How To Assess and Address Subgrade Failures in Pavement

Modern asphalt and concrete pavements have several layers that all play a vital role in ensuring the stability and longevity of the pavement as a whole. Beneath the surface layer that you can see from ground level, there will generally be multiple layers of gravel substrate on top of a subgrade layer made of a sturdy but naturally permeable material, such as silt or clay.

Damage to any of these layers can significantly degrade the functionality of pavement, but subgrade damage tends to be especially harmful, in addition to being difficult to detect and challenging to repair.

While there is no substitute for assistance from experienced paving experts when dealing with a problem like this, below is a brief overview of how to assess and address subgrade failures in pavement, so you can know what to look for and what kind of help a paving professional could provide.

What Does Subgrade Failure Look Like?

Because the subgrade layer of asphalt and concrete pavement is the lowermost layer, subgrade failures typically will not result in visible damage solely to the uppermost layer of the pavement. Surface-level problems—such as raveling and potholes—typically stem either from subpar construction of the pavement’s upper layers, limited penetration of moisture into those layers, or a large amount of traffic over a short period of time. These surface-level problems can often be easily addressed through short-term patching and sealing.

Problems with the subgrade layer, though, tend to produce much more dramatic symptoms, such as:

• Deep rutting in multiple places rather than just in a single high-traffic location
• Alligator cracking, meaning cracks that are webbed together similar to an alligator’s skin
• Deep depressions in the pavement’s surface level with rounded edges rather than the sharp ones characterizing a pothole
• Irregularities such as bumps and ridges developing over time

A qualified paving professional can help assess a particular stretch of pavement for subgrade failures and offer guidance about possible next steps.

Techniques for Fixing Damaged Asphalt Subgrade

Even if you know that subgrade failure is the source of your pavement’s problem, effectively addressing that failure can be far from simple. Since the most significant damage has been done in the bottom layer of the pavement, there is no way to reach that problem area without removing every layer of pavement above it, which can be extremely time-consuming and expensive, even under the most favorable circumstances.

Furthermore, since subgrade layers are often primarily made of soil rather than stone or bitumen, there are not a lot of options for sourcing useful recycled material that will be more stable and less prone to degradation. In practice, this all means that replacing damaged subgrade layers in pavement essentially requires tearing the pavement down to its foundation and mostly or entirely replacing that foundation before repaving it.

Call Today To Have Your Pavement Subgrade Failures Assessed and Addressed

Fortunately, you have support available from the skilled professionals at Integrity Paving & Coatings, who can provide area-leading service, quality, and value, as well as unparalleled honesty and transparency. Call today to learn what we can do for you.