Asphalt driveways can last for decades when they’re built well. Sections of asphalt sink when the foundation beneath is not thick and properly compacted. An effective way to fix sunken asphalt is to pump grout beneath the surface. This stops the damage from spreading and creates a new solid foundation to support the pavement. Do-it-yourselfers will need to rent a slabjacking pump in order to hydraulically lift the asphalt.
Things You'll Need
- Core rill
- 2-inch hose nozzle
- Slabjacking pump
- Screw driver
- Putty knife
Mark a triangle of drill holes in the sunken area with chalk. Space the three holes evenly apart by about 1 to 8 feet and place them at least 1 foot in from the edges of the driveway.
Drill 2-inch holes through the asphalt with a core drill. Stop drilling once you’ve gone through the slab to the foundation beneath.
Thread a hose with a 2-inch nozzle into the lowest-lying hole. Screw the other end of the hose onto a slabjacking pump, and clasp the connection so the hose won’t pop off.
Scoop cementitious slabjacking grout into the pump with a scooper, and turn it on. Pump until the hollow cavity is filled with grout. Repeat this step for each of the holes until the cavity beneath is filled.
Return the hose to the first hole and pump grout until the slab rises by 1 inch. Once the cavity is filled, the pump pressurizes the grout in order to hydraulically lift the slab. Repeat this process on each hole, raising the slab 1 inch with each hole, until the sunken area is level with the rest of the driveway.
Remove the hose and scrape out any grout from the drill hole with a screwdriver, then wipe it with a cloth.
Fill the holes with stiff mortar and scrape off the top with a putty knife so it’s smooth and level. Block off the driveway so the grout can harden for two days.
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