Low carbon materials in transport infrastructure

Embodied carbon surge ahead

Transport infrastructure accounts for the bulk of new-build and maintenance emissions once vehicle tailpipes are electrified. Cement production alone emitted 6 MtCO₂e in 2022; steel added 10.5 MtCO₂e. Both materials dominate roads, rail sleepers, bridges, tunnels and port structures.

Spending is accelerating. The October 2025 Carbon Budget and Growth Delivery Plan and the 10-Year Infrastructure Strategy commit hundreds of billions to new and upgraded networks. Without material substitution, each scheme embeds decades of emissions that cannot be clawed back.

Policy has tightened sharply. Parliament must approve the seventh carbon budget by June 2026. National Highways’ 2025 update already mandates PAS 2080 carbon management for tier-1 suppliers by end-2025 and rolls out low-carbon asphalt demonstrators on active contracts through March 2026. The Department for Energy Security and Net Zero’s low-carbon products framework consultation, closed September 2025, proposes embodied-emissions reporting and green procurement bands for public contracts worth £138 billion annually.

The non-obvious tension is timing versus performance. Low-clinker cements and electric-arc steel cut process emissions but require new supply chains and may alter curing times or fatigue life; timber composites work for lighter bridges yet struggle with heavy-rail loads. Early adoption risks short-term cost and delay; waiting until 2027 CBAM bites hands the market to EU or Asian producers who scaled first.

Procurement is the lever. Government Buying Standards and IDDI pledges commit public clients to Level-3 low-emission procurement by 2030. Contractors ignoring verified EPDs or recycled-content thresholds will lose bids on the very projects designed to grow the economy.