Influences of Mineral Admixture On the Compressive strength of Magnesium Oxysulphate Cement

In this paper, influences of mineral admixtures (fly ash, slag and silica fume) on the compressive strength of magnesium oxysulphate cement have been studied. Results demonstrate that effects on compressive strength of magnesium oxysulphate cement by adding fly ash is related with the initial a-MgO/MgSO4. The strength of cement increased by dosage of fly ash increases at low a-MgO/MgSO4. The addition of fly ash can significantly reduce the strengths of cement with constant water-cement ratio(w/c). Although adding slag is disadvantageous to the early strength of magnesium oxysulphate cement, it has little influence on the later strength. The early strength of the magnesium oxysulphate cement decreases at first and then increases with the increasing dosage of silica fume, and the later strength increases obviously.