硅灰改性压实水泥材料的组成和微观结构

COMPOSITION AND MICROSTRUCTURE OF COMPACTED CEMENT MODIFIED WITH SILICA FUME

用ＤＴＡ、ＸＲＤ及ＳＥＭ分析了不同养护条件下硅灰改性前后压实水泥的组成和微观结构，并探讨了结构与耐久性的关系。结果表明：在常温水养护条件下，除Ｃａ（ＯＨ）２外，硅灰改性前后压实水泥的组成无明显差异；压蒸条件下，随压蒸时间延长伴有产物的转化和晶化，掺入硅灰后，产物向低ＣａＯ／ＳｉＯ２方向转化和晶化；材料结构中未水化水泥颗粒进一步水化以及产物的转化和晶化对材料的结构和性能产生不利影响。

DTA,XRD and SEM are used to characterize the constituents and microstructure of compacted cement with and without silica fume cured in different curing conditions. The relationship between microstructure and its durability is also discussed. The following observations are made:a) apart from Ca(OH) 2,there is no remarkable difference in the composition of hydration products before and after mcdification with silica fume under water curing condition at room temperature; b) the transformation and crystallization of hydration products are observed in autoclaved specimens and hydrates with low CaO/SiO 2 tend to form in specimens with silica fume;c)the further hydration of anhydrated cement particles and the transformation of original hydration products are unfavorable factors for microstructure and properties of compacted cement, which may destroy the existing structure of the material.