硅灰改性水泥/石灰砂浆微观结构的研究

以水泥和石灰为胶凝材料,中细砂为集料,再掺加有机聚合物流化剂制成水泥/石灰砂浆,水泥/石灰砂浆中添加外加剂的文献资料很少,通常是有关水泥砂浆的研究.本实验用硅灰取代10%(质量分数)的普通硅酸盐水泥,水泥、石灰和砂子的质量比为3:1:12,外加有机聚合物对砂浆改性,利用扫描电子显微镜、能谱仪和压汞仪对浆体进行微观分析.分析结果显示,由于硅灰的加入,浆体内部水化产物在早期先以Ⅲ型C-S-H凝胶的形式出现,随后,Ⅲ型和I型的C-S-H凝胶以并存的形式在水化后期出现;正如预期的那样,试样的总的孔隙率也比没加硅灰前有了大幅度的下降,而抗压强度的提高在水化后期才表现出来.

Microstructural Investigation of Silica Fume Modified Cement/Lime Mortar

In this experiment, several additions, minerals and organic such as pozzolanic materials, cementicious materials and polymers,are used in mortars. Literature about the use of additions in masonry mortars (cement/lime/sand mixes) is scarce, often the studies are about concrete mortars. The purpose of this work is to study the microstructural effects of the substitution of 10% of ordinary portland cement by silica fume in a 3:1:12 (cement/lime/sand mix proportion by mass) masonry mortar. Scanning electron microscopy with energy dispersive X-rays analysis (SEM/EDX) shows that, with silica fume, the C-S-H formed is type III at early ages and the type III and type I coexist at later ages. As expected, silica fume lowers the total porosity and increases compressive strength only at later age,and the pore structure of mortar with silica fume is found to be finer than of non-silica fume mortar.