"How long lasting is fly ash concrete?" We don't know. Existing structures that use "Roman Concrete[1]" are (roughly) 2000 years old and counting ... [1] htt

"How long lasting is fly ash concrete?" We don't know. Existing structures that use "Roman Concrete[1]" are (roughly) 2000 years old and counting ... [1] https://en.wikipedia.org/wiki/Roman_concrete https://en.wikipedia.org/wiki/Roman_concrete