The hydration of doped tricalcium aluminate

Abstract

The limit of solid solution of iron in tricalcium aluminate prepared in an oxygen atmosphere increases with increasing temperature to give a solid solution of composition Ca3Al1.85Fe0.15O6 at 1325° C. The lattice parameter of the cubic unit cell increases from 1.5263 to 1.5289 nm. Iron-doping causes a significant retardation in the reactivity of the Ca3Ass hydrated in the presence of gypsum. Not only does the rate of disappearance of the C3Ass decrease as the iron content increases, but also the setting time of the paste, the time taken for the gypsum to be totally consumed, and the time when rapid conversion of the AFt phase into the AFm phase takes place all increase. These observations apply even more to samples with iron contents greater than the solid solution limit, due to the presence of CaO and C4AFss in addition to C3Ass.