中文摘要：

研究了固化模拟放射性核素Sr对磷酸镁水泥性能的影响,通过分析固化体水化热、物相组成及微观形貌,探讨了Sr对磷酸镁水泥水化特性的影响机理。结果表明：固化体的力学性能优异,1 d抗压强度即可达到国家标准的4.5倍以上;磷酸镁水泥固化体具有优异的抗浸出性,42 d浸出率及累计浸出分数远低于国家标准的要求;Sr会阻碍磷酸盐在水化初期的水解及电离,同时MgO溶解及水化产物MgKPO_4·6H_2O生成的速率随Sr掺量增大而减缓;掺入Sr后水化产物生成量大幅下降是水化初期抗压强度降低的主要原因,随着龄期增长,水化产物结晶程度降低、结构改变以及孔隙孔径增大成为固化体抗压强度降低的主要原因。

英文摘要：

Effect of solidifying simulated radionuclide Sr on the performance of magnesium phosphate cement （MPC） was investigated. The mechanism on the hydration characteristics of magnesium phosphate cement after solidifying Sr was discussed via the analysis of the hydration heat, phase composition and microstructures of the solidified bodies. The results show that magnesium phosphate cement solidified bodies have superior mechanical properties, and the compressive strength of solidified bodies at 1 d is 4.5 times greater than that of the national standard. The leaching rate and the cumulative leaching fraction of magnesium phosphate cement solidified bodies at 42 d are less than those of the national standard because of the high resistance of leaching. Sr can hinder the hydrolysis and ionization of phosphate in the early stage of hydration, while the rate of the solution of MgO and the formation of hydration product MgKPO4·6H20 decrease with the increase of Sr content. The yield of hydration products decreases after mixing Sr, which is the main reason for the decrease of compressive strength at the initial stage of hydration. The crystallization degree decreases, the structure of hydration product changes and the pore size increases with the increase of curing time, resulting in the decrease of the compressive strength.