Concrete for the structural slabs was produced in normal plants and poured via mixer truck and by skip with tremie pipe.The new material offers a 62% reduction in CO2e per cubic metre of concrete, compared to a standard CEM I concrete, meeting the same specification in the same raw materials. This represents a saving of 220 tonnes CO₂e for every 1000m3 produced.

Robert Gossling, Tarmac head of commercial engineering solutions, said: “This project underlines the clear benefits which can be unlocked when clients and contractors collaborate, in this case engaging to help understand and accelerate the adoption of this new low carbon concrete solution.

“Together we’ve shown this new concrete is fit for purpose in slabs and walls, with good repeatability and works with standard production and construction methods. This product is a great step along the industry zero carbon routemap, and the demonstration will help accelerate adoption of this new concrete.”

Daniel Altier, project director for Align, said: “It is a strategic imperative for Align, reflecting the priorities of our JV partners and in line with HS2 commitments, to reduce carbon emissions by 50%, to look for opportunities to improve our carbon footprint.

“The early results of this trial are very encouraging and highlight the benefits to be gained through close collaboration with our supply chain partners.”

The trial is now set to be expanded on other available areas of the C1 project.