Roman concrete used salt water, ours uses.... not salt water. We had the recipe but it didn't specify salt water. However: not fact checked.
It sounds, from the article, that they already knew it was made from seawater. But I know nothing about Roman concrete, so you could be right.
I’m less interested in the specifics of Roman concrete, and more interested in the fact that we lost a technology, and we may be starting to rediscover it.
I think I’m mostly curious what knowledge we’ve lost over the ages, as civilizations have risen and fallen. What was in the books in the library of Alexandria? What did the Greeks and Romans know that we didn’t? What failed to get transmitted across the gulf of the dark ages?
I’ve been meaning to write about this for a long time, but: knowledge is fragile. I feel like, given a big enough disruption, it would be easy to lose most of our civilization’s worth of knowledge. If the electrical grid went down completely for 10 years, would we be able to get it back up again? Would we be able to get it up if the reason it went down was that a plague wiped out 95% of humanity?
We store our knowledge in paper and electronic media. Paper decays, and electronic media is hard to access without the proper equipment (and electricity).
Even if we manage to preserve the knowledge, will we have the ability to understand it? If we wait long enough, our language we’ll change, and we’ll lose the ability to understand what was written. Plus, a lot of it will be written in very technical language that’s hard for people to understand even today.
And will people want to preserve the knowledge? In the face of civilizational collapse, I suspect most people will be more interested in surviving than in hoarding and protecting old books.
All the knowledge of our sciences, all the knowledge that forms the bedrock of our civilization – it could vanish almost overnight. And sure, some of it could be recovered, centuries later, through painstaking academic study. But a lot of what we have (especially our art, our literature, our poetry – not to mention our movies and TV shows) would be lost for good.
I think about this a lot, and it makes me especially curious about the actual lost technologies of previous civilizations. The fact that Roman concrete has remained a mystery for 2000 years is sort of a case in point for me, but so is the fact that we’re now starting to rediscover it.
