Recent Progress in Crystal Chemistry of Belite: Intracrystalline Microtextures Induced by Phase Transformations and Application of Remelting Reaction to Improvement of Hydration Reactivity

摘要

The microtextures of belite induced by a remelting reaction and other transformations (e.g., the polymorphic phase transitions of #alpha#->#alpha#'->#beta#) have been reviewed. The remelting reaction, in which the #alpha#-phase belite decomposes into a liquid and the #alpha#' -phase during cooling, is necessarily preceded by the phase transition of #alpha#-#alpha#'; the #alpha#' -phase nucleates as lamellae within the parent #alpha#-phase so that there is good lattice matching across the interface. The resulting lamella boundaries provide heterogeneous nucleation sites for the exsolving liquid by the remelting reaction. A variety of microtextures results depending on the wettability of the belite lamellae by the exsolved liquid as well as on the cooling rate. The belite in which the remelting reaction occurred to a large extent showed higher hydration reactivity and better grindability than the quenched material. Recent years have seen developments in a new application for the remelting reaction that involves modifying belite-rich cement.