Why are cationic asphalt emulsions preferred for siliceous aggregates and damp substrates?

Cationic emulsions improve wetting and bonding on siliceous, acidic aggregates because the positive charge attracts the typically negative mineral surface. On damp substrates, cationic chemistry often maintains better early adhesion and more predictable breaking compared with systems that require a very dry surface to develop bond. This reduces construction risk in variable weather and helps prevent chip loss in surface dressing or weak tack coat bond. However, correct residual rate and compatible sprayer calibration are still essential because too heavy a film can delay break and cause tracking.