The first trial came in August 2021, when graphene was added to bitumen on the A1 in the North East.
Graphene is the strongest compound discovered: 100-300 times stronger than steel. It acts as a reinforcement to the bitumen film surrounding aggregates in asphalt and is thought to provide improved stiffness and resistance to rutting compared to conventional asphalt.
The latest project saw a new surface laid on the A12 northbound, containing 40% reclaimed asphalt - thought to be the highest level ever used in the UK for asphalt with graphene-enhanced polymeric modifier.
The performance will be monitored over several years by AtkinsRéalis, which will look at its carbon footprint and whole-life benefits, measuring it against a control section of standard polymer-modified bitumen asphalt.
The surface course on the A12 incorporates a proprietary graphene-enhanced polymeric additive, called Gipave.
This is the first time Gipave has been applied on the strategic road network, following ongoing trials in Oxfordshire, Kent, Staffordshire and Essex by councils.
Umesh Parajuli, project sponsor and senior pavement advisor at National Highways said: 'We are constantly exploring new ways to improve our road network with a focus on three imperatives: safety, the customer and delivery.
'It’s encouraging to move innovative road materials from the lab to the real world, as they promise more durability and efficiency, while maintaining road user safety and lowering carbon emissions. This trial of graphene-enhanced asphalt supports our 2040 net zero target for construction and maintenance and could provide significant whole-life benefits, improving the service life of both local and national networks.'
National Highways' trial is being co-ordinated by an AtkinsRéalis-Jacobs joint venture as part of a research project, which University of Nottingham and Jean Lefebvre UK will support with the lab testing.
The SPaTS 2 research programme is testing several emerging, low carbon asphalt products. The trial is adopting both hot and warm mix technologies for comparison studies.
Other programme partners include Eurovia, Iterchimica and Directa Plus. Gipave was developed by Iterchimica, which Eurovia UK produced and installed on the A12 with support from specialist Jean Lefebvre UK for the mix design.
Michael Wright, technical director at AtkinsRéalis, said: 'We will closely analyse the performance of this innovative product, which could lead to significant improvements in road durability and reduce environmental impact through a new, sustainable circular economy.'
The graphene technology has previously been adopted internationally including at the new San Giorgio bridge in Genova, Treviso Airport runway, Edinburgh and Rome Fiumicino Airport taxiways, the main motorways in northern Italy – the A4 Turin-Milan and the A4 Brescia-Padua - and the F1 Imola circuit in Italy.
