Study on the Mechanism of Magnesium Sulfate to Cement and C-S-H Gel

Abstract

The microstructure of cement test block and the C-S-H gel attacked by magnesium sulfate is observed by means of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).It is found that the presence of Mg2+ makes C-S-H gel decalcify, dissolve and decompose, which thereby increasing the erosion of SO42- on the concrete. The decomposition of C-S-H and the generation of M-S-H result in the loss of concrete strength and the ultimate destruction of concrete.