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Why was Roman concrete so durable?

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Re: Why was Roman concrete so durable?

#261

Post by stephencanon »

bpbp-mango wrote: post #201
stephencanon wrote: post #197

Earlier quoted context omitted.

Most brutalist buildings are already 60+ ish years old and doing great (actual brutalism, rather than “concrete buildings I don’t like,” was mostly a style of the 1950s and 60s in the west, though it lasted quite a bit longer in Eastern Europe). Even the Boston government services center, everyone’s most hated brutalist building in the US is already past 50.

for many people, myself included, actual brutalism is "concrete buildings I don’t like"

Eh, there’s no accounting for taste, but there have always been shitty buildings in every vernacular. We tend to not see the worst buildings in older styles because they’ve long since been torn down.

Re: Why was Roman concrete so durable?

#262

Post by imtringued »

af78 wrote: post #250

Relevant thread: https://twitter.com/cleptok/status/1611622181665923075 Ok. Let's do a short thread on Roman cement for the 3 people out there that might be interested. You often hear that the Romans had some sort of superior and arcane knowledge on superior cement mixes that has been now lost. And still today we cannot replicate it. This is complete nonsense. Modern day cement (and any other building material, reall…

Honestly, I think a much bigger factor than random chance is the designed lifespan of these buildings. Some of them took decades or even centuries to build. So they must not only last throughout the construction process, they must also last long enough to make the construction process be worth it.

Spending a few decades on experimentally determining an optimal cement mixture is also worth it.

The by far biggest problem is that the vast majority of buildings get demolished and replaced by something else so making them long lasting is not very useful.

Re: Why was Roman concrete so durable?

#263

Post by georgyo »

taetaset wrote: post #238
georgyo wrote: post #46

Earlier quoted context omitted.

> 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.

It's a little unclear to me about that, it is what I thought at first. But it appears that quicklime is not stable at ambient temperatures and recombines with CO2 to make Calcium Carbonate; which is how the self healing works.

Re: Why was Roman concrete so durable?

#264

Post by PakG1 »

aborsu wrote: post #217
PakG1 wrote: post #190

Earlier quoted context omitted.

3 is the limit. More than 3 is bad.

One would think the limit for pie is closer to 3.14159265359

It is, but it's not easy to cut pi slices of pie without being unfair to others who want to have equal slices of pie. Plus, the effort to be so exact may not be worth the utility. You may hit the true pi limit by random luck too.

Re: Why was Roman concrete so durable?

#265

Post by KptMarchewa »

rollcat wrote: post #252
pachico wrote: post #246

Earlier quoted context omitted.

Well, I lived in Italy for 10 years. Going to Rome from time to time wasn't that hard. Now I live in Spain and I continue to fly to Rome now and then. In Europe, distances are easy to overcome.

In Europe, 100km is a long way; in the US, 100 years is a long time.

Unless you fly ryanair for 10$

Re: Why was Roman concrete so durable?

#267

Post by dale_glass »

ricardobeat wrote: post #127
dreen wrote: post #123

Earlier quoted context omitted.

I don't think the knowledge is gone, we could make that or maybe even better. The point is nobody wants it, most things we build need to be torn down after at most a few decades anyway.

The knowledge is actually gone, like Damascus Steel (what we have today is just a visual reproduction) and Greek Fire. For a more recent example: we already "forgot" how to make the spaceships and rockets that went to the moon. Even if you had the full plans - and apparently we don't, a lot of the materials and processes are not around anymore and would have to be 'reinvented'.

Not quite.

For Damascus steel and Greek Fire we almost certainly still have the knowledge. We just lack a document to tell us that "Greek Fire" matches formula #44 of napalm specifically, or what specific process an ancient smith actually followed.

For the spaceships, no, we have the plans, but they're long obsolete. They're made for ancient, manual equipment nobody uses anymore, and old materials that have since been improved on. We technically could dig up and restore ancient manual milling machines, recruit retired engineers and special order obsolete materials and parts, but what for? Unless you're engaging in experimental archaeology what you want is a rocket, not the rocket that has a nostalgic feel to it, and it'd make far more sense to make one with modern methods.

Re: Why was Roman concrete so durable?

#268

Post by beebeepka »

julenx wrote: post #248
mgaunard wrote: post #247

Earlier quoted context omitted.

Italy is wonderful, you should go, only problem is that they speak Italian.

Well, it's also wonderful they speak Italian!

Spanish and Italian sound great to me, even though I don't speak them. They sound, well, human. Can't say the same about English or German

Re: Why was Roman concrete so durable?

#269

Post by krisoft »

benreesman wrote: post #242
pachico wrote: post #239

Earlier quoted context omitted.

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.

With zero sarcasm, when I read “every time I go to Rome” I feel that I took a wrong turn in life somewhere. Fucking awesome mate.

Worth remembering that “Going to Rome” has a very different feel to it if you live in Terni vs if you live in Whichita, Kansas. One is a day trip to shop, the other might be an adventure of a lifetime.

I was born in an East European country and I worked a few years in New York. Many people back at home react to this fact as if I made it. As if shoveling software on Lafayette street makes you a better software engineer than doing the same on the Rákóczi Körút. On the other hand for many people living and working in New York is nothing special. They were born there, it is their normal.

I for one think where you were is not as important as what you made of your time there.

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