r/science • u/mvea Professor | Medicine • Nov 03 '19

Chemistry Scientists replaced 40 percent of cement with rice husk cinder, limestone crushing waste, and silica sand, giving concrete a rubber-like quality, six to nine times more crack-resistant than regular concrete. It self-seals, replaces cement with plentiful waste products, and should be cheaper to use.

https://newatlas.com/materials/rubbery-crack-resistant-cement/
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u/[deleted] Nov 03 '19

Also, a lot of the reason these ancient concrete structures stand for so long is because everything is built in compression. Modern construction uses reinforced concrete, which allows for more efficient building techniques, but the steel reinforcement can rust and decay, causing failure of the member.

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u/jacques_chester Nov 03 '19

There's also simple survivorship bias.

We only see the remarkable structures that survived. We don't see all the crappy structures that didn't.

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u/Ambiwlans Nov 03 '19 edited Nov 03 '19

I wouldn't really count that. It isn't like there were hundreds of pantheons and only one survived. There was only one 2000 years ago and one today.

It held the record for the largest dome ever constructed for well over 1000 years and only beaten by a significant amount in the 1900s.

Edit: It wasn't a dumb comment though. It was good of you to look out for this type of bias.

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u/OneBigBug Nov 03 '19

I wouldn't really count that. It isn't like there were hundreds of pantheons and only one survived. There was only one 2000 years ago and one today.

Somewhat hilariously undermining your point, 2000 years ago there wasn't a Pantheon there at all, then a few years later, one was built at the site of the current Pantheon. It burnt to the ground. Then a few decades later, another one was built. It burnt to the ground. Then, a few decades after that, the current one was built, and is still around.

We're on Pantheon #3 at that location.