In v2.3 of the software, we noticed that in the rehabilitation flexible calibration tab, there are no standard deviation inputs for thermal cracking. They do appear in the new flexible rehabilitation tab. Was standard deviation for thermal cracking removed for flexible rehab designs? If so, when and why?
The thermal cracking model in Pavement ME Design prior to v2.3 only considered the predicted transverse cracks for the overlay layer and not the transverse cracks that reflected through the overlay layer that originated in the existing layer. The standard deviation equations which correspond to the transverse cracking model only, were removed from the rehabilitation design calibration file when the new reflection cracking model was implemented (v2.3).
Currently, the software calculates the total transverse cracking which a function of the reflected transverse cracking from the existing pavement and the thermal/transverse cracking from the new overlay layer. Therefore, the standard deviation equation in the software is now based on the total thermal/transverse cracking value instead.