P/M和W/C对磷酸镁水泥强度的影响分析

Influence of P/M and W/C on the strength of magnesium phosphate cement

为探究磷镁比(P/M)及水灰比(W/C)对磷酸镁水泥强度的影响和作用机理,对其力学性能进行测试,并结合XRD、SEM和FT-IR等测试手段对其物相组成及微观形貌进行表征和分析。研究结果表明:W/C=0.15时,磷酸二氢钾掺量的降低会使磷酸镁水泥的各龄期抗压强度增强,P/M=1:4时其3 h强度超过30 MPa,而当掺量过高时,3 h强度低于20 MPa,其产物MgKPO_(4)·6H_(2)O(K-struvite)的生成量减少且试件存在开裂区域;W/C=0.25时,减少MgO的掺量可以提高磷酸镁水泥的强度,P/M=1:1.5时,3 h的抗压强度接近30 MPa,磷酸镁水泥的水化产物K-struvite形貌结晶完好且排列紧密。

In order to explore the effects of phosphorus to magnesium ratio(P/M)and water-cement ratio(W/C)on the strength of magnesium phosphate cement,its mechanical properties were tested,and its phase composition and microscopic morphology were characterized and analyzed by means of XRD,SEM and FTIR.The results show that:When W/C=0.15,the decrease of potassium dihydrogen phosphate content will enhance the compressive strength of magnesium phosphate cement at each age.When P/M=1:4,the 3 h strength exceeds 30 MPa,while when the content is too high,the 3 h strength is lower than 20 MPa.The amount of MgKPO_(4)·6H_(2)O(K-struvite)was reduced and there were cracking areas in the specimen.When W/C=0.25,the strength of magnesium phosphate cement can be improved by reducing the content of MgO.When P/M=1:1.5,the compressive strength of magnesium phosphate cement for 3 h is close to 30 MPa,and the K-struvite hydration products of magnesium phosphate cement are intact crystalline and closely arranged.