Alligator Cracking

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  • Topic: Pavements, Tarmac, Pavement Condition Index
  • Pages : 4 (1078 words )
  • Download(s) : 444
  • Published : November 24, 2012
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Crocodile cracking, also called fatigue cracking or alligator cracking, is a common type of distress in asphalt pavement. Crocodile cracking is characterized by interconnecting or interlaced cracking in the asphalt layer resembling the hide of a crocodile. Cell sizes can vary in size up to 300 millimetres (12 in) across, but are typically less than 150 millimetres (5.9 in) across. Crocodile cracking is generally a loading failure, but numerous factors can contribute to it. It is often a sign of sub-base failure, poor drainage, or repeated over-loadings. It is important to prevent crocodile cracking, and repair as soon as possible, as advanced cases can be very costly to repair and can lead to formation of potholes or premature pavement failure.

* Crocodile cracking is an asphalt pavement distress most often instigated by failure of the surface due to traffic loading. * Crocodile cracking can be greatly influenced by environmental and other effects while traffic loading remains the direct cause. Frequently, overloading happens because the base or subbase inadequately support the surface layer and subsequently cannot handle loads that it would normally endure. * Poor drainage in the road bed is a frequent cause of this degradation of the base or subgrade. A heavy spring thaw, similarly to poor drainage, can weaken the base course, leading to crocodile cracking. * Stripping or raveling is another possible cause of crocodile cracking. Stripping occurs when poor adhesion between asphalt and aggregate allows the aggregate at the surface to dislodge. If left uncorrected, this reduces the thickness of the pavement, reducing the affected portion's ability to carry its designed loading. This can cause crocodile cracking to develop rapidly, as overloading will happen with loads of less magnitude or frequency.


Failure of surface due to loading...
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