Not fixing damaged asphalt opens the door to further pavement damage — like the sun's UV rays and water and salt infiltration — that'll develop into potholes and other defects that cost more to fix.
According to FHWA, proper preparation is key to long-lasting repairs. This is especially true for cracks that have already been sealed.
The best way to postpone having to seal them yet again is to rout them first. Long-term studies prove that this single step doubles service life compared to non-routed cracks.
Routing is done by a machine (not surprisingly, called a router) that cuts a channel through the center of the crack. The channel acts as a reservoir that holds sealant and increases the amount of material the crack sealing machine delivers.
Previously sealed or fixed cracks will have old repair material in them. It will have pulled free of the crack walls and might be brittle, but it’s still likely to flex. Routing:
- Removes dirt and debris that compromises adhesion with the pavement
- Creates uniform edges, which improves adhesion
- Ensures sealant expands and contracts with seasonal, temperature-induced pavement movement
- Shields sealant from traffic and snowplow contact by delivering the material to the right depth below the pavement surface.
According to Crafco Inc. in Chandler, Ariz., get the best possible reseal by:
Removing as much old material as possible. New sealant applied over old, dirty sealant can pull right off, which wastes time and money.
If the old sealant is brittle, removing it when temperatures are cooler makes the job easier.
If the old sealant is soft and you choose to leave it in the crack, use a hot air lance to warm and turn the old sealant surface shiny-black. This will help the new sealant better adhere to the old sealant.
Removing as much debris and moisture as possible. Use a high-powered air compressor to blow debris from and the hot air lance to dry the crack.
Timing is everything. Resealing should occur immediately after the old sealant is heated.
The problem is that new sealant doesn't make the old sealant hot enough to create a good bond. Use a hot air lance to melt the old sealant right before adding new material.
Filling the crack from the bottom to the top. Sealants are for cracks less than 1.5 inches wide. (Click here for FHWA's application checklist.)
For full-depth cracks and cracks wider than 1.5 inches, ask your crack-sealing vendor for alternate treatments — such as mastic sealant — that may provide a longer-lasting repair.
Overbanding the sealant using an appropriate sealing disk when applying sealant or make a final pass using a U- or V-shaped squeegee. The overband shouldn't be more than 1/16 inch above the pavement surface or extend more than 2 inches beyond each crack edge.
Crafco also supplies repair equipment and material for concrete pavement.