What are "thermal cracks" in asphalt pavements?

Thermal cracks in asphalt pavements are primarily caused by temperature-induced shrinkage. As temperatures drop, the asphalt mat cools and contracts. This contraction can lead to the development of cracks, especially in areas where the asphalt is more brittle or not properly designed to accommodate temperature changes. These cracks can create paths for moisture infiltration, which can further exacerbate pavement deterioration if left unaddressed.

Understanding thermal cracking is crucial for maintenance and design because it highlights the importance of selecting appropriate materials and mixtures that can withstand temperature fluctuations. It also illustrates the necessity for adequate pavement design that takes climate variations into consideration.

The other options relate to different types of pavement distress. For instance, moisture infiltration leads to different crack types and strategies for repair, while improper compaction relates to structural issues rather than temperature effects. Meanwhile, stating that cracks only occur on the surface overlooks the potential for deeper issues within the asphalt structure, which thermal variations can also impact.