Safer roads: Thermo-active road solution to prevent potholes

A new study uncovers a method to upgrade major road networks sustainably in the UK to withstand the impact of climate change, making roads thermo-active.
Shubhangi Dua
UK roads to be upgraded by using existing potholes to extract geothermal energy
UK roads to be upgraded by using existing potholes to extract geothermal energy

kozmoat98 / iStock 

Climate change has long been a looming threat that’s affected the globe in unpredictable ways. In the United Kingdom’s quest to make road maintenance net-zero by 2050, a new study is set to support National Highways’ net-zero plan

The new project will test the use of geothermal energy to control the temperature of road surfaces by employing ground-source heat pumps.

To successfully regulate temperature, scientists aim to extend the lifespan of road surfaces, reduce carbon emissions, and lower the cost of road maintenance.

Dr. Benyi Cao from the University of Surrey is leading the project in collaboration with National Highway. A statement by the team noted that ground source heat pumps will be introduced to cool roads in summer and warm them in winter. 

The new method has been awarded a £625,000 (US$780,000) research fellowship from the Royal Academy of Engineering. The researchers were awarded to upgrade the major road networks in the UK and make them safer to withstand the impacts of climate change.

Fixing inconvenient roadworks sustainably

Dr. Cao, a lecturer in the School of Sustainability, Civil and Environmental Engineering at the University of Surrey, stated: 

“At the moment, a typical motorway or A-road surface lasts 20 years, but this is likely to reduce as extreme weather increases. 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.” 

The new technique will be used at the University of Surrey's Advanced Geotechnical Laboratory. The project is a five-year-long research fellowship that aims to achieve goals through various means.

Scientists are preparing to develop graphene-enhanced microcapsules to improve heat conduction and storage in the soil beneath road surfaces and further conduct laboratory-scale experiments, from numerical modeling to full-scale field trials on UK roads.

According to the statement, the current road technologies generate an estimated 700,000 tonnes of carbon emissions each year. The cost to repair existing potholes in the UK is anticipated to be about £12 billion (US$15 billion) in the next decade.

Thermo-active solution

The new method, which uses thermo-active roads, presents an alternative solution, delivering a low-cost, low-carbon alternative to reduce road damage. 

Statistics indicate potholes on major roads in England have caused 5,000 injuries since 2018. The previous year, England allocated £1.2 billion (US$1.5 billion) toward the maintenance and repair of its roads, a procedure associated with a significant carbon footprint.

“Climate change poses an extra threat to our roads. Thermo-active roads could help mitigate this,” said Dr. Cao. “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. That’s what I aim to demonstrate during my fellowship.” 

The fellowship team intends to work with Versarien – an advanced materials engineering company, to devise a new graphene-enhanced microcapsule. This would allow digging into the soil beneath the surface when roads are resurfaced to improve heat conduction and storage.

The researchers also plan to establish a laboratory scale model road segment with a heat pump at the laboratory, which will evaluate the thermal performance and resilience of roads under controlled climatic and traffic loads.

The statement emphasized that complete advanced numerical modeling, which incorporates meteorological data and findings from the lab model experiments, helps engineers understand how best to build thermo-active roads.

Ground acting as a heat collector

Dr. Cao explained the process to New Atlast, stating that three elements are needed for the formation of potholes: The first is surface cracks that form and expand over time due to traffic, and we can't avoid that. 

“The second is water, and the third is the freeze/thaw cycling. We get these small cracks, and then water seeps into the cracks. In winter, it gets down to about -10 °C (14 °F) in the UK, so that water freezes and expands, pushing open those cracks. In spring, when the temperature rises again, that water thaws and contracts."

The repetition of freezing and thawing and subsequent expansion and contraction can weaken the asphalt binder – the glue of the road surface, New Atlas stated. 

"This causes all kinds of deterioration; potholes are just one problem, but it's a major one. So I started thinking about how to warm up the road surface in winter, so no freezing happens," Dr. Cao noted.

Dr. Cao came up with the idea while hunting for a more efficient and sustainable system. He added, "So I'm thinking, we have a road here, and there's a huge amount of ground underneath the road – why don't we just use this ground itself as a collector and storage for heat in summer, and extract that heat again in winter?"

Alluding to the economic costs, Dr. Cao told New Atlas:

“We haven't done a cost analysis and I feel like we couldn't do one until the field trial. It'll be an additional cost to transport infrastructure, but we think there'll be benefits in terms of carbon emissions from pothole repairs, which are not insignificant – some 700 tons per year, and also in the lifespan of the new roads."

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