粉煤灰-脱硫石膏水泥基材料水化活性及微结构

Microstructure and Hydration Activity of Cement-based Materials Containing Fly Ash-Desulphurization Gypsum

采用DTA-TG、XRD、SEM以及宏观水化收缩和强度试验等手段研究了粉煤灰-脱硫石膏-水泥三元复合胶凝体系的水化过程、活性效应及微观结构等,根据试验结果总结了复合胶凝材料的水化动力学过程。结果表明,粉煤灰-脱硫石膏水泥石的钙矾石吸热峰强于基准样;在各组分相互活性激发和外掺激发剂作用下,粉煤灰-脱硫石膏水泥石中2次水化效应明显;SEM、XRD表明水泥石早期有明显的钙矾石生成,同时粉煤灰颗粒的表面侵蚀现象明显,进一步说明复合胶凝体系的早期活性得到有效激发,硬化后综合性能得到有效保证。且宏观收缩及强度试验也从侧面印证了微观试验结果。粉煤灰-脱硫石膏水泥基复合胶凝材料体系的研发可大量消耗燃煤电厂的工业废渣,具有显著的"绿色"效应。

The hydration process, activity and microstructure of composite cement-based materials containing fly ash（FA）and flue gas desulphurization gypsum（FGD）were investigated by using DTA-TG, XRD, SEM, hydration shrinkage and compressive strength tests. And then the hydration kinetics of composite cement-based materials was discussed and summarized. It is shown that the ettringite（AFt）DTA endothermic peak of the harden cement paste containing FA and FGD is stronger than that of the reference specimen. The secondary hydration effect of hardened FA-FGD cement paste is more obvious under the effects of mutually active excitation and the added activators. The results of SEM and XRD indicate that the AFt in harden cement paste is significantly found and the surface of FA particle is eroded, further illustrating that the early activity of composite cement based materials is effectively motivated, and ensuring the comprehensive properties of hardened composite cement-based materials. On the other hand, the test results of microscopic test were confirmed by the hydration shrinkage and compressive strength tests. Therefore, this research and application of FA-FGD composite cement-based materials can consume a lot of industrial wastes discharged from the power plant. It is a kind of ＂green＂ building material.