Water Vapor Sorption in Cementitious Materials-Measurement, Modeling and Interpretation

Abstract

The rate and extent of uptake and release of moisture are critical in controlling the behavior of cementitious materials ranging from fluid transport to hygral deformations. While classically determined using an equilibrium (static) salt solution method (Baroghel-Bouny in Cem Concr Res 37:414-437, 2007), advanced capabilities offered by gravimetric dynamic vapor sorption (DVS) analyzers, are now permitting acquisition of sorption spectra at microgram (µg) resolution on the order of a few weeks. This work highlights new multicycle determinations of adsorption/desorption isotherms, acquired using a custom-built DVS analyzer for well-hydrated alite and ordinary portland cement pastes over a range of water-to-solid ratios (w/s, mass basis). Special focus is paid to describe measurement aspects relevant to acquiring reliable spectra, and their interpretation. Sorption isotherms are used to assess transport properties, and sorption hysteresis and its irreversibility following first drying. Based on an optimization-based criterion, the Young-Nelson model is selected to simulate sorption evolutions, including the effects of hysteresis. Sensitivity analyses carried out using this model are used to understand the role of parameters, including porosity and w/s, on the hysteresis that develops from the first to subsequent sorption cycles.

Department(s)

Materials Science and Engineering

Keywords and Phrases

BET; Desorption; Hysteresis; Sorption; Surface area; Water vapor

International Standard Serial Number (ISSN)

0169-3913; 1573-1634

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2014 Kluwer Academic Publishers, All rights reserved.

Publication Date

01 May 2014

Link to Full Text

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