Marlborough’s lower carbon streets in Barnet: material choices and lessons for engineers
Reviewed by Joe Ashwell
First reported on The Construction Index
30 Second Briefing
Marlborough Highways has resurfaced three live streets for Barnet Council in six days using Holcim SuperLow asphalt and ACLA, a carbon-negative aggregate alternative from Low Carbon Materials, as part of the borough’s BarNET ZERO programme. ACLA was incorporated in the binder course to cut embodied carbon while maintaining carriageway performance, supported by electric rollers, electric disc cutters and electric vans on a 100% renewable tariff, with HVO-powered plant used where electrification was not viable. The scheme cut the estimated carbon footprint from 62.34t CO₂e to as low as 4.49t CO₂e, with most savings coming from material selection rather than plant changes.
Technical Brief
- ACLA, from Low Carbon Materials, functions as a carbon-negative aggregate substitute within asphalt mixes.
- Holcim SuperLow asphalt was specified for both binder and wearing courses across all three streets.
- Works were executed on live streets without altering the traffic management programme or network operation.
- Marlborough coordinated Holcim UK and Low Carbon Materials within a single supply chain to meet Barnet’s brief.
- Carbon assessment distinguished savings from asphalt specification versus those from plant and transport modifications.
- Electric vans were explicitly supplied on a 100% renewable electricity tariff, closing the loop on site logistics.
- HVO-fuelled plant was retained only where no viable electric or lower-carbon option was available.
- Barnet’s routine resurfacing is being aligned with its borough-wide 2042 net zero target, influencing future specifications.
Our Take
Marlborough Highways’ work with Barnet Council sits alongside its renewed £15m‑per‑year term maintenance deal with Southend‑on‑Sea City Council, suggesting its low‑carbon street model could be replicated at scale across multiple UK authorities.
Holcim UK’s role here aligns with its ECOPact and runway projects in Birmingham and at London Luton Airport, signalling that its lower‑carbon asphalt and concrete offerings are now being deployed from major infrastructure down to small‑scale urban resurfacing.
Within our 45 Materials stories, Holcim UK appears frequently in sustainability‑tagged pieces, and the deep cut in estimated t CO2e on these Barnet streets reinforces its positioning as a preferred supplier for councils targeting net‑zero dates such as Barnet’s 2042 goal.
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.
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