Effects of soluble magnesium on the structure of calcium silicate hydrate

This paper aims to investigate the impact of soluble magnesium on the structure of C-S-H formed at elevated temperature. Magnesium chloride hexahydrate, calcium oxide and silica fume were used in the preparation of Mg2+ modified C-S-H. The obtained solid and liquid samples of synthetic C-S-H were characterized with XRD, FTIR, TGA, etc. to investigate the structural features of Mg2+ modified C-S-H. Results show that the mineralogical compositions of the synthesized C-S-H are highly related to the initial concentration of Mg2+. Large additions of Mg2+ lead to the instability of C-S-H. Meanwhile, magnesium can be incorporated into the structure of C-S-H. A heterogenous distribution of elemental Mg in C-S-H phase on nanoscale is observed.