The mean of the predictions was about the same as for the mixtures for the bending
tests (Table 4.5). Hoy [1998] found that the ‘Solid Suspension Model’ overestimates the
packing density of fibres with sand or coarse aggregates, whereas it underestimates it at
50% sand to total aggregate. The accuracy of the prediction thus depends on the
composition of the aggregates. Fig. 4.9 shows the comparison between the
experimental and numerical results on the packing density. The CPM slightly
underestimate the packing density at high packing densities (Fig. 4.9), while it
overestimates it in case fewer fractions were applied (sand or coarse aggregates).
Mixture 8 contained only three fractions, and the packing density was overestimated.
Therefore, the accuracy of the predictions for mortars with fibres is expected to be
worse.