from the Roman-concrete-lasts-2000-years...-why-not-our-roads? dept.
The story of concrete is so ancient that we don't even know when and where it begins. It is a story of discovery, experimentation, and mystery. Emperors and kings became legends for erecting great concrete structures, some of which are still a mystery to engineers today. Many of history's most skilled architects found inspiration in slabs of the gray building material. Common bricklayers advanced the technology, and a con man played a crucial role in the development of concrete recipes.
Today, the world is literally filled with concrete, from roads and sidewalks to bridges and dams. The word itself has become a synonym for something that is real and tangible. Press your handprints into the sidewalk and sign your name to history. This is the story of concrete.
[...] Let's get this out of the way right here: cement and concrete are not the same thing. Cement, a mixture of powdered limestone and clay, is an ingredient in concrete along with water, sand, and gravel.
So ubiquitous and fundamental, that nobody thinks about it. Its inventor is unknown, but that person changed history.
Related: Volcanic Rocks Resembling Roman Concrete Explain Record Uplift in Italian Caldera
Roman Concrete Explained
Related Stories
Fiber-reinforced rocks discovered at the site of Italy's dormant Campi Flegrei volcano are similar to a wonder-material used by the ancients to construct enduring structures such as the Pantheon, and may lead to improved construction materials.
...
Once again, the drill cores provided the crucial clue. The samples showed that the deep basement of the caldera—the "wall" of the bowl-like depression—consisted of carbonate-bearing rocks similar to limestone, and that interspersed within the carbonate rocks was a needle-shaped mineral called actinolite."The actinolite was the key to understanding all of the other chemical reactions that had to take place to form the natural cement at Campi Flegrei," said Kanitpanyacharoen, who is now at Chulalongkorn University in Thailand.
...
Pozzuoli was the main commercial and military port for the Roman Empire, and it was common for ships to use pozzolana as ballast while trading grain from the eastern Mediterranean. As a result of this practice, volcanic ash from Campi Flegrei-and the use of Roman concrete-spread across the ancient world. Archeologists have recently found that piers in Alexandria, Caesarea, and Cyprus are all made from Roman concrete and have pozzolana as a primary ingredient.
Interesting stuff, and somewhat reminiscent of the discovery that Damascus steel was so strong because the process created carbon nanotubes.
Non-javascript version of the story is available at: http://news.stanford.edu/news/2015/july/concrete-roman-volcano-071015.html
Original Submission
Researchers have unlocked the chemistry of Roman concrete which has resisted the elements for thousands of years.
Ancient sea walls built by the Romans used a concrete made from lime and volcanic ash to bind with rocks.
Now scientists have discovered that elements within the volcanic material reacted with sea water to strengthen the construction.
[...] This new study says the scientists found significant amounts of tobermorite growing through the fabric of the concrete, with a related, porous mineral called phillipsite.
The researchers say that the long-term exposure to sea water helped these crystals to keep on growing over time, reinforcing the concrete and preventing cracks from developing.
Source: BBC News
American Mineralogist DOI: 10.2138/am-2017-5993CCBY
Rice University scientists have developed micron-sized calcium silicate spheres that could lead to stronger and greener concrete, the world's most-used synthetic material.
To Rice materials scientist Rouzbeh Shahsavari and graduate student Sung Hoon Hwang, the spheres represent building blocks that can be made at low cost and promise to mitigate the energy-intensive techniques now used to make cement, the most common binder in concrete.
The researchers formed the spheres in a solution around nanoscale seeds of a common detergent-like surfactant. The spheres can be prompted to self-assemble into solids that are stronger, harder, more elastic and more durable than ubiquitous Portland cement.
[...] The work builds on a 2017 project [DOI: 10.1021/acsami.7b12532] [DX] by Shahsavari and Hwang to develop self-healing materials with porous, microscopic calcium silicate spheres. The new material is not porous, as a solid calcium silicate shell surrounds the surfactant seed.
Size- and Shape-Controlled Synthesis of Calcium Silicate Particles Enables Self-Assembly and Enhanced Mechanical and Durability Properties (DOI: 10.1021/acs.langmuir.8b00917) (DX)
Related: Biologists Create Self-Healing Concrete
Probing Ways to Turn Cement's Weakness to Strength
Roman Concrete Explained
The Rock Solid History of Concrete
Fungi Can Help Concrete Heal Its Own Cracks
(Score: 1, Insightful) by c0lo on Tuesday October 17 2017, @10:10AM (5 children)
Btw, do we know the inventor of the fire? No? How about the wheel? (as invention, not innovation [newscientist.com]). Still no?
How about the inventor of crispy bacon? Ok, ok, I got it, it's the same no.
Then why the hell are you so sure it was invented only once and by a single person?
And why should we wonder the inventors remain unknown?
