Developing Life-Extending Benefit Curves for Asphalt Pavements with Preservation Treatments

Abstract

Over time, new pavements deteriorate due to the effect of traffic loads and the environment. If appropriate treatments are applied during the early stages of deterioration, it is possible to improve pavement conditions and extend pavement life without increasing expenditures. The National Center for Asphalt Technology (NCAT) has partnered with the Minnesota DOT’s Road Research Facility (MnROAD) to conduct a pavement preservation study that evaluates the life-extending benefit of a variety of preservation treatments, ranging from crack sealing to thin overlays. The objective of this research partnership is to develop performance curves for the treated pavements under different conditions (climate, traffic and initial condition of the pavement). In this study, full-scale test sections were treated first in a southern location (Alabama) on roadways subjected to both low and high traffic levels, starting in the summer of 2012. The experiment was extended in 2016 to include test sections in a northern location (Minnesota) to evaluate the effect of cold climate, also for low and high traffic levels. Throughout this time, cracking, roughness, rutting and macrotexture data were collected biweekly to evaluate pavement performance. The observed trends in the first years of the experiment indicate that there is not a significant variation in roughness or rutting over time, and that performance is mainly affected by the amount of cracking. Furthermore, the condition of the pavement at the time of treatment significantly affects the performance of the treated pavements, as pavements that are treated while still in good condition tend to remain in that category for a longer time. The results also demonstrate the effectiveness of applying pavement preservation treatments versus the “do nothing” scenario. After 4.8 years, the amount of cracking observed is less than the amount expected if the sections were left untreated, even for sections treated with applications that are not designed to address cracking. The results shown in this paper should be considered preliminary and used with caution. Data collection efforts continue in both southern and northern locations with the objective of determining the life-extending benefits of pavement preservation treatments as a function of initial condition, climate and traffic.