We've been sporadically documenting the fact that Coal power plant Fly Ash can actually be treated as a resource of great utility in the concrete and construction industries.
It can be utilized both as a raw material, replacing some of the limestone traditionally used, in the making of Portland-type cement itself; it can, after treating, be blended into Portland cement after the cement is made as an additional cementitious component; and, it can also be treated in various other ways for use simply as "aggregate", replacing some of the traditional sand and gravel which is added to the cement in order to make concrete.