For thermal cracking resistance, which design parameter should be used?

• A. Highest maximum temperature
• B. Mid-range design temperature
• C. Average design temperature
• D. Lowest minimum pavement design temperature

Answer: (D)

Thermal cracking occurs when asphalt contracts and becomes brittle at low temperatures, creating cracks under restraint. To prevent this, design choices must ensure the pavement can handle the worst cold conditions, keeping the binder and mix flexible enough even as temperatures drop. That’s why the lowest minimum pavement design temperature is used as the design parameter for resisting thermal cracking—it targets the coldest scenario the pavement will face. Using the highest maximum temperature would only address hot-weather issues, and mid-range or average temperatures would miss the critical cold-temperature stress that leads to cracking.