This study employs a computerized axial tomography scanner (CATSCAN) to measure the spatiotemporal distributions of solidosity for a clay slurry flocculated with a cationic polyelectrolyte. Flocculation produces fast-settling sediment and a clear supernatant. Limited data revealed the finite role of sludge plasticity on rheological characteristics. However, owing to the deterioration of the sludge network structure during settling, the purely elastic constitutive equations properly interpreted the final sediment data. The null-stress solidosity was estimated using three different methods. Polyelectrolyte flocculation renders a low attainable solidosity at the settler bottom, the low null-stress solidosity, and a less-compressible sediment. Most of the sedimentation processes considering well-flocculated slurries is governed by sedimentation compaction. The solid flux in the sediment is not a unique function of solidosity.