*2.1. Materials*

The cement used in this study was a General Purpose Grey Portland cement (PC) supplied by Cockburn Cement of Western Australia. The commercially available class F fly ash (FA) and ultra fine fly ash (UFFA) were used as partial replacement of cement. The UFFA had 18% more amorphous content compared to FA. The chemical composition and physical properties of all materials used in this study are summarised in Table 1. The aggregates used consisted of coarse aggregates with sizes of 20 mm and 10 mm, while the fine aggregate was natural sand.


**Table 1.** Chemical composition and physical properties of materials.
