A numerical algorithm for the ITZ area fraction in concrete with elliptical aggregate particles

In view of the importance of the interfacial transition zone (ITZ) to the macro-properties of concrete, it is essential to determine the ITZ area fraction in concrete. Once the ITZ area fraction is known, the physico-mechanical properties of concrete can be predicted based on the three-phase composite model. The intention of the present paper is to develop a numerical algorithm for the ITZ area fraction in concrete with elliptical aggregate particles. By introducing a contact function for two ellipses, the elliptical aggregate particles with various sizes are distributed within a square element with periodic boundary conditions. The Monte Carlo method is then adopted to evaluate the ITZ area fraction. After verifying the developed numerical algorithm with the analytical solution for the ITZ area fraction in concrete with circular aggregate particles, the effects of key factors that affect the ITZ area fraction are examined in a quantitative manner. It is found in the paper that the ITZ area fraction incre...