What is the primary cause of rutting in asphalt pavements?

The primary cause of rutting in asphalt pavements is excessive traffic load. Rutting occurs when the asphalt layers become deformed under the repeated stress of heavy vehicles. When the weight from vehicles exceeds the pavement's structural capacity, it leads to permanent deformation, resulting in ruts or grooves forming in the wheel paths.

This phenomenon is particularly significant in areas with high traffic volumes and heavier vehicles, as the repeated loading can exacerbate the deformation process. Over time, the asphalt mix may also lose its elasticity and stiffness, worsening the rutting issue. While other factors like material quality, compaction, and weathering can contribute to pavement performance, they are often secondary influences. The primary focus should always be on the impact of traffic loads when addressing rutting in asphalt pavements.