How recycling cut road project emissions by 23%

Processing the tar-bound material for use in resurfacing the A46 Warwick Bypass

Kier Highways has cut the carbon emissions on its latest road resurfacing project by 23%, by recycling 3.5 miles of old dual carriageway material.

Around 17,500 tonnes of old road layer material from the A46 Warwick Bypass in Warwickshire was reused to create a new surface on the route between Warwick and Coventry.

Kier carried out the resurfacing works between the Sherbourne and Leek Wootton roundabouts in partnership with Aggregate Industries for National Highways.

The original northbound carriageway had been repaired many times over the years, but had deteriorated to such an extent that a full depth reconstruction was needed.

Teams from Kier dug down to a depth of 15 inches to replace the layers of road surface.

While “much of the material in the lower levels contained tar which is classed as carcinogenic” and normally treated as hazardous waste, the contractor was able to process and re-mix the material with Aggregate Industries’ ex situ cold recycled Foamix asphalt, into a useable product that could be incorporated into the new road surface.

“This colder mixed material can be handled and compacted at a much safer ambient temperature and reduces the asphalt fumes on site which workers are exposed to during the resurfacing,” said Kier.

“The material was mixed on site to minimise vehicle movements, reducing the scheme’s carbon footprint even further.”

Scott Cooper, managing director, Strategic Highways at Kier Highways, said, “This is the first time that Foamix has been used on this type of road and this work on the A46 scheme really demonstrates how innovation and excellent collaboration across the value chain is needed if Kier and our partners are to succeed with reaching our net-zero ambition and combatting climate change.”

The company, which is aiming to produce no avoidable waste by 2035 and achieve net-zero carbon across their operations and supply chain by 2045, also used the recycled material left over from the project on other works being carried out on National Highways’ Strategic Road Network.

“Using recycled materials also meant there was less raw material needed for the works, meaning around 82,000 road miles were saved on the scheme which ran between late July and September 2021”, Kier added.

Neil Leake, national technical manager at Aggregate Industries, said, “Good collaboration and an innovative approach were at the heart of this scheme, with people working together to achieve the same low carbon goal.

“We had some significant challenges to overcome to make sure this scheme could be delivered on time and still meet the low carbon goal we set ourselves.”