Cold bitumen for National Highways: decarbonisation takeaways for pavement designers
Reviewed by Tom Sullivan
First reported on The Construction Index
30 Second Briefing
Cold bitumen emulsion-based asphalt has been deployed by Roadways as a low-carbon, like-for-like replacement for conventional hot asphalt on a National Highways scheme, with no departures from existing specification. The emulsion mix is produced and laid at significantly lower temperatures than traditional 160–180°C hot-mix, cutting burner fuel use and associated CO₂ emissions while maintaining standard binder and aggregate grading requirements. For pavement designers and contractors, this signals growing scope to decarbonise surfacing works without redesigning layer thicknesses or seeking new approvals.
Technical Brief
- For other trunk road schemes, the approach suggests decarbonisation potential without revisiting pavement structural design models.
Our Take
National Highways’ exploration of cold bitumen sits alongside its recent trials of electric paving equipment and >90% recycled asphalt on the A47, signalling a move to integrate low‑carbon surfacing with low‑emission construction plant on live schemes.
The agency’s plan to apply the £11bn Lower Thames Crossing sustainability framework across its portfolio suggests that cold bitumen, if proven, could be standardised through whole‑life carbon baselining and circular‑economy targets rather than treated as a one‑off innovation.
Within our 796 Infrastructure stories tagged for Projects and Sustainability, National Highways appears frequently as an early adopter of alternative materials, so cold bitumen trials are likely to influence specifications and procurement expectations for other UK road authorities and Tier 1 contractors.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
