How does insufficient tacking affect layer bonding in pavement?

• A. It improves layer bonding
• B. It has no effect
• C. It reduces layer bonding
• D. It increases the likelihood of cracking

Answer: (C)

Insufficient tacking plays a significant role in the bonding between different layers of pavement. The tack coat serves as an adhesive that facilitates the connection between the underlying base or existing surface and the new asphalt layer being applied. When the tack coat is applied in insufficient quantities or inadequately, it fails to create a proper bond between the layers.

This lack of adequate bonding can lead to several detrimental issues during the lifespan of the pavement. For instance, without a strong bond, the layers can easily separate under stress from traffic loads, temperature fluctuations, and moisture infiltration. This separation can result in delamination, which manifests as cracking, raveling, or other forms of surface distress. Consequently, insufficient tacking directly impairs the structural integrity and longevity of the pavement system. The reduction in layer bonding means that the layers cannot effectively transfer loads or stresses, leading to greater susceptibility to damage and overall pavement failure.

Thus, it is clear that insufficient tacking significantly reduces layer bonding, which can ultimately compromise the durability and performance of the pavement.