Viscosity of asphalt decreases as temperature rises.

• A. False
• B. True
• C. Depends on the binder grade
• D. Unchanged

Answer: (B)

Viscosity is a measure of how thick a liquid is and how much it resists flow. For asphalt binder, heating gives the molecules more energy and reduces the forces that hold them together, so the material flows more easily. As a result, viscosity decreases when temperature rises. This is why asphalt is heated for mixing and paving—at higher temperatures it becomes workable and can be pumped and spread more smoothly. When temperatures fall, the opposite happens: the binder cools, becomes stiffer, and its viscosity increases. So the statement is true.