How does hydrated lime affect the stability and breaking characteristics of bitumen emulsions?

Hydrated lime changes surface chemistry and water phase chemistry. In many mixes it can improve adhesion and moisture resistance, but it can also accelerate breaking by raising pH, increasing ionic strength, and interacting with emulsifier charge. This can cause premature breaking in mixers, lines, or at the spray bar if compatibility is not verified. The impact depends on emulsion type, emulsifier chemistry, and dosage. Best practice is to run coating and breaking tests with the exact lime and aggregate source and adjust emulsifier dosage, pH, or grade selection to maintain workable breaking time.