Solid colloidal particles inducing coalescence in bitumen-in-water emulsions.
Silica particles are dispersed in the continuous phase of bitumen-in-water emulsions. The mixture remains dispersed in quiescent storage conditions. However, rapid destabilization occurs once a shear is applied. Observations under the microscope reveal that the bitumen droplets form a colloidal gel and coalesce upon application of a shear. We follow the kinetic evolution of the emulsions viscosity, eta, at constant shear rate: eta remains initially constant and exhibits a dramatic increase after a finite time, tau. We study the influence of various parameters on the evolution of tau: bitumen droplet size and volume fraction, silica diameter and concentration, shear rate, etc.
Legrand
J
J
Laboratoire Colloïdes et Matériaux Divisés, ESPCI, 10 Rue Vauquelin, 75231 PARIS Cedex 05, France.
Chamerois
M
M
Placin
F
F
Poirier
J E
JE
Bibette
J
J
Leal-Calderon
F
F