m(M)/m(P)比值对磷酸镁水泥干燥收缩的影响及机理研究

The effect and mechanism of m(M)/m(P) ratio for the drying shrinkage of magnesium phosphate cement

研究了m(M)/m(P)比值对磷酸镁水泥干燥收缩行为的影响,采用温度记录仪、压汞仪、X射线衍射仪、扫描电镜及能谱仪等分析手段探讨了m(M)/m(P)比值对磷酸镁水泥干燥收缩的作用机理。结果表明,随着m(M)/m(P)比值的增大,磷酸镁水泥水化初期的膨胀量以及干燥收缩减小;水化8h左右水泥开始收缩,龄期达到20d左右收缩趋于稳定;磷酸镁水泥收缩量的减少,是由于m(M)/m(P)比值的增大导致磷酸镁水泥水化温度降低,孔隙率增大,水化产物MgKPO_4·6H_2O减少,水化产物结构趋于疏松。

The effect of m（M）/m（P）ratio for the drying shrinkage and mechanism of magnesium phosphate ce-ment was investigated by temperature recorder,Mercury mercury analyzer,X-ray diffractometer,scanning e-lectron microscope and energy spectrometer.The results show that with the increase of m（M）/m（P）ratio,the expansion and drying shrinkage of magnesium phosphate cement decreases.The drying shrinkage of cement pro-duced about hydrate 8 hours later,and tends to be stable at the age of 20 days.The increase of m（M）/m（P）ra-tio which lends to the decrease of the hydration temperature,the increase of the porosity,the decrease of MgK-PO4？6 H2 O,and the looser structure of the hydration products will results in the decrease of drying shrinkage of magnesium phosphate cement.