硅粉的硅烷化对水泥砂浆阻尼性能的影响

EFFECTS OF SILANE-TREATED SILICA FUME ON DAMPING PROPERTY OF CEMENT MORTAR

利用硅烷偶联剂对硅粉进行了表面改性。用粘弹谱仪在-30～30℃和0.1～2 Hz条件下测定了在水泥砂浆中掺加硅粉和改性硅粉后水泥砂浆的储存模量和损耗因子;用X射线和扫描电镜对掺硅粉和改性硅粉的水泥砂浆试样进行了微观分析;最后对硅烷偶联剂的改性机理进行了分析。试验结果表明:改性硅粉与未改性硅粉相比,使水泥砂浆的损耗因子提高了20％～200％、储存模量提高了10％～20％;微观分析显示:硅烷偶联剂中的X基水解与水泥水化产物CH凝胶形成氢键后脱水形成硅氧键,这种网络搭接结构是提高硅粉水泥砂浆损耗因子的主要原因,而聚合物的减水和填充作用使得硅粉水泥砂浆的储存模量略有提高。试验结果为进一步研究有机和无机材料的融合提供了基础。

The surface modification of silica fume was made by using a silane coupling agent. The storage modulus and the loss tangent of different cement mortars after adding the silane-treated silica fume or as-received silica fume in the cement mortar were measured by the viscoelastic analyzer VA4000 at the temperature range of -30-30°C and the frequency range of 0.1-2 Hz. The microstructure of cement mortar specimens was analyzed by means of X-ray diffraction and scanning electron microscope. The experiment results show that the loss tangent of cement mortar containing the treated silica fume increases 20%-200% and the storage modulus increases 10%-20% compared with that of cement mortar containing as-received silica fume. It is showed that-OH group from -X group of silane coupling agent by hydrolization is connected with -OH group from cement hydration product Ca(OH)2, and then the Si-O bond occurs after dehydration. This net structure is the main reason of improving the loss tangent of cement mortar with the treated silica fume. The storage modulus of cement mortar with the treated silica fume also increases due to the water reduction and the filling function of the treated silica fume.