Institute for Transportation

About the research

Pavement preservation is an essential component of highway asset management, enabling transportation agencies to maintain roadway performance and extend pavement service life while efficiently allocating limited maintenance resources. This study was conducted in collaboration with the Iowa Department of Transportation (Iowa DOT) to evaluate the effectiveness and cost-efficiency of commonly used pavement preservation treatments for both flexible and composite pavements.

Historical pavement management data from the Iowa DOT were analyzed to estimate treatment performance based on two key metrics: life extension, representing the additional service life gained from a treatment, and index benefit, representing the cumulative improvement in pavement condition over time. The analysis considered several preservation treatments, including microsurfacing, patching, slurry seal, crack sealing/filling, seal coat, and hot-mix asphalt (HMA) overlay. To enhance the robustness of the evaluation, national pavement performance data from the Long-Term Pavement Performance (LTPP) dataset were also incorporated to supplement and validate the analysis where appropriate. Historical bid tabulation data from Iowa DOT projects were used to estimate representative treatment costs.

The results provide insights into the relative performance of preservation treatments under different pavement conditions and traffic levels and demonstrate how treatment effectiveness varies depending on the timing of application. These findings were combined with cost information to conduct benefit-cost evaluations and to develop decision-support matrices for flexible and composite pavements. This study provides a data-driven framework to support pavement preservation decision-making. The results and tools developed through this research can assist the Iowa DOT in selecting cost-effective treatments and establishing long-term pavement preservation strategies across the state’s highway network.