Cracks in an asphalt driveway should never be ignored, as they can allow water infiltration and become choked with weedy plants. Reflection cracks, which form when an old crack reforms through fresh asphalt that's been applied over the top of the damage, are no exception. Read on to learn more about reflection cracking and what you can do about it.
Reflection cracks only occur on asphalt that has been heavily patched or repaired with an overlay, which is a thick layer of fresh asphalt that's applied to extend the life of an old driveway. They aren't an issue with new asphalt driveway installations.
Generally, a repair of an old crack should be secure so it doesn't reform in the new paving. Occasionally, though, the underlying asphalt suffers ground movement near the crack, and this shifting causes the crack to form in the overlaying asphalt. The movement isn't usually caused by driving on the asphalt, but by natural settling of the paving or shifting of the soil beneath the base.
Reasons for Concern
Usually, the problem is little more than cosmetic at first. A crack on its own won't immediately compromise the driveway unless the soil has shifted so drastically that the base below the asphalt driveway is no longer stable.
Trouble develops over time. Water will seep into the reflection crack and down through the layers of asphalt. If the crack is deep enough, the water movement can cause erosion of the base materials below. Further, in cold weather, the water can freeze and expand, which will lead to major pothole formation. Reflection cracks should be addressed immediately so further issues can be avoided.
The best repair method depends on the size and severity of the reflection crack. Minor cracks are usually filled with a flexible asphalt and polymer mix, which will allow for some ground movement without resulting in a larger crack.
Larger cracks may require more in-depth repairs. In many cases, the best repair method is to cut out the asphalt damage completely. Minor repairs may be needed to stabilize the base, and then fresh asphalt is applied. To avoid a patchy look from this type of repair, you can have an overlay layer of asphalt applied over the driveway to even out the color of the driveway.
Contact an asphalt paving service in your area if you notice cracks forming in your driveway.