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philipkglasstoday at 6:18 PM0 repliesview on HN

Yes:

"Crushed rock sand – An economical and ecological alternative to natural sand to optimize concrete mix"

https://www.sciencedirect.com/science/article/pii/S221302091...

The main problem is that even though crushing rocks is affordable, illegal sand mining is even cheaper in regions where law enforcement is weak.