New 'greener' bitumen on trial to help cut CO2 in road resurfacing

The council has been progressively reducing the carbon footprint of the materials and methods it uses on our roads since 2020.

So far this has focused on using materials which work at lower temperatures, and maximising use of recycled asphalt, to cut the amount of new fossil fuels used.

Three resurfacing schemes recently completed in Lancaster have taken this further by employing a new type of bitumen partly made from biogenic material.

Most of the new fossil fuels used in road maintenance are contained in the bitumen binder which acts as a glue to stick together the asphalt materials used to construct the road.

The binder used in these new schemes is partly made using a biogenic component. This removes carbon from the atmosphere, storing the carbon as it grows, before being refined and blended into bitumen. This replaces a portion of the bitumen which is derived from fossil fuels. The biogenic element used in the bitumen is sustainably sourced and does not compete with food sources.

It was used to lay 630 tonnes of asphalt on Barley Cop Lane, Malham Close and Birkdale Close during May, saving 9 tonnes of CO_2. The type of asphalt used also works at 'warm' rather than 'hot' temperatures helping to reduce CO₂ output by 24% compared with traditional methods.

County Councillor Rupert Swarbrick, cabinet member for highways and transport, said: "Our highways team has been pioneering low carbon methods for a number of years, and these new schemes represent further valuable progress towards minimising our CO₂ output as far as we possibly can.

"We’re committed to improving the condition of our roads, and our teams are currently really busy making the best use of the good weather to carry out vital repairs and resurfacing across the county.

"We're equally committed to reducing our impact on the environment, and help Lancashire achieve our net zero target.

"We're already expecting to save around 769 tonnes of CO₂ during this year's programme, which is a 28% saving compared with using traditional materials and methods. This new biogenic bitumen will help towards that, and something we hope to make greater use of in the future as the product is developed."

The county council has worked with asphalt supplier Aggregate Industries to develop asphalts which use the biogenic bitumen binder supplied by Shell Construction and Road.

Traditional materials have been used for parts of the Lancaster resurfacing schemes so that the performance of the biogenic binder can be directly compared, helping these companies to test and develop the product.

Lancashire County Council has been recognised nationally for its commitment to sustainable working practices and carbon reduction in maintaining the county's highways.

The council was awarded the Chartered Institution of Highways and Transportation (CIHT) prestigious Climate Action Award last year in recognition of its Highways Decarbonisation Strategy.