National Highways Extends Bio-Binder Asphalt Trials

A new initiative is set to revolutionise the way road surfaces are constructed in the UK, bringing significant improvements in sustainability, durability, and carbon reduction. National Highways has extended its trials of polymer modified bitumen (PMB) bio-binders, testing a more environmentally friendly solution for road surfacing.

The extended trials are focused on integrating warm mix asphalt (WMA) and recycled content into a thin surface course, aligning with National Highways’ net zero goals. These trials are part of a broader effort to create a lower-carbon alternative to traditional road materials, while maintaining the performance and durability required for high-traffic highways.

_{Heidelberg Materials’ CarbonLock Asphalt}

At the core of this innovation is Heidelberg Materials’ CarbonLock asphalt, which utilises PMB bio-binders. These binders are made from natural biogenic materials, which absorb CO2 throughout their lifecycle and lock it within the asphalt. The result is a more sustainable road surface that reduces carbon emissions—even when the asphalt is recycled.

CarbonLock asphalt has been produced as both hot mix and warm mix asphalt, and incorporates up to 30% reclaimed asphalt. This configuration is being tested for its feasibility in real-world conditions, with trials currently taking place on sections of the A2 near Canterbury and A34 near Newbury, following a successful trial on the A30 near Exeter last year.

_{Enhanced Durability and Reduced Maintenance}

One of the key benefits of polymer modified bitumen is its ability to enhance the durability of the road surface. By improving resistance to wear and tear, PMB bio-binders are expected to extend the lifespan of the asphalt, reducing the need for frequent maintenance. This not only lowers long-term costs but also minimises the environmental impact associated with repair work.

These trials represent an important step in the journey towards more sustainable road construction in the UK. The use of warm mix asphalt and recycled materials, combined with the carbon-locking properties of bio-binders, offers a promising solution to reducing the carbon footprint of road infrastructure projects.

With further testing and development, National Highways aims to refine this approach, making it a viable option for widespread use on the UK’s road network.