Researchers are investigating a sustainable alternative to traditional asphalt, which is typically composed of rocks and sand bound by petroleum. This conventional method is not without its drawbacks, as the production and installation of asphalt release harmful emissions that pose health risks to both workers and surrounding communities.
Led by Xianming Shi, the chair of the civil and architectural engineering department at the University of Miami College of Engineering, a research team has received a $1 million grant from the U.S. Department of Agriculture to explore the use of agricultural waste in creating biochar for roadway construction. This three-year initiative aims to transform the transportation sector by decreasing dependence on petroleum-based materials and introducing a carbon-neutral option for infrastructure development.
Shi emphasized the significance of this project, stating, “This is an exciting opportunity, as this is likely the very first solution to truly move asphalt pavement toward net-zero — that is, carbon neutrality.” He noted that this approach could significantly reduce toxic emissions during asphalt production.
At the core of this research is biochar, a carbon-negative substance generated through pyrolysis, which involves heating organic waste—such as orchard trimmings and poultry litter—in a low-oxygen environment. This method not only repurposes millions of tons of agricultural waste produced annually but also helps sequester carbon within asphalt, potentially enhancing road durability.
Currently, vast amounts of organic waste from farms are either discarded or allowed to decompose, releasing methane and other pollutants into the atmosphere.
By converting this waste into biochar (and bio-oil) and incorporating reclaimed asphalt pavement, Shi’s team aims to capture significant carbon amounts within the asphalt itself. This project could also provide economic benefits for farmers and poultry producers by finding better uses for agricultural waste.
Press release: University of Miami College of Engineering
