In the quest for sustainable and durable infrastructure, researchers have made a significant stride in the realm of asphalt technology. A recent study led by David Llopis-Castelló from the Highway Engineering Research Group at the Universitat Politècnica de València has explored the potential of self-healing asphalt mixtures, combining recycled materials and innovative healing techniques. The findings, published in the journal Infrastructures (translated as “Infrastructures”), could revolutionize the way we think about pavement maintenance and longevity.
The research focuses on the synergistic use of steel slag aggregates and steel wool fibers in hot-mix asphalt compositions. Steel slag, a byproduct of the steel industry, and steel wool fibers, typically discarded as waste, are repurposed to create a more sustainable asphalt mixture. This approach not only reduces environmental impact but also enhances the pavement’s ability to heal itself through electromagnetic induction heating.
Llopis-Castelló and his team developed two types of AC16 Surf S mixtures with 35/50 bitumen, one using recycled steel slag and the other using natural porphyritic aggregates. Each mixture was tested with two levels of steel fiber content: 2% and 4%. The self-healing capacity of these mixtures was evaluated using the semi-circular bending (SCB) test, a method that assesses the fracture toughness of the material.
The results were promising. Mixtures containing recycled steel slag performed as well as, or better than, traditional mixes in terms of mechanical behavior. Induction heating triggered partial recovery of fracture toughness, with higher fiber content and repeated heating cycles yielding better healing values. Recovery levels ranged from 14.6% to 40%, demonstrating the practicality of this approach.
“This research offers both an approved approach for assessing healing and real-world recommendations for the construction of low-maintenance, round pavements utilizing induction-based techniques,” said Llopis-Castelló.
The implications for the energy sector are substantial. Self-healing asphalt could significantly reduce the need for frequent maintenance, lowering costs and minimizing disruptions. The use of recycled materials also aligns with the growing demand for sustainable practices in construction.
As the world moves towards more environmentally friendly and cost-effective solutions, this research could shape the future of pavement technology. The development of self-healing asphalt mixtures not only promises to extend the lifespan of roads but also contributes to a circular economy by repurposing industrial byproducts.
In the words of Llopis-Castelló, “These results encourage the development of asphalt mixtures with improved endurance and environmental benefits.” The journey towards sustainable infrastructure is underway, and this research is a significant step in that direction.