No abstract

The progress of the compaction process to produce from an assembly of particles a coherent mass can be achieved by the application of shear and normal stress. The achievement of a densified coherent mass necessitates, together with the yielding of material, the movement of particles over and between each other. In uniaxial compaction the angle of internal friction, δE, is a projection of the unique critical state line which divides a three dimensional relationship between volume change (V), shear stress (ϕ) and normal stress (σ) into yield domains and surfaces. There is one region for failure and flow (the Hvorslev surface) and another region for failure and consolidation (the Roscoe surface). In this paper the concepts of the Roscoe and Hvorslev surfaces together with the Coulomb yield criterion have been applied to the uniaxial compaction, over a range of compactable stresses, of titanium dioxide (20–2000 kPa). The characteristics of applied and shear stress, angle of internal friction (δE), angle of shearing resistance (ϕ) and surface area (SBET) were measured and correlated with the compaction stress (σc) and diametral strength (σf) of the compacts to investigate the phenomena of uniaxial compaction.