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by nobu_the_bard on Tuesday October 17 2017, @12:40PM (2 children)
More importantly, how do you know they weren't all the same guy?
(Score: 2) by curunir_wolf on Tuesday October 17 2017, @08:04PM
I am a crackpot
(Score: 2) by c0lo on Tuesday October 17 2017, @08:31PM
Mmmm... perhaps. If you look at the history [wikipedia.org], one can't exclude the forefather of our aristarchus being involved across centuries and geographies, so maybe you are right.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by HiThere on Tuesday October 17 2017, @02:23PM
Given the existence of hardpan, I think it's quite safe to say that concrete wasn't invented, but rather evolved. Particular formulations were invented by different people, some of whom are known. But concete covers a wide variety of formulations.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Tuesday October 17 2017, @06:30PM
I blame Ja Rule.
(Score: 1, Funny) by Anonymous Coward on Tuesday October 17 2017, @10:14AM (2 children)
There was even a documentary about it a few years ago.
It was in fact someone who worked a lot with rocks, in a quarry.
See here http://www.imdb.com/title/tt0109813/. [imdb.com]
(Score: 0) by Anonymous Coward on Tuesday October 17 2017, @07:00PM
Called it, clicked on link.
Was not disappointed.
(Score: 2) by rylyeh on Wednesday October 18 2017, @12:08AM
"Hey - I know that guy..."
"a vast crenulate shell wherein rode the grey and awful form of primal Nodens, Lord of the Great Abyss."
(Score: 2, Interesting) by Anonymous Coward on Tuesday October 17 2017, @10:36AM (10 children)
(Score: 4, Insightful) by VLM on Tuesday October 17 2017, @12:27PM (5 children)
That's very urban legend. I've seen a lot of concrete from a sailboat. Just google up concrete and seawater. There's a great corps of engineers paper just a short step above "popular science level" from '64 that comes up high in results, for example, but there's plenty of stuff out there.
You can make tough long lived boats out of concrete. They're a little heavy, therefore not terribly popular.
There are modern civilization forces that lead to short lived concrete, but its the same problem we have with roads. Road construction companies only make money when they're working so "force is applied" until roads are built to fail quickly enough to keep the construction company busy but not ridiculously busy. Also good old fashioned corruption WRT stuff designed to a higher standard and built to a lower one. In that way you can see plenty of failed concrete.
There is also the typical urban legend issue where the last surviving log cabin from 700 years ago looks really well made and amazing chemistry and woodworking because it was the best of breed 700 years ago and you need to carefully not notice that everything else from that era has fallen apart. Likewise, yes, 99.99% of modern housing isn't going to make it 700 years but the very best house on the planet from this century might make it 700 years, sure, at which point in 2700 AD they're gonna comment on how great construction was in 2010s and all the buildings today in 2710 are crap that falls apart. Well, yeah, but you didn't see the millions of mcmansion that crumbled to dust in the 2030s or whatever.
(Score: 2, Informative) by Anonymous Coward on Tuesday October 17 2017, @12:57PM (2 children)
Please read what the GP said earlier more carefully. Modern Portland cement-based concrete can last submerged in seawater, perhaps for decades as has been stated, but not for the thousands of years that Roman concrete has been known to last. I don't think there is a ship of any construction that can still be said to be seaworthy for more than a hundred years, at least not without replacement of nearly every key component, so yes, you can probably build a ship out of modern concrete that will last for a few decades. Doesn't change the fact that some Roman concrete has lasted for more than two thousand years.
Indeed, the Romans must have built plenty of shoddy structures back in their day too, but that doesn't make what they did build that managed to withstand the test of time any less remarkable. And any house built today that survives to 2710 will be of interest to any of the archaeologists of that future era for the same reason.
(Score: 2) by rylyeh on Wednesday October 18 2017, @12:12AM
Yes! The secret of was only very recently understood - all should read the above about the Roman Concrete.
"a vast crenulate shell wherein rode the grey and awful form of primal Nodens, Lord of the Great Abyss."
(Score: 2) by VLM on Thursday October 19 2017, @12:36PM
In all honesty you're right AC I made a low quality post.
This concrete thing was all figured out well over half a century ago. Take for example USAR Corps of Engineers paper 6-690 "Effects of seawater on concrete" linked:
https://www.dtic.mil/dtic/tr/fulltext/u2/739563.pdf [dtic.mil]
(I hope dtic isn't paywall for general public. If it is, this is a 50 yr old paper, just google for it there's copies afloat out there)
Yes its true that a century or two ago liberal arts types noticed Romans had a really nice concrete that lasted forever (or rephrased, the concrete we still see was the subset of concrete which was capable of lasting forever) and some/most cheap concrete of the "modern" era didn't last long. And that has gotten copied liberal arts style for a century or two up to today. So to todays date there's mysticism about roman concrete solely from the liberal arts side of academia.
