In:
The Journal of Chemical Physics, AIP Publishing, Vol. 153, No. 1 ( 2020-07-07)
Abstract:
Concrete gains its strength from the precipitation of a calcium–alumino–silicate–hydrate (C–A–S–H) colloidal gel, which acts as its binding phase. However, despite concrete’s ubiquity in the building environment, the atomic-scale mechanism of C–A–S–H precipitation is still unclear. Here, we use reactive molecular dynamics simulations to model the early-age precipitation of a C–A–S–H gel. We find that, upon gelation, silicate and aluminate precursors condensate and polymerize to form an aluminosilicate gel network. Notably, we demonstrate that the gelation reaction is driven by the existence of a mismatch of atomic-level internal stress between Si and Al polytopes, which are initially experiencing some local tension and compression, respectively. The polymerization of Si and Al polytopes enables the release of these competitive stresses.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2020
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
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