What characterizes "slippage cracking" in asphalt pavements?

Slippage cracking in asphalt pavements is primarily characterized by the loss of bond between the asphalt layer and the underlying layers. This phenomenon occurs when the surface layer experiences a significant amount of lateral movement relative to the layers beneath it, typically due to factors such as heavy traffic loads or temperature fluctuations that cause the pavement to expand or contract. When the bond fails, the asphalt can slide over the underlying material, resulting in crescent-shaped cracks that often appear at the edges of the pavement.

The presence of slippage cracks can indicate issues with the adhesive properties of the asphalt or the quality of the underlying layers. These cracks can compromise the structural integrity of the pavement, leading to further deterioration if not addressed. Understanding the mechanisms that lead to slippage cracking can assist in designing better pavements and choosing appropriate materials and application methods to enhance bonding.