Rheological behavior of flocculated suspensions of artificial marine cohesive sediment

The clay mineral type and the organic matter compositions have a strong influence on the mechanical properties of marine sediments. Understanding the viscous behavior of marine sediments composed of flocculated particles is important in many applications such as penetration of heavy objects in the cohesive seafloors and hydrodynamic transport of flocculated sediments among others. In this study, the effects of the clay and organic matter (OM) concentrations and the shear rate on the viscous behavior of the artificial flocs, similar to the ones that are found in the seabed, are studied. It was found that the addition of guar gum increases the viscosity of the floc suspensions significantly. The behavior appears to change from near-Newtonian at low OM concentration to mildly shear-thinning at high OM values. An empirical model was developed that allows to calculate the viscosity of the floc suspensions as a function of clay content, organic matter content and shear rate.