, but only some small portion of those were in the part of the variation that lasted a long time more by luck and happenstance than by planning.

 

[chateauarusi]

And pilfering for newer construction.

I live in a village in Europe that just happens to have a castle on its outskirts. The castle was originally built in the 13th century, and is now partially in ruins. When we get visitors from the States, we usually take them to see and explore the castle. Based on the missing roof and the broken walls, our visitors almost always assume there was some sort of battle here.

But if you know anything about medieval architecture, you can tell at a glance that this is unlikely. The castle's stone walls are fairly thin, around half a meter, and there are several ground-floor windows. This is obviously not the "fortress" type of castle, it's just a big fancy house for the local lord — i.e. a château.

And then you look around the neighborhood, and you see how many nearby houses have yards bounded by low walls that have clearly been in place for hundreds of years, built out of stones which look remarkably similar to the stones in the ruined castle.

History is fun.

 

[Albino_Boo]

One thing I have wondered about is whether standardization was such a widespread concept at all for ancient civilizations in terms of formulas for construction. The likelihood of a single exacting formula for concrete being used across an entire civilization kinda hinges on the concept. It required widespread disemination of information that more or less was equivalent to modern trade secrets. More importantly, strict adherence by crews all across the Roman empire. I think its reasonable to think that there could have been at least several variations of the formula in use. (Materials availability being an easy reason to imagine for adapting the formula to use different and more readily available resources on different areas.)

Southern Italy has easy access to volcanic tephra, I doubt very much that it was hauled over the Alps by cart into Gaul and beyond or sent by ship and cart to the Caucasus. I strongly suspect that local aggregates were used in construction.

 

[AverageDutchGuy]

Hot mixing is mentioned a few times without being clearly defined. Could you potentially include that in the text above? It would make things easier to understand. You mention how Portland cement is made, but not what hot mixing is and how it differs from other approaches. I looked it up, and it is interesting. I think it would be a worthy addition.

https://www.buildingconservation.com/articles/hot-mixed-mortars/hot-mixed-mortars.htm

I had the exact same comment and found the exact same link. Indeed it would have been helpful even if they'd just add the below excerpt:

A hot-mixed lime mortar is one based on three components: quicklime, water and an aggregate such as sand. In a conventional mix, aggregate is mixed with lime which has previously been slaked. In this case, quicklime is mixed with the aggregate and then ‘slaked’ with water. The process generates heat, hence the terms. It may be used immediately as a hot mix or later when cool.

 

[AverageDutchGuy]

Good to know they’ve found concrete evidence…

They started the globalization of domesticated cats. That's enough for me.

I never knew the romans were the first to be used by cats for the global cat distribution system and world domination. Learned something new today.

 

[yyz.Wino]

Remember that up to 40% of people in the Roman Republic/Empire were enslaved. It's great to talk about all the wonders of the Roman world, and they did do a lot, but don't romanticize them too much. In many ways, they were brutal people and often only very few who were wealthy enough could benefit from all those wonders. Even those people still often ended up dying in unspeakably nasty ways if they came out on the wrong end of a political disagreement.

One of the things that I was dumbfounded by in that blog post that I link to above is that the life expectancy of people living in Britain went up after the Romans left. If true that's not the sign of a civilization that is unambiguously benefits its people.

pretty much where the US is heading towards!

 

[FranzJoseph]

They started the globalization of domesticated cats. That's enough for me.

Didn't that start well before the Roman Empire? The cat burial on Crete (or was it Cyprus?) is IIRC from 10,000BCE give or take a few thousand years.

And domestic cats in China haven't arrived well after the (western) Roman Empire ended, 700CE or so. The Chinese still had their own semi‑domesticated commensal cats much earlier, but that was a different genus (leopard cat).

 

[original_mds]

Maybe it's me being tired, but I don't recall the article addressing the fact that the analysis of the construction site concluded that they used volcanic ingredients.

I.e. the construction site located in a city famously buried by volcanic materials so quickly and completely that large numbers of its occupants were killed in place.

Did they address the elephant in the room and I just missed it?

 

[10Nov1775]

Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray's case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the "wet streets cause rain" stories. Paper's full of them.
In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.”― Michael Crichton

The talk about how Vitruvius got the details wrong reminded me of this quote. He wasn't an expert writing a technical manual for people in the trade. You can't expect him to be perfect at everything.

