Dissolution, nucleation, and crystal growth mechanism of calcium aluminate cement

Abstract

This study presents a theoretical prediction of calcium and aluminate ion concentrations of calcium aluminate cement (CAC) system on dissolution and nucleation behavior, induction time (t_ind), interfacial free energy (γ), and crystal growth mechanism. Such data can influence the early-age hydration of CAC. Better understanding of the data is applied to predict and manipulate its early-age hydration. It is well-understood that at 20 °C the CAC compositions of CaAl₂O₄•10H₂O (CAH₁₀) and Ca₂Al₂O₅•8H₂O (C₂AH₈) were the main hydrated products. Results in the study indicated that the nucleation of calcium phase was the controlling nucleation mechanism, not the aluminate. The calculated γ-value of CAH₁₀ was lower than the C₂AH₈; meaningly, CAH₁₀ was more stable than C₂AH₈. SEM images also revealed two-dimensional (2D) mediated growth of CAH₁₀. Based on the theoretical predictions and SEM study, the crystal growth mechanism for CAC system at 20 °C was the 2D-mediated growth mechanism.

Keywords:

• Calcium aluminate cement
• hydration
• dissolution
• nucleation
• crystal growth

Acknowledgment

The authors thank the Kerneos for providing calcium aluminate cement.

Disclosure statement

No potential conflict of interest was reported by the authors.