Worth pointing out that fly ash is already widely used in the concrete industry for the same reasons - it's more environmentally friendly. Using it actually giv

Worth pointing out that fly ash is already widely used in the concrete industry for the same reasons - it's more environmentally friendly. Using it actually gives a building extra LEED points. Fly ash can replace up to 50% of the cement needed in concrete - saying that 'there's no proof it will last' seems fairly ridiculous.