Visual cracking

The damage to the surface layer at crack initiation is determined from:

where winitiation is the damage at crack initiation,

  hAC is the combined thickness of the asphalt layers, and

  a and href are constants (-2 and 250 mm as default for new pavements).

Inversely, the time of crack initiation may be determined from the damage to the surfacing layer.

The amount of cracking, Cr in percent or length/area, is determined from:

where w is the damage to the surfacing layer,

Cri is the cracking corresponding to crack initiation,

Crmax is the maximum cracking, and

 a  is a constant (a = -8 as default for new pavements and -3.5 for reflection cracking).

The amount of cracking at crack initiation must be assumed (in calibration studies values of 5% or 0.5 m/m2 have been used).

The parameters are set in the "Crack_damage" table of the database.