原材料及配比对磷酸镁水泥强度的影响

Effect of Raw Materials and Their Ratio on Compressive Strength of Magnesium Phosphate Cement

研究了M/P比值(Mg O与K2HPO4的质量比),水胶比(W/C),硼砂掺量,Mg O比表面积对磷酸镁水泥早期强度的影响,采用扫描电子显微镜对磷酸镁水泥的微观形貌进行了表征。结果表明:磷酸镁水泥1 h的抗压强度随M/P比值的增大而减小,在水化龄期为3 d和7 d时,M/P比值为4:1时磷酸镁水泥石的强度最高,最高强度达到了74.68 MPa,水胶比对磷酸镁水泥石早期强度影响不大,7 d强度随着水胶比的增大而减小,磷酸镁水泥在水化早期随着硼砂掺量的增加,水化产物晶体变得细小,晶体缺陷增多,结构疏松,其强度随着硼砂掺量增加而降低,后期水化产物连接成一体,结构致密,7 d的强度几乎没有变化。水化龄期在7 d内,磷酸镁水泥石的强度随Mg O比表面积的增大而增大。

The influence of M/P ratio（mass ratio of MgO and K2HPO4）, water/cement ratio（W/C）, borax content, Mg O specific surface area on the early strength of magnesium phosphate cement was studied. And microstructure of magnesium phosphate cement was analyzed by using scanning electron microscope（SEM）. The results show that the compressive strength of magnesium phosphate cement at the age of 1h decreases with the increase of M/P ratio, when hydration age is 3 d and 7 d, M/P ratio is 4：1,magnesium phosphate cement stone has the highest strength, the highest intensity can reach to 74.68 MPa; water-binder ratio has little effect on early strength of magnesium phosphate cement; when hydration age is 7 d, the strength decreases with the increase of water-binder ratio; in the early hydration, with the increasing of borax content, crystal of magnesium phosphate cement hydration products becomes small, the structure becomes loose, the crystal defect increases, so its strength decreases; in the later hydration, the structure becomes compact, the strength after 7 d has little change. Within 7 d, the strength of the magnesium phosphate cement increases with increasing of MgO specific surface area.