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

Why Ancient Roman Concrete Outlasts Our Own (2017)

sci-hubtw.hkvisa.net

Post reply on HN
Print view View original

61–69 of 69 posts

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#61

Post by eru »

he0001 wrote: post #48
eru wrote: post #30

Earlier quoted context omitted.

Yes, of course. I didn't offer a guess why some things lasted longer than others. Might be sheer blind luck, might be deliberate design, might be side-effects of things done for other reasons (like you suggest), or something else. Or a mixture.

I was more referring to the observation bias you mentioned. If they were making informed decisions on which technique to use for it to last a millennia or not then I’d also think there was some sort of observation bias. But if they didn’t, there wouldn’t be any observation bias since the process is then mostly random because they were not really aware of what technique that worked, no? We’re just seeing the results b…

> But if they didn’t, there wouldn’t be any observation bias since the process is then mostly random because they were not really aware of what technique that worked, no?

Not sure I understand the argument. Though something a bit related:

We can assume that the Romans didn't have the modern sophisticated understand to know exactly what they were doing. But we can assume that they had enough experience to eg make something last for a hundred years with very high probability.

After all, they had enough history to be able to observe various things that their ancestors built a hundred years ago.

Now my argument is that if you build something to last a hundred years with very high probability, more often than not, it'll have a reasonably high chance to survive a thousand years.

Similar to how eg Nasa Rovers on Mars were engineered to have a very high probability to last their official mission length of a few weeks, and thanks to that (over) engineering, they ended up lasting much longer.

There's a saying that "Any idiot can build a bridge that stands, but it takes an engineer to build a bridge that barely stands."

The Roman buildings that lasted were pretty much over-engineered, because they didn't have the knowledge to make the fine trade-offs we can today.

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#63

Post by eru »

smt88 wrote: post #20
14 wrote: post #5

Earlier quoted context omitted.

But surely some company would see it as an advantage over competitors and sell it if it was easily accessible. But we don’t see that so there has to be more to it. Maybe cost is too high for the average customer?

> But surely some company would see it as an advantage over competitors and sell it if it was easily accessible. This is not a guarantee. Look at manufacturers of washing machines: every company makes more money by having unreliable machines. There is no financial incentive to build a better product, and it's not easy to even prove you've built a better product.

Would that logic suggest that washing machine brands are equally unreliable? If not, why not?

Eg Miele benefits from having a reputation of building reliable products. They can and do charge more for that reputation, but also have to live up to it, if they want to keep it.

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#64

Post by lakis »

smt88 wrote: post #20
14 wrote: post #5

Earlier quoted context omitted.

But surely some company would see it as an advantage over competitors and sell it if it was easily accessible. But we don’t see that so there has to be more to it. Maybe cost is too high for the average customer?

> But surely some company would see it as an advantage over competitors and sell it if it was easily accessible. This is not a guarantee. Look at manufacturers of washing machines: every company makes more money by having unreliable machines. There is no financial incentive to build a better product, and it's not easy to even prove you've built a better product.

  It's not that simple.
  The consumers do not want washing machines that last forever. 
  Are you sure that you want a washing machine from 1900? It was probably not electric. 
  Aaah, you want an electric one. How about one from the 1920? What do you mean you want intelligent programs, save electricity, be gentle to the clothes and use little water/soap? These are modern improvements of the washing machine. 

  Consumers vote with their money. They stop buying old washing machines because they don't have the features that they want. So companies stop making old washing machines and make new ones with more features.

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#65

Post by perl4ever »

eru wrote: post #9
Phithagoras wrote: post #2

In a second year class I took the prof posed us the question: why don't we do this today? Why is this not part of an ASTM standard? He ended up saying it's too tough to get a hold of proper pozzlanic ash, but I suspect its more a "this is the way we've always done it" difficulty. Does anyone know more to the story?

First, we only see the part of Roman architecture that lasted. There's an observer bias. The Romans also made plenty of ephemeral stuff, just like we are making plenty of ephemeral stuff. See also https://www.youtube.com/watch?v=qL0BB2PRY7k Second, there's more to engineering than making stuff last long. There are different trade-offs. Cost being one of them, but also different material properties. Eg re-inforced con…

Something I'm curious about - there seems to be some sort of maintenance of reinforced concrete, where people periodically jackhammer a small patch and expose some rebar, and then cover it up again.

Anybody know what they are doing? I used to park in a garage where it seemed like they were always doing it.

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#66

Post by markvdb »

eru wrote: post #60
markvdb wrote: post #42

Earlier quoted context omitted.

> we on the other hand can maintain the stuff we want to last a long time. That we don't do it, e.g. infrastructure with the particularly bad maintained bridges in Germany, is not the materials fault, or the original designs fault. I have to respectfully disagree on this one. Humans in general have become spectacularly bad at maintaining physical infrastructure across longer timespans. Technological advances have ena…

> How much does this bridge benefit the local community where it is built? Why does a bridge have to benefit the local community? Why not eg the wider community? > Can we bring the design closer to the layman? Can we for example design a bridge so that it will visually degrade in step with safety degradation? What's the benefit? > I have to respectfully disagree on this one. Humans in general have become spectacularl…

> Why does a bridge have to benefit the local community? Why not eg the wider community?

