Hydration of Portland cement with additions of calcium sulfoaluminates

Gwenn Le Saoût (1) , Barbara Lothenbach , Akihiro Hori , Takayuki Higuchi , Frank Winnefeld

1 EMPA - Swiss Federal Laboratories for Materials Science and Technology [Dübendorf]

The effect of mineral additions based on calcium aluminates on the hydration mechanism of ordinary Portland cement (OPC) was investigated using isothermal calorimetry, thermal analysis, X-ray diffraction, scanning electron microscopy, solid state nuclear magnetic resonance and pore solution analysis. Results show that the addition of a calcium sulfoaluminate cement (CSA) to the OPC does not affect the hydration mechanism of alite but controls the aluminate dissolution. In the second blend investigated, a rapid setting cement, the amorphous calcium aluminate reacts very fast to ettringite. The release of aluminum ions strongly retards the hydration of alite but the C-S-H has a similar composition as in OPC with no additional Al to Si substitution. As in CSA-OPC, the aluminate hydration is controlled by the availability of sulfates. The coupling of thermodynamic modeling with the kinetic equations predicts the amount of hydrates and pore solution compositions as a function of time and validates the model in these systems.

Domaines: Chimie

Gwenn Le Saoût, Barbara Lothenbach, Akihiro Hori, Takayuki Higuchi, Frank Winnefeld. Hydration of Portland cement with additions of calcium sulfoaluminates. Cement and Concrete Research, 2013, 43, pp.81-94. ⟨10.1016/J.CEMCONRES.2012.10.011⟩. ⟨hal-03250546⟩