Characterization of Microstructure of Interfacial Transition Zone in Concrete

The interfacial transition zone (ITZ) refers to the microstructure of cement paste in the vicinity of an aggregate in concrete. In normal concrete, the ITZ has a considerably higher porosity than bulk cement paste and constitutes the weakest link of the normal concrete matrix. This article reports on a study undertaken to quantitatively evaluate the effect of ITZ on the physical and mechanical behavior of concrete. The authors investigated the characteristics of ITZ microstructure in a statistical manner. They developed an algorithm that simulates the three-dimensional distribution of cement particles between aggregates in concrete. After verifying the developed algorithm with experimental data, the authors developed models for the thickness of ITZ and the cement volume density between aggregates, as a function of the water-cement ratio, maximum diameter of cement particle, and the distance from the aggregate surface. These models show that the thickness of ITZ is in a range of 20 to 56 mm for normal concrete and that the cement volume density varies within the ITZ. The models presented in the paper use terms for the design parameters of concrete as they are already used by practical engineers; thus, the models have a real-world application.

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  • Authors:
    • Zheng, Jian Jun
    • Li, Chun Qing
    • Zhou, Xin Zhu
  • Publication Date: 2005-7


  • English

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  • Accession Number: 01003080
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 9 2005 7:15AM