Thermodynamic analysis of ettringite formation reactions using the Born-Haber cycle

The thermodynamic analysis of the reaction of ettringite synthesis of differently composed aluminate phases allowed to rank them by the activity of interaction with calcium sulphate: C3A > S4AH19 > S3AH6 ~ S3AŜH12 > S2AH8. These data make it possible to explain from a common stance the causes of an increase in sulphate resistance of cement stone after hydrothermal treatment of Portland cement with an increased dosage of gypsum in the initial cement and lower calcium ion activity in the liquid phase through the introduction of active hydraulic additives.

Author: I.S. Rakhimbaev, N.M. Tolypina

Section: Science and production

Keywords: ettringite, sulphate corrosion, aluminate phases, ions activity