What is the phenomenon called when bitumen exudes onto the pavement surface, reducing skid resistance?

The phenomenon where bitumen exudes onto the surface of the pavement, reducing skid resistance, is known as bleeding or flushing. This occurs when the asphalt binder in the pavement mixture rises to the surface, creating a layer of excess material that can make the pavement feel slick and less safe for vehicles. Bleeding is typically the result of excess asphalt binder in the mix, excessive heat, or prolonged periods of heavy traffic.

As the bitumen rises, it can create localized areas where the pavement becomes shiny and slippery, increasing the risk of accidents due to the reduced friction between tires and the road surface. Proper mix design and temperature control during the paving process, along with adequate maintenance, are crucial in preventing this issue from occurring.

Raveling, longitudinal cracking, and drip track raveling refer to different pavement distresses that involve surface wear, cracking patterns, or the shedding of aggregate, but they do not specifically describe the exudation of bitumen onto the surface that characterizes bleeding.