HS2 contractor SCS JV (Skanska Costain Strabag Joint Venture) is using ‘Printfrastructure’ cutting-edge on-site 3D reinforced concrete printing technology in the high-speed line’s London tunnels.
A major step forward in construction technology, printing concrete with computer-operated robots will enable SCS JV to make structures on site, instead of transporting them as pre-cast slabs by road before being assembled and lowered into place by large cranes.
3D concrete printing is a flexible, mobile technology that enables it to be deployed in physically restricted areas – avoiding the need to develop complicated and potentially expensive logistical plans. And where HS2 construction is happening besides a live railway, it offers an opportunity to deliver works without disrupting the travelling public.
This is because a robot will print the reinforced concrete, enabling construction to continue and trains to run at the same time. Previously work would have taken place overnight after trains have stopped running, potentially disturbing the local community, or would have required the suspension of services to ensure safe working.
Printing reinforced concrete structures using a computer-controlled robot allows them to have a unique internal lattice structure, which not only strengthens the components and significantly reduces the quantity of concrete required but also cuts waste.
Working with UK advanced materials specialist, Versarien, SCS JV’s Worcestershire-based partner, ChangeMaker 3D combines the concrete printing process with the strongest material ever tested: graphene. Concrete with microscopic strands of graphene – only a few atoms thick – running through it like stripes in a stick of rock replaces traditional steel to help drive improved site safety, greater construction flexibility, shorter build time and a smaller carbon footprint.
SCS JV estimates that the process it is developing with the Midlands firm could reduce the concrete used and contribute toward reducing carbon by up to 50 per cent. By removing steel and simplifying the construction process, which will no longer require cranes and significantly fewer delivery trucks, the carbon reduction could be even greater.
HS2 innovation manager Rob Cairns explained: “The project SCS JV and ChangeMaker 3D are collaborating on is a fantastic demonstration of the kind of far-reaching innovations HS2 enables.
“With a build programme spanning the decade and across the country, the project is creating an ideal environment to develop technologies with the potential to transform how major infrastructure is built.”
SCS JV temporary works manager Andrew Duck added: “Automation enabled by Printfrastructure’s 3D reinforced concrete printing creates a factory-like environmental that delivers a high-quality product that both increases efficient use of materials, and reduces our carbon footprint.
“It is important that we give technologies such as Printfrastructure the opportunity to flourish because of the possibilities it offers the industry to make a step change in how projects are delivered.”
Proof of concept trials are due to begin in Spring 2022.