Title:
Characterization of Microstructure of Interfacial Transition Zone in Concrete
Author(s):
Jian Jun Zheng, Chun Qing Li, and Xin Zhu Zhou
Publication:
Materials Journal
Volume:
102
Issue:
4
Appears on pages(s):
265-271
Keywords:
cement volume density; concrete; particle size distribution
DOI:
10.14359/14620
Date:
7/1/2005
Abstract:
Interfacial transition zone (ITZ) constitutes the weakest link in the normal concrete matrix and significantly affects the properties of the concrete. To quantitatively evaluate the effect of ITZ on the physical and mechanical behavior of concrete, it is imperative to characterize the microstructure of ITZ. The intention of this paper is to investigate the characteristics of ITZ microstructure in a statistical manner. In this paper, an algorithm is developed to simulate the three-dimensional distribution of cement particles between aggregates in concrete. After verifying the developed algorithm with experimental data, models for the thickness of ITZ and the cement volume density between aggregates are developed as a function of the water-cement ratio, maximum diameter of cement particle, and the distance from the aggregate surface. It is found 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. A merit of the developed models is that they are expressed in terms of the design parameters of concrete used by practical engineers. It is concluded in the paper that the thickness of ITZ and the cement volume density between aggregates can effectively explicate the characteristics of the ITZ microstructure.