Understanding road ristresses: Alligator cracking

Unless you are an engineer or road manager, it can be difficult to distinguish between different road distresses. To help you understand different types of road distresses, let’s talk about alligator cracking.

What’s the Big Deal with Alligator Cracking?

Alligator cracks are more serious than they sound, especially if ignored. These interconnected cracks, often referred to as crocodile or spider cracking, commonly occur on asphalt pavements. This form of surface damage usually indicates some structural failure.

Alligator cracks can occur due to several reasons:

The traffic load exceeds the design threshold.
Poor base/sub-base, for example, inadequate compaction
Poor drainage
Stripping, for example, the loss of adhesion between the asphalt and the base layer makes it susceptible to moisture
Raveling leading to moisture entering through the pavement surface

Identify and Fix

As the severity increases, the damage will extend across the width of the pavement. Severe alligator cracking will form a well-developed pattern; street edges will splinter into pieces, and some may even have missing chunks of pavement.

Severe alligator cracking can also occur in small areas due to weak subsurfaces. This usually looks like the pattern of a spider web or a shattered glass window. Since the problem is localized, you might think that repairing it is not a high priority issue.

If the alligator cracking is localized, you will need to remove the damaged section, compact the base, and then patch it up. If alligator cracks are widespread and distributed throughout a pavement section, a thick overlay is recommended.

For roads with continuous heavy truck traffic, experts recommend reconstructing the road entirely. Signs of alligator cracks, especially in highly concentrated areas, imply that there is a deeper problem happening below the asphalt. A simple crack sealing will not be enough, which is why reconstructing the entire pavement is suggested. It might seem tedious, but strengthening the base will prevent premature failure.

Nip the Alligator in the Bud

Be mindful of the signs. Longitudinal, or parallel, cracks are a precursor to alligator cracks. Seal those cracks as soon as possible to prevent moisture from entering the pavement. If delayed, the alligator patterns begin to emerge. At this point, it is already too late, and maintenance costs will drastically increase.

Want to learn more about how Michelin Better Roads can help you monitor the effects of distresses on your pavement? Contact a Better Roads Expert today!

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