Title: May reversible water uptake/release by hydrates explain the thermal expansion of cement paste? - Arguments from an inverse multiscale analysis
Language: English
Authors: Wang, Hui
Hellmich, Christian
Yuan, Yong
Mang, Herbert
Pichler, Bernhard 
Category: Research Article
Issue Date: 2018
Journal: Cement and Concrete Research
ISSN: 1873-3948
Quasi-instantaneous thermal expansion of cement pastes is governed by the relative humidity (RH) within their air-filled pores and by the decrease/increase of this internal RH resulting from a temperature decrease/increase. The latter effect is traced back to quasi-instantaneous water uptake/release by cement hydrates, using microporomechanics and a three-scale representation of mature cement pastes. Partially saturated gel and capillary pores are considered to be connected and spherical, with radii following exponential distributions. The Mori-Tanaka scheme provides the scale transition from effective pore pressures to eigenstrains at the cement paste level. This modeling approach, together with considering mass conservation of water, allows for downscaling macroscopic thermal expansion coefficients, so as to identify the molecular water uptake/release characteristics of the hydrates. The latter characteristics are mixture-independent, as shown by their use for predicting the thermal expansion coefficients of different mature cement pastes, with w/c-ratios ranging from 0.50 to 0.70.
Keywords: Coefficient of thermal expansion; Poromechanics; Poroelasticity; Multiscale analysis; Partial saturation
DOI: 10.1016/j.cemconres.2018.05.008
Library ID: AC15534594
URN: urn:nbn:at:at-ubtuw:3-7964
Organisation: E202 - Institut für Mechanik der Werkstoffe und Strukturen 
Publication Type: Article
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