Funnily enough, Crichton chose the exact wrong subjects to use for his point. National or international affairs are exactly the subjects that journalists DO tend to be experts on—at least, those that report on those areas do.

Which isn't to say that journalists are never ignorant of course—and I'm reminded myself of Terry Pratchett's comment that most journalism seems to be written from the perspective that the world would be a better place if it were run by journalists, which he notes is "hilarious", if memory serves.

It's extra funny when you know that Pratchett was a journalist until his novels hit it big. So it's charmingly self-deprecating in addition to bitingly accurate.

 

[Albino_Boo]

Maybe it's me being tired, but I don't recall the article addressing the fact that the analysis of the construction site concluded that they used volcanic ingredients.

I.e. the construction site located in a city famously buried by volcanic materials so quickly and completely that large numbers of its occupants were killed in place.

Did they address the elephant in the room and I just missed it?

The tomb on the Appian way is around 250 miles North of Pompeii and uses the same construction. The Alban hills south of Rome are the remains of dormant Volcanos that last erupted 260,000 years ago, which the Appian way runs through. You also take samples by drilling into the concrete and the structure is the same all the way through

 

[10Nov1775]

I mean, Masic should know, having also worked on a publication Masic was also a co-author of a 2021 study that:

• Some items will be known by the author but left out for reasons of brevity and scope
• No author will know every detail in a given field

That's in addition to the way that practices in the field will eventually deviate from the documentation, especially given distance and time, and that the Roman Empire was both big and long-lived.

Unless their research has evidence that Vitruvius lived in a time and place where the hot-mixing process was used to produce a specific type of concrete, set out to describe that particular type, and then failed to do so, it seems just as likely that (independent of the chain of custody/transcription issue noted above), Vitruvius could have just as easily been accurately describing a similar, but different concrete that uses the same name.

Name collisions are pretty common. Look at the sweet potato/yam nomenclature or all the different fruits/plants called 'custard apple' https://en.wikipedia.org/wiki/Custard_apple

It's ironic how reverent he is for a (sort of) historical forebear.

Real historians are inordinately fond of hot-take dismissals of ancient sources for no good reason, a practice that, as far as I can tell, has more to do with trying to stand out in a crowded academic specialty than any grounded skepticism.

(I say this, in part, because it is especially common, almost ubiquitous, for Roman history and documents, especially—along with biblical history, where dismissals of buildings and structures and locations as fictitious have been quite common, often at the same time as some archeologist or other was busily digging up structures that confirmed to those descriptions, which emphasizes the fact the initial dismissals were groundless, and not based on any evidence.)

I almost feel sorry for the historians who feel compelled to catalogue these hot takes by their colleagues in any discussion of the subject.

(Various notes to prevent misinterpretation: I'm not a Christian, attach no special importance to the Bible, have no animus towards history or historians, do not believe that what historians do is worthless or without value, etc.)

 

[Gort42]

For a decent period, they did bring peace to 40 million or so people.

They made a desert and called it peace.

 

[Wheels Of Confusion]

Funnily enough, Crichton chose the exact wrong subjects to use for his point.

Also, he went to his grave being a staunch global warming denialist.

 

[10Nov1775]

I'm kind of interested in the chain of custody for the translation - is there a primary text that someone can go back to and do another translation, or is this one of those deals where you're working from a copy of a copy?

Edit: Did a little reading and it seems that it is in fact copies-of-copies, with one of the earliest extant being from the 9th century - so about eight hundred years after Vitruvius was around and writing. It was also missing most of the illustrations, which apparently some folks think that they might have contained some much needed additional context. Maybe some of that context was showing hot mixing.

Literally all Roman documents, unless chiseled on stone somewhere, are copies-of-copies. To the best of my knowledge, we don't have originals for any of it, even the very late stuff.

I'd add that it would really be quite difficult to know if you had an original, anyway. Unless you have some really unique marker, like a jealously guarded, exclusive ink recipe used by exactly one emperor's scribes, or some equally lucky happenstance, you can usually deduce that something is a later copy, but not confirm whether it is an original or not.

