What does bleeding in pavement indicate?

Bleeding in pavement typically indicates the migration of asphalt binder to the surface of the pavement. This phenomenon occurs when excessive asphalt binder rises up through the aggregate and creates a film or sheen on the surface. This can happen due to various factors, such as high temperatures, over-saturation of asphalt during the mixing process, or inappropriate mix design.

When bleeding occurs, it can adversely affect the performance of the pavement. The surface can become slick, leading to reduced skid resistance and increased risk of accidents, particularly in wet conditions. In addition, the presence of excess asphalt on the surface can indicate a poor balance of aggregate and binder in the hot mix asphalt, which may compromise the material's overall strength and stability.

Recognizing bleeding as a symptom of asphalt binder migration highlights the importance of adequate control during production and placement of hot mix asphalt, ensuring optimal performance and longevity of the pavement structure.