The best replacement for fly ash is bottom ash.

The best alternatives to fly ash are rated as following:
★★★★★  bottom ash
★★★★  slag
★★★★  cement
★★  silica fume
★★  coal ash
★  portland cement
★  slag cement
★  pozzolan
★  fly ash
  class c fly ash
  pond ash
  class f

Your alternative for fly ash is not listed? Suggest!
Speaking about fly ash, one probably shouldn't forget about concrete.

Other search terms related to fly ash and their ratings are:
★★★★★ concrete
★★★ cement
★ portland cement
You have in mind a companion for fly ash and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of fly ash in all years. Click on graph for more.
fly ash
bottom ash
slag