【摘要】 硅磷酸钾镁水泥(MSPPC)是一种新型高性能磷酸镁水泥，与使用酸性磷酸二氢钾制成的普通磷酸钾镁水泥(MKPC)不同，其必要原材料包括碱性磷酸氢二钾、氧化镁和硅灰。MKPC不掺缓凝剂难以制备，而MSPPC由于凝结时间较长，无需使用缓凝剂即可制备，硬化后具有比MKPC更优异的力学性能，但其工作性能尚未能很好满足实际工程应用需求，可通过缓凝剂用量来调节凝结时间和流动性。硼砂是磷酸镁水泥常用的缓凝剂，但其具有潜在的毒性迫使人们需要寻找一种安全有效的替代品。本工作研究了葡萄糖酸钠(SG)掺量对MSPPC工作性能、抗压强度、水化温度、pH值、物相组成、孔隙率和微观形貌的影响，并建立了缓凝机理模型。结果表明，SG掺量越高，缓凝效果越显著，当SG掺量为6%时，初凝时间由12 min延长至30 min;净浆流动度由84 mm提升至142 mm;大于0.1μm的孔占比减少，有效改善了孔径分布；水化产物的种类未发生改变，但3 d的抗压强度由64.3 MPa下降到53.9 MPa,下降了16.2%,而56 d的抗压强度下降了6.99%,不利影响减小。更多还原

【Abstract】 Magnesium silicon potassium phosphate cement(MSPPC) is an innovative high-performance magnesium phosphate cement, which is different from ordinary magnesium potassium phosphate cement(MKPC) using acidic potassium dihydrogen phosphate. Its necessary raw materials include basic dipotassium hydrogen phosphate, magnesium oxide and silica fume. MKPC is difficult to prepare without retarder, while MSPPC can be prepared without retarder due to its long setting time. After hardening, MSPPC has better mechanical properties than MKPC, but its working performance has not been able to meet the needs of practical engineering applications. The setting time and fluidity can be adjusted by the amount of retarder. Borax is a commonly used retarder for magnesium phosphate cement, but its potential toxicity problems forces the need to find a safe and effective alternative. This study investigated the influence of sodium gluconate(SG) content on the performance, compressive strength, hydration temperature, pH value, phase composition, porosity, and microstructure of MSPPC, and established a model for the retarding mechanism. The results demonstrated that a higher SG content led to a more pronounced retarding effect. At the SG dosage was 6%, the initial setting time was extended from 12 min to 30 min, and the cement paste fluidity improved from 84 mm to 142 mm. The proportion of pores larger than 0.1 μm was reduced, effectively improving pore size distribution. Although the type of hydration products did not change, there was an adverse effect on the 3 d compressive strength, from 64.3 MPa to 53.9 MPa, a decreased by 16.2%, while the 56 d compressive strength decreased by 6.99% and the adverse effect was reduced.更多还原