کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1330698 | 978971 | 2011 | 9 صفحه PDF | دانلود رایگان |
Hydrothermal synthesis process of tobermorite (5CaO·6SiO2·5H2O) has been investigated by in-situ X-ray diffraction using high-energy X-rays from a synchrotron radiation source in combination with a purpose-build autoclave cell. Dissolution rates of quartz were largely affected by its particle size distribution in the starting mixtures. However, the composition (Ca/Si) of non-crystalline C–S–H at the start of tobermorite formation was identical regardless of the quartz dissolution rate. An effect of water-to-solid ratio (w/s) was investigated for samples using fine particle quartz. Tobermorite did not occur with w/s of 1.7 but occurred with w/s higher than 3.0. Surprisingly, however, the dissolution curves of quartz were nearly identical for all samples with w/s from 1.7 to 9, indicating that the dissolution rate is predominated by surface area. Possible reaction mechanism for tobermorite formation will be discussed in terms of Ca and/or silicate ion concentration in the liquid phase and distribution of Ca/Si in non-crystalline C–S–H.
Time-resolved XRD data set was obtained at up to 190 °C under a saturated steam pressure. Tobermorite (5CaO·6SiO2·5H2O) formation reaction was investigated in detail for several different starting materials.Figure optionsDownload as PowerPoint slideHighlights
► Hydrothermal formation of tobermorite was monitored by in-situ XRD.
► Ca/Si of C–S–H at the start time of tobermorite formation was determined.
► The Ca/Si value was identical regardless of the quartz particle size in the starting mixture.
Journal: Journal of Solid State Chemistry - Volume 184, Issue 8, August 2011, Pages 2066–2074