粉煤灰对复合胶凝材料硬化浆体微结构的影响

Influence of fly ash on microstructure of complex binder pastes

利用XRD和SEM-EDS对复合胶凝材料硬化浆体微结构进行了研究。结果显示:粉煤灰的掺入使胶凝材料中水泥的比例下降,导致硬化浆体中Ca(OH)2的含量降低,360 d龄期时各样品中仍有Ca(OH)2存在。粉煤灰掺入后,硬化浆体的早期微观结构会较为疏松,随着养护龄期的延长,大量低Ca/Si的C-S-H凝胶生成,使复合胶凝材料硬化浆体逐渐致密。

The microstructure of complex binder pastes was investigated by means of XRD and SEM-EDS.The results show that adding fly ash means the decrease of cement content in complex binder,which leads to the decrease of Ca（OH）2 content in complex binder pastes.The Ca（OH）2 crystal still exists in the complex binder pastes at the age of 360 days.By replacing part of cement with fly ash,the early microstructure of complex binder pastes becomes loosened.With the increasing of curing ages,a great quantity of C-S-H gel with low Ca/Si ratio are generated,which makes the hardened pastes compact gradually.