What is asphalt emulsion?

• A. A solvent-based liquid containing dissolved asphalt
• B. A solid asphalt binder with no water
• C. Microscopic asphalt droplets suspended in water
• D. A dry aggregate coated with asphalt

Answer: (C)

An asphalt emulsion is a dispersion where tiny droplets of asphalt are suspended in water, stabilized so they stay evenly distributed rather than separating quickly. This is why the description “microscopic asphalt droplets suspended in water” is the best fit. It’s not solvent-based, where asphalt is dissolved in a liquid other than water, and it’s not a solid asphalt binder with no water. It also isn’t just a dry aggregate coated with asphalt, which describes a different form of asphalt use. Emulsions allow handling at ambient temperatures and break to coat aggregates as the water evaporates or is absorbed.