Influence of Na2Si2O5 on the Hydration of Tetracalcium Aluminoferrite

Abstract

The hydration of C 4 AF was retarded by the addition of Na 2 Si 2 O 5 of up to approximately 0.1mass% and the hydration completely stopped when it exceeded 0.1 mass%. Metastable phases, such as Ca 2 Al(OH) 7 .3H 2 O and Ca 2 Al 2 O 5 . 8H 2 O, etc., were produced when C 4 AF was hydrated in Na 2 Si 2 O 5 solution, whereas hydrogarnet was formed as the main hydration product when C 4 AF was hydrated in water. The ion concentrations of Ca and Al in the liquid phase decreased, and at the same time the period for hydrogarnet formation in the paste was delayed with an increase in the amount of Na 2 Si 2 O 5 added to the liquid phase.