Effects of fly ash and quartz sand on water-resistance and salt-resistance of magnesium phosphate cement

The loss of strength of MPC in water, Na2SO4 solution, and NaCl solution are studied. The samples after soaking in water and solutions are analyzed by XRD and SEM. The results show that, for the same type of the samples soaked in different solutions for a given duration, the effects of solution on strength are in decreasing order: water > NaCl solution > Na2SO4 solution. For the different samples soaked in the same solution for a given duration, the strength of samples containing fly ash is larger than that of samples in absence of fly ash, and the strength of sample containing quartz sand is larger than that of samples in absence of quartz sand.