option 'A' Indicate Alligator cracks

Alligator cracks are also called as map cracking. This is a fatigue failure caused in the asphalt concrete. A series of interconnected cracks are observed due to such distress. The tensile stress is maximum at the asphalt surface (base). This is the position where the cracks are formed, i.e. the area with maximum tensile stress. A parallel of longitudinal cracks will propagate with time and reaches the surface. Repeated loading and stress concentration will help the individual cracks to get connected. These will resemble as a chicken wire or similar to the alligator skin. This is termed as the alligator cracking. It is also known as the crocodile cracking. These cracking is observed only in areas that have repeated traffic loading. Alligator cracking is one of the major structural distress. This distress is later accompanied by rutting. The figure-1 below shows alligator cracks formed in the pavement.