Reactive molecular dynamics simulation of the mechanical behavior of sodium aluminosilicate geopolymer and calcium silicate hydrate composites

Mohammad Rafat Sadat, Krishna Muralidharan, Lianyang Zhang

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

This paper for the first time used reactive molecular dynamics (MD) simulation to study the mechanical behavior of geopolymer binder (GB) and calcium silicate hydrate (CSH) composites. Specifically, GB-CSH composites with different Ca/Si ratios for the CSH phase were constructed and their mechanical behavior in terms of ultimate tensile strength, fracture toughness and strain energy release rates were investigated. It was observed that the Ca/Si ratio of CSH greatly affects the mechanical response of the composite. Increasing the Ca/Si ratio from 1.2 to 1.65 created more disorder in the silica layers in CSH and decreased the mechanical properties of the composite. However, the completely glassy CSH at a Ca/Si ratio of 2.0 showed slight improvement of mechanical properties due to high three-dimensional (3D) tetrahedral network. A detailed analysis of bond evolution and bond angle distribution showed their direct correlation with the observed mechanical response. The failure of the GB-CSH composites were always governed by the breaking of Si–O bonds within the CSH, near the GB-CSH interface. Low Ca/Si ratio structures showed more Si–O bond breakage, while in high Ca/Si ratio structures, deformation mobilization was accompanied by significant change in bond angles within GB.

Original languageEnglish (US)
Pages (from-to)500-509
Number of pages10
JournalComputational Materials Science
Volume150
DOIs
StatePublished - Jul 1 2018

Fingerprint

Silicic Acid
Geopolymers
calcium silicates
Calcium silicate
Aluminosilicates
Mechanical Behavior
Hydrates
Calcium
Sodium
hydrates
Molecular Dynamics Simulation
Molecular dynamics
silicates
Composite
sodium
molecular dynamics
composite materials
Computer simulation
Composite materials
Binders

Keywords

  • Composite
  • CSH
  • Fracture
  • Geopolymer
  • Interface
  • ReaxFF

ASJC Scopus subject areas

  • Computer Science(all)
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Computational Mathematics

Cite this

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abstract = "This paper for the first time used reactive molecular dynamics (MD) simulation to study the mechanical behavior of geopolymer binder (GB) and calcium silicate hydrate (CSH) composites. Specifically, GB-CSH composites with different Ca/Si ratios for the CSH phase were constructed and their mechanical behavior in terms of ultimate tensile strength, fracture toughness and strain energy release rates were investigated. It was observed that the Ca/Si ratio of CSH greatly affects the mechanical response of the composite. Increasing the Ca/Si ratio from 1.2 to 1.65 created more disorder in the silica layers in CSH and decreased the mechanical properties of the composite. However, the completely glassy CSH at a Ca/Si ratio of 2.0 showed slight improvement of mechanical properties due to high three-dimensional (3D) tetrahedral network. A detailed analysis of bond evolution and bond angle distribution showed their direct correlation with the observed mechanical response. The failure of the GB-CSH composites were always governed by the breaking of Si–O bonds within the CSH, near the GB-CSH interface. Low Ca/Si ratio structures showed more Si–O bond breakage, while in high Ca/Si ratio structures, deformation mobilization was accompanied by significant change in bond angles within GB.",
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author = "Sadat, {Mohammad Rafat} and Krishna Muralidharan and Lianyang Zhang",
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AU - Muralidharan, Krishna

AU - Zhang, Lianyang

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AB - This paper for the first time used reactive molecular dynamics (MD) simulation to study the mechanical behavior of geopolymer binder (GB) and calcium silicate hydrate (CSH) composites. Specifically, GB-CSH composites with different Ca/Si ratios for the CSH phase were constructed and their mechanical behavior in terms of ultimate tensile strength, fracture toughness and strain energy release rates were investigated. It was observed that the Ca/Si ratio of CSH greatly affects the mechanical response of the composite. Increasing the Ca/Si ratio from 1.2 to 1.65 created more disorder in the silica layers in CSH and decreased the mechanical properties of the composite. However, the completely glassy CSH at a Ca/Si ratio of 2.0 showed slight improvement of mechanical properties due to high three-dimensional (3D) tetrahedral network. A detailed analysis of bond evolution and bond angle distribution showed their direct correlation with the observed mechanical response. The failure of the GB-CSH composites were always governed by the breaking of Si–O bonds within the CSH, near the GB-CSH interface. Low Ca/Si ratio structures showed more Si–O bond breakage, while in high Ca/Si ratio structures, deformation mobilization was accompanied by significant change in bond angles within GB.

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