Reflection Cracks

Reflection cracks tend to occur whenever older cracked asphalt or concrete is overlaid with a fresh layer of asphalt typically about 1" to 2" thick. The cracks underneath the new asphalt eventually will reflect up through the new layer of asphalt.

This is typically the result of the original pavement structure and the overlay moving relative to each other. This movement tends to wear on the underside of the new asphalt and work its way upward to the surface, resulting in a crack in the new asphalt that is identical to the crack underneath.

Crack Reflection

• Cracks in the original asphalt will reflect up through the overlay given time.
• Reflection can be slowed by using BST treatment (Permaflex), or certain variants of geo-Fabrics (Petromat, etc.).
• Ensure that severely failing areas are repaired prior to an overlay to prevent premature reflection.

The rate at which the reflection occurs can be adjusted using several surface treatment techniques prior to applying the overly. These include Bituminous Surface Treatment (otherwise known as BST, chip seal, or permaflex), applying a bitumen non-woven geotextile fabric, or replacing the worst areas of fatigue prior to an overlay.

The thicker the overlay asphalt layer, the longer the time required for cracks to reflect through.