About the research
While asphalt pavement is one of the most common transportation infrastructures in the United States, it requires proper maintenance. Exposure of asphalt binders to air can result in an oxidation process that can result in brittle behavior and distress in an asphalt pavement surface. To mitigate asphalt road deterioration and extend pavement service lives, various preservation strategies can be employed.
Fog seals are a light application of conventional asphalt emulsion on an asphalt-surfaced road to prevent oxidation and reduce water infiltration. In recent years, bio-based products for pavement preservation have attracted considerable attention due to their relatively low cost and environmentally-friendly properties. A proprietary bio-based sealant, RePLAY, has been commercialized and successfully used in many states.
To evaluate RePLAY performance as an alternative fog sealant for preserving asphalt-surfaced roads in Iowa, a 3.3-mile pilot testing section was selected in Clinton County in June 2016 for investigation of both short- and long-term performance by spraying sections with three different applications of RePLAY. A control section without RePLAY application was also set up for comparison purposes.
The set of performance investigations,conducted for five consecutive years (summer 2016 through summer 2021) included visual distress surveys of surface friction, pavement-marking retroreflectivity, laboratory water absorption, air permeability, and depth of penetration. The field results showed that, while a RePLAY application could reduce surface friction and retroreflectivity at early stages, restoration occured after several weeks. A RePLAY-treated section also exhibited a lower growth rate for cracking.
The laboratory results showed that RePLAY is effective in reducing water absorption and air permeability. A life-cycle cost analysis was also conducted, and the findings suggest that RePLAY can be an effective alternative for Iowa asphalt pavement preservation with savings in maintenance costs.