Hydration of C12A7-based cement (Ternal EP) in a mix with precipitated calcium carbonate

Carboaluminate hydrates have become increasingly important hydrate components in cement-based materials and the monocarbonate dominated paste is expected to be an alternative binder. This study investigates the hydration of C12A7-based cement (CAC) in a mix with precipitated calcium carbonate (PCC) with a multi-method approach including X-ray diffraction (XRD) analyses, in-situ XRD, derivative thermogravimetric (DTG) analyses, isothermal calorimetry and compressive strength test. The results indicated that during early hydration, C2AH8 precipitated as C12A7 dissolved quickly and then monocarbonate and hemicarbonate precipitated at the expense of C2AH8. The hydration reaction in all systems studied was fast and the heat was released mainly during first 24 h. With enough content of PCC added, monocarbonate dominated, leading to a dense microstructure and high early strength development and stable development of strength for a long age.

Automated summary

This study investigates the hydration process of C12A7-based cement in a mix with precipitated calcium carbonate using various methods. The results show that early hydration is fast, with monocarbonate dominating, leading to a dense microstructure and stable strength development.