Evaluation of the Cost Benefits of Continuous Pavement Preservation Design Strategies Versus Reconstruction

The Arizona Department of Transportation (ADOT) has traditionally employed continuous pavement preservation (consisting of a myriad of treatment options that cost-effectively address existing pavement problems) as part of an overall design strategy to maintain the highest levels of service for highway users. However, with concern about the effects of continual weakening of substructure material layers on preservation treatment performance and cost, ADOT sponsored a study to determine the cost-effectiveness of the continuous preservation approach as compared to a reconstruction strategy. Another goal of the study was to determine the break-even point for the continuous preservation and reconstruction strategies (i.e., after how many rehabilitation treatments does reconstruction becomes equally cost-effective as continuous preservation). Using inputs such as pavement performance/life estimated primarily through pavement survival analysis, best estimate unit costs derived from historical data, work zone-related user costs, and a specified analysis period and discount rate, the total life-cycle costs for each of four alternative strategies (one continuous preservation strategy, three reconstruction strategies) for each 15 commonly occurring pavement scenarios in Arizona were determined and compared. The results of the analysis showed a consistent reduction in total life-cycle costs with a corresponding increase (from 0 to 2) in the number of rehabilitations between original construction and the first reconstruction event. Results also showed that for 9 of the 15 scenarios, total life-cycle costs associated with the third reconstruction alternative (i.e., two rehabilitations occurring prior to the first reconstruction event) were within 3 percent (sometimes higher, sometimes lower) of the total life-cycle costs of the continuous preservation strategy. Hence, the break-even point between the two strategies typically occurs after two to three cycles of rehabilitation.