Rehabilitation can be defined as (ITS, 2000):
"Measures to improve, strengthen or salvage existing deficient pavements to continue service with only routine maintenance. Deficient pavements exhibit distress in excess of what can be handled through routine maintenance."
KAPA Pavement Note on Rehabilitation
A wholesale replacement of the entire pavement structure is considered reconstruction rather than rehabilitation since it follows new pavement construction methods.
In other words, although maintenance can slow the rate of pavement deterioration, it cannot stop it. Therefore, eventually the effects of deterioration need to be reversed by adding or replacing material in the existing pavement structure. This is called rehabilitation. Rehabilitation options depend upon local conditions and pavement distress types but typically include:
• HMA overlays. Overlays are used for two primary purposes:
Structural overlays are designed to add structural support to the existing pavement. Because of this, they are structurally designed and are thicker than non-structural overlays.
Non-structural overlays are designed to add or replace the existing pavement wearing course. Because of this they contribute very little to the pavement structure and are generally assumed to provide no additional structural support. Because most agencies consider non-structural overlays to be maintenance items, they are discussed below under Maintenance.
HMA can also be recycled in-place via hot or cold methods.