What Causes Asphalt Upheaval And How Do You Repair It?

If a cracked, bulging ridge appears on an asphalt surface, it's a sign of asphalt upheaval. Asphalt upheaval happens when the surface is pushed upwards from underneath, causing it to split apart. It's a very serious issue that can lead to greater damage later since it causes cracks that go through the entire asphalt layer. Water can enter through the cracks and erode the gravel subgrade and soil beneath it, which will cause the asphalt surface above to shift and crack even further. If you've noticed asphalt upheaval in your driveway or parking lot, read on to learn what causes it and how an asphalt paving contractor can fix it.

What Causes Asphalt Upheaval?

The most common cause of asphalt upheaval is expanding soil below the asphalt subgrade. If the soil becomes saturated with water and shortly after the soil temperature dips below the freezing point, the water will turn into ice and expand. The expanding ice will push up on the asphalt surface above it, causing upheaval.

If the soil underneath the asphalt surface consists mainly of clay or silt, asphalt upheaval can occur regardless of soil temperature. Clay and silt are expansive soil types, so they will swell when they become saturated with water. Like expanding ice, the swelling soil will cause the asphalt surface above it to shift and break apart.

Tree roots are another potential cause of asphalt upheaval. When tree roots start growing in the soil underneath the gravel subgrade, they can push up on the asphalt as they become larger in size.

How Do You Repair Asphalt Upheaval?

Since asphalt upheaval causes a crack that extends through the entire asphalt layer, the only way to repair asphalt upheaval is to remove the damaged asphalt and replace it. An asphalt paving contractor will use a machine to grind away the damaged area and then apply hot mix asphalt to the opened space in the surface. The hot mix asphalt will bond to the undamaged asphalt beside it as it cools and cures, which will fully repair your asphalt surface and prevent water from entering the subgrade.

If the asphalt upheaval was caused by expanding soil, you can improve drainage around the edges of the asphalt surface to prevent the soil underneath the asphalt subgrade from becoming saturated. You can do this by grading the land around the surface so that water flows quickly away from it. If the upheaval was caused by tree roots, you will most likely need to remove the tree that's growing roots in the soil underneath the asphalt surface to ensure that it doesn't cause any more damage.

When you notice the signs of asphalt upheaval, it's important to take action quickly to prevent greater damage to the asphalt surface. Removing the cracked asphalt and replacing it will stop the subgrade from eroding as rainwater leaks into it. To protect your asphalt surface, contact an asphalt paving contractor as soon as possible and have them repair the broken area.

Reach out to an asphalt paving contractor for more information.