Evaluation of bio-based fog seal for low-volume road preservation

While asphalt pavement is common in the United States, it is susceptible to oxidation as being exposed to environmental effects, resulting in the surface deterioration. To maintain the performance of a road surface and extend its service life, traditional fog sealers such as asphalt emulsion are used to mitigate micro-cracking, prevent oxidation and reduce water infiltration. Due to the relatively high cost and environmental concerns of petroleum-based sealants, the use of bio-based products as fog sealers has attracted more and more attention. Some new bio-based sealants derived from agricultural oil have been used as fog sealers in many states. To evaluate the effectiveness of a bio-sealant as an alternative to preserve asphalt pavements, a 5.3 km test section was selected for application of a soy-based fog sealant with three different application rates to conduct a two-year investigation of pavement marking retroreflectivity, surface friction, growth rate of cracking, laboratory water absorption, and air permeability. A control section without bio-sealant was also set up for comparison purposes. The field results revealed that, after application, a short-term decrease in retroreflectivity and skid resistance was restored to the original condition after two weeks and several months, respectively. The treated sections also exhibited a better control of growth rate of cracking than that of control section. The laboratory results indicated that the bio-sealant treated specimens applied at the highest application rate exhibited the lowest water absorption and air permeability. Such findings indicate that bio-sealant can be a sustainable preservation alternative for asphalt pavement