This paper [1] is pretty interesting RE: the effects of fly ash in concrete mixes. It isn't a replacement, certainly, and brings both problems and benefits. [

This paper [1] is pretty interesting RE: the effects of fly ash in concrete mixes. It isn't a replacement, certainly, and brings both problems and benefits. [1] https://www.cement.org/docs/default-source/fc_concrete_technology/is548-optimizing-the-use-of-fly-ash-concrete.pdf https://www.cement.org/docs/default-source/fc_concrete_techn...