This was written in the context of maintainability. I'm obviously not opposed to infrastructure benefiting a larger community.

Imagine two equal bridges. One benefits the people nearby a lot, the other not so much. Which one do you think will get maintained best?

>> Can we bring the design closer to the layman? Can we for example design a bridge so that it will visually degrade in step with safety degradation? > What's the benefit? This was again written in the context of maintainability. Imagine two equally unsafe bridges. One to the layman looks "visually ok", the other "a nightmare of fear crossing this one". Which one do you think gets repaired first?

>> Technological advances have enabled a cheap/fast/overbuild culture. This very much includes the design phase. > You say this like it's a bad thing. If stuff becomes cheap enough to build that every generation can afford to build their own, that's much better, isn't it? I was mostly saying this is not an optimal thing. Cheap/fast/overbuilt can be a real burden in the long term in terms of maintainability. Budget and environmental issues are also very closely related.

> Your comment emphasis closeness in space a lot, with talks of local community etc. So why not emphasis closeness in time, too? Absolutely! That's why I mentioned an example of building infra in now very flood-prone areas out of potentially less durable but cheaper, more quickly replaced materials like wood.

Thank you for your comment. I'm grateful for the opportunity to discuss this. It's a subject that almost naturally attracts my attention. Might have something to do with living between Belgium and Latvia. Belgium has lots of physical infra, often not very well maintained. Cheap/fast/overbuild is definitely a thing. Latvia has a lot less infra. Due to history's course, there's very interesting distinctions in terms of infrastructure. Some of it is cleverly minimalist. Most of its new infra is heavily EU subsidised. Many projects are no doubt very beneficial, but often one can almost smell the bloat of needing to spend those sweet subsidies. In many places, the bulk of infra is Soviet era. A significant part of what's still in active use is often badly maintained or not at all. Then there's the enormous visible scars in the landscape of crumbling disused infra. Some fascinatingly sad examples are the giant former agricultural collective farm buildings that are falling apart all over the country.

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#67

Post by smt88 »

eru wrote: post #63
smt88 wrote: post #20

Earlier quoted context omitted.

> But surely some company would see it as an advantage over competitors and sell it if it was easily accessible. This is not a guarantee. Look at manufacturers of washing machines: every company makes more money by having unreliable machines. There is no financial incentive to build a better product, and it's not easy to even prove you've built a better product.

Would that logic suggest that washing machine brands are equally unreliable? If not, why not? Eg Miele benefits from having a reputation of building reliable products. They can and do charge more for that reputation, but also have to live up to it, if they want to keep it.

I've never heard of Miele. If it's a US brand, it is clearly not doing well.

If it's a brand in the EU, the laws there were fixed to prevent every brand from selling intentionally defective products[1].

1. https://uspirg.org/blogs/blog/usp/you%E2%80%99re-not-crazy-y...

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#68

Post by eru »

smt88 wrote: post #67
eru wrote: post #63

Earlier quoted context omitted.

Would that logic suggest that washing machine brands are equally unreliable? If not, why not? Eg Miele benefits from having a reputation of building reliable products. They can and do charge more for that reputation, but also have to live up to it, if they want to keep it.

I've never heard of Miele. If it's a US brand, it is clearly not doing well. If it's a brand in the EU, the laws there were fixed to prevent every brand from selling intentionally defective products[1]. 1. https://uspirg.org/blogs/blog/usp/you%E2%80%99re-not-crazy-y...

Miele is a German brand with a long history. You can buy them around the world.

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

> Miele (/ˈmiːlə/ MEE-lə; German: [ˈmiːlə]) is a German manufacturer of high-end domestic appliances and commercial equipment, headquartered in Gütersloh, Ostwestfalen-Lippe. The company was founded in 1899 by Carl Miele and Reinhard Zinkann, and it has always been a family-owned and run company.[2]

There might be laws that set some minimum standards. But (a) there are still differences between companies' approaches to quality, and (b) Miele is selling around the world also in jurisdictions were EU rules do not apply, but they still deliver on their reputation for quality.

Re: Why Ancient Roman Concrete Outlasts Our Own (2017)

#69

Post by adgjlsfhk1 »

simonh wrote: post #45
Phithagoras wrote: post #2

In a second year class I took the prof posed us the question: why don't we do this today? Why is this not part of an ASTM standard? He ended up saying it's too tough to get a hold of proper pozzlanic ash, but I suspect its more a "this is the way we've always done it" difficulty. Does anyone know more to the story?

>but I suspect its more a "this is the way we've always done it" difficulty. Is the construction industry really known for resisting the adoption of new materials like that?

Yeah. incorporating unknown materials into million dollar projects is a really good way to lose millions of dollars. New materials can get added, but especially for big projects there is a long delay between tech invention and widespread use (think decades).
Post reply on HN