NMR技术研究水泥-矿渣复合胶凝材料水化产物凝胶的微观结构

Investigation on the microstructure of gel in hardened cement-slag complex binder pastes by NMR

利用固体高分辨魔角旋转29Si核磁共振谱(NM R)研究了不同矿渣含量的水泥-矿渣复合胶凝材料水化产凝胶的微观结构。结果显示:水泥-矿渣复合胶凝材料水化浆体的NMR谱中出现Q2(1Al)峰,表明其水化产物中含有C-A-S-H凝胶;随着矿渣掺量的增加,凝胶的平均直链长度和平均硅铝链长度增加,且C-A-S-H凝胶中AlSi比增大。水泥-矿渣复合胶凝材料早期水化主要生成短直链的二聚体凝胶。随着龄期延长,逐渐转变为立体连接的长链型凝胶,平均链长逐渐增加。随着矿渣掺量的增加,矿渣被激发所需时间延长,早期的水化产物量少,但后期仍能生成更多的C-A-S-H凝胶。

The microstructure of gel in hardened complex binder pastes blended with different dosage of slag was investigated by nuclear magnetic resonance （NMR）based on high -resolution magic -angle spinning （HR MAS ）technology. The results show that Q2（ 1 A1 ） peak appeared on the 29Si NMR spectra of the cement pastes blended with slag,which indicates that there was C-A-S-H gel in the hy- dration products.With the increasing of slag content, the average chain lengths of pure SiO4 tetrahedral and SiO4/A104 tetrahedral in- creased,Al/Si ratio of C-A-S-H gel increased as well.In early ages,the dimer gel with short linear chain was mainly in the cement- slag complex binder pastes. With the prolongation of hydrating ages, the three - dimensionally connected long - chain gel was produced and its average chain length increased gradually. With the increase of slag dosage, the activation of slag was put off and there were few hydration products in early ages ,however ,more C-A-S-H gel was produced in late ages.