Pavement distress occurs in several forms including cracking, deformations and deterioration. These types of distresses indicate how efficient your asphalt pavement is performing and how much longer you can expect it to endure. Pavement distress can be caused by several factors, including traffic, environment, climate, drainage, defective materials, construction, and external factors such as utility cuts. The question is, can it be fixed? The answer is yes; the experts at Andersen Asphalt & Striping can identify the type of distress and formulate a cost-effective repair and maintenance plan to extend the performance and life of your asphalt pavement.
Cracking Asphalt Pavement Distress Identification
Cracking is the most obvious of all forms of pavement distress and can occur for several reasons, the most common being environmental or pavement structure. Environment factors include the cold weather. New asphalt is flexible and can contract in cool temperatures. Yet, aging pavement is further weakened by UV radiation (commonly referred to as oxidation), becomes brittle, and can shrink, which results in cracks. This type of cracking is called thermal cracking and results in evenly spaced gaps that occur in the same direction. The good news is that a seal coating can be applied to create a protective layer over the pavement surface that can effectively slow the aging process to extend the life of your asphalt pavement. Traffic can also cause the brittle pavement to crack and is more commonly known as block cracking as it resembles a pattern similar to a checkerboard. Block cracking is easily repaired and maintained with crack sealant and seal coats or completely rehabilitated with a mill and overlay. On the other hand, structural cracks begin at the bottom of the pavement and can take years to appear. Structural cracks are most often caused by asphalt that is too thin or weakened subgrades. Structure cracks are more commonly referred to as fatigue cracks or alligator cracks. Fatigue cracking can occur in isolated areas or more widespread if the pavement has been under-designed.
Pavement Deformation Failure
Pavement deformations are most often caused by failures in the subgrade, deformations in the asphalt, and freeze/thaw cycles. Deformation appears similar regardless of the underlying issue; for example, in subgrade deformations, the material below the asphalt is too soft and compressed by the traffic flow, creating a depression. Subgrade deformations are often more significant and appear as though the pavement is sagging, forming a basin-like depression that allows water to pool. The asphalt mixture itself can also have deformation issues. Deformations typically occur early on, and depending on how much damage has been caused, they can be repaired with mill patching or, in some cases, full-depth patching may be needed. Deformations can also be caused by weather, for example, during the freeze/thaw of winter. Ice forms below the pavement, causing it to move upward as it swells. Once the ice melts, it will turn into a depression.
Deterioration in Pavement
Just as the name implies, deterioration is the loss of the pavement materials; for example, raveling is used to describe the loss of asphalt from the pavement’s surface and begins with the breaking of the finer particles, which in turn expose the larger particles. Eventually, the larger particles will break loose, creating a rough surface for vehicles to travel and allowing pockets of water to form, more commonly known as potholes. Pavements that show evidence of raveling should be repaired and seal coated to prevent further damage.