Synthesis and Hydration Characteristics of Alinite Cement

A chlorine-bearing alinite cement was synthesized using reagent-grade chemicals, and the phase evolution and hydration behavior of the alinite clinker were examined. The effects of the MgO content on alinite formation and hydration also were investigated. Alinite began to appear at 1000°C from β-C₂S, C₁₁A₇CaCl₂, and unreacted raw materials, and an almost single-phase alinite was obtained at 1300°C. The alinite phase also was produced without MgO addition. However, CaO, β-C₂S, and C₁₁A₇CaCl₂ phases were present. Alinite cements hydrated rapidly after a short incubation period, and the hydration products were C-S-H gels, Ca(OH)₂, and a Fridel's saltlike phase. The local environmental changes of silicon and aluminum during the formation and hydration of alinite were determined using magic-angle-spinning nuclear magnetic resonance spectroscopy. The Cl^?-ion exsolution from the alinite paste during hydration was measured using ion chromatography.