Abstract
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 nm− 1–30 nm− 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 nm− 1–8 nm− 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.
Original language | English |
---|---|
Pages (from-to) | 24-32 |
Number of pages | 9 |
Journal | Cement and Concrete Research |
Volume | 91 |
DOIs | |
Publication status | Published - 2017 Jan 1 |
Keywords
- Adsorption (C)
- Calcium–silicate–hydrate (C–S–H) (B)
- Drying (A)
- Microstructure (B)
- Small-angle X-ray scattering (B)
ASJC Scopus subject areas
- Building and Construction
- Materials Science(all)