纳米级SiO_x与硅灰对水泥基材料的复合改性效应研究

STUDY ON COMPOUND EFFECT OF SILICA FUME AND NANO-SiO_x FOR CEMENTING COMPOSITE MATERIALS

用TEM测试评价了纳米级SiOx 与硅灰的颗粒形貌 ,在分别研究纳米级SiOx、硅灰的活性和其对水泥基复合材料改性的基础上 ,将纳米级SiOx 与硅灰复合作为高活性的掺合料 ,探索了对水泥基材料的复合改性效应 ,除进行宏观力学性能测试评价之外 ,用DTA ,XRD和SEM分析了水泥基材料的组成、显微结构。研究表明 ,纳米级SiOx 和硅灰具有很高的活性和表面效应 ,水泥石基体相的显微结构致密 ,CSH凝胶交织成致密的网状结构 ,结构缺陷显著降低。DTA ,XRD分析表明 ,水泥石中Ca(OH) 2 明显减少 ,由Ca(OH) 2 带来的砂浆和混凝土集料界面过渡区的缺陷将大大改善。此外 ,纳米级SiOx 与硅灰复合后对砂浆的力学性能改善效果比水泥净浆更为显著。

The characteristics of nano-SiOx powder and silica fume were investigated with TEM. The activity of silica fume and nano-SiOx was studied, and the compound effect for cementing composite materials was discussed. The relationship between component, microstructure and performance was evaluated with DTA, XRD and SEM testing. The results show that, the nano-SiOx and silica fume have good pozzolan activity and surface effect, in the hardened cement matrix, and the microstructure is very compacted. The CSH gel forms a dense net structure which is filled by secondary hydrate, so the structure defect is notably reduced. The results of DTA and XRD testing show that, in the hydration products, the Ca(OH)2 phase is notably reduced, and the CSH gel is notably increased with the use of nano-SiOx and silica fume. It is helpful to the improvement of the performance of cementing composite materials. The mechanical performance improvement of cement paste with nano-SiOx and silica fume is very notable than that of mortar.