BIDISPERSE MIXTURES OF SAND: EFFECTS OF GRANULOMETRY ON ITS PACKING AND FLOWABILITY

The present work aims to evaluate the effect of granulometry (particle size and particle size distribution) on the manly physical properties of bidisperse bulk solids, such as bulk density, porosity, cohesion, compressibility and basic flow energy. Therefore, two groups of mixtures comprising commercial sands with different sizes were prepared. The first group (G1) consisted on adding two sort of fine quartz powder (particle undersize of 200 and 600 mesh) into commercial sand 50/60 (coarse). The second group (G2) was formulated adding commercial sand (80/100 and 50/60) added into coarse one (40/50). All mixtures were tested at static and dynamic conditions and at incipient transition (shear test). As result, it was observed higher interactions for smaller quartz’s particles that lead to form agglomerates, increasing bulk porosity and reducing bulk density of non-consolidated mixtures comprising this sort of material. Fine particles at group 1 mixtures have also improved the quality of fluidization, but decrease powder flowability increasing cohesion. The results obtained for group 2 mixtures have revealed no significant changes on bulk properties as increasing fine particle into coarse one. This is could be attributed to the low ratio between fine and coarse particles, changing particle packing, once the interspaces between coarse particles could not be filled with fine one