Background
Asphalt binder is organic in nature, which increases its susceptibility to oxidative aging during its service life in outdoor settings. Oxidative aging is one of the critical factors contributing to the deterioration of asphalt’s mechanical properties and performance. Additionally, asphalt-paved surfaces have been reported as an important and long-lasting potential source of emissions of a complex mixture of volatile organic compounds (VOCs) into the atmosphere.
Accelerated aging of asphalt under high temperatures and sunlight exposure is closely related to the mass loss due to asphalt-related emissions. VOCs act as precursors to the formation of ozone and secondary aerosols that have significant environmental impact. Emissions of asphalt’s hazardous air pollutants not only threaten human health but also have adverse effects on the durability of asphalt. There is a need for safe and durable alternatives to mitigate the hazardous air pollutants of asphalt.
Invention Description
Researchers at Arizona State University have developed HERO (Health of “Ensan” and Road by Bio Oil), a phenol-rich bio-modifier that increases asphalt’s aging resistance and durability. These phenol-rich bio-modifiers can be extracted from woody waste and other lignin-rich biomass, and contain significant amounts of carbon (up to 77%). HERO improves the durability of asphalt by tuning bitumen’s aging resistance and suppressing asphalt emissions using these phenol-rich bio-modifiers.
Bio-oils are considered carbon neutral because the plants that are the source of bio-oils absorb CO2 as they grow. Carbon can be sequestered for an even longer period by using these phenol-rich bio-oils to enrich or partially substitute for petroleum-based products in construction applications.
Potential Applications
- Enhancement of existing asphalt-surfaced areas (e.g., roads, roofs, bridges, airports)
- Construction of new asphalt-surfaced structures
Benefits & Advantages
- Reduces emission of asphalt fumes
- Low-cost method
- Delays oxidative aging of asphalt compounds
- Promotes development of carbon-negative roads
- Enhances sustainability of asphalt-surfaced areas
Related Publication: Phenol-rich bio-oils as free-radical scavengers to hinder oxidative aging in asphalt binder