Figure 8. Contribution of friction and tensile strength on unconfined yield strength.

4.2 Comparison of experimental and DEM results

At the 2000 Pa pre-shear load, the DEM predictions for the shear stress at steady state are compared to the experimentally measured τpre. This comparison is shown in Figure 9; higher τpre values represent poorer flowing systems. The predicted stresses associated with the binary blends are larger than those of the monodispersed particles, exhibiting the same trend as the experimental results. However, the DEM predictions for τpre are lower than the experimental values, possibly due to neglecting the size distribution associated with the large and small glass beads.