But the engineers figured it all out a long time ago, and for well over half a century its "easy" to spec non-bottom of the barrel concretes with specific aggregates that will last eternally in seawater.
I guess a good /. car analogy would be something like historians going on about the Ford model T engine being about 3 liter inline four, and producing about 20 HP, as the pinnacle of technology today in 2017, meanwhile modern (post 1940s?) automotive engineers are laughing at those specs and claims.
(Score: 4, Interesting) by Nuke on Tuesday October 17 2017, @01:21PM
The reason most present-day concrete structures will eventually fall apart is that they use steel re-inforcement, which will rust away. Post-tensioned concrete is even worse as the concrete does not do much to protect the steel.
Early concrete structures (Roman and 19th century) were like monolithic cast concrete versions of brick structures - un-reinforced and nothing in tensile stress. They were inefficient structures in terms of cost and material usage, but they will survive for 1000's of years. In the UK it has been said that the railway viaducts of the former Highland Railway in Scotland will be the artifacts which will survive the longest from the period of the Industrial Revolution - they might puzzle archeologists in the year 10,000 like Stonehenge does now.
(Score: 2) by Arik on Wednesday October 18 2017, @01:15AM
Surprisingly there is a core of truth to this one though. The Romans, amongst others, made excellent concrete long before modern 'portland cement' is supposed to have been invented. But in fact some of the better Roman concrete appears to be functionally identical to it. And they did something sometimes called 'marine concrete' which was really quite remarkable, which has actually lasted in place for many centuries, under sea water, affected by tides etc. It's not that we couldn't *approximate* it now, but we have no experience doing such thing, we don't build things that way anymore, no one has for centuries.
If laughter is the best medicine, who are the best doctors?
(Score: 1) by khallow on Tuesday October 17 2017, @01:57PM (1 child)
No, it's not. Don't make the mistake of confusing the most durable works of ancient times with today's cheap stuff that is not intended to last a few decades, much less centuries.
(Score: 3, Funny) by Osamabobama on Tuesday October 17 2017, @11:47PM
Oh, yeah? Name one modern edifice that has lasted even one millennium, let alone two!
Appended to the end of comments you post. Max: 120 chars.
(Score: 1, Interesting) by Anonymous Coward on Tuesday October 17 2017, @05:59PM (1 child)
While it might have been relatively unknown 50 years ago, the past 20 years has seen a resurgence in research on it and other veins of similiar but different mineral forming chemical reactions.
Flyash is the most common pozzolan you can use for 'Roman' style concrete, and does in fact increase strength over time.
Geopolymers, a related but slightly different field of mineral chemistry from concrete can also use flyash (Look up the Anemone(55?) post on Reddit for an example formula) and in fact provides the chemical non-reactivity of Roman Concrete, with the added benefit of polymer generation making the whole section cast while still in liquid/plastic form a single rock in whatever shape you molded. This was discussed extensively on seasteading.org's forums in regards to cast geopolymer structures for living at sea even in the most adverse of sea and weather conditions.
Another fun read is chiefio's blog entry on geopolymers. He covers a variety of formulas he attempted, links to all the scientific citations for history of Egyptian geopolymers (hint: the Egyptians probably used it for components of quite a few pyramids, either cast in-place, or on-site.) Additionally he discusses the difficulties obtaining a variety of the ingredients needed for the formulas, alternatives (sadly lye is basically unavailable in the US today without ordering it online from soapmaking warehouses, and flagging yourself with the DEA in the process.)
(Score: 0) by Anonymous Coward on Tuesday October 17 2017, @07:27PM
Ace Hardware has it as jars full of granules.
If you want to make buildings though, you need to be thinking about railway access to accept your delivery of lye. Consider making your own lye.
(Score: 3, Interesting) by Nuke on Tuesday October 17 2017, @12:15PM (13 children)
FTFA
As a practising engineer, and an advanced DiY-er at home, I think about concrete, do calculations about concrete, make concrete, mould concrete, drill concrete, chisel concrete, break concrete, and have even tested large cubes of it to destruction in laboratories.
(Score: 3, Funny) by WizardFusion on Tuesday October 17 2017, @12:22PM (3 children)
Nerd
(Score: 2) by GreatAuntAnesthesia on Tuesday October 17 2017, @01:30PM (1 child)
Look up the word "boring" in the yellow pages. It says:
See Civil Engineering.
(Score: 3, Insightful) by Azuma Hazuki on Tuesday October 17 2017, @04:15PM
You mean *good* civil engineering. Bad civil engineering gets "exciting" rather quickly, with deadly results.
I am "that girl" your mother warned you about...
