Potholes could be prevented with ground source heat pumps, researchers say

The initiative could keep roads from melting in the summer and freezing in the winter, therefore preventing the creation of potholes and improving road safety.

The project has been awarded a £800,000 research fellowship from the Royal Academy of Engineering, with the hopes it could improve how major roads across the UK are maintained and upgraded – even as climate change "increases the challenge of keeping them fit for purpose," the university said.

As part of the trial, the researchers plan to introduce ground source heat pumps to cool roads in the summer and warm them in the winter.

"At the moment, a typical motorway or A-road surface lasts 20 years, but this is likely to reduce as extreme weather increases," said project lead Dr Benyi Cao. "However, by regulating the temperature of road surfaces, they should last significantly longer.

"Aside from the safety benefits and reduction to car damage, think of the reduction in expensive, inconvenient roadworks."

In order to achieve this, Cao's team plans to work with advanced materials engineering company Versarien to develop a new graphene-enhanced microcapsule that can dig into the soil beneath the surface when roads are resurfaced to improve heat conduction and storage.

The researchers will also create a laboratory-scale model road segment with a heat pump in the University of Surrey's advanced geotechnical laboratory. The model will allow Cao's team to evaluate the thermal performance and resilience of roads under controlled climatic and traffic loads.

The final step of the project aims to introduce full-scale field trials on UK roads and conduct a full life cycle assessment to understand the environmental and financial costs of thermo-active roads.

"Climate change poses an extra threat to our roads," Cao said. "Thermo-active roads could help mitigate this. They could be introduced gradually as resurfacing takes place, so wouldn't cause any extra disruption for motorists. I think there will be long-term benefits to drivers and taxpayers."

Potholes on England's major roads have caused 5,000 injuries since 2018.

Last year, England spent £1.2bn on road maintenance and repair, with the Asphalt Industry Alliance (AIA) estimating that a further £14bn is needed to fix the backlog of repairs needed on British roads – which would take 11 years to complete.

While half (51 per cent) of local roads are reported to be in good structural condition, the remaining 100,000 miles could continue to deteriorate to the point of needing to be rebuilt within the next 15 years, the report warned.

In addition, the repairs could have a damaging impact on the environment, as current road repair technology has been estimated to create 700,000 tonnes of CO₂ each year.

For these reasons, the Surrey initiative has been presented as a low-cost, low-carbon alternative to reduce road damage. The study is also expected to contribute to National Highways' pledge to make road maintenance net zero by 2040.