Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why was Roman concrete so durable?

news.mit.edu

Post reply on HN
Print view View original

231–240 of 299 posts

Re: Why was Roman concrete so durable?

#231

Post by jacquesm »

Maursault wrote: post #213
akolbe wrote: post #103

Here is a nice picture of the Pantheon, mentioned in the article as a prime example of these incredibly durable Roman concrete structures: https://commons.wikimedia.org/wiki/File:Pantheon11111.jpg#/m... Not bad for something built nearly 2,000 years ago.

> Not bad for something built nearly 2,000 years ago. According to the Pyramids, Stonehenge, Newgrange, Watson Brake, et al., it's a little premature to suggest that. Let's check back in 3,000 years.

Hehe, that's funny. But the OP clearly meant it relative to other stuff built 2000 years ago, most of which has vanished without leaving a trace, maybe a couple of foundation stones buried under a meter of new topsoil.

Have an upvote, it's sad to see you grayed out.

Re: Why was Roman concrete so durable?

#232

Post by jacquesm »

mitthrowaway2 wrote: post #135
adolph wrote: post #90

Earlier quoted context omitted.

One method to reduce cement’s carbon footprint (which accounts for up to 8% of total global greenhouse gas emissions), is to improve the longevity of concrete through the incorporation of self-healing functionalities. The resulting extended use life, combined with a reduction in the need for extensive repair, could thus reduce the environmental impact and improve the economic life cycle of modern cementitious constru…

Survivor bias comes up every time this topic is mentioned, but it really has less explanatory power than most people think. If you meet a man born in 1932 who is still running marathons and doesn't need glasses, it's probably luck, although he might have some valuable diet tips to share. If you meet a man born in 1732 running the same marathon, it's time to rule out luck, and start collecting blood samples because he…

> start collecting blood samples because he might actually be some kind of vampire.

In which case your first worry would be to make sure he doesn't collect your blood samples.

Re: Why was Roman concrete so durable?

#233

Post by jacquesm »

rerdavies wrote: post #225
saalweachter wrote: post #152

Earlier quoted context omitted.

I wonder if generational reputations and transmission of methods from master to apprentice is sufficient. "Secundus was an apprentice to Marius who was an apprentice to Darius, who built that awesome aquaduct; Marcus was an apprentice to Felix who who was an apprentice to Marcellus, whose shit bridge fell down after twenty years. We're going to hire Secundus instead of Marcus."

Real Roman engineering theory came from Marcus Vitruviouss Pollio's De Archetectura. Considered to be the ultimate reference text for building and engineering projects in Rome in 32bce, It's ten volumes cover how to build everything from temples, to aqueducts, to water mills to machines used for construction. A fascinating read, if you're curious how Romans built things. De Architectura provides the sort of long-term…

That's a combination of 'Risks Digest' and the 'Engineering handbook' all in one. I'll have to go read this, thank you so much for the pointer.

Re: Why was Roman concrete so durable?

#234

Post by devoutsalsa »

rootusrootus wrote: post #80

How does this concrete compare to a state-of-the-art mix -- not just the stuff they use to pour my driveway or the highway, but the best we know how to make?

Practical Engineering can answer all your questions with their series on concrete. It’s extremely well done, including a video on “Was Roman Concrete Better?”:

https://youtube.com/playlist?list=PLTZM4MrZKfW90PdaBFt70BLTb...

Re: Why was Roman concrete so durable?

#235

Post by peoplefromibiza »

Maursault wrote: post #213
akolbe wrote: post #103

Here is a nice picture of the Pantheon, mentioned in the article as a prime example of these incredibly durable Roman concrete structures: https://commons.wikimedia.org/wiki/File:Pantheon11111.jpg#/m... Not bad for something built nearly 2,000 years ago.

> Not bad for something built nearly 2,000 years ago. According to the Pyramids, Stonehenge, Newgrange, Watson Brake, et al., it's a little premature to suggest that. Let's check back in 3,000 years.

stone != concrete

edit: we have a > 2,000 years old pyramid in Rome too, and it's in perfect shape, because stone != concrete

https://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Ci...

Re: Why was Roman concrete so durable?

#236

Post by jacquesm »

ogogmad wrote: post #81

For people who don't know the difference between cement, mortar and concrete: Cement is a substance used for producing mortar and concrete. It's never used on its own. It is a "binding agent". Note that the term "cement" is often not used correctly in everyday speech, with people talking about gluing bricks together with cement, when bricks are actually glued together with mortar. Mortar is the glue between bricks. Y…

The baths of Caracalla (sp?) had concrete reinforced with copper!

Re: Why was Roman concrete so durable?

#237

Post by peoplefromibiza »

insane_dreamer wrote: post #105
akolbe wrote: post #103

Here is a nice picture of the Pantheon, mentioned in the article as a prime example of these incredibly durable Roman concrete structures: https://commons.wikimedia.org/wiki/File:Pantheon11111.jpg#/m... Not bad for something built nearly 2,000 years ago.

I wonder what percentage of the original stones are left (given that it was repaired and restored over the centuries)

of the original Pantheon from 27 B.C. very little remained.

It was rebuilt after the fires of 80 A.C. and 110 A.C. damaged the original structure.

It's been mostly unchanged after that.

Re: Why was Roman concrete so durable?

#238

Post by taetaset »

georgyo wrote: post #46
colechristensen wrote: post #14

Tl;dr: Old “riddle solved”: Romans used volcanic ash as an ingredient New “riddle solved”: the good stuff also includes tiny lumps of calcium carbonate that self heal cracks

> the good stuff also includes tiny lumps of calcium carbonate that self heal cracks According the article, they didn't use calcium carbonate directly. They use quicklime (Calcium oxide) which must be mixed in at very hot temperatures. When a crack forms, that stuff melts and forms calcium carbonate that seals the crack.

> which must be mixed in at very hot temperatures

It gets hot when you mix it.

Re: Why was Roman concrete so durable?

#239

Post by pachico »

akolbe wrote: post #103

Here is a nice picture of the Pantheon, mentioned in the article as a prime example of these incredibly durable Roman concrete structures: https://commons.wikimedia.org/wiki/File:Pantheon11111.jpg#/m... Not bad for something built nearly 2,000 years ago.

It doesn't matter how many times I see it, every time I go to Rome and find myself in front of the Pantheon, I get overwhelmed by it.

Re: Why was Roman concrete so durable?

#240

Post by yawboakye »

rerdavies wrote: post #225
saalweachter wrote: post #152

Earlier quoted context omitted.

I wonder if generational reputations and transmission of methods from master to apprentice is sufficient. "Secundus was an apprentice to Marius who was an apprentice to Darius, who built that awesome aquaduct; Marcus was an apprentice to Felix who who was an apprentice to Marcellus, whose shit bridge fell down after twenty years. We're going to hire Secundus instead of Marcus."

Real Roman engineering theory came from Marcus Vitruviouss Pollio's De Archetectura. Considered to be the ultimate reference text for building and engineering projects in Rome in 32bce, It's ten volumes cover how to build everything from temples, to aqueducts, to water mills to machines used for construction. A fascinating read, if you're curious how Romans built things. De Architectura provides the sort of long-term…

as far as i know, vitruvius wasn’t original: he aped the meticulous and more successful greeks. the ten volumes regularly refer to greek knowledge or practice to cement its authority. the method of construction that is uniquely roman is mixing concrete and bricks, usually to produce aqueducts. and here the simple theory was: everything in excess. in fact, the romans may have been unique in their construction of military camps. for more on that see de re militari
Post reply on HN