Why are ambient temperature restrictions based on lift thickness?

• A. To ensure proper compaction and pavement performance
• B. To minimize energy use
• C. To satisfy inspector requests
• D. To simplify planning

Answer: (D)

Ambient temperature restrictions tied to lift thickness exist because temperature directly affects how well the asphalt can be compacted and, in turn, how the pavement will perform. Thicker lifts hold residual heat longer and need enough ambient heat to keep the mat workable long enough for the rollers to densify it to the required level. If it’s too cool, the surface cools too fast and compaction can’t reach the target density, resulting in too many air voids and a pavement that’s more prone to rutting, cracking, and moisture damage. So the restrictions are about ensuring proper compaction and long-term pavement performance, not about saving energy, pleasing inspectors, or simplifying planning.