Dispersions, including suspensions, are employed in a large variety of industrially flows, like coating flows. A common rheological behavior observed in many semi-dense and dense suspensions is shear-thickening, a non-linear fluid response characterized by an increase in the fluid viscosity at moderate and high shear rates. When the viscosity increases mildly, the shear thickening can be classified as continuous (CST). On the other hand, when an abrupt jump in the viscosity curve is seen, discontinuous shear-thickening (DST) is reported. Much progress in the research of shear-thickening fluids have been made over the last decades and nowadays the mostly widely accepted mechanics to explain the transition from CST to DST is the frictional model, in which frictional contacts become dominant over the lubrication interactions at the onset of DST. The study of suspensions in concentrated regimes is quite complex to be performed experimentally due to the many hydrodynamic interactions present in the system. Because of that, a numerical approach is often necessary. A very useful simulation technique that has been proved to be able to predict correctly the rheological behavior of semi-dense and dense suspensions is the Core-Modified Dissipative Particles Dynamics (Core-Modified DPD). In this work, Core-Modified DPD was employed in order to investigate the rheological behavior of a bimodal suspension subjected to a Poiseuille flow. The effect of different body forces (mimicking the pressure difference in a channel) and particle size ratio was investigated over the velocity profiles, rheological response and microstructure of the suspensions in the semi-dense and dense regimes. Results have shown that higher body forces as well as lower particle size ratio lead to a stronger shear-thickening for both semi-dense and dense suspensions. The microstructure analysis correlated well with the rheological trend observed for all the studied systems.