IN Brief:
- Heidelberg Materials UK and Kenson Highways have completed a lower-carbon road scheme in Redbridge.
- The project used evoZero cement, reclaimed asphalt, ACLA, CarbonLock bio-binder, and warm-mix asphalt.
- Initial calculations indicate carbon savings of more than 75 tonnes across the improvement works.
Heidelberg Materials UK has worked with Kenson Highways to deliver a lower-carbon residential road improvement scheme in the London Borough of Redbridge.
The works on Heathcote Avenue in Clayhall combined carriageway resurfacing with flood-mitigation measures, using carbon-captured cement, reclaimed asphalt, warm-mix asphalt production, and a bio-based asphalt binder.
Heidelberg Materials’ evoZero cement was used in the concrete supplied for kerb and edging haunching, as well as in the sub-base of the footway. The cement is manufactured at Brevik in Norway using carbon capture and storage, with carbon savings tracked and allocated through a chain-of-custody model.
The company also supplied asphalt for the carriageway and footway resurfacing. The binder course included 25% reclaimed asphalt and 6.5% ACLA, a negative-carbon product specified by the client.
The 248 tonnes of asphalt surface course incorporated Heidelberg Materials’ CarbonLock bio-binder and was produced using the company’s Era 140 warm-mix process. CarbonLock contains biogenic material that absorbs and stores CO₂ from the atmosphere, with the captured carbon intended to remain within the asphalt even after future recycling.
The Era 140 warm-mix process allows asphalt to be produced at temperatures up to 40ºC lower than conventional hot-mix asphalt. Lower production temperatures reduce fuel use, cut associated production emissions, improve site working conditions, and can support faster completion of resurfacing works.
The footway surface course was also produced using the Era 140 process and included 25% reclaimed asphalt. It is understood to be the first time that level of recycled material has been trialled in a footway mix in Redbridge.
Initial calculations indicate that the scheme saved more than 75 tonnes of carbon overall, with the use of evoZero cement providing the largest single reduction. The combined approach shows how highways clients are starting to stack carbon savings across different layers of the road structure, rather than relying on one material substitution.
Low-carbon construction materials are moving into more routine delivery environments. At Brent Cross Town, calcined clay concrete has already been used as part of efforts to cut cement-related emissions, while Murphy has taken lower-carbon concrete into permanent works. Redbridge adds another practical reference point, this time in local highways maintenance.
Road and footway schemes offer a large market for lower-carbon materials because the volumes are substantial and the work is repeated across local authority programmes. Adoption depends on more than carbon performance, however. Materials must meet durability, laying, compaction, drainage, maintenance, recyclability, and cost requirements before they can move from trial projects into wider specifications.
The Redbridge scheme combines several technologies that are already close to conventional practice. Reclaimed asphalt reduces the need for virgin material. Warm-mix production lowers fuel consumption. Carbon-captured cement addresses emissions in cementitious elements. A bio-based binder adds a further reduction route within the asphalt surface course. Together, those measures create a more practical route for clients that want lower-carbon performance without creating unfamiliar site processes.
Specification acceptance remains the main hurdle. Local authorities need confidence that low-carbon mixes will perform over time, especially where road maintenance budgets are under pressure and premature failures carry public, political, and commercial costs. Demonstrator projects help only if their results can be translated into repeatable procurement and delivery models.
The Redbridge project gives highways teams a quantified example across a residential road improvement package, not a one-off laboratory or showcase environment. As carbon reporting becomes more closely tied to infrastructure procurement, schemes of this type are likely to shape future local authority specifications.
