Advancing Asphalt Durability:

Harnessing Graphene’s Potential for Sustainable Roads

Most of the the world’s road infrastructure is composed of pavement made from a complex system of asphalt, aggregates, and binders that interact at an interface to maintain its strength and structural stability. According to the Asphalt Institute, 87 million tons of asphalt are produced worldwide annually, with around 85% used in the paving industry, which, while offering great load capacity and durability, inevitably suffers damage from constant exposure to radiation, temperature, humidity, and traffic.

The deterioration of asphalt not only impacts a basic transportation infrastructure crucial for socio-economic development but also involves environmental impacts in terms of resource depletion and high CO2 emissions caused by roadworks. These factors add to the reasons for the constant search for modification technologies that increase durability and improve mechanical properties of pavements using fibers, rubber; additives such as thermoplastic elastomers, plastic and synthetic resins, iron powder, hydrated lime, or glass waste. However, in some cases, the application of these products can present practical problems such as special preparation conditions, low storage stability, difficulty in mixing during construction, and complexity in compatibilizing these components with the asphalt system.

Fortunately, carbon nanostructures such as graphene and graphene oxide (GO) reappear on the scene as proposed solutions to these issues with interesting contributions to asphalt regarding stiffness, anti-aging, deformation, and penetration resistance; reduction in rutting, improved consistency, heat transfer capacity; skid resistance, and even a reduction in the effort required for compaction during preparation.

Additionally, among the advantages of graphene is its ability to be mixed with other asphalt modifying technologies such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), polystyrene (PS), granulated rubber, blast furnace slag, epoxy resins, and especially with styrene-butadiene-styrene (SBS), which is one of the most accepted polymers in the asphalt industry, and with which graphene oxide (GO), thanks to its oxygen content, promotes the absorption of aromatics and saturates from SBS with a significant improvement in temperature response, adhesion, and binder stiffness.