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Title: Mechanical behavior of a composite interface: Calcium-silicate-hydrates

The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces.
Authors:
; ;  [1] ;  [2]
  1. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
  2. Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
Publication Date:
OSTI Identifier:
22490796
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BIOLOGICAL MATERIALS; CALCIUM IONS; CALCIUM SILICATES; DENSITY FUNCTIONAL METHOD; HYDRATES; INTERFACES; MOLECULAR DYNAMICS METHOD; NANOSTRUCTURES; SHEAR; SHEAR PROPERTIES; SIMULATION; STACKING FAULTS; STRAINS; STRESSES