Which defect can result from an insufficient amount of asphalt binder in the mix?

Raveling occurs when there is an insufficient amount of asphalt binder in the mix, leading to the loss of fine aggregate particles from the surface of the asphalt pavement. This defect is characterized by the dislodging of aggregate, resulting in a rough and uneven surface that compromises the integrity of the pavement. The lack of adequate binder does not effectively hold the aggregates in place, which results in increased susceptibility to wear and environmental factors, ultimately leading to the raveling effect.

In the context of the other potential defects listed, while longitudinal cracking, bleeding/flushing, and alligator cracking can occur due to various issues in asphalt pavement, raveling specifically directly relates to a deficiency in asphalt binder. Longitudinal cracking is generally associated with poor construction joints or thermal shrinkage, bleeding or flushing is usually a result of excess asphalt, and alligator cracking tends to be indicative of structural failure or overloading rather than an inadequate binder content.