FM Conway and National Highways have repaved a 5.7-mile section of the M4 near Swindon using hydrogen and electric plant and recycled asphalt in what they’re calling a first-of-its-kind low-carbon road project.
The work between Junctions 15 and 16 saw the first use of JCB’s hydrogen 3CX backhoe loader.
The approach prevented 630 tonnes of CO2 from entering the atmosphere, a 50% improvement on conventional methods.
National Highways’ Low Carbon Demonstrator Fund supported the six-week project.
The gear
Other machinery included Sany’s electric planer and 4.5-tonne roller, shipped on Volvo’s electric 42-tonne lorry.
The JCB Hydrogen 3CX backhoe loader is the only machine of its kind run by a hydrogen internal combustion engine.
Ryze Fuels set up a refuelling station at Ringway’s Stanton Depot.
Novel laying technique
To lay the asphalt, FM Conway used a technique called echelon paving, where both lanes of a carriageway are laid simultaneously to remove weak joints between lanes.
It’s faster and took fewer shifts to complete, thus reducing road closures.
The contractor also used laser profiling to detect surface irregularities for a smoother finish with fewer cracks.
Mining other roads for asphalt
Asphalt was recycled from the M11, A34 and A3.
Mixes of 60% recycled were laid in the base and binder courses, while 30% recycled mixes were laid in the surface course.
Manufacturing was fuelled by biogas produced from the anaerobic digestion of organic matter.
Using recycled asphalt made this way itself saved more than 400 tonnes of CO2.
“This isn’t just about testing ideas, but generating real-world learning that can drive wider adoption and help make our network one of the greenest in the world,” said Angela Halliwell, head of carbon and air quality at National Highways.
Andy Weymouth, framework delivery manager at FM Conway, said the effort “took belief in a shared goal and a healthy dose of commitment to integrate the use of these new technologies effectively”.
“This scheme is proof that when we unite expertise and resources, we can accelerate the transition to greener infrastructure and deliver real impact,” he added.
