Water sorption isotherms and hysteresis of cement paste at moderately high temperature, up to 80 °C
Abstract
The constitutive models of concrete often consider water desorption isotherms to be near-equilibrium and significantly affected by moderately high temperature, 40–80 °C, typically through microstructural changes. However literature data suggest that adsorption, not desorption, is near-equilibrium and moderate temperatures do not cause microstructural changes. This work supports the latter theory, through dynamic vapor sorption experiments on cement paste at 20–80 °C. Samples were pre-conditioned at 60% relative humidity and 20 °C, and isotherms were measured for several humidity ranges and testing rates. The results, corroborated by classical DFT simulations, indicate that adsorption is near-equilibrium and mostly unaffected by temperature, whereas desorption is out-of-equilibrium due to the ink-bottle effect at high humidity, and interlayer water at low humidity. Starting from the second cycle, desorption at higher temperatures features a shift of the cavitation pressure and overall a smaller hysteresis. A conceptual model of pore-specific temperature-dependent hysteresis is proposed to qualitatively explain the results.
Additional Information
Attribution 4.0 International (CC BY 4.0) The research leading to this publication benefited from EPSRC funding under grant No. EP/R010161/1 and from support from the UKCRIC Coordination Node, EPSRC grant number EP/R017727/1, which funds UKCRIC's ongoing coordination.Attached Files
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Additional details
- Eprint ID
- 119170
- Resolver ID
- CaltechAUTHORS:20230209-988069100.3
- EP/R010161/1
- Engineering and Physical Sciences Research Council (EPSRC)
- EP/R017727/1
- Engineering and Physical Sciences Research Council (EPSRC)
- Created
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2023-03-15Created from EPrint's datestamp field
- Updated
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2023-03-15Created from EPrint's last_modified field