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Meso-structural modelling in recycled aggregate concrete 455
Figure 15.1 Stress distribution around aggregate.
Figure 15.2 Aggregate/matrix interface: (A) morphology (10,000 3 ); (B) solids, pores and
water in the ITZ. ITZ, Interfacial transition zone.
aggregate accounting for approximately 50% 70% of concrete volume (Kong
et al., 2014). As a result, in some models the ITZ constitutes 27% 20% of the total
volume (Jia et al., 2017; Bernard and Kamali-Bernard, 2015).
As Fig. 15.1 shows, when the matrix is subjected to compression, failure occurs
at the aggregate/mortar ITZ due to the simultaneous action of compressive stress
and shear (Setiawan et al., 2017).
The ITZ (see Fig. 15.2A) spreads outward radially from the surface of the aggre-
gate into the cement matrix. The microstructural properties of the two differ widely:
