Microstructure–toughness relationships in calcium aluminate cement–polymer composites using instrumented scratch testing

Kevin Anderson, Ange Therese Akono*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We investigate the influence of the microstructure on the fracture properties of calcium aluminate cement/polymer composites. We carry out microscopic scratch tests during which a Rockwell C diamond probe pushes across the surface of a polished specimen under a linearly increasing vertical force. We extend the scratch fracture method to heterogeneous materials. The scratch test induces a ductile-to-brittle transition as the penetration depth increases. Scanning electron microscopy imaging shows that the low porosity and the strong cement-binder interphase favor toughening mechanisms such as crack trapping and bridging. Nonlinear fracture mechanics theory yields the fracture toughness in the fracture-driven regime. The fracture toughness of macro-defect-free (MDF) cement is found to decrease as the polymer-to-cement ratio increases. This decrease in the fracture resistance can be explained by the decrease in anhydrous cement content and the increase in the inter-particle distance between cement grains. By evaluating the fracture toughness of the micro-constituents of MDF cement, we show that the high value of the fracture toughness at the composite level stems from tough calcium aluminate phases and a highly packed non-porous granular microstructure.

Original languageEnglish (US)
Pages (from-to)13120-13132
Number of pages13
JournalJournal of Materials Science
Volume52
Issue number22
DOIs
StatePublished - Nov 1 2017

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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