【摘要】 为了确定磷酸盐胶凝材料(MPB)的最佳配合比,研究调凝组份、磷酸盐/MgO(w(P)/w(M))、灰砂比、掺粉煤灰对MPB胶凝材料凝结时间和强度发展等的影响规律,并分析它与传统水泥混凝土间的兼容性及其硬化机理。结果表明:当调凝组份掺量为10%左右时,可使MPB水泥凝结时间控制在15～30min内。当w(P)∶w(M)为1∶2时,MPB水泥浆体的强度达到最高值,3h抗压强度可达到40MPa以上,1d时强度超过50MPa。灰砂比(w(MPB)∶w(S))为1∶1.5时,砂浆强度达到最高值,3h抗压强度达到50MPa,抗折强度达到9.1MPa。在保持流动度不变情况下,掺粉煤灰并不降低MPB胶凝材料强度,并可使其颜色与普通水泥混凝土接近。MPB遇水后生成以MgNH4PO4·6H2O为主的反应产物,它与传统水泥混凝土间具有很好兼容性,因而适合于灾后混凝土工程的快速修复。更多还原

【Abstract】 In order to determine the optimal proportion of magnesium phosphate cement-based binder (MPB),influences of setting adjusting agent,ratio of phosphate to magnesia,ratio of binder to sand,and addition of fly ash on the setting time and strength development of MPB paste and mortar was studied.The compatibility between MPB and traditional concrete and the hardening mechanism of MPB were also investigated.The results showed that the setting time of MPB can be regulated to 15 ～ 30 minutes by the addition of 10% of setting adjusting agent.When the ratio of phosphate to magnesia is 1∶ 2,MPB paste presents the best strength,with compressive strength greater than 40 MPa at 3 hours and 50 MPa at 1 day.When the ratio of MPB binder to sand is 1∶ 1.5,the MPB mortar reaches the highest strength,with compressive strength beyond 50 MPa and flexural strength more than 9.1 MPa at 3 hours.When the flowability of paste is kept the same,the addition of fly ash doesn’t reduce the strength of MPB paste and the color of MPB paste is changed to be very close to traditional concrete.The main reaction product of MPB is MgNH4PO4·6H2O.There is a good compatibility between MPB and traditional concrete,therefore MPB is very suitable for rapid repairing of concrete structures undergone natural disaster.更多还原