Nanostructure of Calcium Silicate Hydrate Gels in Cement Paste |
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Authors: | Xiaozhong Zhang Wenyi Chang Tiejun Zhang Cong K. Ong |
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Affiliation: | Department of Materials Science and Engineering, Laboratory of Advanced Materials, Tsinghua University, Beijing 100084, People's Republic of China;Department of Physics, National University of Singapore, Singapore 119260, Republic of Singapore |
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Abstract: | High-resolution electron microscopy study of calcium silicate hydrate (C-S-H) gels in ordinary portland cement (OPC) and a slag/OPC blend has been performed. Nanocrystalline regions on the scale of ∼5 nm or less in C-S-H are found in both cement pastes, and they are formed after a curing time as brief as 7 d. A change in the d -spacing of the nanocrystalline regions with time is observed for the first time, which is believed to correspond to the development of C-S-H with time. The nanoheterogeneous nature of C-S-H is demonstrated and correlated to the strong Ca:Si ratio fluctuations that are observed. |
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Keywords: | portland cement calcium silicate hydrate microstructure |
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