As part of your pre-project investigation, you may elect to extract pavement cores (samples) of the existing pavement to understand the prevailing conditions (existing pavement thickness & soils type below paved surface).
After some preconstruction investigation, on some projects we have discovered that the underlying surface is PCC. The stresses triggered by a PCC sublayer cause the pavement surfaces to crack prematurely. Simply paving over the PCC using the same approach will almost certainly result in reflective cracking (year or two depending on your region and climate and placement thickness).
Any approach should consider dampening interlayer movement. One approach would be to introduce a interlayer stress absorbing membrane. Stress Absorbing Membrane Interlayer (SAMI-R) is a pavement rehabilitation method that entails placing asphalt-rubber SAMI between distressed pavements and a rubberized hot mix asphalt (RHMA) overlay to seal existing cracks and retard reflective cracking. For example, a project may consider placing two interlayers, a 3/8” and 1/2” aggregate placed over a thick hot-applied binder composed of asphalt blended with approximately 20% by weight rubber, followed by a final 1-1/2” overlay of rubberized hot mix asphalt. Two layer and three-layer systems (includes leveling) can be considered depending on circumstances.