The rapid conversion of calcium aluminate cement hydrates, as revealed by synchrotron energy-dispersive diffraction

The exceptional speeds of data capture available with synchrotron diffraction systems have been adapted and used to examine the structural/dynamic order of events in rapid hydration and conversion of calcium aluminate cements at high temperatures (50–90°C). The time resolution of the results obtained is sufficient to reveal effects that were not detectable or even suspected from conventional laboratory analysis. In particular, C₂AH₈ emerges as a ubiquitous transitionary phase, initiating the formation of C₃AH₆ in both the hydration and conversion processes. The dynamic diffraction data are presented and interpreted in terms of model descriptions of the order of events in high-temperature hydration and conversion.