活性粉末混凝土微观结构及其对强度与抗氯离子渗透性能的影响研究

Influenceof micro-structure on the strength and resistance to chloride ion permeability of reactive powder concrete

在多种矿物掺合料混掺的活性粉末混凝土的强度和电通量试验基础上,运用x射线衍射分析(XRD)、汞压力测孔分析(MIP)及扫描电镜观察(SEM)技术,研究了活性粉末混凝土的主要水化产物、孔结构和微观形貌,探讨了各种矿物掺合料对活性粉末混凝土的强度和抗氯离子渗透性的影响机理.研究结果表明,在各种活性粉末对混凝土的性能增强作用中,硅粉的含量是最主要的因素;掺入矿粉和偏高岭土的活性粉末混凝土样品,比单一使用硅粉的样品孔隙率略低;高温养护下偏高岭土在提高材料抗氯离子渗透性方面的作用比矿粉明显;不论对于哪一种矿物原料的掺合方式,活性粉末混凝土的强度和抗氯离子渗透性能都随着养护温度的提高而有所增强.

The samples of reactive powder concrete mixed with various mineral admixtures were prepared and tested to in- vestigate the strength and electric flux. The hydration products, pore-structure and micro-structure were studied by X-ray diffraction （XRD）, mercury intrusion porosimetry （MIP） and scanning electron microscope （SEM）. The high strength and resistance to chloride ion permeability mechanism of RPC was discussed. The results indicated that the content of sili- ca fume is the most important factor to enhance the performance of reactive powder concrete. The porosities of samples in- corporated with mineral powder and metakaolin are lower than those samples which contain silica fume only. As cured with high temperature, metakaolin is more powerful in improving the resistance to chloride ion permeability than mineral pow- der. With the increasing of curing temperature, the strength and resistance to permeability are increased obviously, and this character is not influenced by the changing of mineral raw materials blending method.