Mineralogical Characterizations and Reaction Path Modeling of the Pozzolanic Reaction of Fly Ash–Lime Systems

Mineralogical studies show that fly ash–lime systems without NaOH produced Al‐rich calcium silicate hydrates and a small amount of ettringite. The presence of NaOH accelerates the pozzolanic reaction of fly ash. Fly ash–lime systems with NaOH produced Al‐rich calcium silicate hydrates, calcite, meixnerite, and NaX‐type zeolite (or zeolite precursor) after 28 days of reaction time. Carbonation of alkali‐activated fly ash–lime systems call for specific studies. The experimental work was supplemented with reaction path modeling, which provided a quantitative procedure to decipher the chemical nature of fly ash hydration and cementitious system formation.