Seal the cracks in an asphalt driveway before more damage occurs

Seal an asphalt driveway crack
Credit: Allen-Douglas

Keeping cracks sealed in an asphalt driveway is import to extend the life of the pavement and for saving money over time.  Water entering into asphalt cracks causes pavement failure. The water attacks the asphalt in two ways.  First, water enters the cracks then seeps into the stone base and soil subgrade below.  This causes the base to weaken.  When heavy cars and truck travel over the asphalt or sit on the asphalt for a long period of time, the lack of structural support causes more cracking the asphalt.  Keep in mind that the oil-based binder that holds the asphalt together is a stress and time dependent material.  If a parked car sits on asphalt, the binder stretches over time and does not rebound into its original shape.  This is the reason that most pavements near a traffic signal are rutted, where cars tend to sit.  Driveways are also a place that cars sit for an extended period of time.  The asphalt rutting further thins the asphalt, creating more need for a dry solid base.

The second way water attacks asphalt is when water seeps into cracks during cold weather.  Ice forms in the cracks.  Water expands when it freezes.  The expanding ice pushes apart and breaks up the driveway material.  If cracks form in an asphalt driveway, it is important to seal them as quickly as possible.

clean out the crack in the asphalt before placing sealant
Credit: Allen-Douglas

Step 1:  On a dry sunny day, clean the surface of the asphalt and inside the crack using water and a scrub brush.  Remove all the loose material and dirt inside and around the cracks.  

Step 2:  Allow the cracks to dry.  The drying time varies based on the air temperature and relative humidity.

Pour asphalt sealant in the cracks

Pour sealant in the asphalt cracks
Credit: Allen-Douglas

Step 3:  Read all the directions on the sealant being used.  Some crack sealing products require a minimum temperature during the curing period.  Check the weather forecast to make sure the overnight temperatures will meet the requirements.  Place a good quantity of crack sealant inside the crack.  Many commercial sealant products are packaged in a squeeze bottle.  Cut off the tip of the bottle so a small amount of material is released with each squeeze.

Smooth out the sealant flush with the asphalt
Credit: Allen-Douglas

Step 4:  Use a putty knife to force the sealer, fully filling the cracks.  Top off the cracks and make the surface flush with the surrounding asphalt using the putty knife.

Step 5:  Allow the asphalt crack sealer to cure before driving over the repaired area.  The curing time is usually 24 hours, but check the manufacturer's instructions.