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Related, Grady Hillhouse on the myth of Roman concrete. > The miracle of modern chemistry has given us a wide variety of admixtures like superplasticizers to i

Related, Grady Hillhouse on the myth of Roman concrete. > The miracle of modern chemistry has given us a wide variety of admixtures like superplasticizers to improve the characteristics of concrete beyond a Roman engineer’s wildest dreams. So why does it seem that our concrete doesn’t last nearly as long as it should? It’s a complicated question, but one answer is economics. There’s a famous quote that says “Anyone can design a bridge that stands. It takes an engineer to build one that barely stands.” Just like the sculptors job is to chip away all the parts of the marble that don’t look like the subject, a structural engineer’s job is to take away all the extraneous parts of a structure that aren’t necessary to meet the design requirements. And lifespan is just one of the many criteria engineers must consider when designing concrete structures. Most infrastructure is paid for by taxes, and the cost of building to Roman standards is rarely impossible, but often beyond what the public would consider reasonable. https://practical.engineering/blog/2019/3/9/was-roman-concrete-better https://practical.engineering/blog/2019/3/9/was-roman-concre... A large part of why Roman concrete lasted longer than ours tends to is that we suffer from a shortage of narcissistic emperors with the means to wield entire economies towards their own immortality.

seydor 3mo ago
> we suffer from a shortage of narcissistic emperors not recently
- defrost 3mo ago
  but not ones willing to put the effort into properly fixing a pond.
  - fragmede 3mo ago
    Who's pond? I'm willing to bet billionaires' estates have well tended ponds, contrary to public ponds. Or a reflecting pool.
  - kQq9oHeAz6wLLS 3mo ago
    If you're talking about the algae, it came back after Obama's $34m renovation, too. Turns out algae is hard to kill, especially when you feed the reflecting pool from a tidal basin.
    - DannyBee 3mo ago
      I don't remember Obama pretending it was being caused by political agitators, etc.
userbinator 3mo ago
Most infrastructure is paid for by taxes, and the cost of building to Roman standards is rarely impossible, but often beyond what the public would consider reasonable. Would you pay 10x more to have something that lasts 100x or even 1000x longer? The upfront cost is higher, but the TCO is ultimately lower. IMHO it's ultimately a form of planned obsolescence. This becomes even more obvious when plenty of expense is spent just on "engineering" to deliberately reduce lifespan.
- TylerE 3mo ago
  The thing is, we're actually pretty crappy at knowing what we'll need 50 years from now, much less 500. Doesn't make sense to overbuild for an unknown future, when hundred years from now us will likely be able to do a far better job anyway.
  - hirako2000 3mo ago
    That's to consider the commons solely materialist utility. The Romans built meaning through arts that still speaks to this day. Efficient construction becomes worthless over time.
    - TylerE 3mo ago
      Efficiency is never worthless in a world where resources (if nothing else, labor) are not infinite.
      - hirako2000 3mo ago
        The kind of efficiency we focus on seem to be plentiful. Labour is a good example, see unemployment rates and the number of bullshit jobs anyway. What's covered in the article is also a great example of material resource that could be used, but short term profiting primes.
    - demosthanos 3mo ago
      Yes, you, too, can have two-thousand-year-old buildings if you're willing to make that longevity be the primary thing you pay for, assuming that your successors don't tear the thing down and replace it with something else, like happened to many Roman monuments. In which case you spent a bunch more than you needed to on a building that didn't last any longer than it would have if you'd chosen a practical end date for it.
modo_mario 3mo ago
The same is said for why we don't build classical buildings anymore and trend towards more featureless stuff... and it's also mostly bullshit with plenty of counterexamples. Truth is it's often just a bit cheaper so we trend that way under capitalism, we change styles faster and have come to subconsciously accept shorter lifespans and the kind of things you can build more practical for cars, large overhangs, etc
- anal_reactor 3mo ago
  But it's also true that modern world changes much faster than in the antiquity. If you built a church, a market, and a few utility buildings like tavern and blacksmith in 500BC you could rest assured they'd still remain used in 1000 years practically unchanged unless the structure or wider economy collapsed. Meanwhile "office building, shopping mall, nightclub, school" all varied highly in popularity within last 50 years, and it's difficult to convert one type of building to another, not to mention the costs of modernizing an old building.
  - AngryData 3mo ago
    Well also building cheaper makes converting such structures to other uses more costly too. You can't simply start notching steel and adding more features and beams without a complicated engineering review because those beam were so carefully designed as to just barely hold up under their original plan. You can't simply add a second story to a mall or walmart or modern school, none of its main structural pillars or beams could hold it. But with an overbuilt structure from 500+ years ago you likely could add another floor or two with minimal improvements to the base structure.
justin66 3mo ago
This is a good link and the Practical Engineering guy doesn’t appear to reference a “myth.” Which is a good thing, because there’s nothing mythological about the high performance of Roman concrete.
- demosthanos 3mo ago
  The myth is that Roman concrete was 'better' and that we don't know how to recreate it. The facts are that it was not better in any way than what we can do now and we have always known how to replicate it. Grady addresses both of those aspects of the myth in the video, and the first part is literally the title of the video: "Was Roman Concrete Better?" The answer is no. What is true is that some Roman concrete structures (but far from all of them) are extremely durable because they were optimized for a different set of requirements than modern buildings usually have, notably "needs to last forever as a symbol of the emperor's power". From the 19th century on that has very rarely been a design constraint, so we optimize for other things instead.

