Can fly ash be used for soil stabilization?
Fly ash, particularly Class C, can effectively be used to stabilize soil for various types of construction. High calcium fly ash (Class C) acts as a good source of calcium hydroxide which “self activates”, reacting with silica and alumina in the fly ash and soil to form a cementitious hydration product. In addition, C3A in fly ash (Class C) can react with sulfates to gain strength relatively quickly. Class F fly ash typically requires outside activation, either from lime or portland cement. The pozzolanic reaction binds up excess free lime, leading to higher soil strengths and lower soil swell potential.