The reality of these copy-of-a-copy manuscripts is also decidedly odd, since it contradicts our naive instincts in either direction:

Yes, copies of ancient manuscripts are riddled with small errors, but also not nearly as many as you might expect. Text transmission is surprisingly good. Most of the meaningful deviations aren't copying mistakes or due to the vagaries of the copying process, but instead are due to later copyists/distributors/would-be editors taking it upon to themselves to "improve" or "fix" the work they copied.

(That's probably my favorite scribal error, where a later writer introduces a defect due to believing, from their limited historical knowledge, that a prior author has erred, leading them to "fix" what they think the ancient writer got wrong about their own world, lol.)

 

[icypioneer]

The discussions over interpretating Vitruvius' recipe for concrete reminds me of the difficulties in interpreting some ancient or medieval cooking recipes--many seemed to expect the reader to know what or how to do something without needing to quantify, explain, or even mention it.

 

[Albino_Boo]

Literally all Roman documents, unless chiseled on stone somewhere, are copies-of-copies. To the best of my knowledge, we don't have originals for any of it, even the very late stuff.

I'd add that it would really be quite difficult to know if you had an original, anyway. Unless you have some really unique marker, like a jealously guarded, exclusive ink recipe used by exactly one emperor's scribes, or some equally lucky happenstance, you can usually deduce that something is a later copy, but not confirm whether it is an original or not.

The reality of these copy-of-a-copy manuscripts is also decidedly odd, since it contradicts our naive instincts in either direction:

Yes, copies of ancient manuscripts are riddled with small errors, but also not nearly as many as you might expect. Text transmission is surprisingly good. Most of the meaningful deviations aren't copying mistakes or due to the vagaries of the copying process, but instead are due to later copyists/distributors/would-be editors taking it upon to themselves to "improve" or "fix" the work they copied.

(That's probably my favorite scribal error, where a later writer introduces a defect due to believing, from their limited historical knowledge, that a prior author has erred, leading them to "fix" what they think the ancient writer got wrong about their own world, lol.)

Theres a whole world of textual analyses and by comparing different copies and spotting the differences and by understanding how othrography of varies over time you can make strong cases for the content original texts. Transliteration into modern languages is whole other argument. In the off chance anyone is intrigued by how people worked back through the errors to get towards the original text this is a good article on the subject
https://antigonejournal.com/2021/09/apparatus-criticus/

 

[ranthog]

It's ironic how reverent he is for a (sort of) historical forebear.

Real historians are inordinately fond of hot-take dismissals of ancient sources for no good reason, a practice that, as far as I can tell, has more to do with trying to stand out in a crowded academic specialty than any grounded skepticism.

(I say this, in part, because it is especially common, almost ubiquitous, for Roman history and documents, especially—along with biblical history, where dismissals of buildings and structures and locations as fictitious have been quite common, often at the same time as some archeologist or other was busily digging up structures that confirmed to those descriptions, which emphasizes the fact the initial dismissals were groundless, and not based on any evidence.)

I almost feel sorry for the historians who feel compelled to catalogue these hot takes by their colleagues in any discussion of the subject.

(Various notes to prevent misinterpretation: I'm not a Christian, attach no special importance to the Bible, have no animus towards history or historians, do not believe that what historians do is worthless or without value, etc.)

That is a rather silly hot take. For one, it is necessary to take many documents skeptically, because they were recorded and passed on for a reason. Often, they were written for political reasons, including propaganda. There is a reason why Herodotus was known as the father of history as well as the father of lies.

A huge challenge once you get down to ancient history is the lack of sources. On a good day you might have multiple sources, but often you may just have one. Sometimes we have no contemporary sources with the events in question.

The bible is a pretty terrible example, because it is not a historical text. Being skeptical of something in it being true does not mean that your dismissal was groundless. It means there was a lack of evidence for it. Not to mention that just because a place exists doesn't mean that the document is accurately recording history. Egypt exists, but the exodus as written isn't particularly plausible based on archeological finds so far. (It is possible it has historical truths behind it, but the story clearly drifted away from historical truth and into just religious truth.)

Probably most importantly, just because an author described a location that exists doesn't necessarily mean the work is reliable or accurate. There are a lot of extremely flawed documents that are still valuable, but not because they give us an accurate picture of what happened.

