Determining life expectancy of preventive maintenance fixes for asphalt-surfaced pavements

A large performance data set from in-service pavements was used in conducting a reliability-based analysis to determine the life expectancy (performance) of several preventive maintenance (PM) fixes. The distress index (DI)-the main pavement performance indicator used by the Michigan Department of Transportation-was used in the analysis. Probability distributions of DI values were developed at successive years after the PM application for five fixes: nonstructural bituminous overlay, surface milling with a nonstructural bituminous overlay, single chip seal, multiple-course microsurfacing, and bituminous crack seal. Reliability tables were then developed to express the probability that a given PM treatment would reach the performance threshold after n years; these tables therefore provide the pavement life expectancy for a given PM treatment at various reliability levels. A highway agency can use these tables to select PM strategies on the basis of expected life extensions.