Fly ash is a supplementary cementitious material (SCM), not an aggregate. Aggregates are your rock (coarse agg) and sand (fine agg). And you're correct, fly ash has been used for decades, and is a byproduct of burning coal. Other SCMs like ground granulated blast furnace slag have also been used for years. Both are commonly used in general blended cements or low heat cements, or where high durability is required in aggressive environments. A lot of "green concrete" is simply replacing cement (i.e. portland cement / general purpose cement) with SCMs like fly ash and slag with the idea that they would otherwise just been discarded (despite fly ash and slag being made in polluting processes themselves), and you're decreasing the amount of CO2 produced should you have just used GP cement (which is made by heating the CO2 out of limestone). It's hard to see how they needed AI to do any of this. The article is so vague there's no way to work out what the AI actually did. Generalising a lot, but you get the picture.

That's because when kids take mobile phones to school they focus more on "constant communication with each other" than learning.