Self-repairing roads: Are sustainable roads finally possible?

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  Quantumrun Foresight
• May 25, 2023

Insight summary

The increased use of vehicles has put tremendous pressure on governments for road maintenance and repairs. New solutions allow for relief in urban governance by automating the process of fixing infrastructure damage.   

Self-repairing roads context

In 2019, state and local governments in the US allocated approximately $203 billion USD, or 6 percent of their total direct general spending, towards highways and roads, according to the Urban Institute. This amount made highways and roads the fifth-largest expenditure in terms of direct general expenditure for that year. This expenditure also attracted the attention of investors interested in devising innovative solutions to maximize the value of these public infrastructure investments. In particular, researchers and startups are experimenting with alternative materials or mixtures to make streets more resilient, capable of naturally closing up cracks.

For example, when heated sufficiently, the asphalt used in traditional roads turns slightly less dense and expands. Researchers in the Netherlands utilized this ability and added steel fibers to the road mix. As an induction machine is driven over the road, the steel heats up, causing the asphalt to expand and fill in any cracks. Even though this method costs 25 percent more than conventional roads, the savings that a doubled lifetime and self-repairing properties can generate is up to $95 million USD annually, according to the Netherlands’ Delft University. Moreover, steel fibers also allow for data transmission, opening up possibilities for autonomous vehicle models.

China also has its version of the concept with Su Jun-Feng of Tianjin Polytechnic using capsules of an expanding polymer. These expand to fill up any cracks and fissures as soon as they form, halting the road’s decay while making the pavement less brittle.   

Disruptive impact 

As materials science continues to improve, governments will likely continue to invest in developing self-repairing roads. For example, scientists at the Imperial College of London created an engineering living material (ELM) made of a particular kind of bacterial cellulose in 2021. The spheroid cell cultures used could sense if they were damaged. When holes were punched in the ELM, they disappeared after three days as the cells adjusted to heal the ELM. As more tests like this become successful, self-repairing roads can save governments considerable resources on road repairs. 

Moreover, the ability to transmit information by integrating steel into roads could allow electric vehicles (EVs) to recharge while on the road, cutting down power costs and extending the distance that these models can travel. Though rebuilding plans may be far off, China’s ‘rejuvenator’ capsules could provide the ability to lengthen the lifespan of roads. In addition, successful experiments with living materials are bound to accelerate research into the area as they are maintenance-free and can be more environmentally friendly than standard components.

However, there may be challenges ahead, mainly when testing these technologies. For example, Europe and the US are quite strict with their concrete regulations. Nonetheless, other countries, such as South Korea, China, and Japan, are already looking into testing hybrid road materials.

Implications of self-repairing roads

Wider implications of self-repairing roads may include:

• Reduced accident and injury risks caused by potholes and other surface imperfections. Likewise, marginally reduced vehicle maintenance costs on a population scale may be realized. 
• A decreasing need for road maintenance and repair work. This benefit can also help reduce annual traffic congestion and delay metrics caused by such maintenance work.
• Better infrastructures to support autonomous and electric vehicles, leading to more widespread adoption of these machines.
• Increasing investments in developing alternative and sustainable materials for future roads, as well as for applications in other public infrastructure projects.
• The private sector integrating these technologies into the development of commercial and residential buildings, especially in earthquake-prone regions.

Questions to consider

• How do you envision self-repairing roads being implemented in practice, and what challenges might need to be addressed to make them a reality?
• What are the most important factors to consider when deciding whether or not to adopt self-repairing roads in a particular location?