What viscosity ranges are required for different applications of bitumen emulsions?

Viscosity targets depend on whether the emulsion is sprayed, mixed with aggregate, or applied as a coating. Tack coats and spray seals typically need a low enough viscosity to atomize and distribute uniformly through nozzles at practical pressures, but high enough to avoid runoff. Slurry seal and microsurfacing emulsions require higher viscosity and controlled rheology to hold aggregate in suspension and prevent segregation. Waterproofing emulsions often use higher viscosity or thixotropic behavior for film build. Because viscosity is temperature dependent, specs usually define a test temperature and a window rather than a single number.