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Comment by simonblack | Hacker News Reader

The Romans were no slouches, they put their resources to work in smart ways that modern cultures can't keep up to.

One example: Roman concrete - still going strong after 2000 years. Modern concrete is lucky to last more than 150-200 years.

Another example: Water and sewerage reticulation - Roman water supplies and sewerage systems are still at work after 2000 years. It's only about 140-150 years ago that New York reached a comparable level of water and sewerage works to those in Rome.

One word: Priorities. Different peoples have different priorities as to what is important in a culture. Just because Roman priorities were different to ours doesn't mean their priorities were not as good as ours.

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The concept that Roman Concrete was somehow better is a strange idea.

First: 99% of Roman concrete has long since turned to dust. Through no intent of it's creators, that stuff did not last.

But the 1% that did last has two important qualities: it's incredibly thick, overbuilt; and through some fluke of chemistry, they unintentionally built it with some input chemicals that actually helped it be stronger.

But it wasn't intentional and it isn't some kind of magic.

Modern concrete is way better. It supports 80+ tons all day everyday. If you put an 80+ ton truck on brand new Roman concrete it wouldn’t last the weekend.

Steel reinforcement (tension strength) and Portland cement.

Pure concrete can only be used for dome like structures as it only has compression strength.

And that steel reinforcement is why modern Portland cement concrete doesn't last as long. Eventually the steel rusts, which means it expands and cracks the concrete.

We also use a lot of asphalt concrete. Even less durable than Portland cement concrete, but really fast for making roads, and extremely recyclable. Just melt the asphalt, maybe add some new aggregates, and lay down a new road surface.

I am not a chemist, I may have this completely wrong, but:

Steel does not rust without cause.

It needs something like a drip on to a part of it to wash away the layer of oxide and create more. Electrical effects then spread the decay.

There are a lot of steel reinforced structures around from the 1920s that are doing very well with no visible signs of structural decay.

Here is one close to me form the nineteenth century. Everything else decayed. It burnt at least once. And it stands, still.

https://en.wikipedia.org/wiki/Cargill's_Castle

It will be interesting to see if continues for another few hundred years....

You should cite sources, Roman concrete is nowhere near what you make of it here in reality.

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