Delivering Low Carbon Concrete for Network Rail on the Routemap to Net Zero

Network Rail is tackling the problem of the GHG (primarily CO2) emissions it produces and is committed to the Government’s pledge to achieve Net Zero carbon emissions by 2050. It recently published its Environmental Sustainability Strategy 2020–2050 (Network Rail, 2020 [1]), which includes setting Science Based Targets for its Scope 1, 2 and 3 emissions. In this context, Expedition Engineering has been supporting Network Rail’s Technical Authority and Decarbonisation Programme in efforts to reduce the CO2e associated with its construction projects, primarily on those using concrete. This has included developing a Routemap to Net Zero Carbon Concrete, partnering with existing supply chains to decarbonise precast platform components used in high volume, and a feasibility piece focused on enabling significant carbon reductions in the ready-mix supply chain. The work has revealed the current difficulties and potential solutions within the UK concrete industry, as well as the value of supply chain partnering and putting research into practice. This paper summarises a combination of works completed and ongoing, and preliminary proposals under review. The route to Net Zero by 2050 must involve reduction in material quantities through design and construction efficiencies and a shift to using and developing materials with reduced CO2e intensity. In the immediate term this will mean maximising Portland cement replacement and accelerating adoption of current state-of-the-art low carbon technology. In the medium- to long-term it is anticipated that use of calcined clay and limestone as cement replacement will form a key part in the progress to reduce CO2e as the availability of PFA and GGBS reduces. The development of a standalone CO2e Reduction Protocol document is proposed as being a useful mechanism to organise new guidance and requirements and tie in with existing standards and contracts.