The mechanism of water-isopropanol exchange in cement pastes evidenced by NMR relaxometry
The mechanism of water-isopropanol exchange in cement pastes evidenced by NMR relaxometry
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DOI：
10.1039/c4ra00889h
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发表时间：
2014-01-01
期刊：
影响因子：
3.9
通讯作者：
McDonald, Peter J.
中科院分区：
文献类型：
--
作者：
Kowalczyk, Radoslaw M.;Gajewicz, Agata M.;McDonald, Peter J.
H-1核磁共振弛豫测量表明，异丙醇交换阻止水泥浆体水化并不是简单地用异丙醇取代孔隙水。异丙醇填充毛细血管空隙。它清除和置换了水化硅酸钙(C-S-H)间孔隙中的水分。在C-S-H凝胶孔隙中，异丙醇吸出水分，但不会以同样的程度取代它。这种交换对C-S-H层间水的影响很小。C-S-H孔结构中的质子-氚化学交换证明了层间-凝胶网络、水合物间孔和毛细孔的连通性，这是首次实验观察到的。异丙醇还揭示了在饱和水的样品中没有检测到的大的毛细管空洞的存在。
H-1 nuclear magnetic resonance (NMR) relaxometry shows that arresting the hydration of cement paste by isopropanol exchange does not involve simple replacement of the pore water with isopropanol. Isopropanol fills capillary voids. It removes and replaces the water in the calcium-silicate-hydrate (C-S-H) interhydrate pores. In the C-S-H gel pores, the isopropanol draws water out, but does not replace it to the same extent. The exchange has only a minor impact on C-S-H interlayer water. The connectivity of the interlayer-gel network and interhydrate pores and capillary voids is evidenced by proton-deuteron chemical exchange in the C-S-H pore structure which is observed experimentally for the first time. Isopropanol also reveals the presence of large capillary voids that are not detected in samples saturated with water.