seydor 3mo ago

> we suffer from a shortage of narcissistic emperors not recently

defrost 3mo ago
but not ones willing to put the effort into properly fixing a pond.
- fragmede 3mo ago
  Who's pond? I'm willing to bet billionaires' estates have well tended ponds, contrary to public ponds. Or a reflecting pool.
- kQq9oHeAz6wLLS 3mo ago
  If you're talking about the algae, it came back after Obama's $34m renovation, too. Turns out algae is hard to kill, especially when you feed the reflecting pool from a tidal basin.
  - DannyBee 3mo ago
    I don't remember Obama pretending it was being caused by political agitators, etc.

userbinator 3mo ago

Most infrastructure is paid for by taxes, and the cost of building to Roman standards is rarely impossible, but often beyond what the public would consider reasonable. Would you pay 10x more to have something that lasts 100x or even 1000x longer? The upfront cost is higher, but the TCO is ultimately lower. IMHO it's ultimately a form of planned obsolescence. This becomes even more obvious when plenty of expense is spent just on "engineering" to deliberately reduce lifespan.

TylerE 3mo ago
The thing is, we're actually pretty crappy at knowing what we'll need 50 years from now, much less 500. Doesn't make sense to overbuild for an unknown future, when hundred years from now us will likely be able to do a far better job anyway.
- hirako2000 3mo ago
  That's to consider the commons solely materialist utility. The Romans built meaning through arts that still speaks to this day. Efficient construction becomes worthless over time.
  - TylerE 3mo ago
    Efficiency is never worthless in a world where resources (if nothing else, labor) are not infinite.
    - hirako2000 3mo ago
      The kind of efficiency we focus on seem to be plentiful. Labour is a good example, see unemployment rates and the number of bullshit jobs anyway. What's covered in the article is also a great example of material resource that could be used, but short term profiting primes.
  - demosthanos 3mo ago
    Yes, you, too, can have two-thousand-year-old buildings if you're willing to make that longevity be the primary thing you pay for, assuming that your successors don't tear the thing down and replace it with something else, like happened to many Roman monuments. In which case you spent a bunch more than you needed to on a building that didn't last any longer than it would have if you'd chosen a practical end date for it.

modo_mario 3mo ago

The same is said for why we don't build classical buildings anymore and trend towards more featureless stuff... and it's also mostly bullshit with plenty of counterexamples. Truth is it's often just a bit cheaper so we trend that way under capitalism, we change styles faster and have come to subconsciously accept shorter lifespans and the kind of things you can build more practical for cars, large overhangs, etc

anal_reactor 3mo ago
But it's also true that modern world changes much faster than in the antiquity. If you built a church, a market, and a few utility buildings like tavern and blacksmith in 500BC you could rest assured they'd still remain used in 1000 years practically unchanged unless the structure or wider economy collapsed. Meanwhile "office building, shopping mall, nightclub, school" all varied highly in popularity within last 50 years, and it's difficult to convert one type of building to another, not to mention the costs of modernizing an old building.
- AngryData 3mo ago
  Well also building cheaper makes converting such structures to other uses more costly too. You can't simply start notching steel and adding more features and beams without a complicated engineering review because those beam were so carefully designed as to just barely hold up under their original plan. You can't simply add a second story to a mall or walmart or modern school, none of its main structural pillars or beams could hold it. But with an overbuilt structure from 500+ years ago you likely could add another floor or two with minimal improvements to the base structure.

justin66 3mo ago

This is a good link and the Practical Engineering guy doesn’t appear to reference a “myth.” Which is a good thing, because there’s nothing mythological about the high performance of Roman concrete.

demosthanos 3mo ago
The myth is that Roman concrete was 'better' and that we don't know how to recreate it. The facts are that it was not better in any way than what we can do now and we have always known how to replicate it. Grady addresses both of those aspects of the myth in the video, and the first part is literally the title of the video: "Was Roman Concrete Better?" The answer is no. What is true is that some Roman concrete structures (but far from all of them) are extremely durable because they were optimized for a different set of requirements than modern buildings usually have, notably "needs to last forever as a symbol of the emperor's power". From the 19th century on that has very rarely been a design constraint, so we optimize for other things instead.