کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5437149 | 1509732 | 2017 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Microstructural changes in white Portland cement paste under the first drying process evaluated by WAXS, SAXS, and USAXS Microstructural changes in white Portland cement paste under the first drying process evaluated by WAXS, SAXS, and USAXS](/preview/png/5437149.png)
Meso- and micro-scale structural changes in matured hardened cement paste dried slowly for 1.5 years at different relative humidities (RHs) are evaluated by small-angle X-ray scattering profiles covering a q range of 0.017 nmâ 1-30 nmâ 1 with a fractal disc-shaped particle analysis and Guinier approximation. The fractal disc-shaped particle analysis revealed that calcium-silicate-hydrate (C-S-H) agglomerations are very thin (~ 2.5 nm) and of relatively large width (~ 35 nm) under high RH conditions. However, the agglomerations are segmented (in width) into ~ 10 nm below an RH of 40%. The Guinier approximation found the possibility that the scattering profiles in the range of 2 nmâ 1-8 nmâ 1 correspond to a spacing between C-S-H monolayers and it showed stepwise changes at 40%-50% RH. The stepwise behavior of the distance between C-S-H monolayers may explain a kink in water vapor desorption at around 40% RH.
Journal: Cement and Concrete Research - Volume 91, January 2017, Pages 24-32