Overestimation of ITZ thickness around regular polygon and ellipse aggregate

The interfacial transition zone (ITZ) between cement paste and aggregate is the weakest part of composites. To quantify the influence of the ITZ on macro-properties of composites, the ITZ area fraction should be considered. In this paper, apparent ITZ thickness around regular polygon and ellipse is determined by using a systematic line sampling algorithm. A generalized formula is proposed to obtain ITZ area fraction of concrete with 2D convex aggregates. Overestimation of ITZ area fraction and concrete diffusivity are calculated. Our study demonstrates that aggregate shape exerts an unneglectable impact on the ITZ thickness, and further on macro-properties of composites.