Microstructure of CPC Paste During Solidification

The microstructure of CPC paste during solidification is studied in this paper. The results showed that the change of microstructure induced by hydrating products was the fundmental cause of setting and hardening. The initial structure of the paste is a net work joined by weak forces such as Van der Waals' forces. As the hydration goes on, the products increase gradually, and the distances between these powders reduce. At last, crystallizing connection takes place and the forces which join the new work change to chemical bondings, and when the plastic flow is limited by chemical bondings and terminated, the paste loses fluidity and sets. The microstructure of CPC paste varies continuously after setting. Petal like products increase, which make capillary pores lessen and the connecting strength between these powders increase gradually, so the compressive strength of the paste increases and hardening takes place.