Gilsonite, Adhesion and Moisture Damage in Asphalt

Stripping — the loss of bond between binder and aggregate in the presence of water — causes ravelling and potholes. Gilsonite can improve adhesion.

Why stripping happens

Water displaces binder from aggregate surfaces, especially with siliceous aggregates and in wet climates.

Gilsonite’s polar chemistry

Gilsonite contains nitrogen-rich polar compounds that bond well to mineral surfaces, improving coating and adhesion.

Testing

• Tensile strength ratio (TSR)
• Boiling water test
• Hamburg wheel tracking in water

Combining with anti-strip agents

For difficult aggregates, gilsonite can be used together with hydrated lime or liquid anti-strip agents.

Signs of stripping in the field

• Ravelling and loss of fines
• Potholes after wet seasons
• Bare aggregate visible in cores

Prevention strategy

Our asphalt modifier gilsonite supports better adhesion. See also mix design tips.