Could new material mark the end of the road for potholes?

Potholes and worn-out surfaces are the bane of every road user's life. But could a new material reinforced with graphene, the world's strongest substance, be the solution?

The results are in - and they are promising.

The first council in the UK to lay a new type of reinforced road surface says it is "very encouraged" to see it outperforming the regular material.

Most UK roads are surfaced with asphalt, a mix of stone aggregate, held together with bitumen.

Essex Highways, the highways authority for Essex County Council, installed hot rolled asphalt enhanced with graphene, the strongest substance ever recorded, on part of the A1016 in Chelmsford in 2022.

Although more expensive than standard hot rolled asphalt, tests have shown it is more resistant to weather and traffic.

Tom Cunningham, Conservative cabinet member for highways, infrastructure and sustainable transport, says: "It's a battle to maintain our 5,000 miles of roads so we have to find innovative ways of making them last longer for residents."

The reinforced material is manufactured by Eurovia, based in Cheshunt, Hertfordshire.

Paul Goosey, managing director, explains: "Traditionally, hot rolled asphalt is a finer mix which can be prone to rutting, and stone mastic asphalt is more coarse and so water can sit in the gaps and cause potholes.

"We're always looking for ways to improve the products and when we found a graphene additive - a thin, strong and flexible form of carbon - which we could mix with our hot rolled asphalt, Essex Highways agreed to be the first to trial it."

The enhanced material cost £2.50 per square metre more to lay than the standard asphalt.

Both were laid side-by-side on a stretch of the A1016 to enable a comparison.

Three years on, core samples have been removed and tested by pavement engineering specialists Jean Lefebvre UK (JLUK) at its laboratory, also in Cheshunt.

Mr Goosey is also a director of this firm, but the UK Accreditation Service, which approves the lab's work, is content that procedures are in place to ensure the impartiality of these results.

Core samples were removed from the A1016 in Chelmsford and sent for testing at a laboratory in Cheshunt, Hertfordshire

Researchers measured how much pressure it took to distort the dry samples and immersed them in water for 72 hours to record the force required to crack them when saturated.

"We found the graphene-enhanced product performed 10% better in the stiffness tests and 20% better in terms of water sensitivity," says James Stokes, JLUK's business unit manager.

"We also found that it was the aggregate which fractured, not the bitumen or the bond between the two - so the graphene was doing its job."

Longer-lasting road surfaces can reduce carbon emissions through fewer repairs, and some argue they could also increase the fuel efficiency, external of vehicles - as cracked and rough roads affect rolling resistance.

Mr Stokes accepts it is difficult to translate the results into how much longer the surface will last in the real world, but says tests will continue to help them understand that.

The enhanced material would not be the correct product to lay on every road, but National Highways is now trialling, external it on a kilometre of dual carriageway between Hatfield Peverel and Witham on the A12 in Essex.

While the product is expected to be cheaper over the lifetime of the road surface, part of the dilemma for local authorities is whether they have the funds to pay more upfront.

While Essex County Council has welcomed the test results, it has not committed to rolling the material out elsewhere in the county.

Cunningham said: "It's very encouraging and we'll definitely give it consideration, but we're looking at a range of options to address the roads problem; different methods of laying surfaces as well as different products.

"With a budget process around the corner, we'll have to look at what gets the best bang for Essex residents."