The most common crack patterns are:
1) Crocodile cracking – normally a traffic induced type of crack with initial longitudinal cracks in the wheel path followed by secondary transverse cracks, all to resemble the pattern on a crocodile’s skin. Brittleness and other material deficiencies will accelerate the crack mechanism. The end result is a crazed and cracked area within the wheel path with closely spaced cracks, narrow in width (below 3mm) and very difficult to seal with crack infilling, normally recycling of the layer or a surface seal is applied (refer section 3).
2)Block cracking – usually caused by shrinkage of cemented layers. Normally the cracks are far apart (3m or greater spacings) and wide (3mm or wider). These cracks lend themselves to infill sealing because the large width and because a surface seal will cover large sound areas, resulting in a waste of sealant.
3)Longitudinal cracking – usually originates from poor construction or problem materials. Initially the cracks are wide open and suitable for a crack infilling type of seal. Exceptionally wide cracks can form when the fills settle and move, leading to cracks much wider than 15mm. 4)Transverse cracking – this type of cracking is normally associated with cracks wider than 3mm and suitable for infill crack sealing. Blanket surface seal cover could then be wasteful.
