Toward Carbon-Negative and Emission-Curbing Roads to Drive Environmental Health

Abstract

Roadway infrastructures are exposed to solar ultraviolet (UV) radiation during their service life. UV rays generate free radicals that diffuse deep into bitumen layers, accelerating the aging and degradation of bituminous composites. Here, we hypothesize that carbonaceous particles grafted by bioderived molecules such as amines and amides can serve as scavengers of free radicals, delaying aging in bituminous composites. To test this hypothesis, we use laboratory experiments and molecular dynamics simulations to compare the efficacy of biochars made from woody biomass and algal biomass in delaying the aging of bituminous composites. We further examine the underlying molecular mechanisms that delay aging by computing the extent of diffusion of free radicals through an amorphous graphite film in the pristine form and in amine-and amidefunctionalized forms. The laboratory results indicate that algal biochar is considerably more effective than woody biochar in delaying aging. The simulation results corroborate laboratory findings showing that even at low concentrations, surface functionals such as amines and amides considerably enhance the efficacy of pristine carbon in shielding the underlying layers against the diffusion of free radicals such as hydrogen peroxide (H 2 O 2 ). At high concentrations (e.g., 10 wt %), amines were found to be more effective than amides in reducing the diffusion rate of H 2 O 2 . This indicates that the scavenging efficacy of carbonaceous particles can be optimized by proper biografting. The algae that were used to make functionalized carbonaceous particles in this study are a means to capture CO 2 from air. Therefore, our findings contribute to extending the sustainability of highway infrastructures while moving toward carbon-negative and emission-curbing roads to promote environmental health.

A Comprehensive Overview of the Utilization of Recycled Waste Materials and Technologies in Asphalt Pavements: Towards Environmental and Sustainable Low-Carbon Roads

“…Also, the CO 2 extraction of biochar from the atmosphere accounts for 1.7 to 3.7 Pg CO 2 equivalent, or 49-59% of this reduction [37]. Ghasemi, et al [40] examined the use of biochar made from algae as a potential carbon capture strategy for absorbing CO 2 from the atmosphere. The biochar was created through pyrolysis, and the researchers discovered that it has the potential to absorb CO 2 , showing its viability as a low-cost and sustainable method of reducing carbon emissions.…”

Systems biology of asphalt pollutants and their human molecular targets

“…Mousavi et al (2021) added functionalized carbon to bitumen and found that the new mixture was able to adsorb specific chemicals known to be emitted from bitumen. In the same lab, a different research team identified that the addition of functionalized carbon to bitumen reduced the diffusion of hydrogen peroxide radicals that contributed to aging thus potentially reducing emissions (Ghaseme et al, 2022).…”

A Comprehensive Review of Biochar Utilization for Low-Carbon Flexible Asphalt Pavements

“…Ghasemi et al [65] recently investigated the effectiveness of biochar and hydrochar in slowing the aging process of asphalt binders. This study produced biochar and hydrochar from woody biomass and algal biomass using both pyrolysis and hydrothermal conversion.…”

“…A recent study by Ghasemi et al [65] utilized biochar produced using algae to simulate the viability of utilizing biochar to absorb atmospheric CO 2 . Another study by Zhou et al [21] evaluated the effect of biochar on the removal of VOCs from asphalt mixtures using various biochar sources.…”