Evaluation for Microsurfacing as Pavement Preservation Treatment

Over the years, the Indiana Department of Transportation (INDOT) has changed its emphasis from construction to preservation of public highways. As such, there is great interest in assessing cost efficacy of a pavement preservation strategy. This paper aims to present the functional and structural benefits of microsurfacing applications at highway sections in Indiana. To achieve this goal, comprehensive monitoring and data analysis was performed using the pavement condition rating (PCR), structure number (SN), and surface roughness [international roughness index (IRI)] for in situ performance evaluation. According to the deflection and roughness analysis, an improvement was observed in SN and IRI during the early life of the pavement. Furthermore, no significant difference was obtained over the following 2 years. Application of the microsurfacing resulted in a significant rise in PCR and SN and decline in IRI. A similar result was found at the resurfacing site. Pavement with microsurface sections had stable roughness with only a 2-point increase every year. The two control sections (SR-68 and SR-145) have had 4-point increases on average. The IRI for SR-58 resurfacing was $762\mathrm{mm}/\mathrm{km}$ ($48\mathrm{in}\mathrm{.}/\mathrm{mi}$) in 2009 (after construction), which is almost half of the 2008 (before construction) IRI value. The rates of decline of the SN and IRI were no different statistically for untreated control sections, and the rate of decline of the PCR was slightly higher than in the pavement preservation project, including resurfacing and microsurfacing. The cost study indicated that microsurfacing would be deemed cost effective if it could provide more than 1.6 years of service life, and resurfacing would be cost effective if it could provide more than 3 years of service life. Considering cost as well as performance, pavement preservation should be an effective strategy to eliminate or retard damage. If applied properly, microsurfacing is an economical alternative to conventional resurfacing. The case study results demonstrate that microsurfacing is a cost-effectiveness treatment in addressing pavement distresses and in extending pavement life in general.