Abstract
The hydration of cement is often modeled as a phase boundary nucleation and growth (pBNG) process. Classical pBNG models, based on the use of isotropic and constant growth rate of the main hydrate, that is, calcium-silicate-hydrate (C-S-H), are unable to explain the lack of any significant effect of the water-to-cement (w/c) ratio on the hydration kinetics of cement. This paper presents a modified form of the pBNG model, in which the anisotropic growth of C-S-H is allowed to vary in relation to the nonlinear evolution of its supersaturation in solution. Results show that once the supercritical C-S-H nuclei form, their growth remains confined within a region in proximity to the cement particles. This is hypothesized to be a manifestation of the sedimentation of cement particles, which imposes a space constraint for C-S-H growth. In pastes wherein the sedimentation of cement particles is disrupted, the hydration kinetics are no longer unresponsive to changes in w/c. Unlike C-S-H, the ions in solution are not confined, and hence, the supersaturation-dependent growth rate of C-S-H diminishes monotonically with increasing w/c. Overall, the outcomes of this work highlight important aspects that need to be considered in employing pBNG models for simulating hydration of cement-based systems.
Recommended Citation
A. M. Ley-Hernandez et al., "Elucidating the Effect of Water-To-Cement Ratio on the Hydration Mechanisms of Cement," ACS Omega, vol. 3, no. 5, pp. 5092 - 5105, American Chemical Society (ACS), May 2018.
The definitive version is available at https://doi.org/10.1021/acsomega.8b00097
Department(s)
Materials Science and Engineering
Second Department
Civil, Architectural and Environmental Engineering
International Standard Serial Number (ISSN)
2470-1343
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2018 American Chemical Society (ACS), All rights reserved.
Publication Date
01 May 2018
Comments
This research was conducted in the Materials Research Center (MRC) at Missouri S&T. The authors gratefully acknowledge the financial support that has made these laboratories and their operations possible. Funding for this research was provided by the National Science Foundation [NSF, CMMI: 1661609], MRC at Missouri S&T [MRC Young Investigator Seed Funding] and the University of Missouri Research Board [UMRB].