DEM analysis on the role of aggregates on concrete strength

P. Wang, N. Gao, K. Ji, L. Stewart, C. Arson

Research output: Journal article publicationJournal articleAcademic researchpeer-review

29 Citations (Scopus)

Abstract

This study aims to understand the micro-mechanisms that drive fracture propagation in concrete and to assess the roles of the strength of aggregates and of the aggregate/mortar interfacial transition zone (ITZ) on concrete strength. We use the Discrete Element Method (DEM) to model concrete samples. Mortar is represented by a volume of bonded spherical elements. Bonds are governed by a new displacement-softening law. Aggregate centroids are randomly placed in the DEM sample. We use CT scan images of real aggregates to plot 3D aggregate contours. The spherical elements that are contained in 3D contours around the randomly placed centroids are replaced by clusters with aggregate properties. The number and the size of the clusters are determined from the experimental Particle Size Distribution. The DEM concrete model is calibrated against uniaxial compression tests and Brazilian tests of both mortar and concrete. It is found that: At same aggregate volume fraction, a concrete sample with randomly placed aggregates and ITZ bonds is stronger; Concrete strength is linearly related to aggregate tensile strength; A linear relationship exists between the contact ratio in the mortar/aggregate ITZ and concrete strength; The ITZ has more influence on concrete strength than aggregate tensile strength.

Original languageEnglish
Article number103290
JournalComputers and Geotechnics
Volume119
DOIs
Publication statusPublished - Mar 2020
Externally publishedYes

Keywords

  • Aggregates
  • Concrete strength
  • CT scan
  • DEM
  • Interfacial transition zone
  • Physical tests

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Computer Science Applications

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