How is the optimal spray rate for K1-60 bitumen emulsion calculated for road works?

Optimal spray rate is calculated from the target residual binder application in kg per square meter, adjusted for emulsion binder content and density. The contractor sets a residual binder target based on surface type, texture, traffic, and climate, then converts it to emulsion volume using laboratory confirmed binder content and specific gravity. Field calibration confirms nozzle output at the chosen speed and pressure, and a tray test verifies uniformity across the spray bar. Rate should also account for absorption, surface moisture, and breaking behavior. Final optimization is done with a short trial strip and adhesion or chip retention observations.