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粉煤灰–水泥水化的核磁共振定量分析

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Abstract:

利用高分辨固体核磁共振仪结合去卷积技术,定量分析了粉煤灰水泥浆体中水泥和粉煤灰的水化程度以及C–S–H凝胶中硅氧–铝氧链平均长度,同时研究了粉煤灰火山灰反应对C–S–H结构的影响。结果表明水化3d时,系统中约47%的水泥和14%的粉煤灰参与了水化反应,C–S–H平均链长为3.2;水化120d时,水泥和粉煤灰的水化程度分别为89%和33%,C–S–H平均链长约为3.8,远大于纯水泥浆体中C–S–H的平均链长(为2.7)。水化3d时粉煤灰玻璃相结构中的Si—O—Si,Si—O—和Al—Al共价键断裂,形成了单体硅酸根和单体铝酸根,这些单体结构桥连体系中的二聚体单元进而提高了C–S–H平均链长。粉煤灰掺入并不会因为C–S–H聚合度提高以及ACL增加就能促进粉煤灰水泥浆体强度。

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