CAC-Based Expansive Cement Reactions

Particulates in the form of different calcium aluminate hydrates, e g., CAHio, C2AH8, and CjAHg, or pre-hydrated CAC/CH (H-CAC/CH) have varying effects on ettringite formation and expansion of expansive cement pastes. 

Mixtures containing different calcium aluminate hydrates can be prepared by hydrating ealcium aluminate cement (CAC) at different temperatures (Table 2). Either CAHjo, C2AHg, or CjAHg is the major component for each different mixture. The major component of the H-CAC/CH mixture also is C3 AHg. Addition of CHto CAC appeared to promote C3 AHg formation. The use of ealcium aluminate mixtures prepared from CAC hydration rather than pure S5mthetic calcium aluminates is based on practical considerations. 

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