Life-cycle economic performance for hot mix asphalt pavement rehabilitation strategies

Hot mix asphalt pavements comprise approximately 96% of the paved roadway surfaces in North America. Strategies employed to rehabilitate these surfaces vary widely at a cost of approximately $600 million annually. The Colorado Department of Transportation maintains approximately 28,000 lane miles of asphalt pavements. Of the many rehabilitation strategies employed to maintain this network, three strategies have been utilized most frequently. These strategies are: 1) overlays, 2) cold milling with overlay, and 3) heater scarification and overlay. This research was conducted to determine the expected life-cycle of these strategies. Performance was judged based on smoothness, permanent deformation, and cracking. Independent variables included asphalt binder, traffic, aggregate gradation, and climate. Results of this analysis indicate two of the rehabilitation strategies perform approximately equally 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. Some pavements were rehabilitated after reaching the zero-remaining-service-life threshold. 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.