A Study of the Performance of Three Asphalt Pavement Rehabilitation Strategies

This study analyzes the performance of three common hot mix asphalt rehabilitation strategies on 149 pavements over a period of seven years. All three strategies place two-inch overlays on the pavement to be rehabilitated. The first strategy includes an overlay on the existing pavement after sweeping the surface and applying a tack coat. The second strategy places the overlay after removing two inches of the existing pavement by cold milling. The third strategy places the overlay after treating the existing pavement using the heater scarification process. Performance was evaluated with respect to PG binder temperature range, traffic volume, overlay nominal maximum aggregate size, and climate. Data analyzed in the study was obtained from a pavement management system that is updated annually with respect to pavement condition. Results of this analysis indicate that two of the rehabilitation strategies perform approximately equal with one performing slightly better than the other, and both performing significantly better than the third. Polymer modified asphalts enhanced pavement performance depending on which rehabilitation strategy was utilized. Pavements were generally rehabilitated before reaching the zero service life threshold. However, when fatigue cracking was present in the original pavements, this was not the case. These pavements were rehabilitated when the zero remaining service life threshold had been reached or when pavement condition exceeded this threshold. This indicates rehabilitation would have been warranted earlier in the life of these pavements. As a result, the expected life of the rehabilitation strategies utilized on these pavements may be shorter than could be expected had rehabilitation been done before distress reached this high level