Bio-Carbon as a Means of Carbon Management in Roads

This paper introduces biocarbon, referred to as biochar, as a novel eco-friendly and cost-effective additive to increase interactions among bitumen components while facilitating carbon management in roadway infrastructures. It is hypothesized that functional groups on biochar surfaces enhance interactions between biochar and bitumen constituents. This in turn enhances mechanical properties and durability of asphalt pavements. This study uses biochars derived from six different types of woody biomass and one type of algae, and polyethylene terephthalate granules as a carrier to introduce biochar to bitumen. Quantum-based molecular modeling and noncovalent interaction analysis show that algal biochar interacts more effectively with bitumen components. The enhanced interaction of algal biochar is attributed to its surface functional groups including reactive nitrogen- and oxygen-carrying functional groups. The rheological characterization of bitumen doped with different biochars confirms that the lowest separation index occurs for bitumen containing algal biochar, which also exhibits the highest percent of elastic recovery and resistance to permanent deformation. The study suggests that asphalt pavement durability can be enhanced by selection of the proper biochar to increase intermolecular interactions. Promising results for the algae biochar promote its use in carbon management for roadway infrastructure by sequestering CO2 from air through photosynthesis of algae biomass.