(Score: 2) by Nuke on Wednesday October 18 2017, @08:23AM
Try calling a builder a "nerd". LoL :-
https://www.youtube.com/watch?v=zyuS8GcENfQ [youtube.com]
(Score: 1, Insightful) by Anonymous Coward on Tuesday October 17 2017, @01:08PM (5 children)
(Score: 0) by Anonymous Coward on Tuesday October 17 2017, @09:08PM (1 child)
Yes, it is. How hard would it be to add the word "almost" in front of "nobody thinks about it"? Not very. Be more precise.
(Score: 0) by Anonymous Coward on Wednesday October 18 2017, @08:42AM
Nobody gives a shit.
(Score: 2) by Osamabobama on Tuesday October 17 2017, @11:50PM
Alas, nobody thinks about anything anymore...
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by Nuke on Wednesday October 18 2017, @08:28AM
Sounds like those are the white collar guys; you forgot the manual site workers with concrete. In the UK, building seems to be the only industry that is thriving, there are so many immigrants to accomodate. Building and advertising.
(Score: 2) by GreatAuntAnesthesia on Wednesday October 18 2017, @10:07AM
(Score: 2) by Phoenix666 on Tuesday October 17 2017, @01:31PM
By that token it's equally valid to say large numbers of people think about star formation or chip design?
Washington DC delenda est.
(Score: 1, Interesting) by Anonymous Coward on Tuesday October 17 2017, @01:41PM
so you should know: how much more expensive is it to make concrete that resists the freeze-thaw cycle (directly exposed to the elements) than to make regular concrete and dress it up properly (i.e. insulation + paint etc). I am typing this from a brand new building with full walls of plain concrete exposed to the outside, and I want to know how much I can blame this on corruption (seeing the walls like this feels deeply wrong somehow).
(Score: 2) by richtopia on Tuesday October 17 2017, @04:13PM
I'm not a Civil Engineer, but I agree. I've researched concrete for diy foundations, refractory cement, and countertops. I have not used it myself but I am curious how a house using autoclaved aerated concrete [wikipedia.org] fairs compared to the standard wood frame construction here in the USA.
(Score: 3, Funny) by realDonaldTrump on Tuesday October 17 2017, @01:01PM
Being a builder is like being flat-chested. A person who is very flat-chested is very hard to be a 10. And a person who is a builder has a very hard time getting noticed. A very hard time getting respect. My whole life really has been a "no" and I fought through it. It has not been easy for me. It has not been easy for me. I started off in Brooklyn. My father gave me a small loan of a million dollars. I came into Manhattan and I had to pay him back, and I had to pay him back with interest. Let me tell you, a million dollars isn't very much compared to what I built. I mean, I built one of the great companies. My father made me president of his company. I came into Manhattan, I started buying up properties, and I did great. I did a good job. But I was always told that would never work. In Manhattan we have the UN. The cheap 12-inch square marble tiles behind the speaker at the UN always bothered me. UGLY, UGLY TILES! I will replace them with beautiful large marble slabs if they ask me. But they won't ask. It's like I don't exist. To them I'm a nothing. I'm a fantastic builder but they ignore me. I have a great environmental record. I have a record that, in my opinion, everybody would love. But it's very hard to get my message out.
(Score: 0) by Anonymous Coward on Tuesday October 17 2017, @07:48PM (1 child)
i dunno what the big deal is.
if you can find good stones and are apt at forming stones you can make pretty spectacular stuff.
thus you have to be a mediocre stone artist or a good stone mason.
with concrete it's just liquid stone. the good part is that you can pump it.
however there is still some workmanship required only this time it is (mostly) with wood.
thus you have to be mediocre wood artist or a good carpenter.
in my minds eye, cement is a "glue" and sand and stones/gravel is just "filler" so you
dont' need so much cement powder.
concrete is three (four) things: cement, sand, stone (and water)
As a whole it is as strong as the weakest element.
my guess the stones/gravel are junk.
Another perceived insight is that liquid cement is a precursor to growing your own crystal
akin to buying a pack of seamonkey and adding them to water ...
as with all crystals, a seed is required and i assume that if the stones/gravel added to
cement have crystal inclusion (quartz?) that is helps the cement settle better/stronger?
also let's not forget that concrete needs time to cure, thus it might be beneficial to keep
it from drying out to fast.
there's a (personal) notion that covering/packing fresh concrete with
ALU-SI clay (wet) will let the crystals grow from the outer direction also?
however, kaolin, says wikipedia is "destroyed" once dried ... thus adding to the heap of waste
already containing the wood form-work?
(Score: 0) by Anonymous Coward on Wednesday October 18 2017, @09:09AM
>As a whole it is as strong as the weakest element.
>my guess the stones/gravel are junk.
It's a composite material. My guess is that the inclusions (sand or gravel) tend to inhibit the growth of cracks.