One of the main problems affecting the flow of cement bulk powder is the formation of cohesive arching at the outlet of the hopper, causing blockage of the silo opening and bridge formation. A simple concept is established which outlines these complications.
In this context, the interactions of particles lead to a high degree of consolidation of the cement powder and an increase of adhesion force due to the small size and the large surface area of the cement particles. The results from the consolidation test and the flow properties (cohesion) show that the cement powder flow is mainly controlled by internal forces (Van der Waals and adhesion forces) and external forces.
These forces have a direct influence on the powder structure, leading to a variable packing behaviour. Since the problem is attributable mainly to interparticle forces, before storage of the cement powder in the silo, the powder should be fluidised with air at a high velocity to disintegrate the cohesive structure and to overcome this undesirable property of cement flow.
Keywords: compressive strength modelling rheological/rheological properties