Why Ancient Roman Concrete Outlasts Our Own (2017)
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Why Ancient Roman Concrete Outlasts Our Own (2017)
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Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#2In 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?
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#3In 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?
Maybe industries “planned obsolescence” practice?
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#4In 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?
Concrete is typically made with local materials, because shipping them is rather expensive. Maybe that’s one reason?
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#5In 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?
Maybe industries “planned obsolescence” practice?
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?
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#6In 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?
Concrete is typically made with local materials, because shipping them is rather expensive. Maybe that’s one reason?
> Concrete is typically made with local materials
Not really, especially jot for large contructions. Not everybody has a few thousand to million tons of sands of the right composition in their backyard, and cement comes from a factory.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#7Earlier quoted context omitted.
Maybe industries “planned obsolescence” practice?
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?
> Maybe cost is too high for the average customer?
Well yes, and even for the non-average one. Plus the goal is generally to build things which barely stand, a building which can face the vagaries of time for thousands of years would generally be way over-engineered.
Countries where pozzolanic ash is readily available do use it but that’s not usually the case. Fly ash is also being explored for that role.
An other issue is understanding of the material’s properties over time.
Also our modern world makes a lot of concrete.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#8Earlier quoted context omitted.
Concrete is typically made with local materials, because shipping them is rather expensive. Maybe that’s one reason?
> Concrete is typically made with local materials Not really, especially jot for large contructions. Not everybody has a few thousand to million tons of sands of the right composition in their backyard, and cement comes from a factory.
Yes, and these factories are many, and are not concentrated in one place, because shipping cement is expensive. It’s the same with aggregate: not everyone has sand in their backyard, but there typically is good amount of suitable sand within a few dozen miles.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#9In 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 concrete is awesome for lots and lots of applications that the Romans couldn't even have dreamed of. Alas, it's not economical to make re-inforced concrete that lasts forever. (Not even sure if it's physically possible.)
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#10Earlier quoted context omitted.
> Concrete is typically made with local materials Not really, especially jot for large contructions. Not everybody has a few thousand to million tons of sands of the right composition in their backyard, and cement comes from a factory.
Yes, and these factories are many, and are not concentrated in one place, because shipping cement is expensive. It’s the same with aggregate: not everyone has sand in their backyard, but there typically is good amount of suitable sand within a few dozen miles.
It's even more interesting that than!
There's actually plenty of drama around sand for concrete. There's talks about 'sand mafias' in India. And Malaysia has banned exporting sand to Singapore.
See eg https://www.bbc.com/future/article/20191108-why-the-world-is...