纳米硅溶胶对水泥砂浆力学性能的影响及其作用机理初探

Effect of Nano-silica Sol on Mechanical Properties of Cement Mortar and the Action Mechanism

在水泥基材料中掺入不同pH值的纳米硅溶胶,研究了其对水泥胶砂力学性能的作用规律,并通过XRD、SEM微观测试手段分析了硅溶胶中纳米SiO2的火山灰活性及其对水泥石微观结构的影响。研究结果表明:酸性、中性及碱性硅溶胶在适当掺量下可提高水泥砂浆的力学性质、改善水泥石的微观结构;酸性和中性硅溶胶在碱性条件下极易团聚,纳米二氧化硅粒子的火山灰效应难以充分发挥,在最佳掺量下其对水泥砂浆的增强效果不及碱性硅溶胶。

By mixing the nano-silica sol with different pH values into cement-based material, its strengthen effect on the cement mortar was studied. With the XRD, SEM micro-test methods, the pozzolanic activity of nano-SiO2 in the silica sol and its effect on the cement stone have been analysised. The results showed that acid, neutral and alkaline silica sol can enhance the strength of the cement mortar and improve the micro-structure of the cement stone with appropriate mixing amount. The acid and neutral silica sol are easily agglomerated in the alkaline condition, in this case the pozzolanic activity of the nano-SiO2 particale can not be completely stimulated developed, and have weaker enhancing effect on the strength of cement mortar compared to the alkaline silica sol.