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Old article from 2017. More advances were published earlier this year:

https://news.mit.edu/2023/roman-concrete-durability-lime-cas...

That's really cool research. Using quicklime heats up the concrete a bunch more than some other methods, and the result is concrete that fills its own cracks.

People who think A.I. will kill us should be worried that concrete will kill us.

There are many materials that could be superior in quality and environmentally benign than Portland cement-based concrete not least the Sulfur concrete which is commonly used in China today

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7660051/

and particularly Geopolymer concrete

https://en.wikipedia.org/wiki/Geopolymer

but all of these face resistance from the Portland cement industry which has already standardized products for regulators.

Having seen the state of concrete buildings in China, I'd prefer the alternative.

It's not a conspiracy. Fly ash contains heavy metals that would leach out of the cement. There are more challenges remaining to be solved than the Wikipedia article suggests.

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