Size effect on biaxial flexural strength of concrete

Goangseup Zi, Jihwan Kim, Zdeněk P. Bažant

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


The size effect on the tensile strength of concrete is investigated experimentally for the case of equi-biaxial tension. Tests of tensile strength under uniaxial tension were carried out for comparison using four-point bend beams. For measuring the biaxial tensile strength, the ASTM C1550 test and the biaxial flexure test were examined. To study the size effect, unreinforced circular plates of three different sizes are tested, with 13 specimens per size. The size effect on the equi-biaxial tensile strength is found to be stronger than it is on the uniaxial tensile strength, and to exhibit the characteristics of the deterministic Type I size effect. The detailed experimental procedure and the results are reported in this paper. Under the assumption that a distinct continuous crack develops only after the peak load, the approximate law of size effect is derived from the stress redistribution due to a boundary layer of cracking. The analysis leads to a deterministic Type I size effect.

Original languageEnglish
Pages (from-to)319-326
Number of pages8
JournalACI Materials Journal
Issue number3
Publication statusPublished - 2014


  • Biaxial tensile strength
  • Flexural tensile strength
  • Fracture mechanics
  • Material testing
  • Size effect
  • Strength scaling

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science


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