Pseudo-Viscosity of emulsions | STV

The determination of the pseudo-viscosity of bitumen emulsions, which is described in the test standard EN 12846-1, is a basic test specified in standard EN 13808, in the same way as the breaking index, the water content and the sieve residue . The viscosity of the emulsions depends on the binder content of the emulsion, of the particle size as ell as the viscosity of the individual phases. More generally, the mecanical and chemical means used for production determine the physico-chemical properties of the resulting emulsions. Yhe viscosity is a key parameter that needs to be tailored to the application, the treated surface as well as the climatic conditions.

The pseudo-viscosity is determined using a flow viscometer, better known as the “Standard Tar Viscometer (STV). This device measures the time, in seconds, taken by a sample of 50 mL of emulsion to flow through a 2, 4 or 10 mm ∅ hole, at a specified temperature (40°C in general). The property that is being measured is the pseudo-viscosity because the flow time is an indirect measure of viscosity.

For all temperatures and hole diameters, the flow time must not exceed 600 s. For highly viscous emulsions, standard EN 13302 must be used.

EN 12846 – 1/2