Study on the Drying Shrinkage Property of Magnesium Phosphate Cement

The influence of magnesium to phosphate weight ratios (M/P ratio), borax content, water to cement ratio (w/c ratio), fly ash, slag on magnesium phosphate cement of drying shrinkage is examined.The results show that the drying shrinkage of magnesium phosphate cementcan be affected at some extent by M/P ratio, w/c ratio,boraxcontent. Both the former two factors and the effects are significant.It was found that the drying shrinkage of magnesium phosphate cement decrease with the increase of M/P ratio,borax content, w/c ratio. If the 10%, 15% offly ashinstead of magnesium phosphate cement was added, drying shrinkage rate decreases with increases of dosage fly ash. When the 15% of magnesium phosphate cement is replaced by fly ash, the shrinkage rate of hydration 20d reachs11.2×10-5. When the 10% of magnesium phosphate cementis replaced by slag, the drying shrinkage rate reducedto 87.6%.comparing to the bench mark ,the drying shrinkage rate of 20d is only 2.78×10-5.