How is specific gravity of bitumen emulsion defined and why is it critical for quality control?

Specific gravity is the ratio of emulsion density to water density at the same reference temperature, and it is closely related to binder content and water fraction. It is critical because many field controls rely on volume based measurements: sprayer application rate, binder application per square meter, and tank inventory calculations. If specific gravity drifts, the same sprayed volume can deliver too little or too much residual bitumen, affecting bonding and cost. Inline density measurement also helps detect off ratio dosing, water contamination, or settling during storage.