What causes potholes?

halifax pothole

pothole in roadwayPotholes are a common problem found in asphalt surfaces. Potholes occur on streets, highways and residential driveways. Potholes are frustrating and cause thousands of dollars in damage to vehicles.

So what causes potholes?

Asphalt is designed to be non pores, meaning water cannot get under or through it. Asphalt is placed over a gravel base that is compacted and solid enough to support the weight of the asphalt and vehicles traveling over it. Asphalt is used on roads and highways due to the face that it has some flexibility to it. It is able to move with the ground and vehicles that travel over it. However, overtime the asphalt drys out and the light organic compounds leave the surface causing the asphalt to become more brittle.

Hard asphalt that has lost its flexibility characteristics is prone to cracking. When a crack forms water is able to enter and collect under the pavement between the asphalt and gravel base.

Water plus freeze and thaw cycles is the problem

The water alone will not cause the majority of the damage. However, when the water freezes it expands and having nowhere to go, it pushes up on sections of the asphalt. This causes the cracks to spread breaking up the asphalt into smaller pieces. Soon enough a vehicle will drive over the broken asphalt causing the pieces to move and pop out of their place creating the pothole.

How are asphalt potholes prevented or repaired?

To prevent asphalt potholes its important that the driveway or roadway be properly constructed. This means a good sold base and the correct asphalt thickness for the load requirements. When we pave a driveway we ensure every job meets our set specifications and in some cases where heavy loads are expected additional asphalt or base depth will be used. Potholes can be prevented through sealing and especially crack sealing. Keeping the water out of the cracks will greatly reduce the risk of potholes in any asphalt surface. Typically, repairing potholes involves adding new asphalt to the hole or removing surrounding asphalt and then adding new base and asphalt depending on the extent of the damage.

If you have potholes or other damage to your driveway its important that you have it fixed promptly as asphalt surfaces will quickly deteriorate once the damage has started.