Assessment of Life-Cycle Benefits of Bio-Based Fog Sealant for Low-Volume Asphalt Pavement Preservation

Abstract

Bituminous pavement can become brittle and distressed over time as a result of the oxidation of bitumen associated with exposure to air, and multiple preservation methods could be implemented to prevent oxidation and prolong the lifespans of asphalt roads. Fog seal, a common preservation strategy, refers to applying a thin layer of emulsion on an existing surface to mitigate oxidation and moisture penetration. Over recent decades, some innovative sealants derived from biomass have drawn considerable attention given their economic benefits and eco-friendly properties, including a proprietary soybean-derived sealer that has been successfully applied in many states. While some studies have investigated its performance and concluded that it could effectively preserve asphalt roads and potentially prolong their lifespans, there has been little comprehensive life-cycle cost analysis (LCCA) based on field performance and actual construction cost which would support appropriate recommendations to local public agencies. To fill this gap, this study selected a low-volume asphalt pavement in Clinton County, Iowa, and during summer 2016 sprayed a proprietary bio-based fog sealant on it for five consecutive years of investigation, including an annual distress survey conducted on both untreated and bio-based fog sealant-treated sections for comparison purposes. Field assessment during this five-year period indicated that bio-based fog seal treatment could control crack growth of asphalt-surfaced roads. Bio-based fog sealant installation and road maintenance costs were combined and LCCA was employed, with results suggesting that, among the various options investigated in this study, applying three treatments at five-year intervasl during a service period was the most cost-effective.