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Why was Roman concrete so durable?

news.mit.edu

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Re: Why was Roman concrete so durable?

#112
post #103

Here is a nice picture of the Pantheon, mentioned in the article as a prime example of these incredibly durable Roman concrete structures: https://commons.wikimedia.org/wiki/File:Pantheon11111.jpg#/m... Not bad for something built nearly 2,000 years ago.

I wonder what percentage of the original stones are left (given that it was repaired and restored over the centuries)

I don't believe the dome structure was radically altered across time. It's possible I misunderstood but my belief was it was only cosmetic changes to the dome itself. Other structural changes were made to the portico and doorways.

Re: Why was Roman concrete so durable?

#116

I read the article quickly but couldn't see whether this discovery is applicable to modern concrete (in other words, could the same technique be applied to modern methods for making concrete that would make it more durable)?

"To prove that this was indeed the mechanism responsible for the durability of the Roman concrete, the team produced samples of hot-mixed concrete that incorporated both ancient and modern formulations, [...] cracked them, and then ran water through the cracks. [...] Within two weeks the cracks had completely healed [...] As a result of these successful tests, the team is working to commercialize this modified cement material."

Re: Why was Roman concrete so durable?

#117
post #103

Here is a nice picture of the Pantheon, mentioned in the article as a prime example of these incredibly durable Roman concrete structures: https://commons.wikimedia.org/wiki/File:Pantheon11111.jpg#/m... Not bad for something built nearly 2,000 years ago.

I wonder what percentage of the original stones are left (given that it was repaired and restored over the centuries)

Unlike many ancient structures, the Pantheon has mostly been left intact across the millennia. The Dome is entirely original and so is most of the remaining structure. From what I know, the majority of the restoration and renovation work has been to the interior ground-level walls and some of the exterior along the ground level, but even these are mostly minor renovations. In this case, what you see truly is for the most part what always was, and especially for the main awe-inspiring part, the great dome.

Re: Why was Roman concrete so durable?

#118

Earlier quoted context omitted.

cobblestones for the roads

for slow neighborhood roads I see no reason why brick isn't used more often. my hometown had brick roads everywhere and once every 3-5 years a few bricks would get replaced here and there. in the 1990s I'd look around and see a lot of the bricks on those roads that were made in the 1930s, and there were probably older bricks to be found if I'd looked harder. the rough ride kept speeding down a lot more than the polic…

Speaking as someone who grew up in a neighborhood with brick streets,...

They're insanely slippery when wet. A freeze-thaw cycle tends to make them move, eventually leading to weird dips and ridges. They're expensive to install and more expensive to maintain.

Re: Why was Roman concrete so durable?

#119

I read the article quickly but couldn't see whether this discovery is applicable to modern concrete (in other words, could the same technique be applied to modern methods for making concrete that would make it more durable)?

"To prove that this was indeed the mechanism responsible for the durability of the Roman concrete, the team produced samples of hot-mixed concrete that incorporated both ancient and modern formulations, [...] cracked them, and then ran water through the cracks. [...] Within two weeks the cracks had completely healed [...] As a result of these successful tests, the team is working to commercialize this modified cement…

thanks
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