Representative AI image of modern university campus road. (Image Credits: ChatGpt)
In 2018, the University of California San Diego tested a different approach on a section of campus roadway, using recycled plastic materials in place of petroleum-based bitumen. As per the university’s October 2018 news report , Gary Oshima, a construction commodity manager at UC San Diego, discovered the technology through a Facebook post featuring a TED Talk by MacRebur co-founder and chief executive Toby McCartney. A 2020 Australian laboratory study, published two years after the campus test, found that recycled-plastic products led to an increase in binder resistance to flow and elasticity. A review by Mashaan and colleagues in 2019, a year after the campus test, discussed studies and affirmed that the amount of plastic used also mattered, recommending different proportions of waste high-density polyethene and polyethene terephthalate for particular asphalt applications.
Because of chemical incompatibility and differences in viscosity and density, conversely, the wet process could separate the plastic from the binder. What later research found Studies conducted in several countries have reported improvements, particularly in asphalt properties after recycled plastic was introduced.
Use of Recycled Plastic in Asphalt and Concrete Pavement Applications , there are different technical challenges when these two methods are used, according to the study . Road surfaces rely on bitumen, a petroleum-derived binder that holds the mineral aggregates in asphalt together. The project simultaneously addressed the growing volume of discarded plastic and the ongoing need to maintain roads. MacRebur, instead of treating plastic as just a material to be disposed of or recycled, developed a process for blending it into asphalt mixtures. This led Oshima to contact the company, which found a receptive response in their desire to make their debut in America. The National Centre for Asphalt Technology cautioned that the dry process could result in inconsistent mixture quality. The performance of the binder increased by three to four levels, and the resulting mixtures became stiffer and more deformation-resistant. However, the study did not find any notable improvements in terms of crack resistance or resistance to moisture damage. However, those recommendations were in relation to the formulations examined; they do not establish a universal optimum for plastic-modified roads. The California Department of Transportation’s review also exhibited a shortage of domestic research and long-term field evidence. at the time they could not determine the behaviour of plastic-modified pavement over many years of traffic, weather exposure and maintenance Although laboratory experiments and pilot installations opened up avenues for further investigation. The UC San Diego road has now carried traffic for eight years, yet no public condition data has surfaced, so its long-term performance remains unverified.
