How the Pantheon, which was built over 2000 years ago, is still standing when buildings made 150 years ago are about to crumble.

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Edit- After reading most of the comments the general consensus is listed below:

1. The unique composite matrix of the concrete used gives it a self-healing property. When cracks form in the concrete, it will naturally seal them.
2. The Pantheon was a very significant structure which led to meticulous maintenance and restorations
3. The Romans didn’t have modern engineering. So they didn’t know exactly how strong they’d have to build the Pantheon to make it last. Their solution was to overbuild the hell out of it.
4. Survivorship bias. There were thousands of buildings constructed by the Romans but very few remain which are the ones we marvel at.

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33 Answers

Anonymous 0 Comments

I’ve actually got the answer to this!!

It was documented and discovered recently.. but it is all to do with Roman concrete! Their concrete is so strong it can repair itself. No, it really fucking fixes itself.
We couldn’t figure out exactly how they made their concrete until recently, we knew the main components but the process wasn’t fully understood.

Essentially, they heat their concrete mixture, whereas we now cold mix our concrete, and most importantly they grind the components coarsely then add larger chunks of calcium carbonate into the mixture.
This settles, solidfys and when an earthquake hits say, and the concrete cracks, its been observed that the fractal lines are always where the chunks of calcium carbonate are.
The rain water works its way into the cracks, reacts with the calcium carbonate and I think I read it makes limestone?? It makes some kind of stone, that is stronger then concrete that was there in there first place. It breaks, it fixes its and Increases strength in the process.
Thats how the roman buildings such as the Pantheon are still standing like they’re 200 years old

Edit – [Source](https://www.reuters.com/lifestyle/science/scientists-chip-away-how-ancient-roman-concrete-stood-test-time-2023-01-09/).

Anonymous 0 Comments

There was an excellent article on this a couple of days ago (tldr: the way they made concrete)

https://www.cnn.com/style/amp/roman-concrete-mystery-ingredient-scn/index.html

Anonymous 0 Comments

I love my home town of Asbury Park, NJ.

When I would look into the history of certain addresses it was hard to find what use to be there. Through lots of research I was able to find many hotels and apartments buildings that were really cool and historic looking. They all burnt down, sometimes blocks at a time. Almost all of them build in the 1800s and early 1900s.

Lots buildings burn down and fall, especially wood ones.
Then people will be like ,’ these new buildings stink , look at these amazing built house from 1905, they dont build houses like that anymore ‘. People dont realize there where crappy places from that era, but now they are gone.

Anonymous 0 Comments

The high school built in my city back in 1890 is still standing, is beautiful, and is used as a courthouse today. It’s replacement, built in the 1970’s, was a farce of construction, and was demolished two years ago. But the builder still got paid for his shitty work, didn’t he? The new high school cost $150 million and will take 30 years for the homeowners in my city to pay off through increased taxes. I predict we will be having this exact same conversation in 30 years. Wanna bet? Modern capitalism doesn’t design or build for longevity. They build for profit. Nothing else. THIS is the American way.

Anonymous 0 Comments

Every house within 3 miles of me is over 140 years old.
I live in Salford, Manchester UK.
Reasonably well built bricks and mortar lasts well with maintenance.
Mostly it’s about good roofs.
Pantheon is a concrete dome, pretty damn amazing from the outset, but it has been maintained and repaired, plus its got a great roof.
Wooden houses, poorly maintained, dont last long.

Anonymous 0 Comments

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Anonymous 0 Comments

believe it or not, houses last longer when people live inside of them regularly. the condensation prevents walls and foundations from crumbling to dust from drying out. it makes sense, as soon as you get a crack in a foundation any plant can start rooting and pushing the foundation apart.

Anonymous 0 Comments

The Pantheon is made of very large rocks. Most modern buildings are not made of very large rocks. If we build something out of very large rocks (and no one actively tries to knock it down), then something we build today is likely to stand for 2000 years.

Note: concrete is not a very large rock. Concrete is many small rocks.

Anonymous 0 Comments

Fun fact that no one will care about: a lot of Roman and Greek ancient buildings (ex. The Colosseum) are so decayed not because of poor engineering or lack of maintenance, but because they were literally dismantled to get marble and other materials to build new buildings.

Or because they were bombed during WWII, an occurrence that ancient Romans obviously didn’t think about.

That’s also the reason why a lot of medieval buildings are still standing, because they were not made with pricey materials but built well enough to survive centuries.

Imagine being the Pope and going like: “need marble? Just take it from the Colosseum, no one cares about that old sh*t”

Anonymous 0 Comments

So a couple of reasons:

1: survivorship bias. You notice the buildings that are around. Not the ones that fell over.

2: it was a place of great significance meaning it for more attention and maintenence than Joe-relius’ Flatbread shop.

3: the method with which it was built and designed. The Roman’s didn’t have steel reinforcement like we do. Concrete on its own can’t really take any tension (things pulling it apart) but is really good at compression. Steel is the opposite. When you mix the two together like we do you get a material that is good at both tension and compression.

So the Roman’s had to build structures to always be in compression because of this. The only way to do that really is to use a very veery large amount of concrete. This means that Roman buildings are essentially just giant cast in place rocks and rocks last a really long time. There’s not much to rust or degrade like our new buildings full of steel and other new materials.

Basically comes down to the fact that concrete really likes being concrete and so doesn’t change much over the years but steel really doesn’t want to be steel so it tries changing as fast as it can.