Could self-healing roads solve the UK’s pothole problem?

Self-healing roads, made from biomass waste and designed using AI, could offer a solution to the country’s £143 million pothole problem.

An interdisciplinary team of scientists from King’s College London and Swansea University, in collaboration with scientists in Chile, is designing a new type of self-healing asphalt that can mend its own cracks over time – without requiring any maintenance or human intervention.

Cracks occur when bitumen (the sticky black material used in the asphalt mixture) hardens through oxidisation, but the exact processes behind this are unknown. The team found a way to reverse the cracking and develop methods to "stitch" asphalt back together – building more durable and sustainable roads.

During the research, a type of AI known as machine learning was used to study organic molecules in complex fluids like bitumen. The team developed a new data-driven model to accelerate atomistic simulations, advancing research into bitumen oxidation and crack formation. The team is also collaborating with Google Cloud to simulate the behaviour of the bitumen on a computer.

To make the asphalt ‘self-healing’, the team incorporated tiny porous materials known as ‘spores’. These are smaller than a strand of hair and made from plants. The spores are filled with recycled oils, which are released when the asphalt begins to fracture. This reverses the cracking process.

Scientists are increasingly using recycled materials in asphalt to reduce the use of fossil fuels and make roads more sustainable.

In laboratory experiments, this advanced asphalt material was shown to completely heal a “microcrack” on its surface in less than an hour.

Potholes are a substantial issue in England and Wales, where £143.5 million is spent annually to fill them in, with an estimated £16.3 billion needed to bring roads up to scratch (ALARM survey).

Dr Francisco Martin-Martinez, an expert in Computational Chemistry at King’s College London, said: “In our research, we want to mimic the healing properties observed in nature. For example, when a tree or animal is cut, their wounds naturally heal over time, using their own biology. Creating asphalt that can heal itself will increase the durability of roads and reduce the need for people to fill in potholes.

“We are also using sustainable materials in our new asphalt, including biomass waste. This will reduce our dependence on petroleum and natural resources. Biomass waste is available locally and everywhere, and it is cheap. Producing infrastructure materials from local resources like waste reduces the dependence on petroleum availability, which helps those areas of the world that have limited access to petroleum-based asphalt.”

Dr Jose Norambuena-Contreras, an expert in Self-Healing Asphalt at Swansea University, said: "In our interdisciplinary study, we are bringing together experts in civil engineering, chemistry, and computer science to investigate the self-healing properties of a modified bitumen. By combining this knowledge with the state-of-the-art AI tools of Google Cloud, we aimed to enhance our understanding of bitumen’s healing capabilities through a bottom-up molecular design approach.

“We are proud to be advancing the development of self-healing asphalt using biomass waste and artificial intelligence. This approach positions our research at the forefront of sustainable infrastructure innovation, contributing to the development of net-zero roads with enhanced durability."

Iain Burgess, UKI Public Sector Leader at Google Cloud, added: “We first worked with Dr Francisco Martin-Martinez when he joined the Google Cloud Research Innovators Programme in 2022, providing him access to Google experts, technical resources and training to support his research. Now, it is inspiring to see how teams at Swansea and King’s College London are unlocking the power of cloud-based and AI tools, including Gemini and Vertex AI, to drive more efficient processes and discover chemical properties.”

While still in development and yet to be published, this innovation has enormous potential to improve infrastructure and advance sustainability around the world.

The highway sector increasingly prioritises carbon reduction to support the UK Government's goal of achieving net zero emissions by 2050. A substantial portion of carbon emissions from roads is linked to asphalt production. Consequently, advancing innovative bituminous materials to achieve net-zero targets for asphalt roads has become a key research priority for the UK government.

Notes to Editors

• For detailed statistics and costs about UK roads and potholes, go to: ALARM Annual Local Authority Road Maintenance Survey Report. (2024). https://www.asphaltuk.org/wp-content/uploads/ALARM_Survey_2024.pdf