A method for determining the hydration degree of magnesium potassium phosphate cements

Abstract

The investigation on the hydration kinetics of magnesium potassium phosphate cements (MKPC) is crucial to understand the development law of engineering properties of MKPC. In this work, isothermal calorimetry and deconvolution operation were used to obtain the hydration degree of MKPC suspension system at various stages under different M/P conditions. A complete mathematical equation for hydration degree was obtained by integrating the parameters of the log–normal function at different stages of hydration. The results show that the hydration process of MKPC were successfully and accurately determined using the lognormal function and deconvolution method. Hydration kinetic parameters were given accurate physical significance by comparing the relationship between the lognormal function and the exact hydration reaction rate. The dissolution process of magnesium oxide (peak I), the formation process of amorphous phase (peak II) and the formation process of phosphate minerals (peak III) of MKPC proceed sequentially, yet partially overlap, and the time of occurrence of the former process influences the latter process.

Graphical abstract