Design criteria

The format of the default design criterion is:

where MN is the number of ESAL applications in millions,

 E is the modulus of the material, and

 CA, ca, cb and Eref are constants.

The response may be either the vertical compressive strain or stress at the top of a layer or the maximum horizontal strain or stress at the bottom of a layer. In the database these are indicated by Type ev, zv, eh, and zh, respectively. The criteria may apply either to an asphalt material (AC) or to an unbound material (UB).

The default criteria are the Asphalt Institute criteria (highlighted in the table). For AC the default Asphalt Institute criterion assumes a volume percent binder of 11 and an air voids percent of 5. The program has an option for modifying the Asphalt Institute criterion to other values of volume percent binder and air voids percent.

The user may enter other design criteria (for example from the above table) using the "Edit materials parameters" on the Structure form or directly  in the Materials or ProjectMaterials table in the DesignData*.mdb (fields starting by "C " as shown above). With the default value of pass/coverage ratio of 2 in the Classical method the value of CA in the table above must be multiplied by 2ca.