Colloidal nano silica (CNS) demonstrated positive effects in enhancing the water stability of magnesium phosphate cement (MPC), and the underlying mechanism was investigated systematically in this paper. The experimental results showed that the nucleation effect of CNS accelerated the intermediate phase transition process and significantly enhanced the struvite early formation rate of MPC. Moreover, the addition of CNS led to a shift from macropore to gel pores observed from pore size distribution. Notably, the filling effect of CNS and the formation of novel hydration products were identified as critical factors in enhancing water stability and optimizing pore structure. Simulation experiments provided further validation that CNS could directly react with dead-burnt magnesium oxide to generate a novel gel phase-magnesium silicate hydrate (M-S-H) which confirmed a possible hydration reaction of silica in MPC.

中文翻译：

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胶体纳米二氧化硅改性磷酸镁水泥的水稳定性改善及机理


胶体纳米二氧化硅 （CNS） 在增强磷酸镁水泥 （MPC） 的水稳定性方面表现出积极作用，本文系统研究了其潜在机制。实验结果表明，CNS 的成核效应加速了中间相变过程，显著提高了 MPC 的鸟粪石早期形成速率。此外，CNS 的添加导致从孔径分布观察到的从大孔到凝胶孔的转变。值得注意的是，CNS 的填充作用和新型水合产物的形成被确定为增强水稳定性和优化孔隙结构的关键因素。模拟实验进一步验证了 CNS 可以直接与枯烧的氧化镁反应生成新型凝胶相-硅酸镁水合物 （M-S-H），这证实了二氧化硅在 MPC 中可能存在水合反应。