I must be missing something. I’ve never used scihub before, and I can’t find the link to read the paper. All I see on this link is the name of the paper and the authors.
Yeah, same. Came in comments to look for alternative link but none so far.
Why Ancient Roman Concrete Outlasts Our Own (2017)
21–30 of 69 posts
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#22Earlier 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?
Brother printers are low cost, cheap replacing the ink/toner and make good drivers. I definitely buy them only.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#23I must be missing something. I’ve never used scihub before, and I can’t find the link to read the paper. All I see on this link is the name of the paper and the authors.
This looks like the journal page: https://pubs.geoscienceworld.org/msa/ammin/article/102/7/143...
Also has a link to download the PDF for free.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#24Earlier 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?
> 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 is…
> Plus the goal is generally to build things which barely stand...
Since when?
Design criteria baked into international building code is quite robust; not just naive static load, but wind, snow, seismic activity, fire/flood/termite resistance, etc. are all considered. That's a far stretch from something that can "barely stand".
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#25In 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?
A lot of the answer is that the types of structures you can build with concrete that isn't rebar reinforced is fairly limiting. You're pretty much stuck with arch bridges, dams, and domed buildings. Unfortunately, arch bridges don't scale that well (they take concrete proportional to length cubed), and people like buildings in shapes other than domes. As a result, you often have to have designs that hold together partially under tension, and the cost is it won't stay up for 2000 years (if you use rebar which rusts).
That said, in the past few decades there has started to be experiments with fiber reinforced concrete. This has the significant advantage of not corroding, but costs a good bit more than traditional rebar. That said, it might be the future for buildings where long life is desired.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#26I must be missing something. I’ve never used scihub before, and I can’t find the link to read the paper. All I see on this link is the name of the paper and the authors.
Yeah, same. Came in comments to look for alternative link but none so far.
Right hand panel for me was a clickable download of the pdf.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#27Earlier quoted context omitted.
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...
Similar stuff has happened in Germany, in fairly recent times. You could make your own cement, no problem. But good luck trying to unload it anywhere in Germany without paying a fee to certain individuals.
Interesting. Do you have any links with background information? In German is fine.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#28Earlier quoted context omitted.
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…
Are you essentially saying that you don't think there are important material and chemical differences between Roman and modern concrete that might be responsible for orders-of-magnitude differences in durability, aside from the absence of rebar, and that it's basically a matter of building so many bridges, harbours, and aqueducts that some of them end up lasting for thousands of years despite being immersed in runnin…
No. That's not what I am saying.
Both us and the Romans are and were building lots of different things for lots of different purposes with lots of different properties and trade-offs.
Some of the earliest re-inforced concrete was used to make better flowerpots. https://en.wikipedia.org/wiki/Reinforced_concrete#History
You can bet your hat that this was a very different type of (re-inforced) concrete than what we are using to build houses these days. We use yet other kinds of concrete for tunnels or underwater. Just like the Romans used different building materials.
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#29In 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…
> First, we only see the part of Roman architecture that lasted. There's an observer bias.
Couldn’t it also possible that the romans had some techniques that they weren’t aware of that would last longer than others?
Re: Why Ancient Roman Concrete Outlasts Our Own (2017)
#30Earlier quoted context omitted.
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…
> First, we only see the part of Roman architecture that lasted. There's an observer bias. Couldn’t it also possible that the romans had some techniques that they weren’t aware of that would last longer than others?
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.