Rutting due to asphalt surface issue is associated with which conditions?

• A. Weathering of the entire surface.
• B. Insufficient compaction.
• C. Low voids, excess sand, excess asphalt.
• D. Route and seal, surface treatments.

Answer: (C)

Rutting happens when the pavement can’t resist permanent deformation under repeated traffic loads, especially in hot weather. If the asphalt mat has very low air voids, it’s very dense and has little room to accommodate stress, so the mixture tends to squeeze and deform along the wheel paths. Adding excess asphalt makes the binder film thicker and the mix more plastic, increasing its tendency to creep under load. Excess sand (fines) disrupts the aggregate interlock and reduces stiffness, further lowering resistance to deformation. Put together, these conditions make rutting more likely. The other options describe different distress mechanisms (weathering, poor compaction leading to higher voids and moisture issues, or maintenance-seeming items) rather than the specific mix conditions that cause rutting.