I have heard of companies that can use sonar or some kind of radar system to detect moisture problems etc in the sub-grad. Not sure what it takes to identify pending or lurking problems in extreme cold or hot temps. Anyone else no anything about this?
Core samples can be taken and an ultrasound (?) can detect pavement degradation. Being porous, moisture will eventually make it’s way into the subgrade. De-icing Chemicals will also heighten these opportunities as they are not good for pavement.