A new type of low carbon reinforced concrete is being trialled on National Highways’ M42 Junction 6 improvement scheme – hailed as an ‘industry-first’.
The trial, led by Skanska, in partnership with the National Composites Centre and funded by National Highways (NH), compares traditional steel reinforced concrete with a low carbon concrete reinforced with basalt fibre.
According to Skanska, the combination of the low carbon concrete and the replacement of the steel with a lightweight composite reinforcement cuts embodied carbon by 50%.
Tarmac supplied two types of concrete for the trial: a mix comprising conventional blended cementitious material and a low carbon alternative mix incorporating an alkali activated cementitious material (AACM) in place of the cement.
Robert Gossling, head of commercial engineering at Tarmac, said: “Tarmac has developed new low carbon concrete technology and this trial is a great opportunity to collaborate with industry leading project partners to test its performance through an ideal, real-life application.
“Manufactured at a conventional concrete plant located close to the project and installed in exactly the same way as traditional materials, this new sustainable product delivers a carbon footprint up to 80% lower than a standard CEM I concrete.”
The basalt fibre reinforcement was supplied by Basalt Technologies, whose director Malcolm Newton explains: “Basalt is a lightweight composite material consuming 62% less CO2e than steel during its manufacture.
“It comprises a non-metallic inert material that does not corrode, making it more durable than steel. Basalt Fibre reinforcement is also four to five times lighter than steel, making it safer to handle, fix and transport with fewer lorry movements.”
The trial is also expected to provide a better understanding of the impact of the use of these materials ahead of the proposed revision to Eurocode 2 standards that will include use of composites in the design of concrete structures. This is currently being developed.
Image credit: Skanska
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