A scattered series of interconnected crack lines in pavement is called fatigued cracking. The structural failure of an HMA (hot asphalt mix) surface or stabilized base is generally caused by repetitive loading and heavy traffic. There are several reasons why asphalt pavement can be affected and damaged in this way, all of which involving inadequate structural support. Continue reading to learn more about fatigue cracking in pavement, and who to call for professional paving repair service you can trust.
In thinner pavement, the bottom of an HMA layer is where the flexible stress is the highest. Fracturing begins here, and then spreads to the surface in the form of longitudinal cracks. This type of cracking is also known as “classical” or “bottom-up” fatigue cracking.
In thicker pavements, the top layers have the highest tensile stress levels due to tire activity, asphalt-binder aging, and other types of wear and tear. For this reason, fatigued cracking usually begins at the top. This form of fatigued cracking is called “top-down” cracking.
As mentioned, inadequate structural support is the umbrella cause for fatigued asphalt cracking. Inadequate construction, structural design, compaction, drainage, and more are just a few common examples that lead to the formation of fatigue cracks. Other possible causes include a decrease in sub-grade support or base stability from water infiltration and freeze-thaw cycles. It can also occur from improper stripping on the bottom HMA layers.
The formation of fatigued cracking is unique and easily distinguishable. Many agree it somewhat takes on the appearance of alligator skin or distressed leather. To be sure, it is important to have a professional paver assess the cracking in your asphalt pavement to accurately diagnose the damage, identify the cause, and implement safe and effective solutions. This process involves digging a hole or pit to evaluate the structural makeup of the pavement. This method also helps determine if subsurface moisture is contributing issue. Fatigued cracks cannot simply be sealed as a means of repair. Instead, they must be patched or overlaid, depending on their size.