 

[FranzJoseph]

That is a rather silly hot take. For one, it is necessary to take many documents skeptically, because they were recorded and passed on for a reason. Often, they were written for political reasons, including propaganda. There is a reason why Herodotus was known as the father of history as well as the father of lies.

A huge challenge once you get down to ancient history is the lack of sources. On a good day you might have multiple sources, but often you may just have one. Sometimes we have no contemporary sources with the events in question.

The bible is a pretty terrible example, because it is not a historical text. Being skeptical of something in it being true does not mean that your dismissal was groundless. It means there was a lack of evidence for it. Not to mention that just because a place exists doesn't mean that the document is accurately recording history. Egypt exists, but the exodus as written isn't particularly plausible based on archeological finds so far. (It is possible it has historical truths behind it, but the story clearly drifted away from historical truth and into just religious truth.)

Probably most importantly, just because an author described a location that exists doesn't necessarily mean the work is reliable or accurate. There are a lot of extremely flawed documents that are still valuable, but not because they give us an accurate picture of what happened.

As well as even if you have sources, they are almost invariably written by wealthy male aristocrats, and only from their point of view. There might be a nice surviving treatise in how to "run" a Roman aristocratic villa (i.e. how many slaves it needs et cetera), but it won't tell you how the actual day to day running is done, as that would be the purview of the maior domus and his servants, i.e. all slaves who don't exactly have the free time to indulge in writing literature.

 

[Albino_Boo]

It's ironic how reverent he is for a (sort of) historical forebear.

Real historians are inordinately fond of hot-take dismissals of ancient sources for no good reason, a practice that, as far as I can tell, has more to do with trying to stand out in a crowded academic specialty than any grounded skepticism.

(I say this, in part, because it is especially common, almost ubiquitous, for Roman history and documents, especially—along with biblical history, where dismissals of buildings and structures and locations as fictitious have been quite common, often at the same time as some archeologist or other was busily digging up structures that confirmed to those descriptions, which emphasizes the fact the initial dismissals were groundless, and not based on any evidence.)

I almost feel sorry for the historians who feel compelled to catalogue these hot takes by their colleagues in any discussion of the subject.

(Various notes to prevent misinterpretation: I'm not a Christian, attach no special importance to the Bible, have no animus towards history or historians, do not believe that what historians do is worthless or without value, etc.)

An awful lot of writing about history isn't about history but trying to give historical justification for a current world view. The 18th century Enlightenment historians were using classical texts to justify there own political ascendancy as a new golden age. Which is was perfectly true as long as a you were a rich white man. If you weren't one those, things were not so golden. In recent times we had everything was about class, then climate change and now everything is about gender and race. In 20 years time it will be something different again. There are fashions and cycles of interpretations. Its archeology and more recently science thats have pushed history up against hard facts. The last 50 odd years the main view has been that people adopted a cultural package rather than large scale migrations but PCR testing of ancient DNA has proved that migration and population replacement happened.

 

[Tom the Melaniephile]

It makes me wonder if adding quicklime to modern concrete would produce similar self-healing properties.

Only if it resulted in embedded lime clasts (ie, chunks) which are the functional "healing" component in the resulting concrete.

 

[ranthog]

As well as even if you have sources, they are almost invariably written by wealthy male aristocrats, and only from their point of view. There might be a nice surviving treatise in how to "run" a Roman aristocratic villa (i.e. how many slaves it needs et cetera), but it won't tell you how the actual day to day running is done, as that would be the purview of the maior domus and his servants, i.e. all slaves who don't exactly have the free time to indulge in writing literature.

A good examples is that a lot of the surviving writings about a lot of emperors that we have were written during the reign of the people who murdered them. How do you separate what actually happened from slander intended to justify the murder?

 

[Tom the Melaniephile]

Literally all Roman documents, unless chiseled on stone somewhere, are copies-of-copies. To the best of my knowledge, we don't have originals for any of it, even the very late stuff.

Then you will be pleased to learn that while information recovery is still in very early days, over 1800 carbonized scrolls from 79AD were recovered from Herculaneum.

It's unfortunate that so many have been destroyed since discovery.

 

[Snark218]

Good to know they’ve found concrete evidence…

jesus dad