Why the Pantheon has not crumbled: Roman concrete mortar used secret ingredient that could reduce

[bemildred]

Carbon Emissions.

Ancient Roman architecture has managed to stand the test of time for 2,000 years because the concrete mortar used for the structures included a secret ingredient, scientists have discovered.

Monuments such as the Pantheon, Colosseum, and Trajan's Markets were built with mortar made from volcanic ash, researchers at the US Department of Energy's Lawrence Berkeley National Laboratory have found.

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"The dense intergrowths of the platy crystals obstruct crack propagation and preserve cohesion at the micron scale, which in turn enables the concrete to maintain its chemical resilience and structural integrity in a seismically active environment at the millennial scale," Jackson said.

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Modern concretes are mostly bound by limestone-based Portland cement, which requires heating to 1,450C – a process that releases an estimated 7% of the total carbon emitted into the atmosphere every year.


http://www.ibtimes.co.uk/why-pantheon-has-not-crumbled-roman-concrete-mortar-used-secret-ingredient-that-could-reduce-1479938

The old ways are best.

[malaise]

1. Well those folks in Montserrat

should be exporting all that ash about now.

Great post - thanks.

[bemildred]

2. Plenty of ash laying around.

My pleasure.

[BKH70041]

3. We tend to scoff at the ways of the ancients.

But we can't scoff at them in person, to their faces, and this is what annoys me. - Jack Handey

[bhikkhu]

29. The old Chinese mortar mixed with sticky rice water was another great innovation, rediscovered

http://news.discovery.com/history/sticky-rice-ancient-chinese-buildings.htm

My own brick house is about 90 years old, and the mortar is in pretty bad shape. There's plenty of 1500 year old mortar in China that's withstood weathering and earthquakes for ages, still doing its job well.

[djean111]

4. Is there a ready supply of volcanic rock that can be used? If so, that's fantastic!

I did laugh about "secret ingredient" and then being told the secret ingredient. The Romans just used what was available - great serendipity, that. I had no idea that those emissions are 7% of the total carbon emissions released each year - that is, honestly, a LOT, in my opinion. Not all that far from 10%, and cutting those emissions down would really mean something. I think cutting emissions will be an accrual of many small cuts and changes across the board, not just the big disgusting belching coal-fired stuff that should be just stopped.

[bemildred]

8. I doubt it was just a matter of convenience.

It might have been a matter of economics, they could not be as profligate with energy as we are. But I would wager they worked it out by experiment, both because they had more than one variety of concrete and because they did not mass produce things iike we do, and thus were not concerned with profit so much as quaiity, so they wouldn't want the cheapest ingredient, but the longest lasting. They built to last. We build in obsolesence for a few years, most things.

[djean111]

14. You are right, of course.

I don't think anything is built to last these days. Just built to successfully withstand lawsuits.

[tanyev]

5. Cool. Marking to read later.

[hobbit709]

6. They also had concrete that didn't deteriorate in salt water.

[FSogol]

7. Sorry, but this is hardly a new discovery. We have known about the use of volcanic ash in concrete

for a long time. Ever been to Venice? Those buildings would be impossible without the addition of volcanic ash added to the concrete. Google "pozzolana" for more info.

BTW,

[bemildred]

9. Well the story is that now they know why. nt

[FSogol]

10. The professor in my Structural Engineering class back in '92 seemed to know why.

So did the text books.

[bemildred]

11. He knew about the "dense intergrowths of the platy crystals"? nt

[NewDeal_Dem]

33. No, it's actually old news too. I learned of it when I was googling around about

mosaic techniques years ago.

Still interesting but not new news.

[bemildred]

36. That's why it's in General Discussion, not LBN? nt

[NewDeal_Dem]

37. I guess so. I was just responding to your statement.

[bemildred]

38. "The old ways are best"?

That's what you got from it? That it's "new news" or something?

Several people have brought that up.

[NewDeal_Dem]

39. No. I got from *your* statement that this was new news in the sense you stated,

"Well the story is that now they know why. nt"

But it's not the case. They knew why before this article came out.

[bemildred]

40. Ah, you think stories are news. nt

[NewDeal_Dem]

44. Unsure why you choose to be combative. Goodbye.

[bemildred]

45. Adios. nt

[Jesus Malverde]

12. Concrete mortar? Lame!

[FSogol]

13. Those crazy Incas!

Those rocks are earthquake proof without the use of mortar.

[Kalidurga]

15. machu picchu?

[Jesus Malverde]

16. Saksaywaman

https://en.wikipedia.org/wiki/Saksaywaman

[bemildred]

17. LOL. +1.

Great shot.

[Scuba]

18. Just amazing!

[packman]

21. Goes to show you

what mankind was capable of doing before the internet, TV, and video games. "Hey, Larry. Let's go out and grind some stones tonight so they fit together without any pissass mortar."

[BeanMusical]

25. Wow, I've always been amazed by these.

[global1]

19. They Need To Start Using It For The Chicago Area Streets......

no more potholes!!!!!!!! Yeah!!!!!!

[FailureToCommunicate]

20. The Pantheon! One of the wonders of that age. Made so well that even the barbarians left it be

Made of (volcanic) concrete, the dome is thicker at bottom tapering to a thiner - open! - circle at the top.



http://www.romanconcrete.com/Article2Pantheon.pdf

[packman]

22. Old news

read about this years ago and several times since. After all, what else could they do with all that volcanic ash after Pompeii?

[eppur_se_muova]

23. Well ... yeah ... I saw this on some TV show ages and ages ago ...

It's well known that you can claim the same discovery several times over ... just look at all the UNLIMITED FUEL FROM SEAWATER!!! threads that get posted, even at DU ...

http://www.democraticunderground.com/10023026131

http://www.democraticunderground.com/112745838

[BeanMusical]

24. I doubt that they used ash from that particular eruption of Mt. Vesuvius.

Pompeii, along with Herculaneum, was destroyed in 79 AD while The Pantheon was built between 27 and 25 BC.

[packman]

26. I never let facts get in the way of my postings

Thanks for the info - regardless, there are quite a number of volcano's, both inactive and active, in Italy to get ash from- 30 or so , with MT. Etna still rumbling.

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

[KitSileya]

42. Sorry, the *original* Pantheon was built by Marcus Agrippa,

The current one is a reconstruction by Hadrian 150 years later.

[CBGLuthier]

27. Gonna see them in two weeks.

Doing a six day journey through Italy before moving to Mauritius. Will be in Rome the first and second of January.

[Odin2005]

28. IIRC most of the ash came from near Mt. Vesuvius.

[MisterP]

30. Byzantium: ooooh, you mean that old recipe? suuuuure you can have it; we have our own now ...

[LibertyLover]

31. Volcanic ash

was also used by the Romans to make their set-up-in-water concrete. It's how they were able to build harbors like Ostia.

[bemildred]

32. Thank you, didn't know that. nt

[joeglow3]

34. Yeah, but whats the profit margin?

[Arugula Latte]

35. The ground bones of barbarians they conquered?

Let's do it here!

[hunter]

41. Then again, the Romans made a lot of cut-down-all-the-trees mortars and plasters too.

It was probably sold at the Roman version of Wal-Mart.

Destroys the forests and doesn't last centuries, but it's cheap!

[bemildred]

43. Yeah, you can't always find volcanic ash handy.

And the Romans were not known for their sensitivity.