Please use this identifier to cite or link to this item:
https://hdl.handle.net/20.500.14279/1522
Title: | The nanogranular nature of c-s-h |
Authors: | Constantinides, Georgios Ulm, Franz Josef |
metadata.dc.contributor.other: | Κωνσταντινίδης, Γιώργος |
Major Field of Science: | Engineering and Technology |
Keywords: | Granular materials;Statistical methods;Minerals;Nanostructured materials;Hydrates |
Issue Date: | Jan-2007 |
Source: | Journal of the Mechanics and Physics of Solids, 2007, vol. 55, no. 1, pp. 64-90. |
Volume: | 55 |
Issue: | 1 |
Start page: | 64 |
End page: | 90 |
Journal: | Journal of the Mechanics and Physics of Solids |
Abstract: | Despite its ubiquitous presence as binding phase in all cementitious materials, the mechanical behavior of calcium-silicate-hydrates (C-S-H) is still an enigma that has deceived many decoding attempts from experimental and theoretical sides. In this paper, we propose and validate a new technique and experimental protocol to rationally assess the nanomechanical behavior of C-S-H based on a statistical analysis of hundreds of nanoindentation tests. By means of this grid indentation technique we identify in situ two structurally distinct but compositionally similar C-S-H phases heretofore hypothesized to exist as low density (LD) C-S-H and high density (HD) C-S-H, or outer and inner products. The main finding of this paper is that both phases exhibit a unique nanogranular behavior which is driven by particle-to-particle contact forces rather than by mineral properties. We argue that this nanomechanical blueprint of material invariant behavior of C-S-H is a consequence of the hydration reactions during which precipitating C-S-H nanoparticles percolate generating contact surfaces. As hydration proceeds, these nanoparticles pack closer to center on-average around two characteristic limit packing densities, the random packing limit (η = 64 %) and the ordered face-centered cubic (fcc) or hexagonal close-packed (hcp) packing limit (η = 74 %), forming a characteristic LD C-S-H and HD C-S-H phase. |
URI: | https://hdl.handle.net/20.500.14279/1522 |
ISSN: | 00225096 |
DOI: | 10.1016/j.jmps.2006.06.003 |
Rights: | © Elsevier |
Type: | Article |
Affiliation: | Massachusetts Institute of Technology |
Affiliation : | Massachusetts Institute of Technology |
Publication Type: | Peer Reviewed |
Appears in Collections: | Άρθρα/Articles |
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