Moisture Ingress Effect on Stiffness

For a given unbound layer, the moisture barrier becomes broken when all of the asphaltic materials above have reach certain threshold of damage. Details on how CalME determines moisture ingress can be found here.

If the stiffness of the asphalt layers all have decreased to a certain fraction of the initial stiffness, the stiffness of the unbound layer may be divided by a value. By default, this value is 1.20 for aggregate base and 2.0 for subgrade.