Which option is NOT a class of emulsified asphalt?

• A. Anionic: Electro-negatively charged asphalt particles
• B. Cationic: Electro-positively charged asphalt particles
• C. Nonionic: Neutral charge asphalt particles
• D. Ionic: Electrically charged asphalt particles

Answer: (D)

Emulsified asphalt is classified by the electrical charge carried by the droplets after emulsification. The common categories are anionic, with negatively charged particles; cationic, with positively charged particles; and nonionic, where there is little to no net charge. The term ionic isn’t used as a separate, formal class. If an emulsion has charge, it’s described as either anionic or cationic depending on the sign of the charge; “ionic” would be vague and redundant. Because of that, the option describing ionic as a distinct class is not a valid category, making it the one that isn’t a recognized class of emulsified asphalt.